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Web audio codec guide - Web media technologies
the processing of audio data to encode and decode it is handled by an audio codec (coder/decoder).
... in this article, we look at audio codecs used on the web to compress and decompress audio, what their capabilities and use cases are, and offer guidance when choosing audio codecs to use for your content.
... additionally, webrtc implementations generally use a subset of these codecs for their encoding and decoding of media, and may support additional codecs as well, for optimal cross-platform support of video and audio conferencing, and to integrate better with legacy telecommunication solutions.
...And 65 more matches
Codecs used by WebRTC - Web media technologies
to communicate, the two devices need to be able to agree upon a mutually-understood codec for each track so they can successfully communicate and present the shared media.
... this guide reviews the codecs that browsers are required to implement as well as other codecs that some or all browsers support for webrtc.
...which codecs can be within those tracks is not mandated by the webrtc specification.
...And 62 more matches
Web video codec guide - Web media technologies
this is where video codecs come in.
... just as audio codecs do for the sound data, video codecs compress the video data and encode it into a format that can later be decoded and played back or edited.
... most video codecs are lossy, in that the decoded video does not precisely match the source.
...And 58 more matches
The "codecs" parameter in common media types - Web media technologies
for that reason, the codecs parameter can be added to the mime type describing media content.
...this information may include things like the profile of the video codec, the type used for the audio tracks, and so forth.
... this guide briefly examines the syntax of the media type codecs parameter and how it's used with the mime type string to provide details about the contents of audio or video media beyond simply indicating the container type.
...And 46 more matches
RTCRtpTransceiver.setCodecPreferences() - Web APIs
the rtcrtptransceiver method setcodecpreferences() configures the transceiver's codecs given a list of rtcrtpcodeccapability objects specifying the new preferences for each codec.
... the specified set of codecs and configurations will be used for all future connections including this transceiver until this method is called again.
... when preparing to open an rtcpeerconnection, you can change the codec parameters from the user agent's default configuration by calling setcodecparameters() before calling either rtcpeerconnection.createoffer() or createanswer().
...And 14 more matches
RTCRtpCodecCapability - Web APIs
the webrtc api's rtcrtpcodeccapability dictionary provides information describing the capabilities of a single media codec.
... properties channels optional an unsigned integer value indicating the maximum number of channels supported by the codec; for example, a codec that supports only mono sound would have a value of 1; stereo codecs would have a 2, etc.
... clockrate an unsigned long integer specifying the codec's clock rate in hertz (hz).
...And 7 more matches
RTCRtpCodecParameters - Web APIs
the rtcrtpcodecparameters dictionary, part of the webrtc api, is used to describe the configuration parameters for a single media codec.
... in addition to being the type of the rtcrtpparameters.codecs property, it's used when calling rtcrtptransceiver.setcodecpreferences() to configure a transceiver's codecs before beginning the offer/answer process to establish a webrtc peer connection.
... properties payloadtype optional the rtp payload type used to identify this codec.
...And 7 more matches
JS_EncodeCharacters
syntax jsbool js_encodecharacters(jscontext *cx, const jschar *src, size_t srclen, char *dst, size_t *dstlen); name type description cx jscontext * a context.
... description js_encodecharacters copies the characters of a jschar array into a char array, converting the 16-bit values to 8-bit values.
... to calculate the number of bytes needed, call js_encodecharacters twice, like this: /* determine how many bytes to allocate.
...And 4 more matches
Codec - MDN Web Docs Glossary: Definitions of Web-related terms
a codec (a blend word derived from "coder-decoder") is a program, algorithm, or device that encodes or decodes a data stream.
... a given codec knows how to handle a specific encoding or compression technology.
... learn more general knowledge codec on wikipedia technical reference web video codec guide web audio codec guide guide to media types and formats on the web ...
RTCRtpStreamStats.codecId - Web APIs
the rtcrtpstreamstats dictionary's codecid property is a string which uniquely identifies the object that was inspected to produce the data in the rtccodecstats for the rtp stream.
... syntax var codecid = rtcrtpstreamstats.codecid; value a domstring which uniquely identifies the object from which the contents of the stream's rtccodecstats are derived.
... specifications specification status comment identifiers for webrtc's statistics apithe definition of 'rtcrtpstreamstats.codecid' in that specification.
nsIScriptableUnicodeConverter
inherits from: nsisupports last changed in gecko 1.8 (firefox 1.5 / thunderbird 1.5 / seamonkey 1.0) implemented by: @mozilla.org/intl/scriptableunicodeconverter.
... to create an instance, use: var converter = components.classes["@mozilla.org/intl/scriptableunicodeconverter"] .createinstance(components.interfaces.nsiscriptableunicodeconverter); method overview acstring convertfromunicode(in astring asrc); acstring finish(); astring converttounicode(in acstring asrc); astring convertfrombytearray([const,array,size_is(acount)] in octet adata, in unsigned long acount); void converttobytearray(in astring astring,[optional] out unsigned long alen,[array, size_is(alen),retval] out octet adata); nsiinputstream converttoinputstream(in astring astring); attributes attribute type description charset string current character set.
Media container formats (file types) - Web media technologies
the format of audio and video media files is defined in two parts (three if a file has both audio and video in it, of course): the audio and/or video codecs used and the media container format (or file type) used.
...see codecs used by webrtc for information about codecs commonly used for making webrtc calls, as well as browser compatibility information around codec support in webrtc.
...not all of these are broadly supported by browsers, however; some combinations of container and codec are sometimes given their own file extensions and mime types as a matter of convenience, or because of their ubiquity.
...And 35 more matches
Digital audio concepts - Web media technologies
this guide is an overview examining how audio is represented digitally, and how codecs are used to encode and decode audio for use on the web.
...the audio bandwidth is also affected by the codec, if it chooses to discard any frequency bands while encoding the sound.
... the process of compressing and decompressing audio is performed by encoding and decoding it using an audio codec (coder/decoder).
...And 28 more matches
Video and audio content - Learn web development
they define a structure in which the audio and/or video tracks that make up the media are stored, along with metadata describing the media, what codecs are used to encode its channels, and so forth.
... the audio and video tracks within the container hold data in the appropriate format for the codec used to encode that media.
...each audio track is encoded using an audio codec, while video tracks are encoded using (as you probably have guessed) a video codec.
...And 11 more matches
Index - Web APIs
WebAPIIndex
the api can be used to query the browser about the decoding abilities of the device based on codecs, profile, resolution, and bitrates.
... 2403 mediarecorder: error event event the mediarecorder interface's error event is fired when an error occurs: for example because recording wasn't allowed or was attempted using an unsupported codec.
...01 rtcoutboundrtpstreamstats.qualitylimitationreason api, media, property, quality, rtcoutboundrtpstreamstats, reference, statistics, stats, webrtc, webrtc api, qualitylimitationreason, reason, stream the qualitylimitationreason property of the rtcoutboundrtpstreamstats dictionary is a string indicating the reason why the media quality in the stream is currently being reduced by the codec during encoding, or none if no quality reduction is being performed.
...And 10 more matches
MIME types (IANA media types) - HTTP
audio and video types as is the case for images, html doesn't mandate that web browsers support any specific file and codec types for the <audio> and <video> elements, so it's important to consider your target audience and the range of browsers (and versions of those browsers) they may be using when choosing the file type and codecs to use for media.
... the audio codec and video codec guides list the various codecs that web browsers often support, providing compatibility details along with technical information such as how many audio channels they support, what sort of compression is used, and what bit rates and so forth they're useful at.
... the codecs used by webrtc guide expands upon this by specifically covering the codecs supported by the major web browsers, so you can choose the codecs that best cover the range of browsers you wish to support.
...And 7 more matches
Media type and format guide: image, audio, and video content - Web media technologies
WebMediaFormats
this guide provides an overview of the media file types, codecs, and algorithms that may comprise media used on the web.
... media file types and codecs media containers (file types) a guide to the file types that contain media data.
... web audio codec guide a guide to the audio codecs allowed for by the common media containers, as well as by the major browsers.
...And 7 more matches
Transcoding assets for Media Source Extensions - Web APIs
getting started the first and most important step is to ensure that your files are comprised of a container and codec that users' browsers support.
... depending on the codec, you might need to fragment the file to comply with the iso bmff spec.
...if you don't need it, add --audio-codec=aac to the mp4-dash-encode.py command line.
...And 6 more matches
RTCRtpCapabilities - Web APIs
an rtcrtpcapabilities object contains an array of objects conforming to rtcrtpcodeccapability (each describing the capabilities of one codec) and an array of the supported rtp header extensions for that codec.
... properties codecs an array of rtcrtpcodeccapability objects, each describing one of the codecs supported by the rtcrtpsender or rtcrtpreceiver.
... there are some special entries in this array, described below in the section the codecs array.
...And 4 more matches
Using the Media Capabilities API - Web APIs
these parameters may include the codecs, resolutions, bit rates, frame rates, and other such details.
... const videoconfiguration = { type: "file", video: { contenttype: "video/webm;codecs=vp8", width: 800, height: 600, bitrate: 10000, framerate: 15 } }; had we been querying the decodability of an audio file, we would create an audio configuration including the number of channels and sample rate, leaving out the properties that apply only to video—namely, the dimensions and the frame rate: const audioconfiguration = { type: "file", audio: { ...
...there are a few reasons why an error might occur, including: the specified type isn't one of the two permtited values: file or media-source the contenttype given is the error can be due to the type not being one of the two possible values, the contenttype not being a valid codec mime type, or invalid or omitted definitions required in the videoconfiguration.
...And 3 more matches
RTCRtpStreamStats - Web APIs
standard fields included for all media types codecid a domstring which uniquely identifies the object which was inspected to produce the rtccodecstats object associated with this rtp stream.
...this value will match that of the media type indicated by rtccodecstats.codec, as well as the track's kind property.
...combined with rtcreceivedrtpstreamstats.framesdecoded or rtcsentrtpstreamstats.framesencoded, you can approximate the average qp over those frames, keeping in mind that codecs often vary the quantizer values even within frames.
...And 2 more matches
Setting up adaptive streaming media sources - Developer guides
the mpd file tells the browser where the various pieces of media are located, it also includes meta data such as mimetype and codecs and there are other details such as byte-ranges in there too - it is an xml document and in many cases will be generated for you.
...w3.org/2001/xmlschema-instance" xmlns="urn:mpeg:dash:schema:mpd:2011" xsi:schemalocation="urn:mpeg:dash:schema:mpd:2011 dash-mpd.xsd" type="static" mediapresentationduration="pt654s" minbuffertime="pt2s" profiles="urn:mpeg:dash:profile:isoff-on-demand:2011"> <baseurl>http://example.com/ondemand/</baseurl> <period> <!-- english audio --> <adaptationset mimetype="audio/mp4" codecs="mp4a.40.5" lang="en" subsegmentalignment="true" subsegmentstartswithsap="1"> <representation id="1" bandwidth="64000"> <baseurl>elephantsdream_aac48k_064.mp4.dash</baseurl> </representation> </adaptationset> <!-- video --> <adaptationset mimetype="video/mp4" codecs="avc1.42401e" subsegmentalignment="true" subsegmentstartswithsap="1"> <representation id="2" ...
...www.w3.org/2001/xmlschema-instance" xmlns="urn:mpeg:dash:schema:mpd:2011" xsi:schemalocation="urn:mpeg:dash:schema:mpd:2011" profiles="urn:mpeg:dash:profile:isoff-main:2011" type="static" mediapresentationduration="pt0h9m56.46s"> <baseurl> http://example.com/segments </baseurl> <period start="pt0s"> <adaptationset bitstreamswitching="true"> <representation id="0" codecs="avc1" mimetype="video/mp4" width="320" height="240" startwithsap="1" bandwidth="46986"> <segmentbase> <initialization sourceurl="main/news100/1.m4s" range="0-862"/> </segmentbase> <segmentlist duration="1"> <segmenturl media="main/news100/2.m4s" mediarange="863-7113"/> <segmenturl media="main/news100/3.m4s" mediarange="7114-14104...
...And 2 more matches
<video>: The Video Embed element - HTML: Hypertext Markup Language
WebHTMLElementvideo
here is a <a href="myvideo.mp4">link to the video</a> instead.</p> </video> we offer a substantive and thorough guide to media file types and the guide to the codecs supported for video.
... also available is a guide to audio codecs that can be used with them.
... multiple sources example this example builds on the last one, offering three different sources for the media; this allows the video to be watched regardless of which video codecs are supported by the browser.
...And 2 more matches
Reading textual data - Archive of obsolete content
you will have to manually read a block of data and convert it using nsiscriptableunicodeconverter.
... for example: // first, get and initialize the converter var converter = components.classes["@mozilla.org/intl/scriptableunicodeconverter"] .createinstance(components.interfaces.nsiscriptableunicodeconverter); converter.charset = /* the character encoding you want, using utf-8 here */ "utf-8"; // now, read from the stream // this assumes istream is the stream you want to read from var scriptablestream = components.classes["@mozilla.org/scriptableinputstream;1"] .createinstance(components.interfaces.nsiscriptableinputstream); scriptablestream.init(istream); var chunk = scriptablestream.read(4096); var text = converter.converttounicode(chunk); however, you must be aware that this method will not work for character encodings that have...
... for the limited use case of reading lines from a local file, the following code using nsiscriptableunicodeconverter works.
... this code will not work for character encodings that contain embedded nulls such as utf-16 and utf-32 // first, get and initialize the converter var converter = components.classes["@mozilla.org/intl/scriptableunicodeconverter"] .createinstance(components.interfaces.nsiscriptableunicodeconverter); converter.charset = /* the character encoding you want, using utf-8 here */ "utf-8"; // this assumes that 'file' is a variable that contains the file you want to read, as an nsifile var fis = components.classes["@mozilla.org/network/file-input-stream;1"] .createinstance(components.interfaces.nsifileinputstream); fis.init(file, -1, -1, 0); var lis = fis.queryinterface(components.interfaces.nsilineinputstream); var linedata = {}; var cont; do { cont = l...
Enc Dec MAC Using Key Wrap CertReq PKCS10 CSR
ta = null; /* read in the entire file specified with the -i argument */ rv = readderfromfile(&certder, infilename, ascii); if (rv != secsuccess) { pr_fprintf(pr_stderr, "unable to read input file %s : %s\n", infilename, port_errortostring(rv)); goto cleanup; } /* read in an ascii cert and return a certcertificate */ cert = cert_decodecertfrompackage((char *)certder.data, certder.len); if (!cert) { pr_fprintf(pr_stderr, "could not obtain certificate from file\n"); rv = secfailure; goto cleanup; } /* create a cert trust */ trust = (certcerttrust *)port_zalloc(sizeof(certcerttrust)); if (!trust) { pr_fprintf(pr_stderr, "unable to allocate cert trust\n"); rv = se...
...== pr_success) { pr_delete(encryptedfilename); } /* read certificate from header file */ rv = readfromheaderfile(headerfilename, certenc, &data, pr_true); if (rv != secsuccess) { pr_fprintf(pr_stderr, "could not read certificate from header file\n"); goto cleanup; } /* read in an ascii cert and return a certcertificate */ cert = cert_decodecertfrompackage((char *)data.data, data.len); if (!cert) { pr_fprintf(pr_stderr, "could not obtain certificate from file\n"); rv = secfailure; goto cleanup; } /* extract the public key from certificate */ pubkey = cert_extractpublickey(cert); if (!pubkey) { pr_fprintf(pr_stderr, "could not get key from certificate\n"); rv = secfa...
...); rv = secfailure; goto cleanup; } /* read certificate from header file */ rv = readfromheaderfile(headerfilename, certvfy, &certdata, pr_true); if (rv != secsuccess) { pr_fprintf(pr_stderr, "could not read certificate from header file\n"); goto cleanup; } /* read in an ascii cert and return a certcertificate */ cert = cert_decodecertfrompackage((char *)certdata.data, certdata.len); if (!cert) { pr_fprintf(pr_stderr, "could not obtain certificate from file\n"); rv = secfailure; goto cleanup; } /* extract the public key from certificate */ pubkey = cert_extractpublickey(cert); if (!pubkey) { pr_fprintf(pr_stderr, "could not get key from certificate\n"); rv...
...adfromheaderfile(headerfilename, pad, &paditem, pr_true); if (rv != secsuccess) { pr_fprintf(pr_stderr, "could not retrieve pad detail from header file\n"); goto cleanup; } paddinglength = (unsigned int)paditem.data[0]; infilelength = filesize(encryptedfilename); /* read in an ascii cert and return a certcertificate */ cert = cert_decodecertfrompackage((char *)data.data, data.len); if (!cert) { pr_fprintf(pr_stderr, "could not obtain certificate from file\n"); rv = secfailure; goto cleanup; } /* find private key from certificate */ pvtkey = pk11_findkeybyanycert(cert, null); if (pvtkey == null) { fprintf(stderr, "couldn't find private key for cert\n"); rv = sec...
sample2
ertcerttrust *trust = null; certcertificate *cert = null; certder.data = null; /* read in the entire file specified with the -i argument */ rv = readderfromfile(&certder, infilename, ascii); if (rv != secsuccess) { pr_fprintf(pr_stderr, "unable to read input file %s : %s\n", infilename, port_errortostring(rv)); goto cleanup; } /* read in an ascii cert and return a certcertificate */ cert = cert_decodecertfrompackage((char *)certder.data, certder.len); if (!cert) { pr_fprintf(pr_stderr, "could not obtain certificate from file\n"); rv = secfailure; goto cleanup; } /* create a cert trust */ trust = (certcerttrust *)port_zalloc(sizeof(certcerttrust)); if (!trust) { pr_fprintf(pr_stderr, "unable to allocate cert trust\n"); rv = secfailure; goto cleanup; } rv = cert_decodetruststring(trust, trusts); ...
...elete it*/ if (pr_access(encryptedfilename, pr_access_exists) == pr_success) { pr_delete(encryptedfilename); } /* read certificate from header file */ rv = readfromheaderfile(headerfilename, certenc, &data, pr_true); if (rv != secsuccess) { pr_fprintf(pr_stderr, "could not read certificate from header file\n"); goto cleanup; } /* read in an ascii cert and return a certcertificate */ cert = cert_decodecertfrompackage((char *)data.data, data.len); if (!cert) { pr_fprintf(pr_stderr, "could not obtain certificate from file\n"); rv = secfailure; goto cleanup; } /* extract the public key from certificate */ pubkey = cert_extractpublickey(cert); if (!pubkey) { pr_fprintf(pr_stderr, "could not get key from certificate\n"); rv = secfailure; goto cleanup; } /* open the encrypted file for writing */ encfi...
...rintf(pr_stderr, "unable to open \"%s\" for writing.\n", headerfilename); rv = secfailure; goto cleanup; } /* read certificate from header file */ rv = readfromheaderfile(headerfilename, certvfy, &certdata, pr_true); if (rv != secsuccess) { pr_fprintf(pr_stderr, "could not read certificate from header file\n"); goto cleanup; } /* read in an ascii cert and return a certcertificate */ cert = cert_decodecertfrompackage((char *)certdata.data, certdata.len); if (!cert) { pr_fprintf(pr_stderr, "could not obtain certificate from file\n"); rv = secfailure; goto cleanup; } /* extract the public key from certificate */ pubkey = cert_extractpublickey(cert); if (!pubkey) { pr_fprintf(pr_stderr, "could not get key from certificate\n"); rv = secfailure; goto cleanup; } /* read signature from header file */ r...
...\n"); goto cleanup; } /* read padding from header file */ rv = readfromheaderfile(headerfilename, pad, &paditem, pr_true); if (rv != secsuccess) { pr_fprintf(pr_stderr, "could not retrieve pad detail from header file\n"); goto cleanup; } paddinglength = (unsigned int)paditem.data[0]; infilelength = filesize(encryptedfilename); /* read in an ascii cert and return a certcertificate */ cert = cert_decodecertfrompackage((char *)data.data, data.len); if (!cert) { pr_fprintf(pr_stderr, "could not obtain certificate from file\n"); rv = secfailure; goto cleanup; } /* find private key from certificate */ pvtkey = pk11_findkeybyanycert(cert, null); if (pvtkey == null) { fprintf(stderr, "couldn't find private key for cert\n"); rv = secfailure; goto cleanup; } /* open the out file to write */ outfile = pr_...
MediaRecorder.mimeType - Web APIs
keep in mind that not all codecs are supported by a given container; if you write media using a codec that is not supported by a given media container, the resulting file may not work reliably if at all when you try to play it back.
... see our media type and format guide for information about container and codec support across browsers.
...this string may include the codecs parameter, giving details about the codecs and the codec configurations used by the media recorder.
... mimetype: 'video/mp4; codecs="avc1.424028, mp4a.40.2"' assuming this configuration is acceptable to the user agent, the value returned later by m.mimetype would then be video/mp4; codecs="avc1.424028, mp4a.40.2".
RTCInboundRtpStreamStats.qpSum - Web APIs
also, the exact meaning of the qp value depends on the codec being used.
... for example, for the vp8 codec, the qp value can be anywhere from 1 to 127 and is found in the frame header element "y_ac_qi", whose value is defined in rfc 6386: 19.2.
...additionally, qp is not likely to be the only parameter the codec uses to adjust the compression.
... see the individual codec specifications for details.
RTCOutboundRtpStreamStats.qpSum - Web APIs
also, the exact meaning of the qp value depends on the codec being used.
... for example, for the vp8 codec, the qp value can be anywhere from 1 to 127 and is found in the frame header element "y_ac_qi", whose value is defined in rfc 6386: 19.2.
...additionally, qp is not likely to be the only parameter the codec uses to adjust the compression.
... see the individual codec specifications for details.
RTCRtpReceiver.getCapabilities() static function - Web APIs
the static function rtcrtpreceiver.getcapabilities() returns an rtcrtpcapabilities object describing the codecs and capabilities supported by rtcrtpreceivers on the current device.
... because the set of capabilities available tend to be stable for a length of time (people don't install and uninstall codecs and the like very often), the media capabilities can in whole or in part provide a cross-origin method for identifying a user.
... for that reason, in privacy-sensitive contexts, the browser may choose to obscure the capabilities; this might be done, for example, by leaving out rarely-used codec configurations.
... function canreceiveh264() { let capabilities = rtcrtpreceiver.getcapabilities("video"); capabilities.codecs.foreach((codec) => { if (codec.mimetype === "video/h264") { return true; } }); return false; } specifications specification status comment webrtc 1.0: real-time communication between browsersthe definition of 'rtcrtpreceiver.getcapabilities()' in that specification.
RTCRtpSender.getCapabilities() static function - Web APIs
the static function rtcrtpsender.getcapabilities() returns an rtcrtpcapabilities object describing the codecs and capabilities supported by the rtcrtpsender.
... because the set of capabilities available tend to be stable for a length of time (people don't install and uninstall codecs and the like very often), the media capabilities can in whole or in part provide a cross-origin method for identifying a user.
... for that reason, in privacy-sensitive contexts, the browser may choose to obscure the capabilities; this might be done, for example, by leaving out rarely-used codec configurations.
... function cansendh264() { let capabilities = rtcrtpsender.getcapabilities("video"); capabilities.codecs.foreach((codec) => { if (codec.mimetype === "video/h264") { return true; } }); return false; } specifications specification status comment webrtc 1.0: real-time communication between browsersthe definition of 'rtcrtpsender.getcapabilities()' in that specification.
RTCRtpSender.replaceTrack() - Web APIs
the promise is rejected if the track cannot be replaced for any reason; this is commonly because the change would require renegotiation of the codec, which is not allowed (see things that require negotiation).
... the new track's frame rate is high enough to cause the codec's block rate to be exceeded.
... media sources that have built-in encoders — such as hardware encoders — may not be able to provide the negotiated codec.
... software sources may not implement the negotiated codec.
RTCRtpStreamStats.qpSum - Web APIs
also, the exact meaning of the qp value depends on the codec being used.
... for example, for the vp8 codec, the qp value can be anywhere from 1 to 127 and is found in the frame header element "y_ac_qi", whose value is defined in rfc 6386: 19.2.
...additionally, qp is not likely to be the only parameter the codec uses to adjust the compression.
... see the individual codec specifications for details.
Signaling and video calling - Web APIs
at this point, the two participants know which codecs and codec parameters are to be used for this call.
... if conditions change—for example the network connection deteriorates—one or both peers might suggest switching to a lower-bandwidth media resolution, or to an alternative codec.
... this triggers a new exchange of candidates, after which a another media format and/or codec change may take place.
... you can learn more about the codecs which webrtc requires browsers to support, which additional codecs are supported by which browsers, and how to choose the best codecs to use in the guide codecs used by webrtc.
WebRTC API - Web APIs
interoperability because implementations of webrtc are still evolving, and because each browser has different levels of support for codecs and webrtc features, you should strongly consider making use of the adapter.js library provided by google before you begin to write your code.
... codecs used by webrtc a guide to the codecs which webrtc requires browsers to support as well as the optional ones supported by various popular browsers.
... included is a guide to help you choose the best codecs for your needs.
... resources protocols webrtc-proper protocols application layer protocol negotiation for web real-time communications webrtc audio codec and processing requirements rtcweb data channels rtcweb data channel protocol web real-time communication (webrtc): media transport and use of rtp webrtc security architecture transports for rtcweb related supporting protocols interactive connectivity establishment (ice): a protocol for network address translator (nat) traversal for offer/answer protocol session traversal utilities for...
<audio>: The Embed Audio element - HTML: Hypertext Markup Language
WebHTMLElementaudio
waiting playback has stopped because of a temporary lack of data usage notes browsers don't all support the same file types and audio codecs; you can provide multiple sources inside nested <source> elements, and the browser will then use the first one it understands: <audio controls> <source src="myaudio.mp3" type="audio/mpeg"> <source src="myaudio.ogg" type="audio/ogg"> <p>your browser doesn't support html5 audio.
... here is a <a href="myaudio.mp4">link to the audio</a> instead.</p> </audio> we offer a substantive and thorough guide to media file types and the audio codecs that can be used within them.
... also available is a guide to the codecs supported for video.
...the browser tries to load the first source element (opus) if it is able to play it; if not it falls back to the second (vorbis) and finally back to mp3: <audio controls> <source src="foo.opus" type="audio/ogg; codecs=opus"/> <source src="foo.ogg" type="audio/ogg; codecs=vorbis"/> <source src="foo.mp3" type="audio/mpeg"/> </audio> accessibility concerns audio with spoken dialog should provide both captions and transcripts that accurately describe its content.
Writing textual data - Archive of obsolete content
they work by manually converting the string you want to write to a byte sequence using nsiscriptableunicodeconverter, and writing that to the stream.
... here's an example: // first, get and initialize the converter var converter = components.classes["@mozilla.org/intl/scriptableunicodeconverter"] .createinstance(components.interfaces.nsiscriptableunicodeconverter); converter.charset = /* the character encoding you want, using utf-8 for this example */ "utf-8"; now you can convert and write to the stream: // this code assumes that os is your nsioutputstream // your_string here is the string you want to write.
... nsiscriptableunicodeconverter has a simple method to do that: // first, get and initialize the converter var converter = components.classes["@mozilla.org/intl/scriptableunicodeconverter"] .createinstance(components.interfaces.nsiscriptableunicodeconverter); converter.charset = /* the charset you want to use.
Index - MDN Web Docs Glossary: Definitions of Web-related terms
82 codec glossary, webmechanics a codec (a blend word derived from "coder-decoder") is a program, algorithm, or device that encodes or decodes a data stream.
... a given codec knows how to handle a specific encoding or compression technology.
...sdp contains the codec, source address, and timing information of audio and video.
Certificate functions
gecerttrust mxr 3.2 and later cert_checkcertvalidtimes mxr 3.2 and later cert_checknamespace mxr 3.12 and later cert_checkcertusage mxr 3.3 and later cert_comparename mxr 3.2 and later cert_comparevaliditytimes mxr 3.11 and later cert_completecrldecodeentries mxr 3.6 and later cert_convertanddecodecertificate mxr 3.9.3 and later cert_copyname mxr 3.4 and later cert_copyrdn mxr 3.5 and later cert_createava mxr 3.2.1 and later cert_createcertificate mxr 3.5 and later cert_createcertificaterequest mxr 3.2 and later cert_createname mxr 3.2.1 and later cert_createocspcertid mxr 3.6 and l...
...xr 3.5 and later cert_crlcacherefreshissuer mxr 3.7 and later cert_decodealtnameextension mxr 3.10 and later cert_decodeauthinfoaccessextension mxr 3.10 and later cert_decodeauthkeyid mxr 3.10 and later cert_decodeavavalue mxr 3.4 and later cert_decodebasicconstraintvalue mxr 3.2 and later cert_decodecertfrompackage mxr 3.4 and later cert_decodecertificatepoliciesextension mxr 3.2 and later cert_decodecertpackage mxr 3.2 and later cert_decodecrldistributionpoints mxr 3.10 and later cert_decodedercrl mxr 3.2 and later cert_decodedercrlwithflags mxr 3.6 and later cert_decodegeneralname mxr 3.4 and late...
...ficate mxr 3.2 and later cert_dupcertlist mxr 3.2 and later cert_enableocspchecking mxr 3.2 and later cert_encodealtnameextension mxr 3.7 and later cert_encodeandaddbitstrextension mxr 3.5 and later cert_encodeauthkeyid mxr 3.5 and later cert_encodebasicconstraintvalue mxr 3.5 and later cert_encodecertpoliciesextension mxr 3.12 and later cert_encodecrldistributionpoints mxr 3.5 and later cert_encodegeneralname mxr 3.4 and later cert_encodeinfoaccessextension mxr 3.12 and later cert_encodeinhibitanyextension mxr 3.12 and later cert_encodenoticereference mxr 3.12 and later cert_encodeocsprequest mxr ...
NSS functions
gecerttrust mxr 3.2 and later cert_checkcertvalidtimes mxr 3.2 and later cert_checknamespace mxr 3.12 and later cert_checkcertusage mxr 3.3 and later cert_comparename mxr 3.2 and later cert_comparevaliditytimes mxr 3.11 and later cert_completecrldecodeentries mxr 3.6 and later cert_convertanddecodecertificate mxr 3.9.3 and later cert_copyname mxr 3.4 and later cert_copyrdn mxr 3.5 and later cert_createava mxr 3.2.1 and later cert_createcertificate mxr 3.5 and later cert_createcertificaterequest mxr 3.2 and later cert_createname mxr 3.2.1 and later cert_createocspcertid mxr 3.6 and l...
...xr 3.5 and later cert_crlcacherefreshissuer mxr 3.7 and later cert_decodealtnameextension mxr 3.10 and later cert_decodeauthinfoaccessextension mxr 3.10 and later cert_decodeauthkeyid mxr 3.10 and later cert_decodeavavalue mxr 3.4 and later cert_decodebasicconstraintvalue mxr 3.2 and later cert_decodecertfrompackage mxr 3.4 and later cert_decodecertificatepoliciesextension mxr 3.2 and later cert_decodecertpackage mxr 3.2 and later cert_decodecrldistributionpoints mxr 3.10 and later cert_decodedercrl mxr 3.2 and later cert_decodedercrlwithflags mxr 3.6 and later cert_decodegeneralname mxr 3.4 and late...
...ficate mxr 3.2 and later cert_dupcertlist mxr 3.2 and later cert_enableocspchecking mxr 3.2 and later cert_encodealtnameextension mxr 3.7 and later cert_encodeandaddbitstrextension mxr 3.5 and later cert_encodeauthkeyid mxr 3.5 and later cert_encodebasicconstraintvalue mxr 3.5 and later cert_encodecertpoliciesextension mxr 3.12 and later cert_encodecrldistributionpoints mxr 3.5 and later cert_encodegeneralname mxr 3.4 and later cert_encodeinfoaccessextension mxr 3.12 and later cert_encodeinhibitanyextension mxr 3.12 and later cert_encodenoticereference mxr 3.12 and later cert_encodeocsprequest mxr ...
nsICryptoHash
since hash functions are computed over bytes, you will first need to convert the string to a series of bytes using nsiscriptableunicodeconverter and a unicode encoding that you specify.
... var str = "hello world"; var converter = components.classes["@mozilla.org/intl/scriptableunicodeconverter"].
... createinstance(components.interfaces.nsiscriptableunicodeconverter); // we use utf-8 here, you can choose other encodings.
nsIDOMHTMLSourceElement
the codecs parameter may be specified and might be necessary to specify exactly how the resource is encoded.
... example <video controls> <source src="foo.webm" type="video/webm; codecs=&quot;vp9, opus&quot;"> your browser does not support the <code>video</code> element.
...the type is specified as "video/ogg", and the source element also specifies that the video file uses the dirac and speex codecs.
MediaSource.endOfStream() - Web APIs
this can be used to indicate that a parsing error has occured while fetching media data; maybe the data is corrupt, or is encoded using a codec that the browser doesn't know how to decode.
...their sourcebuffer.updating property is true.) example the following snippet is from a simple example written by nick desaulniers (view the full demo live, or download the source for further investigation.) var asseturl = 'frag_bunny.mp4'; // need to be specific for blink regarding codecs // ./mp4info frag_bunny.mp4 | grep codec var mimecodec = 'video/mp4; codecs="avc1.42e01e, mp4a.40.2"'; if ('mediasource' in window && mediasource.istypesupported(mimecodec)) { var mediasource = new mediasource; //console.log(mediasource.readystate); // closed video.src = url.createobjecturl(mediasource); mediasource.addeventlistener('sourceopen', sourceopen); } else { console.error('u...
...nsupported mime type or codec: ', mimecodec); } function sourceopen (_) { //console.log(this.readystate); // open var mediasource = this; var sourcebuffer = mediasource.addsourcebuffer(mimecodec); fetchab(asseturl, function (buf) { sourcebuffer.addeventlistener('updateend', function (_) { mediasource.endofstream(); video.play(); //console.log(mediasource.readystate); // ended }); sourcebuffer.appendbuffer(buf); }); }; specifications specification status comment media source extensionsthe definition of 'endofstream()' in that specification.
MediaSource.isTypeSupported() - Web APIs
this may include the codecs parameter to provide added details about the codecs used within the file.
... example the following snippet is from an example written by nick desaulniers (view the full demo live, or download the source for further investigation.) var asseturl = 'frag_bunny.mp4'; // need to be specific for blink regarding codecs // ./mp4info frag_bunny.mp4 | grep codec var mimecodec = 'video/mp4; codecs="avc1.42e01e, mp4a.40.2"'; if ('mediasource' in window && mediasource.istypesupported(mimecodec)) { var mediasource = new mediasource; //console.log(mediasource.readystate); // closed video.src = url.createobjecturl(mediasource); mediasource.addeventlistener('sourceopen', sourceopen); } else { console.error('u...
...nsupported mime type or codec: ', mimecodec); } function sourceopen (_) { //console.log(this.readystate); // open var mediasource = this; var sourcebuffer = mediasource.addsourcebuffer(mimecodec); fetchab(asseturl, function (buf) { sourcebuffer.addeventlistener('updateend', function (_) { mediasource.endofstream(); video.play(); //console.log(mediasource.readystate); // ended }); sourcebuffer.appendbuffer(buf); }); }; specifications specification status comment media source extensionsthe definition of 'istypesupported()' in that specification.
Media Capabilities API - Web APIs
'' : 'not ') + 'power efficient.') }) .catch(() => { console.log("decodinginfo error: " + contenttype) }); } media capabilities api concepts and usage there are a myriad of video and audio codecs.
...the media capabilities api enables determining which codecs are supported and how performant a media file will be both in terms of smoothness and power efficiency.
... media capabilities interfaces mediacapabilities provides information about the decoding abilities of the device, system and browser based on codecs, profile, resolution, and bitrates.
Audio and video manipulation - Developer guides
javascript codecs it's also possible to manipulate audio at a low level using javascript.
... this can be useful should you want to create audio codecs.
... libraries currently exist for the following formats : aac: aac.js alac: alac.js flac: flac.js mp3: mp3.js opus: opus.js vorbis: vorbis.js note: at audiocogs, you can try out a few demos; audiocogs also provides a framework, aurora.js, which is intended to help you author your own codecs in javascript.
File I/O - Archive of obsolete content
it defaults to // fileutils.mode_wronly | fileutils.mode_create | fileutils.mode_truncate; var ostream = fileutils.opensafefileoutputstream(file); var converter = components.classes["@mozilla.org/intl/scriptableunicodeconverter"].
... createinstance(components.interfaces.nsiscriptableunicodeconverter); converter.charset = "utf-8"; var istream = converter.converttoinputstream(data); // the last argument (the callback) is optional.
Chapter 5: Let's build a Firefox extension - Archive of obsolete content
createinstance(components.interfaces.nsifileoutputstream); stream.init(afile, 0x02 | 0x08 | 0x20, 0600, 0); // convert to utf-8 var converter = components.classes["@mozilla.org/intl/scriptableunicodeconverter"].
... createinstance(components.interfaces.nsiscriptableunicodeconverter); converter.charset = "utf-8"; var converteddata = converter.convertfromunicode(adata); converteddata += converter.finish(); // write and close stream stream.write(converteddata, converteddata.length); if (stream instanceof components.interfaces.nsisafeoutputstream) { stream.finish(); } else { stream.close(); } }, createmenu method this event handler is called when the session store submenu opens.
Chapter 4: Using XPCOM—Implementing advanced processes - Archive of obsolete content
in these cases, you can easily convert between encodings using the nsiscriptableunicodeconverter.
... listing 17: converting text from unicode to euc-jp var converter = components.classes['@mozilla.org/intl/scriptableunicodeconverter'] .getservice(components.interfaces.nsiscriptableunicodeconverter); converter.charset = 'euc-jp'; var unicode_str = '\u5909\u63db\u30c6\u30b9\u30c8'; var eucjp_str = converter.convertfromunicode(unicode_str); converting from other encodings to unicode listing 18 shows how to do the reverse, converting from text saved as iso-2022-jp to unicode.
Aprender y obtener ayuda - Learn web development
codecademy for example is a learning site where the tutorials mainly consist of interactive code editors where you have to directly write code and see if the desired result was achieved.
... see also coursera: learning to learn freecodecamp codecademy ...
imgIEncoder
1.0 66 introduced gecko 1.8 inherits from: nsiasyncinputstream last changed in gecko 1.9 (firefox 3) method overview void addimageframe( [array, size_is(length), const] in pruint8 data, in unsigned long length, in pruint32 width, in pruint32 height, in pruint32 stride, in pruint32 frameformat, in astring frameoptions); void encodeclipboardimage(in nsiclipboardimage aclipboardimage, out nsifile aimagefile); obsolete since gecko 1.9 void endimageencode(); void initfromdata([array, size_is(length), const] in pruint8 data, in unsigned long length, in pruint32 width, in pruint32 height, in pruint32 stride, in pruint32 inputformat, in astring outputoptions); void startimageencode(in pruint32 width, in pruint32 height, in ...
...frameformat missing description frameoptions missing description encodeclipboardimage() obsolete since gecko 1.9 (firefox 3) void encodeclipboardimage( in nsiclipboardimage aclipboardimage, out nsifile aimagefile ); parameters aclipboardimage missing description aimagefile missing description endimageencode() void endimageencode(); parameters none.
MediaCapabilities.encodingInfo() - Web APIs
return value a promise fulfilling with a mediacapabilitiesinfo interface containing three boolean attributes: supported smooth powerefficient exceptions a typeerror is raised if the mediaconfiguration passed to the encodinginfo() method is invalid, either because the type is not video or audio, the contenttype is not a valid codec mime type, or any other error in the media configuration passed to the method, including omitting any of the media encoding configuration elements.
... example //create media configuration to be tested const mediaconfig = { type : 'record', // or 'transmission' video : { contenttype : "video/webm;codecs=vp8.0", // valid content type width : 1920, // width of the video height : 1080, // height of the video bitrate : 120000, // number of bits used to encode 1s of video framerate : 48 // number of frames making up that 1s.
MediaRecorder() - Web APIs
the object can optionally be configured to record using a specific media container (file type), and, further, can specify the exact codec and codec configuration(s) to use by specifying the codecs parameter.
... options optional a dictionary object that can contain the following properties: mimetype: a mime type specifying the format for the resulting media; you may simply specify the container format (the browser will select its preferred codecs for audio and/or video), or you may use the codecs parameter and/or the profiles parameter to provide detailed information about which codecs to use and how to configure them.
MediaRecorder: dataavailable event - Web APIs
var chunks = []; mediarecorder.addeventlistener('stop', (event) => { console.log("data available after mediarecorder.stop() called."); var audio = document.createelement('audio'); audio.controls = true; var blob = new blob(chunks, { 'type' : 'audio/ogg; codecs=opus' }); var audiourl = window.url.createobjecturl(blob); audio.src = audiourl; console.log("recorder stopped"); }); mediarecorder.addeventlistener('dataavailable', (event) => { chunks.push(event.data); }); ...
... var chunks = []; mediarecorder.onstop = function(e) { console.log("data available after mediarecorder.stop() called."); var audio = document.createelement('audio'); audio.controls = true; var blob = new blob(chunks, { 'type' : 'audio/ogg; codecs=opus' }); var audiourl = window.url.createobjecturl(blob); audio.src = audiourl; console.log("recorder stopped"); } mediarecorder.ondataavailable = function(e) { chunks.push(e.data); } ...
MediaRecorder - Web APIs
error fired when an error occurs: for example because recording wasn't allowed or was attempted using an unsupported codec.
...t.add('clip'); audio.setattribute('controls', ''); deletebutton.innerhtml = "delete"; cliplabel.innerhtml = clipname; clipcontainer.appendchild(audio); clipcontainer.appendchild(cliplabel); clipcontainer.appendchild(deletebutton); soundclips.appendchild(clipcontainer); audio.controls = true; var blob = new blob(chunks, { 'type' : 'audio/ogg; codecs=opus' }); chunks = []; var audiourl = url.createobjecturl(blob); audio.src = audiourl; console.log("recorder stopped"); deletebutton.onclick = function(e) { evttgt = e.target; evttgt.parentnode.parentnode.removechild(evttgt.parentnode); } } mediarecorder.ondataavailable = function(e) { chunks.push(e.data); } }) .catch(fu...
MediaSource.MediaSource() - Web APIs
example the following snippet is taken from a simple example written by nick desaulniers (view the full demo live, or download the source for further investigation.) var video = document.queryselector('video'); var asseturl = 'frag_bunny.mp4'; // need to be specific for blink regarding codecs // ./mp4info frag_bunny.mp4 | grep codec var mimecodec = 'video/mp4; codecs="avc1.42e01e, mp4a.40.2"'; if ('mediasource' in window && mediasource.istypesupported(mimecodec)) { var mediasource = new mediasource; //console.log(mediasource.readystate); // closed video.src = url.createobjecturl(mediasource); mediasource.addeventlistener('sourceopen', sourceopen); } else { console.error('u...
...nsupported mime type or codec: ', mimecodec); } ...
MediaSource.addSourceBuffer() - Web APIs
example the following snippet is from a simple example written by nick desaulniers (view the full demo live, or download the source for further investigation.) var asseturl = 'frag_bunny.mp4'; // need to be specific for blink regarding codecs // ./mp4info frag_bunny.mp4 | grep codec var mimecodec = 'video/mp4; codecs="avc1.42e01e, mp4a.40.2"'; if ('mediasource' in window && mediasource.istypesupported(mimecodec)) { var mediasource = new mediasource; //console.log(mediasource.readystate); // closed video.src = url.createobjecturl(mediasource); mediasource.addeventlistener('sourceopen', sourceopen); } else { console.error('u...
...nsupported mime type or codec: ', mimecodec); } function sourceopen (_) { //console.log(this.readystate); // open var mediasource = this; var sourcebuffer = mediasource.addsourcebuffer(mimecodec); fetchab(asseturl, function (buf) { sourcebuffer.addeventlistener('updateend', function (_) { mediasource.endofstream(); video.play(); //console.log(mediasource.readystate); // ended }); sourcebuffer.appendbuffer(buf); }); }; specifications specification status comment media source extensionsthe definition of 'addsourcebuffer()' in that specification.
MediaSource.readyState - Web APIs
example the following snippet is from a simple example written by nick desaulniers (view the full demo live, or download the source for further investigation.) if ('mediasource' in window && mediasource.istypesupported(mimecodec)) { var mediasource = new mediasource; //console.log(mediasource.readystate); // closed video.src = url.createobjecturl(mediasource); mediasource.addeventlistener('sourceopen', sourceopen); } else { console.error('unsupported mime type or codec: ', mimecodec); } function sourceopen (_) { //console.log(this.readystate); // open var mediasource = this; var sourcebuffer = mediasourc...
...e.addsourcebuffer(mimecodec); fetchab(asseturl, function (buf) { sourcebuffer.addeventlistener('updateend', function (_) { mediasource.endofstream(); video.play(); //console.log(mediasource.readystate); // ended }); sourcebuffer.appendbuffer(buf); }); }; specifications specification status comment media source extensionsthe definition of 'readystate' in that specification.
MediaSource - Web APIs
this example was written by nick desaulniers and can be viewed live here (you can also download the source for further investigation.) var video = document.queryselector('video'); var asseturl = 'frag_bunny.mp4'; // need to be specific for blink regarding codecs // ./mp4info frag_bunny.mp4 | grep codec var mimecodec = 'video/mp4; codecs="avc1.42e01e, mp4a.40.2"'; if ('mediasource' in window && mediasource.istypesupported(mimecodec)) { var mediasource = new mediasource(); //console.log(mediasource.readystate); // closed video.src = url.createobjecturl(mediasource); mediasource.addeventlistener('sourceopen', sourceopen); } else { console.error(...
...'unsupported mime type or codec: ', mimecodec); } function sourceopen (_) { //console.log(this.readystate); // open var mediasource = this; var sourcebuffer = mediasource.addsourcebuffer(mimecodec); fetchab(asseturl, function (buf) { sourcebuffer.addeventlistener('updateend', function (_) { mediasource.endofstream(); video.play(); //console.log(mediasource.readystate); // ended }); sourcebuffer.appendbuffer(buf); }); }; function fetchab (url, cb) { console.log(url); var xhr = new xmlhttprequest; xhr.open('get', url); xhr.responsetype = 'arraybuffer'; xhr.onload = function () { cb(xhr.response); }; xhr.send(); }; specifications specification status comment media source extensionsthe definition of 'mediasource' ...
Media Source API - Web APIs
while browser support for the various media containers with mse is spotty, usage of the h.264 video codec, aac audio codec, and mp4 container format is a common baseline.
... mse also provides an api for runtime detection of container and codec support.
RTCOutboundRtpStreamStats - Web APIs
targetbitrate a value indicating the bit rate the rtcrtpsender's codec is configured to attempt to achieve in its output media.
... totalencodedbytestarget a cumulative sum of the target frame sizes (the targeted maximum size of the frame in bytes when the codec is asked to compress it) for all of the frames encoded so far.
RTCPeerConnection.createOffer() - Web APIs
the sdp offer includes information about any mediastreamtracks already attached to the webrtc session, codec, and options supported by the browser, and any candidates already gathered by the ice agent, for the purpose of being sent over the signaling channel to a potential peer to request a connection or to update the configuration of an existing connection.
... voiceactivitydetection optional some codecs and hardware are able to detect when audio begins and ends by watching for "silence" (or relatively low sound levels) to occur.
RTCRtpEncodingParameters - Web APIs
an instance of the webrtc api's rtcrtpencodingparameters dictionary describes a single configuration of a codec for an rtcrtpsender.
... codecpayloadtype when describing a codec for an rtcrtpsender, codecpayloadtype is a single 8-bit byte (or octet) specifying the codec to use for sending the stream; the value matches one from the owning rtcrtpparameters object's codecs parameter.
RTCRtpSendParameters.encodings - Web APIs
syntax sendparameters.encodings = encodingparameterlist; encodingparameterlist = sendparameters.encodings; value an array of objects conforming to the rtcrtpencodingparameters dictionary, each of which contains properties which provide settings and parameters that describe and configure a single codec that could be used to encode the track.
... codecpayloadtype when describing a codec for an rtcrtpsender, codecpayloadtype is a single 8-bit byte (or octet) specifying the codec to use for sending the stream; the value matches one from the owning rtcrtpparameters object's codecs parameter.
RTCRtpSender.setParameters() - Web APIs
syntax var promise = rtcrtpsender.setparameters(parameters) parameters parameters an object conforming with the rtcrtpsendparameters dictionary, specifying options for the rtcrtpsender; these include potential codecs that could be use for encoding the sender's track.
... encodings an array of rtcrtpencodingparameters objects, each specifying the parameters for a single codec that could be used to encode the track's media.
SourceBuffer.changeType() - Web APIs
this makes it possible to change codecs or container type mid-stream.
... one scenario in which this is helpful is to support adapting the media source to changing bandwidth availability, by transitioning from one codec to another as resource constraints change.
SourceBuffer - Web APIs
this example was written by nick desaulniers and can be viewed live here (you can also download the source for further investigation.) var video = document.queryselector('video'); var asseturl = 'frag_bunny.mp4'; // need to be specific for blink regarding codecs // ./mp4info frag_bunny.mp4 | grep codec var mimecodec = 'video/mp4; codecs="avc1.42e01e, mp4a.40.2"'; if ('mediasource' in window && mediasource.istypesupported(mimecodec)) { var mediasource = new mediasource(); //console.log(mediasource.readystate); // closed video.src = url.createobjecturl(mediasource); mediasource.addeventlistener('sourceopen', sourceopen); } else { console.error(...
...'unsupported mime type or codec: ', mimecodec); } function sourceopen (_) { //console.log(this.readystate); // open var mediasource = this; var sourcebuffer = mediasource.addsourcebuffer(mimecodec); fetchab(asseturl, function (buf) { sourcebuffer.addeventlistener('updateend', function (_) { mediasource.endofstream(); video.play(); //console.log(mediasource.readystate); // ended }); sourcebuffer.appendbuffer(buf); }); } function fetchab (url, cb) { console.log(url); var xhr = new xmlhttprequest; xhr.open('get', url); xhr.responsetype = 'arraybuffer'; xhr.onload = function () { cb(xhr.response); }; xhr.send(); } specifications specification status comment media source extensionsthe definition of 'sourcebuffer' i...
VideoConfiguration - Web APIs
see our web video codec guide for types which may be supported.
... examples // create media configuration to be tested const mediaconfig = { type : 'file', // see mediadecodingconfiguration and mediaencodingconfiguration video : { contenttype : "video/webm;codecs=vp8", // valid content type width : 800, // width of the video height : 600, // height of the video bitrate : 10000, // number of bits used to encode 1s of video framerate : 30 // number of frames making up that 1s.
WebRTC connectivity - Web APIs
see the individual articles on these properties and methods for more specifics, and codecs used by webrtc for information about codecs supported by webrtc and which are compatible with which browsers.
... the codecs guide also offers guidance to help you choose the best codecs for your needs.
Lifetime of a WebRTC session - Web APIs
signaling signaling is the process of sending control information between two devices to determine the communication protocols, channels, media codecs and formats, and method of data transfer, as well as any required routing information.
... media capability negotiation: what codecs and media data formats can the peers understand?
WebRTC Statistics API - Web APIs
rtccertificatestats rtcstats codec statistics about a specific codec being used by streams being sent or received by this connection.
... rtccodecstats rtcstats csrc statistics for a single contributing source (csrc) that contributed to one of the connection's inbound rtp streams.
Cross-browser audio basics - Developer guides
browser support the following tables list basic audio support across desktop and mobile browsers, and what audio codecs are supported.
... chrome 4+ firefox 3.5+ internet explorer 9+ opera 10.5+ safari 4+ mobile mobile browser version chrome (android) 32+ firefox (android) 26+ ie mobile 10+ opera mobile 11+ safari (ios) 4+ android browser 2.3+ blackberry 7+ audio codec support browser ogg mp3 aac pcm opus firefox 3.5+ ✓ ✓ *26+ ✓ ✓ *14+ safari 5+ ✓ ✓ chrome 6+ ✓ ✓ ✓ ✓ *9+ opera 10.5+ ✓ internet explorer 9+ ✓ ✓ firefox mobile ✓ ✓ ✓ ✓ ✓ s...
Live streaming web audio and video - Developer guides
music and speech can be optimized in different ways and opus uses the silk and celt codecs to achieve this.
...through its plugin system, gstreamer provides support for more than a hundred codecs (including mpeg-1, mpeg-2, mpeg-4, h.261, h.263, h.264, realvideo, mp3, wmv, and flv.) gstreamer plugins such as souphttpclientsink and shout2send exist to stream media over http.
Digital video concepts - Web media technologies
there are several color models, and video codec makes use of one or more of these to represent their pixels during the encoding process as well as after decoding the video frames.
...for example, in the av1 codec, a record stores the encoded luma for a tile, and a second record contains the chroma data in the form of the u and v values.
Web media technologies
guide to media types and formats on the web a guide to the file types and codecs available for images, audio, and video media on the web.
... this includes recommendations for what formats to use for what kinds of content, best practices including how to provide fallbacks and how to prioritize media types, and also includes general browser support information for each media container and codec.
Tutorials
codecademy codecademy is an easy way to learn how to code javascript.
... freecodecamp freecodecamp teaches a variety of languages and frameworks for web development.
HTML - MDN Web Docs Glossary: Definitions of Web-related terms
learn more general knowledge html on wikipedia learning html our html tutorial the web course on codecademy.com technical reference the html documentation on mdn the html specification ...
JavaScript - MDN Web Docs Glossary: Definitions of Web-related terms
learn more general knowledge javascript on wikipedia learning javascript the javascript guide on mdn the "javascripting" workshop on nodeschool the javascript course on codecademy.com john resig's learning advanced javascript technical reference the latest ecmascript standard the javascript reference on mdn the eloquent javascript book ...
Latency - MDN Web Docs Glossary: Definitions of Web-related terms
latency can be a factor in any kind of data flow, but is most commonly discussed in terms of network latency (the time it takes for a packet of data to travel from source to destination) and media codec latency (the time it takes for the source data to be encoded or decoded and reach the consumer of the resulting data).
SDP - MDN Web Docs Glossary: Definitions of Web-related terms
sdp contains the codec, source address, and timing information of audio and video.
MDN Web Docs Glossary: Definitions of Web-related terms
ting carddav caret cdn certificate authority certified challenge-response authentication character character encoding character set chrome cia cipher cipher suite ciphertext class client hints closure cms code splitting codec compile compile time computer programming conditional constant constructor continuous media control flow cookie copyleft cors cors-safelisted request header cors-safelisted response header crawler crlf cross axis cross-site scripting cru...
How can we design for all types of users? - Learn web development
many users don't have time, or lack the proper plugin or codec.
Publishing your website - Learn web development
deploy a website: a nice tutorial from codecademy that goes a bit further and shows some additional techniques.
Multimedia: video - Learn web development
<video autoplay="" loop="" muted="true" playsinline="" id="hero-video"> <source src="banner_video.webm" type='video/webm; codecs="vp8, vorbis"'> <source src="web_banner.mp4" type="video/mp4"> </video> this hero-video code (above) is common to conference websites and corporate home pages.
Client-side tooling overview - Learn web development
great starting places is to search web sites like css tricks, dev, freecodecamp, and smashing magazine, as they’re tailored to the web development industry.
NSS_3.12.1_release_notes.html
code from nss source tree bug 372241: need more versatile form of cert_nametoascii bug 390296: nss ignores subject cn even when san contains no dnsname bug 401928: support generalized pkcs#5 v2 pbes bug 403543: pkix: need a way to enable/disable aia cert fetching bug 408847: pkix_ocspchecker_check does not support specified responder (and given signercert) bug 414003: crash [[@ cert_decodecertpackage] sometimes with this testcase bug 415167: memory leak in certutil bug 417399: arena allocation results are not checked in pkix_pl_infoaccess_parselocation bug 420644: improve ssl tracing of key derivation bug 426886: use const char* in pk11_importcertforkey bug 428103: cert_encodesubjectkeyid is not defined in any public header file bug 429716: debug builds of libpkix uncond...
NSS_3.12.2_release_notes.html
bug 456854: cert_decodecertpackage does not set nspr error code upon error bug 457980: hundreds of kilobytes of useless strings in libpkix bug 457984: enable pkcs11 module logging in optimized builds bug 458905: memory leaks in pkix bridge certificates.
NSS 3.12.4 release notes
cert_decodecrlissuingdistributionpoint cert_findcrlissuingdistpointexten the old documentation of the expression matching syntax rules was incorrect, and the new corrected documentation is as follows for public nssutil functions (see portreq.h): port_regexpvalid port_regexpsearch port_regexpcasesearch these functions will match a string with a shell expression.
NSS_3.12_release_notes.html
nss 3.12 libraries have the following versions: sqlite3: 3.3.17 nssckbi: 1.70 softokn3 and freebl3: 3.12.0.3 other nss libraries: 3.12.0.3 new in nss 3.12 3 new shared library are shipped with nss 3.12: nssutil sqlite nssdbm 1 new include file is shipped with nss3.12: utilrename.h new functions in the nss shared library: cert_checknamespace (see cert.h) cert_encodecertpoliciesextension (see cert.h) cert_encodeinfoaccessextension (see cert.h) cert_encodeinhibitanyextension (see cert.h) cert_encodenoticereference (see cert.h) cert_encodepolicyconstraintsextension (see cert.h) cert_encodepolicymappingextension (see cert.h) cert_encodesubjectkeyid (see certdb/cert.h) cert_encodeusernotice (see cert.h) cert_findcrlentryreasonexten (see cert.h) cert_findcrlnumbere...
NSS 3.44 release notes
bugs fixed in nss 3.44 1501542 - implement checkarmsupport for android 1531244 - use __builtin_bswap64 in crypto_primitives.h 1533216 - cert_decodecertpackage() crash with netscape certificate sequences 1533616 - sdb_getattributevaluenolock should make at most one sql query, rather than one for each attribute 1531236 - provide accessor for certcertificate.dercert 1536734 - lib/freebl/crypto_primitives.c assumes a big endian machine 1532384 - in nss test certificates, use @example.com (not @bogus.com) 1538479 - post-handshake messages aft...
Index
in pseudocode: 250 js_encodecharacters jsapi reference, obsolete, spidermonkey js_encodecharacters copies the characters of a jschar array into a char array, converting the 16-bit values to 8-bit values.
JS_CStringsAreUTF8
enabling this option also causes js_getstringbytes and js_encodecharacters to produce utf-8 strings instead of latin-1.
JSAPI reference
te since jsapi 1.8.5 js_getstringcharsz obsolete since jsapi 33 js_getstringcharsandlength added in jsapi 1.8.5 obsolete since jsapi 33 js_getstringcharsz added in spidermonkey 1.8.5 obsolete since jsapi 33 js_getstringcharszandlength added in spidermonkey 1.8.5 obsolete since jsapi 33 js_getflatstringchars obsolete since jsapi 33 js_makestringimmutable obsolete since javascript 1.8.5 js_encodecharacters obsolete since jsapi 19 js_cstringsareutf8 obsolete since jsapi 19 js_setcstringsareutf8 obsolete since jsapi 19 interning strings tells the spidermonkey engine to reuse existing string objects when possible.
XPCOM Stream Guide
MozillaTechXPCOMGuideStreams
var converter = components.classes["@mozilla.org/intl/scriptableunicodeconverter"] .createinstance(components.interfaces.nsiscriptableunicodeconverter); converter.charset = "utf-8"; var stream = converter.converttoinputstream(string); javascript modules are your friends there are several useful javascript modules at your disposal.
Index
MozillaTechXPCOMIndex
887 nsiscriptableunescapehtml interfaces, interfaces:scriptable, xpcom, xpcom interface reference implemented by: @mozilla.org/feed-unescapehtml;1 as a service: 888 nsiscriptableunicodeconverter interfaces, interfaces:scriptable, unicode, xpcom, xpcom interface reference this legacy api represents binary data using the lower haft of each 16-bit code unit in a javascript string.
Language bindings
the scriptable methods on the nsicomponentmanager interface can be called directly on this object.components.resultscomponents.results is a read-only object whose properties are the names listed as the first parameters of the macros in js/xpconnect/src/xpc.msg (also at table of errors), with the value of each corresponding to that constant's value.components.returncodecomponents.stackcomponents.stack is a read only property of type nsistackframe (idl definition) that represents a snapshot of the current javascript callstack.
nsIContentSniffer
let charset = "iso-8859-1"; try { // this pref has been removed, see bug 910192 charset = services.prefs.getcomplexvalue("intl.charset.default", ci.nsipreflocalizedstring).data; } catch (e) { } let conv = cc["@mozilla.org/intl/scriptableunicodeconverter"] .createinstance(ci.nsiscriptableunicodeconverter); conv.charset = charset; try { let str = conv.convertfrombytearray(adata, alength); if (str.substring(0, 5) == "%pdf-") return "application/pdf"; // we detected a pdf file } catch (e) { // try to get information from arequest } ...
XPCOM Interface Reference
lproxyservicensiproxyinfonsipushmessagensipushservicensipushsubscriptionnsiradiointerfacelayernsirandomgeneratornsirequestnsirequestobservernsiresumablechannelnsirunnablensishentrynsishistorynsishistorylistenernsisockssocketinfonsisslerrorlistenernsisslsocketcontrolnsiscreennsiscreenmanagernsiscripterrornsiscripterror2nsiscriptableionsiscriptableinputstreamnsiscriptableunescapehtmlnsiscriptableunicodeconverternsiscrollablensisearchenginensisearchsubmissionnsisecuritycheckedcomponentnsiseekablestreamnsiselectionnsiselection2nsiselection3nsiselectioncontrollernsiselectionimageservicensiselectionprivatensiserversocketnsiserversocketlistenernsiservicemanagernsisessionstartupnsisessionstorensisimpleenumeratornsismsdatabaseservicensismsrequestmanagernsismsservicensisocketprovidernsisocketproviderserv...
XPCOM Interface Reference by grouping
cessiblehypertext nsiaccessibleimage nsiaccessibleprovider nsiaccessibleretrieval nsiaccessiblerole nsiaccessiblescrolltype nsiaccessibleselectable nsiaccessiblestates nsiaccessibletable nsiaccessibletext nsiaccessibletreecache nsiaccessiblevalue nsiaccessnode nsisyncmessagesender script nsiscriptableunescapehtml nsiscriptableunicodeconverter nsiscripterror nsiscripterror2 stylesheet nsistylesheetservice url nsiuri nsiurl util nsidomserializer nsidomxpathevaluator nsidomxpathexception nsidomxpathexpression nsidomxpathresult xslt nsixsltexception nsixsltprocessor download nsidownload nsidownloadmanager nsidownloadprogresslistener...
AudioConfiguration - Web APIs
properties the audioconfiguration dictionary is made up of four audio properties, including: contenttype: a valid audio mime type, for information on possible values and what they mean, see the web audio codec guide.
AudioContext.createMediaStreamDestination() - Web APIs
var blob = new blob(chunks, { 'type' : 'audio/ogg; codecs=opus' }); document.queryselector("audio").src = url.createobjecturl(blob); }; </script> </body> </html> note: you can view this example live, or study the source code, on github.
BasicCardResponse.cardSecurityCode - Web APIs
desktopmobilechromeedgefirefoxinternet exploreroperasafariandroid webviewchrome for androidfirefox for androidopera for androidsafari on iossamsung internetcardsecuritycodechrome no support noedge no support ≤18 — 79firefox full support 56notes disabled full support 56notes disabled notes available only in nightly builds.disabled from version 56: this feature is behind the dom.payments.request.enabled pr...
BasicCardResponse - Web APIs
samsung internet android full support 7.0cardsecuritycodechrome no support noedge no support ≤18 — 79firefox full support 56notes disabled full support 56notes disabled notes available only in nightly builds.disabled from version 56: this feature is behind the dom.payments.request.enabled pr...
DOMException.code - Web APIs
WebAPIDOMExceptioncode
desktopmobilechromeedgefirefoxinternet exploreroperasafariandroid webviewchrome for androidfirefox for androidopera for androidsafari on iossamsung internetcodechrome full support yesedge full support 12firefox full support 1ie ?
HTMLMediaElement - Web APIs
htmlmediaelement.canplaytype() given a string specifying a mime media type (potentially with the codecs parameter included), canplaytype() returns the string probably if the media should be playable, maybe if there's not enough information to determine whether the media will play or not, or an empty string if the media cannot be played.
MediaCapabilities.decodingInfo() - Web APIs
return value a promise fulfilling with a mediacapabilitiesinfo interface containing three boolean attributes: supported smooth powerefficient exceptions a typeerror is raised if the mediaconfiguration passed to the decodinginfo() method is invalid, either because the type is not video or audio, the contenttype is not a valid codec mime type, the media decoding configuration is not a valid value for the media decoding type, or any other error in the media configuration passed to the method, including omitting values required in the media decoding configuration.
MediaCapabilities - Web APIs
the api can be used to query the browser about the decoding abilities of the device based on codecs, profile, resolution, and bitrates.
MediaCapabilitiesInfo - Web APIs
all supported audio codecs are reported to be power efficient.
MediaConfiguration - Web APIs
example //create a video configuration to be tested const videodecoderconfig = { type : 'file', // 'record', 'transmission', or 'media-source' video : { contenttype : "video/webm;codecs=vp8", // valid content type width : 800, // width of the video height : 600, // height of the video bitrate : 10000, // number of bits used to encode 1s of video framerate : 30 // number of frames making up that 1s.
MediaDecodingConfiguration - Web APIs
examples //create media configuration to be tested const mediaconfig = { type : 'file', // or 'media-source' video : { contenttype : "video/webm;codecs=vp8", // valid content type width : 800, // width of the video height : 600, // height of the video bitrate : 10000, // number of bits used to encode 1s of video framerate : 30 // number of frames making up that 1s.
MediaEncodingConfiguration - Web APIs
examples //create media configuration to be tested const mediaconfig = { type : 'record', // or 'transmission' video : { contenttype : "video/webm;codecs=vp8", // valid content type width : 800, // width of the video height : 600, // height of the video bitrate : 10000, // number of bits used to encode 1s of video framerate : 30 // number of frames making up that 1s.
MediaRecorder: error event - Web APIs
the mediarecorder interface's error event is fired when an error occurs: for example because recording wasn't allowed or was attempted using an unsupported codec.
MediaRecorder.isTypeSupported - Web APIs
example var types = ["video/webm", "audio/webm", "video/webm\;codecs=vp8", "video/webm\;codecs=daala", "video/webm\;codecs=h264", "audio/webm\;codecs=opus", "video/mpeg"]; for (var i in types) { console.log( "is " + types[i] + " supported?
MediaRecorder.ondataavailable - Web APIs
var chunks = []; mediarecorder.onstop = function(e) { console.log("data available after mediarecorder.stop() called."); var audio = document.createelement('audio'); audio.controls = true; var blob = new blob(chunks, { 'type' : 'audio/ogg; codecs=opus' }); var audiourl = window.url.createobjecturl(blob); audio.src = audiourl; console.log("recorder stopped"); } mediarecorder.ondataavailable = function(e) { chunks.push(e.data); } ...
MediaRecorder.onerror - Web APIs
notsupportederror an attempt was made to instantiate a mediarecorder using a mime type that isn't supported on the user's device; one or more of the requested container, codecs, or profiles as well as other information may be invalid.
MediaRecorder.onstop - Web APIs
mediarecorder.onstop = function(e) { console.log("data available after mediarecorder.stop() called."); var audio = document.createelement('audio'); audio.controls = true; var blob = new blob(chunks, { 'type' : 'audio/ogg; codecs=opus' }); var audiourl = window.url.createobjecturl(blob); audio.src = audiourl; console.log("recorder stopped"); } mediarecorder.ondataavailable = function(e) { chunks.push(e.data); } ...
MediaSource.activeSourceBuffers - Web APIs
example the following snippet is based on a simple example written by nick desaulniers (view the full demo live, or download the source for further investigation.) function sourceopen (_) { //console.log(this.readystate); // open var mediasource = this; var sourcebuffer = mediasource.addsourcebuffer(mimecodec); fetchab(asseturl, function (buf) { sourcebuffer.addeventlistener('updateend', function (_) { mediasource.endofstream(); console.log(mediasource.activesourcebuffers); // will contain the source buffer that was added above, // as it is selected for playing in the video player video.play(); //console.log(mediasource.readystate); // ended }); source...
MediaSource.duration - Web APIs
their sourcebuffer.updating property is true.) example the following snippet is based on a simple example written by nick desaulniers (view the full demo live, or download the source for further investigation.) function sourceopen (_) { //console.log(this.readystate); // open var mediasource = this; var sourcebuffer = mediasource.addsourcebuffer(mimecodec); fetchab(asseturl, function (buf) { sourcebuffer.addeventlistener('updateend', function (_) { mediasource.endofstream(); mediasource.duration = 120; video.play(); //console.log(mediasource.readystate); // ended }); sourcebuffer.appendbuffer(buf); }); }; ...
MediaSource.removeSourceBuffer() - Web APIs
examples for (i = 0; i < 10; i++) { var sourcebuffer = mediasource.addsourcebuffer(mimecodec); } mediasource.removesourcebuffer(mediasource.sourcebuffers[0]); specifications specification status comment media source extensionsthe definition of 'removesourcebuffer()' in that specification.
MediaSource.sourceBuffers - Web APIs
example the following snippet is based on a simple example written by nick desaulniers (view the full demo live, or download the source for further investigation.) function sourceopen (_) { //console.log(this.readystate); // open var mediasource = this; var sourcebuffer = mediasource.addsourcebuffer(mimecodec); fetchab(asseturl, function (buf) { sourcebuffer.addeventlistener('updateend', function (_) { mediasource.endofstream(); console.log(mediasource.sourcebuffers); // will contain the source buffer that was added above video.play(); //console.log(mediasource.readystate); // ended }); sourcebuffer.appendbuffer(buf); }); }; ...
Using the MediaStream Recording API - Web APIs
document.createelement('button'); clipcontainer.classlist.add('clip'); audio.setattribute('controls', ''); deletebutton.innerhtml = "delete"; cliplabel.innerhtml = clipname; clipcontainer.appendchild(audio); clipcontainer.appendchild(cliplabel); clipcontainer.appendchild(deletebutton); soundclips.appendchild(clipcontainer); const blob = new blob(chunks, { 'type' : 'audio/ogg; codecs=opus' }); chunks = []; const audiourl = window.url.createobjecturl(blob); audio.src = audiourl; deletebutton.onclick = function(e) { let evttgt = e.target; evttgt.parentnode.parentnode.removechild(evttgt.parentnode); } } let's go through the above code and look at what's happening.
MediaStream Recording API - Web APIs
var stream = canvas.capturestream(25); var recordedchunks = []; console.log(stream); var options = { mimetype: "video/webm; codecs=vp9" }; mediarecorder = new mediarecorder(stream, options); mediarecorder.ondataavailable = handledataavailable; mediarecorder.start(); function handledataavailable(event) { console.log("data-available"); if (event.data.size > 0) { recordedchunks.push(event.data); console.log(recordedchunks); download(); } else { // ...
Navigator.requestMediaKeySystemAccess() - Web APIs
notsupportederror either the specified keysystem isn't supported by the platform or the browser, or none of the configurations specified by supportedconfigurations can be satisfied (if, for example, none of the codecs specified in contenttype are available).
RTCInboundRtpStreamStats.sliCount - Web APIs
this is a very technical part of how video codecs work.
RTCOfferAnswerOptions - Web APIs
properties voiceactivitydetection optional for configurations of systems and codecs that are able to detect when the user is speaking and toggle muting on and off automatically, this option enables and disables that behavior.
RTCOutboundRtpStreamStats.pliCount - Web APIs
this is often achieved by methods such as increasing the compression or lowering resolution, although the mechanisms available to reduce the bit rate of the stream vary from codec to codec.
RTCOutboundRtpStreamStats.qualityLimitationReason - Web APIs
the qualitylimitationreason property of the rtcoutboundrtpstreamstats dictionary is a string indicating the reason why the media quality in the stream is currently being reduced by the codec during encoding, or none if no quality reduction is being performed.
RTCOutboundRtpStreamStats.sliCount - Web APIs
this is a very technical part of how video codecs work.
RTCPeerConnection.createAnswer() - Web APIs
the answer contains information about any media already attached to the session, codecs and options supported by the browser, and any ice candidates already gathered.
RTCPeerConnection - Web APIs
the answer contains information about any media already attached to the session, codecs and options supported by the browser, and any ice candidates already gathered.
RTCRtpParameters - Web APIs
to obtain the parameters of a sender or receiver, call its getparameters() method: getparameters() getparameters() properties codecs an array of rtcrtpcodecparameters objects describing the set of codecs from which the sender or receiver will choose.
RTCRtpSendParameters - Web APIs
encodings an array of rtcrtpencodingparameters objects, each specifying the parameters for a single codec that could be used to encode the track's media.
RTCRtpStreamStats.kind - Web APIs
it will also match the statistics object's rtccodecstats.codec property's media type.
RTCRtpTransceiver - Web APIs
methods setcodecpreferences() a list of rtcrtpcodecparameters objects which override the default preferences used by the user agent for the transceiver's codecs.
RTCStatsReport - Web APIs
codec an rtccodecstats object containing statistics about a codec currently being used by rtp streams to send or receive data for the rtcpeerconnection.
RTCStatsType - Web APIs
codec an rtccodecstats object containing statistics about a codec currently being used by rtp streams to send or receive data for the rtcpeerconnection.
Introduction to WebRTC protocols - Web APIs
sdp session description protocol (sdp) is a standard for describing the multimedia content of the connection such as resolution, formats, codecs, encryption, etc.
Web APIs
WebAPI
le rtciceserver rtcicetcpcandidatetype rtcicetransport rtcicetransportstate rtcidentityassertion rtcidentityerrorevent rtcidentityevent rtcinboundrtpstreamstats rtcnetworktype rtcofferansweroptions rtcofferoptions rtcoutboundrtpstreamstats rtcpeerconnection rtcpeerconnectioniceerrorevent rtcpeerconnectioniceevent rtcremoteoutboundrtpstreamstats rtcrtcpparameters rtcrtpcapabilities rtcrtpcodeccapability rtcrtpcodecparameters rtcrtpcontributingsource rtcrtpencodingparameters rtcrtpparameters rtcrtpreceiveparameters rtcrtpreceiver rtcrtpsendparameters rtcrtpsender rtcrtpstreamstats rtcrtpsynchronizationsource rtcrtptransceiver rtcrtptransceiverdirection rtcrtptransceiverinit rtcsctptransport rtcsessiondescription rtcsessiondescriptioncallback rtcstats rtcstatsicecandidatepairstate ...
Audio and Video Delivery - Developer guides
consider this html: <video> <source id="mp4_src" src="video.mp4" type='video/mp4; codecs="avc1.42e01e, mp4a.40.2"'> </source> <source id="3gp_src" src="video.3gp" type='video/3gpp; codecs="mp4v.20.8, samr"'> </source> <source id="ogg_src" src="video.ogv" type='video/ogv; codecs="theora, vorbis"'> </source> </video> since firefox doesn't support mp4 and 3gp on some platforms due to their patent-encumbered nature, the <source> elements with the ids "mp4_src" and "3gp_src" wil...
DASH Adaptive Streaming for HTML 5 Video - HTML: Hypertext Markup Language
for example: the file in.video can be any container with at least one audio and one video stream that can be decoded by ffmpeg, create the audio using: ffmpeg -i in.video -vn -acodec libvorbis -ab 128k -dash 1 my_audio.webm create each video variant.
<source>: The Media or Image Source element - HTML: Hypertext Markup Language
WebHTMLElementsource
type the mime media type of the resource, optionally with a codecs parameter.
Configuring servers for Ogg media - HTTP
for apache, you can add the following to your configuration: addtype audio/ogg .oga addtype video/ogg .ogv addtype application/ogg .ogg you can find specific information about possible media file types and the codecs used within them in our comprehensive guide to media types and formats on the web.
Image file type and format guide - Web media technologies
webp image webp supports lossy compression via predictive coding based on the vp8 video codec, and lossless compression that uses substitutions for repeating data.
Handling media support issues in web content - Web media technologies
there is a drawback, however: because there are so many to choose from, with so many different kinds of licenses and design principles involved, each web browser developer is left to its own devices when deciding which media file types and codecs to support.
Compiling an Existing C Module to WebAssembly - WebAssembly
the source for the webp codec is written in c and available on github as well as some extensive api documentation.