All MIME types supported by MediaRecorder in Firefox and Chrome?

Where can I find a list of all MIME types that are supported by Firefox or Chrome? All examples I've seen so far using video/webm only.

I've not seen any sort of comprehensive list yet for Firefox but I have managed to find something (via a post on the MediaRecorder API from Google's web updates section) that links to this test set that seems to shed some light on things.

Essentially, it looks like the following are (at time of writing) accepted MIME types for video/audio in Chrome:

• video/webm

• video/webm;codecs=vp8

• video/webm;codecs=vp9

• video/webm;codecs=vp8.0

• video/webm;codecs=vp9.0

• video/webm;codecs=h264

• video/webm;codecs=H264

• video/webm;codecs=avc1

• video/webm;codecs=vp8,opus

• video/WEBM;codecs=VP8,OPUS

• video/webm;codecs=vp9,opus

• video/webm;codecs=vp8,vp9,opus

• video/webm;codecs=h264,opus

• video/webm;codecs=h264,vp9,opus

• video/x-matroska;codecs=avc1

• audio/webm

• audio/webm;codecs=opus

(EDITED 2019-02-10: Updated to include brianchirls' link find)

I made this small function in my utils.js to get the best supported codec, with support for multiple possible naming variations (example : firefox support video/webm;codecs:vp9 but not video/webm;codecs=vp9)

You can reorder videoTypes, audioTypes and codecs arrays by priority, depending on your needs, so you'll always fall on the next supported type.

EDIT: Add support for audio, fixed mimetype duplicates

function getSupportedMimeTypes(media, types, codecs) {
  const isSupported = MediaRecorder.isTypeSupported;
  const supported = [];
  types.forEach((type) => {
    const mimeType = `${media}/${type}`;
    codecs.forEach((codec) => [
      	`${mimeType};codecs=${codec}`,
        `${mimeType};codecs=${codec.toUpperCase()}`,
        // /!\ false positive /!\
        // `${mimeType};codecs:${codec}`,
        // `${mimeType};codecs:${codec.toUpperCase()}` 
      ].forEach(variation => {
      	if(isSupported(variation)) 
        	supported.push(variation);
    }));
    if (isSupported(mimeType))
      supported.push(mimeType);
  });
  return supported;
};

// Usage ------------------

const videoTypes = ["webm", "ogg", "mp4", "x-matroska"];
const audioTypes = ["webm", "ogg", "mp3", "x-matroska"];
const codecs = ["should-not-be-supported","vp9", "vp9.0", "vp8", "vp8.0", "avc1", "av1", "h265", "h.265", "h264", "h.264", "opus", "pcm", "aac", "mpeg", "mp4a"];

const supportedVideos = getSupportedMimeTypes("video", videoTypes, codecs);
const supportedAudios = getSupportedMimeTypes("audio", audioTypes, codecs);

console.log('-- Top supported Video : ', supportedVideos[0])
console.log('-- Top supported Audio : ', supportedAudios[0])
console.log('-- All supported Videos : ', supportedVideos)
console.log('-- All supported Audios : ', supportedAudios)

For Firefox, the accepted mimetypes can be found in MediaRecorder.cpp and confirmed using MediaRecorder.isTypeSupported(...)

Example:

21:31:27.189 MediaRecorder.isTypeSupported('video/webm;codecs=vp8')
21:31:27.135 true
21:31:41.598 MediaRecorder.isTypeSupported('video/webm;codecs=vp8.0')
21:31:41.544 true
21:32:10.477 MediaRecorder.isTypeSupported('video/webm;codecs=vp9')
21:32:10.431 false
21:31:50.534 MediaRecorder.isTypeSupported('audio/ogg;codecs=opus')
21:31:50.479 true
21:31:59.198 MediaRecorder.isTypeSupported('audio/webm')
21:31:59.143 false

MediaRecorder support for common audio codecs:

MediaRecorder.isTypeSupported('audio/webm;codecs=opus'); // true on chrome, true on firefox => SO OPUS IT IS!
MediaRecorder.isTypeSupported('audio/ogg;codecs=opus'); // false on chrome, true on firefox
MediaRecorder.isTypeSupported('audio/webm;codecs=vorbis'); // false on chrome, false on firefox
MediaRecorder.isTypeSupported('audio/ogg;codecs=vorbis'); // false on chrome, false on firefox

> Firefox used Vorbis for audio recording in the 1st implementations but it > moved to Opus since.

So OPUS it is!

---

This may prove of interest:

• MediaRecorder is currently experimental on Safari (August 2020.)
• caniuse Opus
• caniuse MediaRecorder

Sorry, can't add comments; but thought it important to note: Implementation of recording raw samples via ScriptProcessor or audioWorklet is flawed for a number of reasons, one here - mainly because it connects you to an output node, and clock 'correction' happens before you see the data.

So lack of audio/wav or other raw format really kills.

But just maybe.... seems 'audio/webm;codecs=pcm' is supported in chrome.

Based on @MillenniumFennec's answer (+ audio + removing duplicates + some other improvements):

function getAllSupportedMimeTypes(...mediaTypes) { if (!mediaTypes.length) mediaTypes.push(...['video', 'audio']) const FILE_EXTENSIONS = ['webm', 'ogg', 'mp4', 'x-matroska'] const CODECS = ['vp9', 'vp9.0', 'vp8', 'vp8.0', 'avc1', 'av1', 'h265', 'h.265', 'h264', 'h.264', 'opus']

return [...new Set( FILE_EXTENSIONS.flatMap(ext => CODECS.flatMap(codec => mediaTypes.flatMap(mediaType => [ ${mediaType}/${ext};codecs:${codec}, ${mediaType}/${ext};codecs=${codec}, ${mediaType}/${ext};codecs:${codec.toUpperCase()}, ${mediaType}/${ext};codecs=${codec.toUpperCase()}, ${mediaType}/${ext}, ]), ), ), )].filter(variation => MediaRecorder.isTypeSupported(variation)) }

console.log(getAllSupportedMimeTypes('video', 'audio'))

ISTYPESUPPORTED

Building on the previous answers (thanks @Fennec), I have created a jsfiddle to list all the supported types: https://jsfiddle.net/luiru72/rfhLcu26/5/. I also added a non-existent codec ("notatall").

Among the results of this script, if you call it from Firefox, you will find:

video/webm;codecs:vp9.0
video/webm;codecs=vp8
video/webm;codecs:vp8
video/webm;codecs:notatall

Note that you will not find "video/webm;codecs=vp9.0", and you will not find "video/webm;codecs=notatall" either.

This is because isTypeSupported on Firefox is able to understand the request "video/webm;codecs=vp9.0" or "video/webm;codecs=notatall" and it responds that it is not supported; but it is not able to understand the request "video/webm;codecs:vp9.0" or "video/webm;codecs:notatall", so isTypeSupported on Firefox (as of version 92.0, 2021-09-14) responds that it is supported.

MEDIARECORDER

I have created another jsfiddle to experiment with MediaRecorder: https://jsfiddle.net/luiru72/b9q4nsdv/42/

If you try to create a MediaRecorder on Firefox using the wrong syntax "video/webm;codecs:vp9,opus" or "video/webm;codecs:notatall,opus", you do not get an error, you just get a video encoded in VP8 and Opus. If you open the file using a tool like MediaInfo https://sourceforge.net/projects/mediainfo/, you realize that it is encoded in VP8,Opus.

If you specify "video/webm;codecs=vp8", you get an error because vp8 cannot encode audio. You need to specify both: "video/webm;codecs=vp8,opus", or you can just rely on defaults, specifying only the container format "video/webm". In this way, you now get the file encoded in VP8,Opus, but the actual video and audio encoder defaults could change over time, so if you want to be sure that VP8 and Opus are used, you need to specify them.

Key take away points:

1. you should use the syntax: video/webm;codecs=vp8, not video/webm;codecs:vp8

2. when creating a MediaRecorder, you should take extra-care: for example, on Firefox, video/webm;codecs=vp8 is supported, but when creating a MediaRecorder you should use "video/webm" or "video/webm;codecs=vp8,opus

3. if you specify an incorrect syntax, for example video/webm;codecs:vp9,opus in Firefox, you do not get an error, you just get a file that is encoded in VP8,opus. You only realize that it is in a different format from the one intended if you open it with a program like MediaInfo that is able to show you the codecs that have been used

I found a solution today which involves using var canRecordVp9 = MediaRecorder.isTypeSupported('video/webm;codecs=vp9');

to differentiate between Chrome(and Opera) and Firefox, and then do if (canRecordVp9) { mediaRecorder = new MediaRecorder(stream, {mimeType : 'video/webm;codecs=vp9'}); } else { mediaRecorder = new MediaRecorder(stream); }

to construct the MediaRecorder accordingly.

Then, when grabbing the blob: if (canRecordVp9) { blob = new Blob([myArrayBuffer], { "type" : "video/webm;codecs=vp9" }); } else { blob = new Blob([myArrayBuffer], { "type" : "video/webm" }); }

and finally, use the FileReader to get the blob as a dataUrl: `

var reader = new FileReader();
reader.onload = function(event)
{
    var blobDataUrl = event.target.result;
}
reader.readAsDataURL(blob);`

I then save the blobDataUrl as a webm file, and videos recorded in Chrome work fine in Firefox, and vice-versa.