All MIME types supported by MediaRecorder in Firefox and Chrome?

Question

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.

Answer 1

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)

Answer 2

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

Answer 3

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.