1708123 - Confusing error message when recording audio with unrecognized media type

Status: RESOLVED FIXED

(Core :: Audio/Video: Recording, defect)

Description

[Dominique Hazaël-Massieux]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:90.0) Gecko/20100101 Firefox/90.0

Steps to reproduce:

Quoting from https://github.com/mdn/content/issues/3317#issue-836807601, the following code
navigator.mediaDevices.getUserMedia({audio: true}).then((stream) => {

var mediaRecorder = new MediaRecorder(stream, {mimeType: 'audio/mp4'});

mediaRecorder.ondataavailable = function(event) {
    var blob = event.data;
    if (blob && blob.size > 0) {
        sendBlobToServer(blob);
    }
};

mediaRecorder.start(5000);

})

Actual results:

It raises an error saying "Video cannot be recorded with audio/mp4 as it is an audio type" (from https://github.com/mozilla/gecko-dev/blob/be413c29deeb86be6cdac22445e0d0b035cb9e04/dom/media/MediaRecorder.cpp#L225)

Expected results:

The problem is actually that audio/mp4 is not accepted by Firefox as a coded for MediaRecorder, since replacing "audio/mp4" with "audio/webm" works.

The error message should be fixed in that situation to say that audio/mp4 is not available to record audio.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::Audio/Video: Recording' component, and is moving the bug to that component. Please revert this change in case you think the bot is wrong.

Comment 2

[Karl Tomlinson (:karlt)]

Guessing this is during MediaRecorder construction and comes from IsTypeSupportedImpl(), which may be able to do a better job of merging the two TypeSupports.

Comment 3

[Karl Tomlinson (:karlt)]

https://hg.mozilla.org/try/rev/3f527010eebbb50a1c0638f5ef91ebfa35e36ddc

Comment 4

[Karl Tomlinson (:karlt)]

Attachment: Bug 1708123 choose the better message on lack of MIME type support in MediaRecorder constructor r?jib

Comment 5

[Karl Tomlinson (:karlt)]

Attachment: Bug 1708123 test MediaRecorder constructor error messages r?jib

Depends on D113916

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/0ba3efcd5023
choose the better message on lack of MIME type support in MediaRecorder constructor r=jib
https://hg.mozilla.org/integration/autoland/rev/3a418c38c3e4
test MediaRecorder constructor error messages r=jib

Comment 7

[Iulian Moraru]

https://hg.mozilla.org/mozilla-central/rev/0ba3efcd5023
https://hg.mozilla.org/mozilla-central/rev/3a418c38c3e4