1100210 - video mp4 file incorrectly assumed to be h264/aac when it's h264/mp3

Status: VERIFIED FIXED

(Core :: Audio/Video, defect)

Description

[Jean-Yves Avenard [:jya]]

Here is an example of mp4 file with h264 and mp3 audio:

http://download.wavetlan.com/SVV/Media/HTTP/MP4/ConvertedFiles/MediaCoder/MediaCoder_test1_1m9s_AVC_VBR_256kbps_640x480_24fps_MPEG2Layer3_CBR_160kbps_Stereo_22050Hz.mp4

MP4Reader pass the mime-type "audio/mp4a-latm" to the audio MediaDataDecoder
this causes errors later, and as such file plays with no audio.

Comment 1

[Jean-Yves Avenard [:jya]]

While searching something else, I found this interesting post:
http://stackoverflow.com/questions/3987850/mp4-atom-how-to-discriminate-the-audio-codec-is-it-aac-or-mp3?rq=1

We should determine the type of codec using the first byte of content of the esds atom: the objectTypeIndication

Comment 2

[Jean-Yves Avenard [:jya]]

Attachment: Mark MPEG2 Layer 1,2,3 audio as MP3

mark mpeg2 L1,L2,L3 as audio/mpeg mimetype

Comment 3

[Jean-Yves Avenard [:jya]]

remote:   https://hg.mozilla.org/integration/mozilla-inbound/rev/0d271a1f28a0

Comment 4

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/0d271a1f28a0

Comment 5

[Jean-Yves Avenard [:jya]]

marking for uplift approval, allows to play some files we wouldn't have before

Comment 6

[Ralph Giles (:rillian)]

Comment on attachment 8577700 [details] [diff] [review]
Mark MPEG2 Layer 1,2,3 audio as MP3

Nominating for 38, since this small change improves our playback coverage.

Approval Request Comment
[Feature/regressing bug #]: Video playback
[User impact if declined]: mp4 files with mp3 audio (instead of more common aac) won't play.
[Describe test coverage new/current, TreeHerder]: Landed on m-c, now aurora, some time ago.
[Risks and why]: The main risk that that we will try to play such files and fail, instead of skipping the audio tracks outright. However, our normal decoders handle mp3, so I think the risk of that is low, and such files aren't common to begin with. It's a one-line change and easy to trace and revert in the case of problems.
[String/UUID change made/needed]: None.

Comment 7

[Sylvestre Ledru [:Sylvestre]]

Comment on attachment 8577700 [details] [diff] [review]
Mark MPEG2 Layer 1,2,3 audio as MP3

Should be in 38 beta 3

Comment 8

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-beta/rev/a72d76b284ea

Comment 9

[Petruta Horea [:phorea], Desktop QA]

Reproduced on Nightly 2014-11-16 under Win 7 64-bit.
Verified as fixed using Firefox 38 beta 4 and Developer Edition 39.0a2 2015-04-14, Win 7 64-bit.