1900972 - Audio has started playing at a slow speed with mono output (accessibility.monoaudio.enable)

Status: VERIFIED FIXED

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

Description

[Kestrel]

STR:

1. Set accessibility.monoaudio.enable = true on Ubuntu 24.04.
2. Play a youtube video.

Audio is played slowly with low pitch, sounds like half speed.

Regression window:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=5e6f6e0723be0759e720d417dd4e2de7817f42d5&tochange=fb10bab6cd18b43ae0bd2ef55de94b9c9db3a3a3

Regressed by Bug 1889978.

Comment 1

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

:padenot, since you are the author of the regressor, bug 1889978, could you take a look? Also, could you set the severity field?

For more information, please visit BugBot documentation.

Comment 2

[Haik Aftandilian [:haik]]

[Tracking Requested - why for this release]: Per Paul, we should consider this for an uplift. accessibility.monoaudio.enable is disabled by default, but may be manually set for accessibility reasons and the fix is likely to be small and low risk.

Comment 3

[Pascal Chevrel:pascalc]

We could take a fix in the planned dot release.

Comment 4

[Paul Adenot (:padenot)]

Attachment: Bug 1900972 - Properly pass the channel map instead of the channel count in FFmpegAudioDecoder.cpp. r?#media-playback-reviewers

Comment 5

[Paul Adenot (:padenot)]

Fix is absolutely trivial indeed, clearly something we can take in release. It's unfortunately not the easiest thing to test since we're not well setup to test audio output in CI.

Comment 6

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

Set release status flags based on info from the regressing bug 1889978

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/mozilla-central/rev/95aeb046465a
Properly pass the channel map instead of the channel count in FFmpegAudioDecoder.cpp. r=pehrsons

Comment 8

[Iulian Moraru]

https://hg.mozilla.org/mozilla-central/rev/95aeb046465a

Comment 9

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

The patch landed in nightly and beta is affected.
:padenot, is this bug important enough to require an uplift?

• If yes, please nominate the patch for beta approval.
• If no, please set status-firefox128 to wontfix.

For more information, please visit BugBot documentation.

Comment 10

[Paul Adenot (:padenot)]

Comment on attachment 9406409 [details]
Bug 1900972 - Properly pass the channel map instead of the channel count in FFmpegAudioDecoder.cpp. r?#media-playback-reviewers

Beta/Release Uplift Approval Request

• User impact if declined: An accessibility feature (accessibility.monoaudio.enable, that forces mono playback for all audio) is broken. It's unfortunately hard to write a test for this, but the patch is absolutely trivial.
• Is this code covered by automated tests?: No
• Has the fix been verified in Nightly?: Yes
• Needs manual test from QE?: Yes
• If yes, steps to reproduce: Flip the pref: accessibility.monoaudio.enable, check the audio is the same pitch / speed as without the pref flipped (but it shouldn't be stereo anymore).
• List of other uplifts needed: non
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): We're simply incorrectly specifying a value related to channel layout, there's no risk.
• String changes made/needed: none
• Is Android affected?: Yes

Comment 11

[Ryan VanderMeulen [:RyanVM]]

Comment on attachment 9406409 [details]
Bug 1900972 - Properly pass the channel map instead of the channel count in FFmpegAudioDecoder.cpp. r?#media-playback-reviewers

Approved for 128.0b3.

Comment 12

[Pulsebot]

https://hg.mozilla.org/releases/mozilla-beta/rev/dd1b7a293c20

Comment 13

[Ciprian Georgiu, Desktop QA]

I've reproduced this issue using an affected Nightly build from 2024-06-06, on macOS 14.

The issue is verified as fixed on latest Nightly 129.0a1 and Beta 128.0b3 (treeherder build) running macOS 14, Ubuntu 20.04 and Win 11.

Comment 15

[Pascal Chevrel:pascalc]

Comment on attachment 9406409 [details]
Bug 1900972 - Properly pass the channel map instead of the channel count in FFmpegAudioDecoder.cpp. r?#media-playback-reviewers

Approved for 127.0.1, thanks.

Comment 16

[Pulsebot]

https://hg.mozilla.org/releases/mozilla-release/rev/c0a044c12ab7

Comment 17

[Peter Magyari (Desktop QA)]

Verified fixed using Firefox 127.0.1 (20240617164919) on MacOS 14, Windows 10 and Ubuntu 24.04.