1914570 - smleaks.com - Audio is distorted

Status: RESOLVED FIXED

(Core :: Audio/Video: Playback, defect, P3)

Description

[Raul Bucata]

Environment:
Operating system: Linux
Firefox version: Firefox 130.0

Steps to reproduce:

1. Navigate to: https://smleaks.com
2. Click on "Next Play audio" button
3. Play an audio from the newly opened page and observe

Expected Behavior:
Audio plays as expected

Actual Behavior:
Audio is very distorted

Notes:

• Reproduces regardless of the status of ETP
• Reproduces in Firefox Nightly, and Firefox Release
• Does not reproduce in Chrome

Created from https://github.com/webcompat/web-bugs/issues/140651

Comment 1

[Liam England]

NI?ing for this audio issue, should probably be moved to Core :: Audio/Video: Playback also. Fiddle link: https://jsfiddle.net/e6dkqguj/

Comment 2

[Paul Adenot (:padenot)]

Attachment: Bug 1914570 - Print the mimetype when logging an AudioInfo. r?#media-playback-reviewers

Comment 3

[Paul Adenot (:padenot)]

Attachment: Bug 1914570 - Use the SubFormat field to determine sample format when the format code is WAVE_FORMAT_EXTENSIBLE. r?#media-playback-reviewers

This refactors the method that fetches the layout from the same struct, and uses
it to fetch the SubFormat (that comes after the layout).

Spec: https://www.mmsp.ece.mcgill.ca/Documents/AudioFormats/WAVE/WAVE.html

but it's clearer here:
https://learn.microsoft.com/fr-fr/previous-versions/dd757713(v=vs.85)
https://learn.microsoft.com/fr-fr/windows/win32/api/mmreg/ns-mmreg-waveformatextensible?redirectedfrom=MSDN

The first two bytes of the SubFormast (that is a GUID) is the format we're
looking for.

Comment 4

[Paul Adenot (:padenot)]

Attachment: Bug 1914570 - Test pcm f32 decoding when the demuxer is used. r?#media-playback-reviewers

Web Audio API allows exercising the demuxer (unlike the Web Codecs API). I opted
to compare the audio instead of the files because there's various ways to make
valid RIFF files, and the existing method would compare byte per byte, and the
headers could be different.

Comparing the audio works well here.

Files generated like so:

sox -n -c 8 -r 48000 sine.wav synth 0.1 sine 480
ffmpeg -i sine.wav -c:a pcm_s16le 8ch-s16.wav
ffmpeg -i sine.wav -c:a pcm_f32le 8ch-f32le.wav

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/adbcf85fdaad
Print the mimetype when logging an AudioInfo. r=media-playback-reviewers,karlt
https://hg.mozilla.org/integration/autoland/rev/86f6571b3872
Use the SubFormat field to determine sample format when the format code is WAVE_FORMAT_EXTENSIBLE. r=media-playback-reviewers,karlt
https://hg.mozilla.org/integration/autoland/rev/585aec33c0aa
Test pcm f32 decoding when the demuxer is used. r=media-playback-reviewers,karlt

Comment 6

[Cristian Tuns]

https://hg.mozilla.org/mozilla-central/rev/adbcf85fdaad
https://hg.mozilla.org/mozilla-central/rev/86f6571b3872
https://hg.mozilla.org/mozilla-central/rev/585aec33c0aa