1624548 - video.playbackRate no long has any effect if sound effect apply to video

Status: RESOLVED DUPLICATE of bug 1517199

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

Description

[abc]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:74.0) Gecko/20100101 Firefox/74.0

Steps to reproduce:

1. open https://www.bilibili.com/video/BV1GE411N7ss on firefox
2. right click on video area and click 音效调节(sound effect) contextmenu
3. select 超重低音(Bass Booster) button and close panel
4. click video area to play video
5. right click on video area and select 播放速度(playbackRate)>2.0 button

Actual results:

video playbackRate is 1x(normal) although video.playbackRate = 2

Expected results:

video playbackRate should be 2x

Chrome works fine.

Comment 1

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

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

Comment 2

[Alastor Wu [:alwu]]

I can reproduce this issue, will check.

Comment 3

[Alastor Wu [:alwu]]

During the mode of applying the sound effect, we would use DecodedStream as the media sink, which didn't apply the playback rate change on the media stream. [1]

[1] https://searchfox.org/mozilla-central/rev/b712398b7fae54ef377a558d6f16dede7a7f8530/dom/media/mediasink/DecodedStream.cpp#575

---

Paul,
Any idea how to fix this one? If the fix is not too difficult then I would like to give it a try. I've tried to modify the rate [2] by multiplying playback rate on it, but that didn't work. (I assume that the rate controls how many audio samples we send to the MediaTrackGraph, and if we have higher playback rate, we have to send more audio samples to the graph)

Thank you.

[2] https://searchfox.org/mozilla-central/rev/b712398b7fae54ef377a558d6f16dede7a7f8530/dom/media/mediasink/DecodedStream.cpp#648

Comment 4

[Paul Adenot (:padenot)]

Alastor, this is not very hard to fix, but also not trivial, we can discuss on the main bug. I'd be happy to see this fixed.