1156524 - Videos with Opus audio go out of sync

Status: RESOLVED INVALID

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

Description

[M8R-p7]

Attachment: signpost_vp9+opus.webm

Since the 2015-04-17 Nightly (40a1) and 2015-04-18 Dev Edition (Aurora 39a2) videos with Opus audio tracks go out of sync.

STR:

1. Record or obtain a video with clear visual cues for its audio.
2. Convert the video to a <video>-supported format. I used today's ffmpeg build with this command: `ffmpeg -i video.avi -c:v libvpx-vp9 -c:a opus output.webm` - my output is attached.
3. Play the video in a recent Firefox build, on a fresh profile.

Expected Results:

The video and audio should remain as in-sync in Firefox as it does in other browsers and media players.

Actual Results:

Firefox plays the video too slowly and so does not keep pace with the audio. Videos with audio tracks in other codecs, such as Vorbis, play correctly. Seeking will re-sync the audio and video, but drift will continue.

Comment 1

[Loic]

I'm not able to reproduce the issue with the current Nightly and the webm you attached.

Comment 2

[M8R-p7]

It happens on both of my Win7 x64 machines (laptop, desktop), in both x86 and x64 builds. Both machines have AMD-based graphics- I can post my about:support and hardwares if that's likely to be helpful.

It also happening in 38 Beta6 (but not Beta5) - is there a chance it's related to bug1136360 ? I see it's to do with AV sync, and was uplifted on the 17th.

Comment 3

[M8R-p7]

This went away for me when bug1136360 was backed out, and has not been reintroduced when it re-landed. I'm guessing that makes this RESOLVED INVALID, but please correct as necessary.