FS#65940 - [ffmpeg] 1:4.2.2-3 : video and audio unsynchronized

Attached to Project: Arch Linux
Opened by Thomas Bucaioni (Thomasb) - Sunday, 22 March 2020, 22:02 GMT
Last edited by Maxime Gauduin (Alucryd) - Monday, 23 March 2020, 09:59 GMT
Task Type Bug Report
Category Packages: Extra
Status Closed
Assigned To Maxime Gauduin (Alucryd)
Architecture x86_64
Severity High
Priority Normal
Reported Version
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 0
Private No

Details

Description:
The command
ffmpeg -f v4l2 -video_size 640x480 -i /dev/video0 -f alsa -i default -c:v libx264 -preset ultrafast -c:a aac webcam.mp4
gives a video with a lag between sound and image.

Additional info:
* package : 1:4.2.2-3

Steps to reproduce:

~.~.~.~.~
$ ffmpeg -f v4l2 -video_size 640x480 -i /dev/video0 -f alsa -i default -c:v libx264 -preset ultrafast -c:a aac webcam.mp4

$ mpv webcam.mp4
~.~.~.~.~
This task depends upon

Closed by  Maxime Gauduin (Alucryd)
Monday, 23 March 2020, 09:59 GMT
Reason for closing:  Upstream
Comment by Maxime Gauduin (Alucryd) - Monday, 23 March 2020, 08:42 GMT
Can you please open an issue upstream? I doubt this is a packaging issue.
Comment by Thomas Bucaioni (Thomasb) - Monday, 23 March 2020, 08:45 GMT
Other softwares have an issue: cheese, zart and kamoso. So it could come from the same origin...
Comment by Maxime Gauduin (Alucryd) - Monday, 23 March 2020, 08:48 GMT
So that's definitely not an issue with ffmpeg (chesse for instance uses gstreamer). That's likely a driver issue or a hardware issue, you may want to open an issue on the kernel bugtracker then. I won't be able to help with this.
Comment by Thomas Bucaioni (Thomasb) - Monday, 23 March 2020, 08:50 GMT
Sure, what should I do ?
Comment by Maxime Gauduin (Alucryd) - Monday, 23 March 2020, 08:56 GMT
Here's how to report a bug: https://www.kernel.org/doc/html/v4.10/admin-guide/reporting-bugs.html

Here's an example of a past V4L2 bug: https://bugzilla.kernel.org/show_bug.cgi?id=199575

Would be nice if you could point them to a last working kernel, if any.
Comment by Thomas Bucaioni (Thomasb) - Monday, 23 March 2020, 09:02 GMT
Last week kernel used to work with cheese, so it should do. Many thanks
Comment by Thomas Bucaioni (Thomasb) - Monday, 23 March 2020, 09:17 GMT
Here: https://bugzilla.kernel.org/show_bug.cgi?id=206925
Comment by Maxime Gauduin (Alucryd) - Monday, 23 March 2020, 09:58 GMT
Thanks!

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