Audio capture not working with video/audio cap in VLC 2.1.0

[tand]

When using vlc 2.0.0 - 2.1.0 (git repo) with USB video/audio capture devices (em28xx-based), sound is not working.
The same setup works with vlc 1.1.12.
When testing with a video file, the sound works for both 1.1.12 and 2.1.0.
The test configuration is using /dev/video0 for video and hw:2,0 for audio.
The distribution is Xubuntu 11.10.
Is this a known problem or should I create a ticket?
Any workarounds or changes that could be applied?

[Rémi Denis-Courmont]

vlc.git works fine here. There is a known bug in PulseAudio input in 2.0.0/2.0.1, but that should not affect ALSA.

Maybe you need to increase live-caching.

[tand]

Tested with different values for live-caching; 300, 1000, 10000, with no effect.
An observation is that sound works when vlc 2.1.0 is installed on top of 1.1.12, but disappears after reboot.
Some kind of changed setup?

[Rémi Denis-Courmont]

I don't know. I have not looked at the ALSA input due to lack of motivation. The PulseAudio input in VLC 2.0.2+ works better for me.

[tand]

Some tests performed on VLC media player 2.1.0-git Rincewind (revision 2.1.0~~git20120324+r1286).
Pulse audio works standalone:

Code: Select all

vlc pulse://alsa_input.usb-TerraTec_Electronic_GmbH_TerraTec_Grabby-01-Grabby.analog-stereo

Alsa audio also works:

Code: Select all

vlc alsa://hw:2,0

Video capture without sound also works:

Code: Select all

vlc v4l2:///dev/video0:standard=PAL

However, when trying to combine v4l2 and pulse, no sound is heard and the video is stuttering.

Code: Select all

vlc v4l2:///dev/video0:standard=PAL --input-slave=pulse://alsa_input.usb-TerraTec_Electronic_GmbH_TerraTec_Grabby-01-Grabby.analog-stereo

Do I use the wrong arguments for input-slave or is this problem related to ticket #5068 (V4L2 and ALSA capture do not synch)?
Changing live-caching does not seem to help either.
Also tested yesterday on a freshly built checkout from git (needed to revert commit 4c16bb9f49017f115675cbba8c6874db05955573 in order to build). The result was actually worse as I got a blue-tinted video and no sound. Might be some v4l2-header mismatch, though

[Rémi Denis-Courmont]

Looks correct. Works fine here; cannot reproduce. Patch welcome.

[tand]

@Rémi
May I ask, which Linux distribution do you run?

[Rémi Denis-Courmont]

That would be Debian Sid. But I believe the bug depends on the kernel drivers and the actual hardware rather than the distribution.

[tand]

Additional feedback; Hauppage USB-Live 2 works out of the box with Xubuntu 12-04 Beta 2 and VLC 2.0.2 Twoflower (revision 2.0.1+git20120404+r151).
Sound does not work on Terratec Grabby and Dazzle DVC100.
Also tested on VLC media player 2.1.0-git Rincewind (revision 2.1.0~~git20120401+r1309) with the same result.

[Rémi Denis-Courmont]

As I said, I cannot reproduce your problem with my hardware. You are going to need to investigate this yourself, I cannot help you at this stage.

[tand]

I will use the working interface at the moment and commence with further troubleshooting on the other interfaces if needed.