[MEncoder-users] USB audio problems

[Tushar Bhatnagar]

Hello everybody,

I'm having a little problem with mencoder.  I have an Osprey 100 video
capture card and it works perfectly fine on my Dell with its
integrated sound built-in to the motherboard.  I use the following
command:
mencoder tv:// -o encoded.avi -ovc lavc -oac pcm \
-lavcopts vcodec=msmpeg4v2:vbitrate=1800:autoaspect=1 \
-tv driver=v4l2:input=3:width=768:height=480:norm=ntsc:device=/dev/video0:forceaudio:adevice=/dev/dsp:amode=1

The above command works perfectly - capturing video and audio.  I got
a new computer that did not come with integrated sound on the
motherboard.  So when testing the video capture card without sound I
used this command:
mencoder tv:// -o encoded.avi -ovc lavc -oac pcm \
-lavcopts vcodec=msmpeg4v2:vbitrate=1800:autoaspect=1 \
-tv driver=v4l2:input=3:width=768:height=480:norm=ntsc:device=/dev/video0:noaudio
Basically the same as above, but with the 'noaudio' option set for tv
so that it didn't look for a nonexistent audio device, and that worked
perfectly fine.

I just got some USB audio devices and they work perfectly fine
outputting sound and inputting sound.  But when I issue the first
command above (with audio), I get this: 'video buffer full - dropping
frame' from mencoder.  When playing back the video, the sound works
flawlessly, but the video is extremely choppy because so many frames
were dropped.

I thought the problem might be my alsamixer settings for the usb
device, so I tried correcting those.  This is my output from 'amixer':
Simple mixer control 'PCM',0
  Capabilities: cvolume cswitch cswitch-joined
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 128
  Front Left: Capture 78 [61%] [on]
  Front Right: Capture 78 [61%] [on]
Simple mixer control 'PCM Capture Source',0
  Capabilities: enum
  Items: 'Mic' 'Input 1'
  Item0: 'Input 1'
Simple mixer control 'Mic',0
  Capabilities: pvolume pvolume-joined cvolume pswitch pswitch-joined
cswitch cswitch-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: Playback 0 - 255 Capture 0 - 128
  Mono: Playback 82 [32%] [off] Capture 0 [0%] [off]
Simple mixer control 'Auto Gain Control',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'Speaker',0
  Capabilities: pvolume pswitch pswitch-joined
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 255
  Mono:
  Front Left: Playback 191 [75%] [off]
  Front Right: Playback 191 [75%] [off]
Simple mixer control 'Speaker',1
  Capabilities: pvolume pswitch pswitch-joined
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 255
  Mono:
  Front Left: Playback 103 [40%] [on]
  Front Right: Playback 103 [40%] [on]

I don't really know what the problem could be, so I came to this list.
 If anyone can give any advice, I would really appreciate it.  Thanks.

- Tushar