[MPlayer-users] audio half-speed in mencoder v4l TV recording

Mike Holland myk at plug.linux.org.au
Fri Nov 29 11:04:02 CET 2002


Looks like a bug in mono TV recording?

On Thu, 28 Nov 2002, Jindrich Makovicka wrote:

> On Thu, Nov 28, 2002 at 12:17:23PM -0500, D Richard Felker III wrote:

> > >   AUDIO: 44100 Hz, 1 ch, 16 bit (0x10), ratio: 88200->88200 (705.6 kbit)
> > 
> > For some reason your audio device is only recording mono! You should

Yes, my TV card doesn't support the A2 stereo used here.

> > play around with the -tv options to let it know you're recording mono,
> > or else fix this (probably requires trashing your junky onboard sound
> > that doesn't support stereo :).

( My "junky" onboard sound supports Dolby 5.1 . Soon onboard sound will be 
as normal as onboard serial ports. )

> try to specify the audio mode with "amode" and eventually use the
> "forcechan" option. mencoder tells you if it finds it may be necessary.

Thanks Jindrich,

The amode has no effect. Log output and sound is same for 0 and 1.
I also tried '-lameopts mode=3'.

The TV option 'forcechan=2' seems to fix it. So now I'm recording two 
audio channels OK.   Still, amode has no effect.
I can then add "-lameopts mode=3" to get a working 1-channel AVI.
Is this a reasonable work-around? Not wasting much CPU?

  Without the 'forcechan=2', the verbose log shows 1-channel everywhere,
but on playback I see:

  Channels: 1, copyright: No, original: Yes, CRC: No, emphasis: 0
  AUDIO: 44100 Hz, 2 ch, 16 bit (0x10), ratio: 14000->176400 (112.0 kbit)

Is that OK? Does the '2 ch' just refer to output, not the input AVI file?

Are other people recording mono TV succesfully, or does everybody else 
have stereo?   And should I be making a bug-report to the other mail list?

-- 
        The origin of Truth is Doubt - Socrates





More information about the MPlayer-users mailing list