[MEncoder-users] Recording TV with WinTV bt878

[Guennadi Liakhovetski]

On Sun, 5 Dec 2004, Barton Bosch wrote:

> Guennadi Liakhovetski wrote:
> > I now seem to have the same problem - cannot record audio. My TV-card

...

> Uh, yeah.  I thought I knew all the alsamixer gotchas after going through the
> unmuting thing last year, heh.
> 
> Haven't done any recording through external lines til now though. After two
> days of trial and error I saw the LcapturR indicator that needs to be over
> linein rather than mic to get signal from the TV card's external cable...

Yep, I've figured that out too by now:-)) I used xmix on the first PC, and 
there you can select the recording source. On this PC I used gkrellm 
volume plugin, which is very nice, but doesn't have that control... I also 
used aumix, and that one doesn't have it either... So, I just forgot it 
was necessary:-( As soon as I set line-in as the source, everything 
worked.

> The effort wasn't a total wash because I did stumble on some other useful
> info.  Which bttv options are you all using? 

Attached are my experiments so far... I played with 2-pass encoding, first 
dumping the data-stream with avicap. Beware, some of those command might 
be wrong, might not work at all... But I found that options like "-vop pp", 
"-vf pp", "-lavcopts ...:vhq:..." are important.

> What is pll?

I don't remember how the abbreviation expands... It is some oscilator. 
"Programmable", "loopback", "logic" come to mind, not sure exactly though.

> According to
> modinfo bttv it has something to do with a crystal (tuner?).  Do I need to
> throw it?  What about fieldnr?  Is that obsolete now?  Does the number of
> gbuffers have any impact on CPU usage?
> 
> I'd really appreciate some tips towards minimizing CPU usage when capturing
> TV.

Yep, me too. Even a bit more generically: I am prepared to do several 
passes: first - in real time, with minimal (bot not zero) compression, so 
that the CPU load is reduced somewhat and the data rate too. And then one 
/ too more passes at leasure to further compress the video and audio, 
preserving as much quality as possible.

> So far, any time I record through the lacv mpeg4 option I max the CPU and
> start dropping mass frames. 

I am dropping lots of frames also with raw data recording. On a Duron 
900MHz, 512MB SDRAM, UDMA 100.

> Is there a format which is smaller than raw video
> but less computationally intense than mpeg4 but with comparable quality?

Thanks
Guennadi
---
Guennadi Liakhovetski
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  246  mencoder tv:// -tv driver=v4l2 -oac mp3lame br=128:cbr:mode=3:vol=8 -ovc lavc -lavcopts vcodec=mpeg4
  247  mencoder tv:// -tv driver=v4l2  -ovc lavc -lavcopts vcodec=mpeg4 -oac mp3lame br=128:cbr:mode=3:vol=8 
  249  mencoder tv:// -tv driver=v4l2  -ovc lavc -oac mp3lame br=128:cbr:mode=3:vol=8 
  251  mencoder tv:// -tv driver=v4l2  -ovc lavc -oac mp3lame br=128:mode=3:vol=8 
  253  mencoder tv:// -tv driver=v4l2  -ovc lavc -lavcopts vbitrate=1200 -oac mp3lame mode=3:vol=8 
  256  mencoder tv:// -tv driver=v4l2  -ovc lavc -lavcopts vbitrate=1200 -oac mp3lame mode=3:vol=8 -endpos 15
  258  mencoder tv:// -tv driver=v4l2 -oac mp3lame -ovc lavc 
  261  mencoder tv:// -tv driver=v4l2:device=/dev/video0:adevice=/dev/dsp:audiorate=32000:forceaudio -oac mp3lame -ovc lavc 
  265  mencoder tv:// -tv driver=v4l2:device=/dev/video0:adevice=/dev/dsp:audiorate=32000:forceaudio -oac mp3lame -lameopts vol=8 -ovc lavc 
  271  mencoder tv:// -tv driver=v4l2:device=/dev/video0:adevice=/dev/dsp:audiorate=32000:forceaudio -oac mp3lame -lameopts vol=8 -ovc lavc 
  273  mencoder tv:// -tv driver=v4l2:device=/dev/video0:adevice=/dev/dsp:audiorate=32000:forceaudio:forcechan=1 -oac mp3lame -lameopts vol=8 -ovc lavc 
  285  mencoder tv:// -tv driver=v4l2:device=/dev/video0:adevice=/dev/dsp:audiorate=32000:forceaudio:forcechan=1 -oac mp3lame -lameopts vol=8 -ovc lavc 
  420  mencoder movie.avi -ovc divx4 -divx4opts br=1800 -vop pp -npp lb -o movie_enc.avi
  421  mencoder movie.avi -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vpass=1 -vop pp -npp lb -o movie_1.avi
  422  mencoder movie.avi -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vpass=1 -vop pp -vf pp -o movie_1.avi
  423  mencoder movie.avi -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vpass=1 -vop pp -vf pp -aoc lame -o movie_1.avi
  424  mencoder movie.avi -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vpass=1 -vop pp -vf pp -oac lame -o movie_1.avi
  426  mencoder movie.avi -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vpass=1 -vop pp -vf pp -oac mp3lame -o movie_1.avi
  430  mencoder movie.avi -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vpass=2 -vop pp -vf pp -oac mp3lame -o movie_2.avi
  434  mencoder tv:// -tv  -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vpass=1 -vop pp -vf pp -oac mp3lame -o movie_1.avi
  435  mencoder tv:// -tv driver=v4l2:input=0:norm=pal:channel=108:chanlist=europe-west:outfmt=yuy2:device=/dev/video0:adevice=/dev/dsp:audiorate=32000:forceaudio:forcechan=1 -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vpass=1 -vop pp -vf pp -oac mp3lame -lameopts br=128:cbr:mode=3:vol=8 -endpos 20 -o movie_tv.avi
  439  mencoder movie_tv.avi -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vpass=2 -vop pp -vf pp -oac mp3lame -o movie_tv_2.avi
  442  mencoder tv:// -tv driver=v4l2:input=0:norm=pal:channel=108:chanlist=europe-west:outfmt=yuy2:device=/dev/video0:adevice=/dev/dsp:audiorate=48000:forceaudio:forcechan=1 -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vpass=1 -vop pp -vf pp -oac mp3lame -lameopts cbr:mode=3 -endpos 20 -o movie_tv2.avi
  447  mencoder movie_tv2.avi -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vpass=2 -vop pp -vf pp -oac mp3lame -o movie_tv2_2.avi
  455  mencoder tv:// -tv driver=v4l2:input=0:norm=pal:channel=108:chanlist=europe-west:width=768;height=576:outfmt=yuy2:device=/dev/video0:adevice=/dev/dsp:audiorate=48000:forceaudio:forcechan=1 -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vpass=1 -vop pp -vf pp -oac mp3lame -lameopts cbr:mode=3 -endpos 60 -o movie_tv3.avi
  457  mencoder tv:// -tv driver=v4l2:input=0:norm=pal:channel=108:chanlist=europe-west:width=768;height=576:outfmt=yuy2:device=/dev/video0:adevice=/dev/dsp:audiorate=48000:forceaudio:forcechan=1 -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vpass=1 -vop pp -vf pp -oac mp3lame -lameopts cbr:mode=3 -endpos 60 -o movie_tv3.avi
  459  mencoder tv:// -tv driver=v4l2:input=0:norm=pal:channel=108:chanlist=europe-west:width=768:height=576:outfmt=yuy2:device=/dev/video0:adevice=/dev/dsp:audiorate=48000:forceaudio:forcechan=1 -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vpass=1 -vop pp -vf pp -oac mp3lame -lameopts cbr:mode=3 -endpos 60 -o movie_tv3.avi
  460  mencoder movie_tv3.avi -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vpass=2 -vop pp -vf pp -oac mp3lame -o movie_tv3_2.avi
  476  mencoder /usr/src/movie.avi -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vpass=1 -vop pp -vf pp -oac mp3lame -o /usr/src/movie_1.avi
  477  mencoder /usr/src/movie_pal.avi -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vpass=1 -vop pp -vf pp -oac mp3lame -o /usr/src/movie_pal_1.avi
  479  mencoder /usr/src/movie.avi -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vpass=2 -vop pp -vf pp -oac mp3lame -o /usr/src/movie_2.avi
  480  mencoder /usr/src/movie_pal.avi -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1000:vhq:vpass=2 -vop pp -vf pp -oac mp3lame -o /usr/src/movie_pal_2.avi