[MPlayer-users] Digitizing VHS tapes with mencoder

[Josef Wolf]

On Tue, Apr 06, 2010 at 02:47:52PM +0100, Steve Fosdick wrote:
> On Tue, 6 Apr 2010 13:55:38 +0200
> Josef Wolf <jw at raven.inka.de> wrote:
[ ... ]
> 1. Some form of decimation, i.e. reduce the number of pixels in each
> frame or reduce the colour depth.
> 2. Capture to MJPEG, i.e. where each frame is encoded as a JPEG image
> but no inter-frame coding is done.

I think I'd go with option 2.

So for the grab I use following command:

streamer -i composite1 -b 64 -s 768x576 -n pal -f mjpeg -j 100 -r 25 -F stereo -o file.avi

This gives about 650MB per minute.
BTW: when I use S-Video input, I get only black-white :-(

> I reckon the factor by which CPUs have got faster these last ten years
> is much greater than the factor by which disk I/O has got faster so it
> may be worth trying to see if it is possible to encode direct to your
> final format in real time.

I'd prefer two-pass encoding for better quality, so direct capture+encode
would not work anyway.

> > BTW: I've seen various resolution recommendations for PAL varying from
> >      384x288 to 768x576. What is the correct setting?
> 
> In the output from a PAL VHS machine there should be 625 scan lines,
> only 576 of which would normally be visible.  As the output is analogue
> there isn't an number of pixels to be applied to the horizontal axis
> but as the aspect ratio is 4:3 you could go for the same level of
> detail in both directions and set the horizontal to 768.
> 
> For the original VHS the video bandwidth is only 3Mhz so the 768
> horizontal resolution may be overkill - the Wikipedia article suggests
> 480 pixels may be sufficient.

But don't I need 768 to keep aspect ratio? Some howtos suggest 720 for DVD.
Won't this break aspect?

I'd like to encode into avi, but in such a way that I can create DVDs from
that file without reencoding.

Here is how I currently do the encoding:

 mencoder infile.avi -vf yadif=0 -mc 0 -noskip -ovc lavc -lavcopts \
  vcodec=mpeg4:trell:nr=400:vqscale=10:mbd=2:scplx_mask=0.2:turbo:vpass=1 \
  -nosound -o /dev/null
 
 mencoder infile.avi -vf yadif=0 -mc 0 -noskip -ovc lavc -lavcopts \
  vcodec=mpeg4:trell:nr=400:vqscale=10:mbd=2:scplx_mask=0.2:vpass=2 \
  -oac mp3lame -lameopts preset=standard:mode=2 -o outfile.avi

This seems to give reasonable results. Any suggestions for improvement?