[MEncoder-users] VHS capturing 2 avi

Rich Felker dalias at aerifal.cx
Fri Dec 16 20:46:24 CET 2005

On Sat, Dec 17, 2005 at 12:09:47AM +1100, Allen wrote:
> It is timely that your question popped onto the list.  I have been
> trying many combinations for capturing our home movies onto the PC such
> that they can then be converted and played back by (S)VCD and later DVD.
> My focus has been to attempt to capture interlaced content for playback
> on a TV, hence a little bit different I think from your own tests.
> The command I use at the moment is:
> mencoder -tv driver=v4l2:input=1:width=720:height=576:norm=PAL -ovc lavc
> -oac lavc -lavcopts
> vcodec=mpeg4:trell:ildct:ilme:vbitrate=1400:acodec=mp2:abitrate=112
> -endpos 5336 -o my-movie.avi tv://

You also need to use -mc 0 and -noskip when capturing interlaced
content. Any frame skips/duplication will be very very bad. However
this can lead to a/v sync issues if your timers aren't in sync.
Unfortunately mencoder sucks and has no good solution for tv capture..

> I think for animated shows, I think I need to deinterlace the content,
> rather than recording interlaced.

No, you need to do pulldown reversal. This is true for movies too, and
for anything not produced with an (interlaced) video camera.

However: animation is normally created at 24fps and telecined to 60
fields/sec in _NTSC_ form. If you have animation recorded in PAL and
the show was not originally produced in a PAL country, it's ruined
beyond all hope of repair. The only way you can keep it watchable even
on TV is just encoding as interlaced.

> I have tried to capture and scale to a smaller size, but no matter the
> bitrate I seem to end up with very blocky content, and the file size
> ends up the same as above anyway.
> Any comments or suggestions are much appreciated.

You need a much higher bitrate than 1400 for one-pass encoding (which
TV capture will always be). Interlacing increases the bitrate
requirement even more. Try 5000 or so. :)


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