[MPlayer-users] Digitizing VHS tapes with mencoder

[Alexander Roalter]

On 07.04.2010 13:17, Josef Wolf wrote:
> On Tue, Apr 06, 2010 at 06:49:14PM -0700, Ken Bass wrote:
> 
>> I typically capture via hardware mjpeg (my card does the compression), and
>> encode via lavc to mpeg4. After re-indexing, I run the video through
>> mencoder for finer processing, using a two or more pass encoding.
> 
> Glad you mentioned this. Turns out that my card also has a hardware mjpeg
> decoder, I guess the quality will be better with this decoder than with
> software-decoder?
> 
> But with the hardware-decoder, it records 704x576 (full size PAL), and
> all the people are too tall =:-().
> 
> I am really, really confused by all those different resolutions. Anybody out
> there to recommend how properly handle this resolution thing?

704x576 is actually correct, you have to keep in mind that in PAL the
pixels aren't square. Playing back the video with -aspect 4:3 (or
-aspect 16:9) uses the correct aspect ratio and stretches the pixels
horizontally to either 768 or 1024 square pixels.

I'm not sure if you need to specify -vf dsize=768:576 or something like
it in the final stages.

In MPEG, there are only two a few aspect ratios possible, and 4:3 and
16:9 are amongst them, so if you produce an MPEG stream you won't get
too tall people (except the case where a 16:9 anamorphic stream is
erroneously recognized as 4:3. Here you'll have to manually set the 16:9
mode somehow.

-- 
cheers,
Alex