[MPlayer-users] mjpeg and mencoder

[D Richard Felker III]

On Thu, Jan 09, 2003 at 05:40:00AM +0200, Jukka Tastula wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> On Thursday 09 January 2003 03:04, Brad Barnett wrote:
> 
> > I'd doing TV / Satelite capture.  I want a lossless method to capture,
> > that doesn't take 50 gigs / 2 hours.  Aside from that, if I can't do
> > lossless, I want next-to-lossless quality.  In both cases I'll be
> > re-encoding.
> > Why?  Because I can't do live TV capture unless I use mjpeg.  DIVX is just
> > too slow ;(  There are some things I want captured at 640x480 instead of
> > 320x240 or what not :/
> 
> How do you people do this stuff with mencoder anyway? I can't see segmented 
> avi writing support anywhere and the damn thing doesn't support avis over 
> 2GB? Trying to crush a two hour movie into 2GB mjpeg is going to look pretty 
> damn crappy at full resolution (that's just my opinion of course). Even in 
> divx I doubt it being very good for transcoding.
> 
> Does capturing full frames into divx really make sense anyway? I read 
> somewhere that it doesn't understand interlacing but thinks the effect is 
> just detail which results in something described as very very ugly.
> Maybe I'm completely off here but deinterlacing just seems like a VERY VERY 
> BAD idea as my target is SVCD compliant MPEG2. And then there's the problem 
> called commercials: with divx you have to play around keyframes where as in 
> mjpeg you can cut anywhere with one frame accuracy.
> 
> And everyone remembers these bt8x8 chips have that nasty color bug that 
> appears when capturing half or less vertical resolution (right?) ... so I'd 
> certainly want a format that "understands" fields even if my target was 
> something like vcd resolution mpeg1 (mjpeg and huffyuv being the only ones I 
> _know_ can do that).
> 
> So in short: how to get around the 2GB limit?-)

I doubt it matters. mencoder will probably write a bogus header/index
that won't work, but you should still be able to transcode the file
with -noidx. Perhaps not though; test before using it for anything
important. BTW, lavc does have an interlaced DCT mode now, which would
improve mpeg4 compression of interlaced material, but it still lacks
interlaced motion estimation. Of course, if you capture intra-only
mpeg4, motion est won't take place anyway, so that seems like your
best bet.

BTW what is this "bug" with bt8x8 and half vertical res? I've
certainly never seen it. Even if such a thing does exist, you could
avoid it by capturing in yuy2 format at half-res, I would think...

Rich