[MPlayer-users] mjpeg and mencoder

Brad Barnett bb at L8R.net
Wed Jan 8 00:29:10 CET 2003


On Wed, 8 Jan 2003 00:15:09 +0100
Arpi <arpi at thot.banki.hu> wrote:

> [Automatic answer: RTFM (read DOCS, FAQ), also read
> DOCS/bugreports.html] Hi,
> 
> > I've been looking for a way to control the quality of mjpeg lavc
> > encoding with mencoder.  So far, the vbitrate option doesn't seem to
> > make any significant difference.  If I set it to 600 or to 10000, I'm
> > just as likely to get the same size file out, and the same image
> > quality.
> 
> hmm. vbitrate should work. anyway you won't get any enjoyable quality
> under 8000...  even mpeg2 requires at least 8000 for good quality at
> 720x576
> 
> also you can try vqscale=[1..31] for constant quality (but variable
> bitrate)


Cool.  I'm trying to basically get as close to lossless compression as I
can.  I can't do rawrgb, it's just too large.  However, why does something
like:

/usr/bin/mencoder -tv on:driver=v4l:width=640:height=480:input=1:norm=ntsc
-ovc lavc -lavcopts vcodec=mjpeg:vhq:vqscale=1  -oac mp3lame -lameopts
cbr:br=192 -o /mnt/c/test.avi -endpos 60

use more cpu than something like:

/usr/bin/mencoder -tv on:driver=v4l:width=640:height=480:input=1:norm=ntsc
-ovc lavc -lavcopts vcodec=mjpeg:vhq:vqscale=2  -oac mp3lame -lameopts
cbr:br=192 -o /mnt/c/test.avi -endpos 60

Shouldn't it be the other way around?!  After all, I'm doing less
compression with vqscale=1 than vqscale=2.  Also, what's the best method
for deinterlacing?  I've tried lavcdeint, but it seems to add artifacts...

Thanks again!@



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