[MPlayer-users] SIGSEGV: mencoder + mpeg2video + psnr opion

[Jeff Clagg]

On Thu, Nov 18, 2004 at 12:32:28PM +0500, byavl wrote:
> Hi All
> 
> Here is command that passed ok:
> $ mencoder a1.mjpg -o a1.mjpg.mpeg -vf hqdn3d=2:1:2 -of mpeg -ovc lavc
>   -lavcopts vcodec=mpeg2video:v4mv:mbd=2:vqmax=10:vbitrate=5000
>   -oac copy

v4mv is not possible in mpeg2. In fact I don't see why this command
worked at all - I'm pretty sure it should fail to write a video stream
and/or segfault.

Also, you should know that the file mencoder writes is mpeg2 inside
an mpeg1 container. It's completely in violation of standards and you
can't expect other players to play it. Correct mpeg2 muxing is not (yet)
supported. IMO the quickest and easiest way to do what you're trying to
do is to use ffmpeg.

> Below is not. Only ":psnr:" option was added.

My first guess was that this turns out to be an empty or horribly broken
video stream, which confuses PSNR calculations...

> Here is a trouble:
> 
> (gdb) run mencoder a1.mjpg -o a1.mjpg.mpeg -vf hqdn3d=2:1:2 -of mpeg
> -ovc lavc -lavcopts vcodec=mpeg2video:psnr:v4mv:mbd=2:
> vqmax=10:vbitrate=5000 -oac copy
> 
> MEncoder dev-CVS-041115-10:00-3.2.2 (C) 2000-2004 MPlayer Team
> [...]
> Writing AVI index...
> Fixing AVI header...
> 
> Video stream: 0,000 kbit/s (0 bps)  size:0 bytes 1,520 secs  40 frames

I guessed right.

> Audio stream: 1411,200 kbit/s (176400 bps) size:352800 bytes 2,000 secs