[MPlayer-users] [BUG] Mencoder crash with vb_strategy=2

[Firon Draak]

On 9/25/06, Corey Hickey <bugfood-ml at fatooh.org> wrote:
>
>
> This isn't relevant to the bug you found, but bear in mind that mencoder
> will output to an AVI file regardless of what you name it, so you'll get
> an AVI file called target.m1v. If you want to make a different
> container, use the '-of <format>' option.
Interestingly enough, the encodes I'm doing are used with a homebrew
MPEG-1 decoder for the Nintendo DS called Moonshell (combined with MP2
audio and a weird header the program's coder made; copied together,
not interleaved), yet it doesn't seem to complain at all about the
video container being AVI. The 'official' encoder for Moonshell uses
-of rawvideo when calling mencoder instead (and -nosound).

Thanks for telling me though, I didn't know that it'd output as avi.

> I've never seen a video called .m1v in the wild, but according to a
> quick bit of googling it's a QuickTime mov file. In that case you would
> have to use '-of lavf -lavfopts format=mov'; however, mencoder and '-of
> lavf' doesn't handle B-frames correctly, so you're out of luck if you
> want that; using ffmpeg directly might work.

m1v is supposed to be an MPEG-1 video elementary stream.

>
> It appears the fatal combination is mpeg1video, b-frames, and
> vb_strategy=2. That's not too surprising; I don't think anybody ever
> tested vb_strategy=2 with any codec other than mpeg4.

I was worried at first that I'd done something wrong or that the
option had been removed and the man pages hadn't been updated. :P

> Normally, I would tell you to follow the bugreporting procedures and
> send a bugreport and a backtrace to ffmpeg-devel, but since it appears
> you are using Windows I suspect that would be very difficult for you
> (setting up a decent development environment is much harder than it is
> on Linux). So, I went ahead and reported it myself:
>
> http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2006-September/045652.html
>
> You can mail me a root beer sometime for my effort. ;)

Thank you very much! I appreciate the effort. :D

I only wish it was as easy to compile and do similar tasks on Windows
as it is on Linux.

> Meanwhile, try using vb_strategy=1:b_sensitivity=10 ; see here for the
> rationale:
>
> http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2006-May/011523.html
>
> Also, don't forget to use 2-pass encoding. The effects of the various
> B-frame strategies only effect the second pass.
>
So, using only a single pass makes vb_strategy useless? That's good to know.