[Ffmpeg-devel] r6338 broke snow encoding

[Michael Niedermayer]

Hi

On Sat, Oct 07, 2006 at 12:36:37AM +0200, Luca Abeni wrote:
> Hi all,
> 
> it seems that r6338 broke rate control in snow encoding. Something like
> ./ffmpeg -y -i /tmp/test.avi -strict -2 -vcodec snow /tmp/out.avi
> always returns
> FFmpeg version SVN-r6569, Copyright (c) 2000-2006 Fabrice Bellard, et al.
>   configuration:  
>   libavutil version: 49.0.1
>   libavcodec version: 51.16.0
>   libavformat version: 50.5.0
>   built on Oct  7 2006 00:16:13, gcc: 3.3.5 (Debian 1:3.3.5-13)
> Input #0, avi, from '/tmp/noncioilcasco.avi':
>   Duration: 00:00:23.1, start: 0.000000, bitrate: 1034 kb/s
>   Stream #0.0: Video: msmpeg4v2, yuv420p, 360x288, 25.00 fps(r)
>   Stream #0.1: Audio: mp3, 44100 Hz, mono, 64 kb/s
> Output #0, avi, to '/tmp/c.avi':
>   Stream #0.0: Video: snow, yuv420p, 360x288, q=2-31, 200 kb/s, 25.00 fps(c)
>   Stream #0.1: Audio: mp2, 44100 Hz, mono, 64 kb/s
> Stream mapping:
>   Stream #0.0 -> #0.0
>   Stream #0.1 -> #0.1
> Press [q] to stop encoding
> Video encoding failed
> 
> It looks like ratecontrol_1pass(s, pict) at line 4186 returns a negative
> delta_qlog, so encode_frame() fails. Now, I do not fully understand the
> ratecontol stuff in snow.c, but it seems to me that a negative
> delta_qlog is valid...
> On the other hand, encode_frame() does not really seem to use
> delta_qlog, but it only needs to check if such value is different from
> 0, or if ratecontrol_1pass() failed. So, I think the attached patch is
> ok...

fixed

PS: bugreports which refer to a specfic revision which broke something
should ideally also mention who was the person commiting that and the
commit message, that way its a little easier for everyone to check if
they broke something ...

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In the past you could go to a library and read, borrow or copy any book
Today you'd get arrested for mere telling someone where the library is