[Ffmpeg-devel] [PATCH] ported SGI decoder to the new API

[Michael Niedermayer]

Hi

On Sat, Apr 07, 2007 at 08:39:06PM +0800, Xiaohui Sun wrote:
> Michael Niedermayer wrote:
> >Hi
> >
> >On Sat, Apr 07, 2007 at 11:34:57AM +0800, Xiaohui Sun wrote:
> >  
> >>Michael Niedermayer wrote:
> >>    
> >>>Hi
> >>>
> >>>On Fri, Apr 06, 2007 at 08:30:05PM +0200, Diego Biurrun wrote:
> >>> 
> >>>      
> >>>>On Sat, Apr 07, 2007 at 12:03:37AM +0800, Xiaohui Sun wrote:
> >>>>   
> >>>>        
> >>>>>patch updated.
> >>>>>
> >>>>>Diego Biurrun wrote:
> >>>>>     
> >>>>>          
> >>>>>>On Fri, Apr 06, 2007 at 12:34:05AM +0800, Xiaohui Sun wrote:
> >>>>>>
> >>>>>>       
> >>>>>>            
> >>>>>>>patch updated.
> >>>>>>>
> >>>>>>>--- libavcodec/sgidec.c	(revision 0)
> >>>>>>>+++ libavcodec/sgidec.c	(revision 0)
> >>>>>>>@@ -0,0 +1,267 @@
> >>>>>>>+
> >>>>>>>+#include "sgi.h"
> >>>>>>>         
> >>>>>>>              
> >>>>>>Where is sgi.h ???
> >>>>>>       
> >>>>>>            
> >>>>>Sorry , I forgot attach it, try this new patch.
> >>>>>     
> >>>>>          
> >>>>Patch applied.
> >>>>   
> >>>>        
> >>>the code doesnt work (see regresion tests, encoding does something
> >>>but decoding does just produce
> >>>
> >>>ffmpeg -i b-libav02.sgi -y test.avi
> >>>FFmpeg version SVN-r8635, Copyright (c) 2000-2007 Fabrice Bellard, et al.
> >>> configuration: --enable-pthreads --cc=/home/michael/bin/colorgcc 
> >>> --enable-libmp3lame --enable-liba52 --enable-libvorbis --enable-libfaad 
> >>> --enable-gpl --enable-libogg --enable-libfaac --enable-x264
> >>> libavutil version: 49.4.0
> >>> libavcodec version: 51.40.2
> >>> libavformat version: 51.11.0
> >>> built on Apr  6 2007 22:26:57, gcc: 4.1.2 20061115 (prerelease) (Debian 
> >>> 4.1.1-21)
> >>>Input #0, image2, from 'b-libav02.sgi':
> >>> Duration: 00:00:00.0, start: 0.000000, bitrate: N/A
> >>> Stream #0.0: Video: sgi, rgb24, 352x288, 25.00 fps(r)
> >>>Output #0, avi, to 'test.avi':
> >>> Stream #0.0: Video: mpeg4, yuv420p, 352x288, q=2-31, 200 kb/s, 25.00 
> >>> fps(c)
> >>>Stream mapping:
> >>> Stream #0.0 -> #0.0
> >>>Press [q] to stop encoding
> >>>Error while decoding stream #0.0
> >>>frame=    0 fps=  0 q=0.0 Lsize=       6kB time=10000000000.0 bitrate=   
> >>>0.0kbits/s    video:0kB audio:0kB global headers:0kB muxing overhead inf%
> >>> 
> >>>      
> >>I think the problem lies in the RLE encoding, which should count up to 
> >>127 consecutive pixels and I have sent the path before.
> >>Please use the attached path and have a test, thanks.
> >>    
> >
> >this change needs testing to see what effects it has on compression rate 
> >with
> >a few of the stanard test images like lena, ...
> >  
> 
> I think another solution is addint an additional parameter or let SGI 
> use another RLE encoder.

adding a redundant rle encoder is unaccpetable adding an additional
parameter and thus complexity and lower speed needs some justification
like some compression gain (=encoding with a few test images)

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

1. write clean, simple and working code
2. high level optimizations
3. low level optimizations
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