[Ffmpeg-devel] [PATCH] from DivX, Part 4: LAME ABR encoding

[Steve Lhomme]

Michael Niedermayer wrote:
> Hi
> 
> On Fri, Dec 16, 2005 at 06:49:29PM -0500, Rich Felker wrote:
> 
>>On Fri, Dec 16, 2005 at 11:34:11AM -1000, Steve Lhomme wrote:
>>
>>>As the name suggests, this adds a flag to FFMPEG to allow Average 
>>>Bitrate encoding using LAME.
>>
>>>Index: libavcodec/avcodec.h
>>>===================================================================
>>>RCS file: /cvsroot/ffmpeg/ffmpeg/libavcodec/avcodec.h,v
>>>retrieving revision 1.430
>>>diff -u -r1.430 avcodec.h
>>>--- libavcodec/avcodec.h	9 Dec 2005 16:08:18 -0000	1.430
>>>+++ libavcodec/avcodec.h	16 Dec 2005 21:30:04 -0000
>>>@@ -320,6 +320,7 @@
>>> 
>>> #define CODEC_FLAG_QSCALE 0x0002  ///< use fixed qscale 
>>> #define CODEC_FLAG_4MV    0x0004  ///< 4 MV per MB allowed / Advanced prediction for H263
>>>+#define CODEC_FLAG_ABR    0x0008  ///< use ABR mode (DivX Inc)
>>
>>Is this really necessary? IMO lavc should always be in 'abr' mode
>>unless minrate/maxrate are set (cbr) or constant quality (vbr) is
>>set...
> 
> 
> well i agree somehow, but if theres no volunteer who would implement that
> then id say apply the CODEC_FLAG_ABR patch if its ok otherwise

The other thing about CBR is that it's way faster than ABR. So for live 
encoding, CBR might be a better choice.