Michael Niedermayer <[EMAIL PROTECTED]> added the comment:

On Mon, Nov 17, 2008 at 03:34:52AM +0000, hjr wrote:
> 
> New submission from hjr <[EMAIL PROTECTED]>:
> 
> FFmpeg version SVN-r15841, Copyright (c) 2000-2008 Fabrice Bellard, et al.
>   configuration: --cc=cc --prefix=/usr/local --disable-debug
> --enable-memalign-hack --enable-shared --enable-postproc
> --extra-cflags=-I/usr/local/include/vorbis -I/usr/local/include
> --extra-ldflags=-L/usr/local/lib  --extra-libs=-pthread --enable-gpl
> --enable-pthreads --enable-swscale --mandir=/usr/local/man --disable-libfaac
> --enable-libfaad --enable-libfaadbin --enable-libamr-nb --enable-nonfree
> --enable-libamr-wb --enable-nonfree --disable-mmx --enable-libgsm
> --enable-libmp3lame --disable-ffplay --enable-libtheora --enable-libvorbis
> --disable-libx264 --disable-libxvid --enable-libmp3lame --enable-encoder=mp3
> --disable-devices --disable-network --enable-encoder=libmp3lame
> 
> FreeBSD 7.0-RC2 @ amd64
> 
> Note: Some of these configs are maybe non-sense, but that was just my best try
> to get the latest svn version to compile on FreeBSD. Later versions in the
> FreeBSD ports collection suffered from the same problem (SVN-r14424).
> 
> I use ffmpeg solely for audio re-encoding. For some files, I get many lines of
> "lame: output buffer too small" and the output file is truncated. This 
> happened
> only with some files and then I found out that decreasing the target audio
> quality would solve the problem.
> 
> File: http://tmp.tomas-muller.net/32.mp3 (~6 MB).
> 
> ffmpeg -i 32.mp3 -acodec libmp3lame -aq 2 -ar 44100 -ac 2 test-bad.mp3
> 
> exhibits the error, while
> 
> ffmpeg -i 32.mp3 -acodec libmp3lame -aq 3 -ar 44100 -ac 2 test-bad.mp3
> 
> (decreased audio quality) does not. When I increased the buffer size at
> libavcodec/libmp3lame.c (line 31: #define BUFFER_SIZE) and recompiled, problem
> was solved. My guess is that increasing the BUFFER_SIZE to accommodate the
> maximum mp3 bitrate (320kbps) would fix this.
> 
> libavcodec/libmp3lame.c(31): #define BUFFER_SIZE (7200 + MPA_FRAME_SIZE +
> MPA_FRAME_SIZE/4)
> 

> Shouldn't this be MPA_MAX_CODED_FRAME_SIZE ?

no, lame.h clearly says:
 * The required mp3buf_size can be computed from num_samples, 
 * samplerate and encoding rate, but here is a worst case estimate:
 *
 * mp3buf_size in bytes = 1.25*num_samples + 7200

[...]

______________________________________________________
FFmpeg issue tracker <[EMAIL PROTECTED]>
<https://roundup.mplayerhq.hu/roundup/ffmpeg/issue719>
______________________________________________________

Reply via email to