[FFmpeg-user] target pal-dvd: rc buffer underflow

[Peter B.]

When creating an MPEG video, I'm always receiving "rc buffer underflow".
The very first frame of the video consists of very ugly macroblock  
artefacts [1] and if I'm not mistaken, this might be related to buffer  
underflow warning.

I've tried to follow some tips from an ancient thread on the  
"transcode" mailinglist [2] on how to avoid this buffer underflow, but  
to no avail.

Here's my commandline and uncut console output:

//-------------------------------
$ ffmpeg -i vx-04690_01-026s.avi -target pal-dvd -vcodec mpeg2video  
-threads 1 client/mpeg-duration/out/026s-ffmpegx.mpg
//-------------------------------

ffmpeg version N-36863-g811de35 Copyright (c) 2000-2012 the FFmpeg developers
   built on Jan 16 2012 11:00:19 with gcc 4.4.5
   configuration: --prefix=/usr/local --enable-gpl --enable-nonfree  
--enable-postproc --enable-swscale --enable-avfilter --enable-pthreads  
--enable-bzlib --enable-libmp3lame --enable-libvorbis --enable-libxvid  
--enable-zlib --enable-libopenjpeg --enable-decoder=png  
--enable-encoder=png --enable-libdirac --enable-libschroedinger
   libavutil      51. 34.100 / 51. 34.100
   libavcodec     53. 55.105 / 53. 55.105
   libavformat    53. 29.100 / 53. 29.100
   libavdevice    53.  4.100 / 53.  4.100
   libavfilter     2. 59.100 /  2. 59.100
   libswscale      2.  1.100 /  2.  1.100
   libswresample   0.  6.100 /  0.  6.100
   libpostproc    51.  2.100 / 51.  2.100
Input #0, avi, from 'vx-04690_01-026s.avi':
   Metadata:
     encoder         : Lavf53.28.100
   Duration: 00:01:00.00, start: 0.000000, bitrate: 37457 kb/s
     Stream #0:0: Video: ffv1 (FFV1 / 0x31564646), yuv422p, 720x576,  
25 tbr, 25 tbn, 25 tbc
     Stream #0:1: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 48000 Hz,  
2 channels, s16, 1536 kb/s
[buffer @ 0x9c5cc60] w:720 h:576 pixfmt:yuv422p tb:1/1000000 sar:0/1  
sws_param:
[buffersink @ 0x9c54a40] auto-inserting filter 'auto-inserted scale 0'  
between the filter 'src' and the filter 'out'
[scale @ 0x9c54f60] w:720 h:576 fmt:yuv422p -> w:720 h:576 fmt:yuv420p  
flags:0x4
Incompatible sample format 's16' for codec 'ac3', auto-selecting format 'flt'
[ac3 @ 0x9c52da0] channel_layout not specified
[ac3 @ 0x9c52da0] No channel layout specified. The encoder will guess  
the layout, but it might be incorrect.
Output #0, dvd, to 'client/mpeg-duration/out/026s-ffmpegx.mpg':
   Metadata:
     encoder         : Lavf53.29.100
     Stream #0:0: Video: mpeg2video, yuv420p, 720x576, q=2-31, 6000  
kb/s, 90k tbn, 25 tbc
     Stream #0:1: Audio: ac3, 48000 Hz, stereo, flt, 448 kb/s
Stream mapping:
   Stream #0:0 -> #0:0 (ffv1 -> mpeg2video)
   Stream #0:1 -> #0:1 (pcm_s16le -> ac3)
Press [q] to stop, [?] for help
[mpeg2video @ 0x9c4fea0] rc buffer underflow
frame= 1500 fps= 23 q=2.0 Lsize=   33152kB time=00:00:59.96  
bitrate=4529.4kbits/s
video:29146kB audio:3281kB global headers:0kB muxing overhead 2.234009%


== References:
[1]  
http://download.das-werkstatt.com/pb/mthk/examples/mencoder_mpeg/vx-04690_01-026s-ffmpeg.png
[2]  
http://itdp.fh-biergarten.de/~itdp/html/transcode-users/2005-03/msg00051.html