[FFmpeg-user] VBV buffer size not set, muxing may fail

[Roger Pack]

I was surprised to get this dire looking warning message, when using
default mpeg2video encoder:
 VBV buffer size not set, muxing may fail VBV buffer size not set,
muxing may fail

Is this expected?
Thank you.
-roger-

$ ffmpeg -i sintel.mpg -y sintel2.mpg
ffmpeg version N-47116-g109268c Copyright (c) 2000-2012 the FFmpeg developers
  built on Nov 26 2012 17:00:52 with gcc 4.7.2 (GCC)
  configuration: --enable-memalign-hack --arch=x86 --enable-gpl
--enable-libx264 --enable-avisynth --enable-libxvid
--target-os=mingw32
--cross-prefix=/home/rdp/dev/ffmpeg-windows-build-helpers/sandbox/mingw-w64-i686/bin/i686-w64-mingw32-
--pkg-config=pkg-config --enable-libmp3lame --enable-version3
--enable-libvpx --enable-zlib --enable-librtmp --enable-libvorbis
--enable-libtheora --enable-libspeex --enable-libopenjpeg
--enable-gnutls --enable-libgsm --enable-libfreetype
--enable-fontconfig --enable-libass --enable-libutvideo
--enable-libopus --disable-w32threads --enable-frei0r
--enable-filter=frei0r --enable-libvo-aacenc --enable-bzlib
--enable-static --enable-libxavs
 --extra-cflags=-DPTW32_STATIC_LIB --enable-runtime-cpudetect
  libavutil      52.  9.102 / 52.  9.102
  libavcodec     54. 77.100 / 54. 77.100
  libavformat    54. 37.100 / 54. 37.100
  libavdevice    54.  3.100 / 54.  3.100
  libavfilter     3. 23.102 /  3. 23.102
  libswscale      2.  1.102 /  2.  1.102
  libswresample   0. 17.101 /  0. 17.101
  libpostproc    52.  2.100 / 52.  2.100
[mpeg2video @ 03cbd600] ac-tex damaged at 40 7
[mpeg2video @ 03cbd600] Warning MVs not available
[mpeg2video @ 03cbd600] concealing 1035 DC, 1035 AC, 1035 MV errors in I frame
[mpeg @ 03cc7ae0] max_analyze_duration 5000000 reached at 5024000
Input #0, mpeg, from 'sintel.mpg':
  Duration: 00:14:47.58, start: 0.233367, bitrate: 4132 kb/s
    Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x480
[SAR 32:27 DAR 16:9], 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
    Stream #0:1[0x80]: Audio: ac3, 48000 Hz, 5.1(side), s16, 448 kb/s
[mpeg @ 03cbd9e0] VBV buffer size not set, muxing may fail
Output #0, mpeg, to 'sintel2.mpg':
  Metadata:
    encoder         : Lavf54.37.100
    Stream #0:0: Video: mpeg1video, yuv420p, 720x480 [SAR 32:27 DAR
16:9], q=2-31, 200 kb/s, 90k tbn, 29.97 tbc
    Stream #0:1: Audio: mp2, 48000 Hz, stereo, s16, 128 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (mpeg2video -> mpeg1video)
  Stream #0:1 -> #0:1 (ac3 -> mp2)
Press [q] to stop, [?] for help
[mpeg2video @ 03cbd600] ac-tex damaged at 40 7
[mpeg2video @ 03cbd600] Warning MVs not available
[mpeg2video @ 03cbd600] concealing 1035 DC, 1035 AC, 1035 MV errors in I frame
frame=  477 fps=247 q=24.8 Lsize=    1194kB time=00:00:15.92 bitrate=
614.2kbits/s dup=42 drop=0
video:932kB audio:249kB subtitle:0 global headers:0kB muxing overhead 1.100762%