[FFmpeg-trac] #3494(undetermined:new): scary warning message when using mpeg

[FFmpeg]

#3494: scary warning message when using mpeg
-------------------------------------+-------------------------------------
             Reporter:  rogerdpack   |                     Type:
               Status:  new          |  enhancement
            Component:               |                 Priority:  normal
  undetermined                       |                  Version:
             Keywords:               |  unspecified
             Blocking:               |               Blocked By:
Analyzed by developer:  0            |  Reproduced by developer:  0
-------------------------------------+-------------------------------------
 Summary of the bug: warning message output when using mpeg with default
 values.

 Specifically:
 $ ffmpeg -f lavfi -i testsrc yo.mpg
 ...
 [mpeg @ 026ed0c0] VBV buffer size not set, muxing may fail

 I doubt that using default "muxing may fail" could this error message be
 clarified somehow?  Or are the defaults not enough and muxing might fail?
 It makes it feel like muxing to mpg by default "might be broken"

 How to reproduce:
 {{{
 ffmpeg -f lavfi -i testsrc yo.mpg
 ffmpeg version N-61760-g5df8dfe Copyright (c) 2000-2014 the FFmpeg
 developers
   built on Mar 24 2014 11:42:36 with gcc 4.8.2 (GCC)
   configuration: --arch=x86 --target-os=mingw32 --cross-
 prefix=/home/rogerdpack/dev/ffmpeg-windows-build-
 helpers/sandbox/mingw-w64-i686/bin/i686-w64-mingw32- --pkg-config=pkg-
 config --enable-gpl --enable-libx264 --enable-avisynth --enable-libxvid
 --enable-libmp3lame --enable-version3 --enable-zlib --enable-librtmp
 --enable-libvorbis --enable-libtheora --enable-libspeex --enable-
 libopenjpeg --enable-gnutls --enable-libgsm --enable-libfreetype --enable-
 libopus --disable-w32threads --enable-frei0r --enable-filter=frei0r
 --enable-libvo-aacenc --enable-bzlib --enable-libxavs --extra-
 cflags=-DPTW32_STATIC_LIB --enable-libopencore-amrnb --enable-libopencore-
 amrwb --enable-libvo-amrwbenc --enable-libschroedinger --enable-libvpx
 --enable-libilbc --prefix=/home/rogerdpack/dev/ffmpeg-windows-build-
 helpers/sandbox/mingw-w64-i686/i686-w64-mingw32 --enable-static --disable-
 shared --enable-libsoxr --enable-fontconfig --enable-libass --enable-
 libutvideo --enable-libbluray --enable-iconv --enable-libtwolame --extra-
 cflags=-DLIBTWOLAME_STATIC --enable-libzvbi --enable-libcaca --enable-
 libmodplug --extra-libs=-lstdc++ --extra-libs=-lpng --enable-libvidstab
 --enable-libx265 --extra-cflags= --extra-cflags= --enable-runtime-
 cpudetect
   libavutil      52. 67.100 / 52. 67.100
   libavcodec     55. 52.103 / 55. 52.103
   libavformat    55. 34.101 / 55. 34.101
   libavdevice    55. 11.100 / 55. 11.100
   libswscale      2.  5.102 /  2.  5.102
   libswresample   0. 18.100 /  0. 18.100
   libpostproc    52.  3.100 / 52.  3.100
 Input #0, lavfi, from 'testsrc':
   Duration: N/A, start: 0.000000, bitrate: N/A
     Stream #0:0: Video: rawvideo (RGB[24] / 0x18424752), rgb24, 320x240
 [SAR 1:1 DAR 4:3], 25 tbr, 25 tbn, 25 tbc
 File 'yo.mpg' already exists. Overwrite ? [y/N] y
 [mpeg @ 026ed0c0] VBV buffer size not set, muxing may fail
 Output #0, mpeg, to 'yo.mpg':
   Metadata:
     encoder         : Lavf55.34.101
     Stream #0:0: Video: mpeg1video, yuv420p, 320x240 [SAR 1:1 DAR 4:3],
 q=2-31,
  200 kb/s, 90k tbn, 25 tbc
 Stream mapping:
   Stream #0:0 -> #0:0 (rawvideo -> mpeg1video)
 Press [q] to stop, [?] for help
 frame=  330 fps=0.0 q=3.2 size=     520kB time=00:00:13.12 bitrate=
 324.7kbits/frame=  675 fps=674 q=5.7 size=     946kB time=00:00:26.92
 bitrate= 287.9kbits/frame=  950 fps=674 q=5.9 Lsize=    1242kB
 time=00:00:37.96 bitrate= 268.0kbits/s
 video:1231kB audio:0kB subtitle:0 data:0 global headers:0kB muxing
 overhead 0.889020%
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/3494>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker