ffmpeg尝试创建mpeg视频时出错

Question

I am having trouble creating mpeg files, I have 2 bitmaps (2592*2160 32bit). I am trying to combine them into an mpeg file but I cant get it to work, the command I have tried is:

ffmpeg -i %d.bmp -b:v 99.99M -r 1 -s 2592x2160 vid.mpg

the output is

ffmpeg -i %d.bmp -b:v 99.99M -r 1 -s 2592x2160  vid.mpg
ffmpeg version N-41416-g718607b Copyright (c) 2000-2012 the FFmpeg developers
  built on Jun  8 2012 12:46:19 with gcc 4.6.3
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-ru
ntime-cpudetect --enable-avisynth --enable-bzlib --enable-frei0r --enable-libass
 --enable-libcelt --enable-libopencore-amrnb --enable-libopencore-amrwb --enable
-libfreetype --enable-libgsm --enable-libmp3lame --enable-libnut --enable-libope
njpeg --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libth
eora --enable-libutvideo --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-
libvorbis --enable-libvpx --ena  libavutil      51. 56.100 / 51. 56.100
  libavcodec     54. 25.100 / 54. 25.100
  libavformat    54.  6.101 / 54.  6.101
  libavdevice    54.  0.100 / 54.  0.100
  libavfilter     2. 78.101 /  2. 78.101
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0. 15.100 /  0. 15.100
  libpostproc    52.  0.100 / 52.  0.100
[image2 @ 01e6be40] Stream #0: not enough frames to estimate rate; consider incr
easing probesize
Input #0, image2, from '%d.bmp':
  Duration: 00:00:00.08, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: bmp, pal8, 2592x2160, 25 tbr, 25 tbn, 25 tbc
File 'vid.mpg' already exists. Overwrite ? [y/N] y
w:2592 h:2160 pixfmt:pal8 tb:1/25 sar:0/1 sws_param:flags=2
[ffmpeg_buffersink @ 02bb3ce0] No opaque field provided
[scale @ 02bb3f20] w:2592 h:2160 fmt:pal8 sar:0/1 -> w:2592 h:2160 fmt:yuv420p s
ar:0/1 flags:0x4
[mpeg1video @ 02b864a0] bitrate tolerance too small for bitrate
Output #0, mpeg, to 'vid.mpg':
    Stream #0:0: Video: mpeg1video, yuv420p, 2592x2160, q=2-31, 99990 kb/s, 90k
tbn, 5 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (bmp -> mpeg1video)
Error while opening encoder for output stream #0:0 - maybe incorrect parameters
such as bit_rate, rate, width or height

If I leave out the -r parameter (ffmpeg -i %d.bmp -b:v 99.99M -s 2592x2160 vid.mpg) the output changes to:

[mpeg @ 02f80120] buffer underflow i=0 bufi=749380 size=950639
[mpeg @ 02f80120] buffer underflow i=0 bufi=751421 size=950639
[mpeg @ 02f80120] packet too large, ignoring buffer limits to mux it
[mpeg @ 02f80120] buffer underflow i=0 bufi=751421 size=950639
[mpeg @ 02f80120] buffer underflow i=0 bufi=753462 size=950639
[mpeg @ 02f80120] packet too large, ignoring buffer limits to mux it
[mpeg @ 02f80120] buffer underflow i=0 bufi=753462 size=950639
[mpeg @ 02f80120] buffer underflow i=0 bufi=755503 size=950639
...

what am I doing wrong?

Answer 1

You're getting the first error because I don't think ffmpeg reads the "M" character for millions, so it's reading your parameter as 99.99 kb/s, which is not nearly high enough to handle what you want to do, hence the "bitrate tolerance too small for bitrate" warning. Try specifying your bitrate in ###k using something large enough and it should go forward. As for the second part, the reason it partially works when you leave out the -r parameter is because the mpeg container doesn't support many different frame rates. So, if you want a video that forces a frame rate to be 1 frame per second, you'll need to use a different container. Also, with the current placement of the -r parameter, all you're saying is that the output video will play at one frame per second, not that each bitmap will represent one frame in the video. To do the latter, you need to specify the input frame rate before you specify the input.

For example, to make a two second avi video (one bitmap per second in this case) with the bitrate you specified, you'd want to do something like:

ffmpeg -r 1 -i %d.bmp -b:v 990k -s 2592x2160 vid.avi