我在使用 ffmpeg 转换 .flv 视频时遇到问题。输出文件格式的扩展名也是 .flv。这是我的命令：
ffmpeg -i 8617854d-77e1-4538-b7ea-2853bcb06ee2.flv -s 400x240 -vcodec flv -b 500k -r 18000000/642857 -ar 11025 -y out.flv
错误：
[buffer @ 0x23bf080] Changing frame properties on the fly is not supported
这是终端上的输出消息：
Seems stream 0 codec frame rate differs from container frame rate: 28.00 (18000000/642857) -> 14.00 (18000000/1285714)
Input #0, flv, from '8617854d-77e1-4538-b7ea-2853bcb06ee2.flv':
Metadata:
creationdate : Wed Jan 29 09:14:32
Duration: 00:03:37.21,
start: 0.007000,
bitrate: N/A Stream #0.0: Video: h264 (Baseline), yuv420p, 264x198 [PAR 1:1 DAR 4:3], 14 tbr, 1k tbn, 28 tbc
Stream #0.1: Audio: libspeex, 16000 Hz, 1 channels, s16
[buffer @ 0x23bf080] w:264 h:198 pixfmt:yuv420p
[scale @ 0x23c1040] w:264 h:198 fmt:yuv420p -> w:400 h:240 fmt:yuv420p flags:0x4
[libspeex @ 0x23bc880] Missing Speex header, assuming defaults.
Output #0, flv, to 'out.flv':
Metadata:
creationdate : Wed Jan 29 09:14:32
encoder : Lavf53.21.1
Stream #0.0: Video: flv, yuv420p, 400x240 [PAR 4:5 DAR 4:3], q=2-31, 500 kb/s, 1k tbn, 28 tbc
Stream #0.1: Audio: libmp3lame, 11025 Hz, 1 channels, s16, 500 kb/s
Stream mapping:
Stream #0.0 -> #0.0
Stream #0.1 -> #0.1
Press ctrl-c to stop encoding
[buffer @ 0x23bf080] Changing frame properties on the fly is not supported.
Last message repeated 1562 times
420kB time=9.71 bitrate= 353.8kbits/s
frame= 71 fps= 24 q=2.5 Lsize= 2104kB time=9.71 bitrate=1774.3kbits/s
video:339kB audio:1698kB global headers:0kB muxing overhead 3.262082%
我目前正在使用 Debian 系统（Wheezy），ffmpeg 版本为 0.8.9-6:0.8.9-1。
更新：
将当前安装更新为“git-2014-01-31-dd4237f”。
我的主要目的是转换视频以填补元信息中的一些空白，例如视频比特率、音频比特率等，这些似乎在文件中缺失。输入文件是网络摄像头录制的文件（通过“OpenTok”录制），这导致视频无法在诸如 flowplayer 之类的 flash 播放器上播放。这是最新 ffmpeg 版本的完整输出：
ffmpeg -i a91274db-595c-43cc-86f5-30824d4c9527 -vcodec libx264 -acodec copy -s 400x240 -ar 22050 -y out.flv
ffmpeg version git-2014-01-31-dd4237f Copyright (c) 2000-2014 the FFmpeg developers
built on Jan 31 2014 06:24:45 with gcc 4.7 (Debian 4.7.2-5)
configuration: --prefix=/home/user/ffmpeg_build --extra-cflags=-I/home/user/ffmpeg_build/include --extra-ldflags=-L/home/user/ffmpeg_build/lib --bindir=/home/user/bin --extra-libs=-ldl --enable-gpl --enable-libass --enable-libfdk-aac --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-nonfree --enable-x11grab
libavutil 52. 63.100 / 52. 63.100
libavcodec 55. 49.101 / 55. 49.101
libavformat 55. 28.101 / 55. 28.101
libavdevice 55. 7.100 / 55. 7.100
libavfilter 4. 1.101 / 4. 1.101
libswscale 2. 5.101 / 2. 5.101
libswresample 0. 17.104 / 0. 17.104
libpostproc 52. 3.100 / 52. 3.100
[h264 @ 0x2c00460] AVC: nal size 21102612
[h264 @ 0x2c00460] missing picture in access unit with size 61
Input #0, flv, from 'a91274db-595c-43cc-86f5-30824d4c9527':
Metadata:
creationdate : Mon Feb 3 08:11:35
Duration: 00:05:44.74, start: 0.000000, bitrate: 184 kb/s
Stream #0:0: Video: h264 (Baseline), yuv420p(tv), 264x198 [SAR 1:1 DAR 4:3], 14.08 fps, 7.50 tbr, 1k tbn, 28 tbc
Stream #0:1: Audio: speex, 16000 Hz, mono
[libx264 @ 0x2c1fc40] using SAR=4/5
[libx264 @ 0x2c1fc40] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
[libx264 @ 0x2c1fc40] profile High, level 1.2
[libx264 @ 0x2c1fc40] 264 - core 142 r2 956c8d8 - H.264/MPEG-4 AVC codec - Copyleft 2003-2014 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=12 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=7 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, flv, to 'out.flv':
Metadata:
creationdate : Mon Feb 3 08:11:35
encoder : Lavf55.28.101
Stream #0:0: Video: h264 (libx264) ([7][0][0][0] / 0x0007), yuv420p, 400x240 [SAR 4:5 DAR 4:3], q=-1--1, 1k tbn, 7.50 tbc
Stream #0:1: Audio: speex ([11][0][0][0] / 0x000B), 16000 Hz, mono
Stream mapping:
Stream #0:0 -> #0:0 (h264 -> libx264)
Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
[h264 @ 0x2c00460] AVC: nal size 21102612
[h264 @ 0x2c00460] missing picture in access unit with size 61
[flv @ 0x2c07800] Warning: Speex stream has more than 8 frames per packet. Adobe Flash Player cannot handle this!
[h264 @ 0x2c00460] AVC: nal size 21102612
[h264 @ 0x2c00460] missing picture in access unit with size 61
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x3966f40] Reinit context to 416x320, pix_fmt: yuv420p
Input stream #0:0 frame changed from size:264x198 fmt:yuv420p to size:416x312 fmt:yuv420p
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613B time=00:00:31.80 bitrate= 98.3kbits/s dup=0 drop=7
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613B time=00:01:07.63 bitrate= 93.2kbits/s dup=0 drop=7
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613B time=00:01:42.55 bitrate= 92.1kbits/s dup=0 drop=7
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613B time=00:02:17.71 bitrate= 92.4kbits/s dup=0 drop=7
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613B time=00:02:50.23 bitrate= 95.1kbits/s dup=0 drop=7
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613B time=00:03:25.83 bitrate= 94.0kbits/s dup=0 drop=7
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613B time=00:03:59.67 bitrate= 95.3kbits/s dup=0 drop=7
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613B time=00:04:36.85 bitrate= 93.9kbits/s dup=0 drop=7
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613B time=00:05:11.11 bitrate= 94.2kbits/s dup=0 drop=7
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
[h264 @ 0x2c00460] AVC: nal size 21102613
[h264 @ 0x2c00460] missing picture in access unit with size 60
frame= 2582 fps=505 q=-1.0 Lsize= 4120kB time=00:05:44.73 bitrate= 97.9kbits/s dup=0 drop=7
video:3596kB audio:203kB subtitle:0 data:0 global headers:0kB muxing overhead 8.423537%
[libx264 @ 0x2c1fc40] frame I:12 Avg QP:16.00 size: 13286
[libx264 @ 0x2c1fc40] frame P:768 Avg QP:18.47 size: 3684
[libx264 @ 0x2c1fc40] frame B:1802 Avg QP:22.03 size: 385
[libx264 @ 0x2c1fc40] consecutive B-frames: 3.9% 6.7% 7.7% 81.8%
[libx264 @ 0x2c1fc40] mb I I16..4: 7.4% 55.1% 37.5%
[libx264 @ 0x2c1fc40] mb P I16..4: 2.1% 4.5% 1.1% P16..4: 37.9% 25.8% 15.0% 0.0% 0.0% skip:13.7%
[libx264 @ 0x2c1fc40] mb B I16..4: 0.1% 0.2% 0.0% B16..8: 32.7% 3.3% 0.5% direct: 1.5% skip:61.6% L0:40.5% L1:52.3% BI: 7.2%
[libx264 @ 0x2c1fc40] 8x8 transform intra:57.9% inter:60.8%
[libx264 @ 0x2c1fc40] coded y,uvDC,uvAC intra: 55.0% 68.7% 41.5% inter: 16.3% 22.2% 2.6%
[libx264 @ 0x2c1fc40] i16 v,h,dc,p: 19% 20% 5% 56%
[libx264 @ 0x2c1fc40] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 20% 23% 20% 5% 7% 6% 8% 6% 7%
[libx264 @ 0x2c1fc40] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 31% 21% 12% 5% 7% 6% 7% 6% 6%
[libx264 @ 0x2c1fc40] i8c dc,h,v,p: 51% 20% 22% 6%
[libx264 @ 0x2c1fc40] Weighted P-Frames: Y:4.2% UV:2.2%
[libx264 @ 0x2c1fc40] ref P L0: 57.4% 13.0% 22.6% 6.9% 0.1%
[libx264 @ 0x2c1fc40] ref B L0: 86.4% 11.2% 2.4%
[libx264 @ 0x2c1fc40] ref B L1: 95.6% 4.4%
[libx264 @ 0x2c1fc40] kb/s:85.40
“访问单元中缺少具有尺寸的图片”是什么意思？
提前致谢 。