我想将我的h.264 avi容器转换为带有ffmpeg的mp4容器。我发现这有效：
./ffmpeg -i myfile.avi -vcodec copy myfile.mp4
ffmpeg version N-51169-gcedf276 Copyright (c) 2000-2013 the FFmpeg developers
built on Mar 21 2013 05:12:00 with gcc 4.6 (Debian 4.6.3-1)
configuration: --prefix=/root/ffmpeg-static/32bit --arch=x86_32 --extra-cflags='-m32 -I/root/ffmpeg-static/32bit/include -static' --extra-ldflags='-m32 -L/root/ffmpeg-static/32bit/lib -static' --extra-libs='-lxml2 -lexpat -lfreetype' --enable-static --disable-shared --disable-ffserver --disable-doc --enable-bzlib --enable-zlib --enable-postproc --enable-runtime-cpudetect --enable-libx264 --enable-gpl --enable-libtheora --enable-libvorbis --enable-libmp3lame --enable-gray --enable-libass --enable-libfreetype --enable-libopenjpeg --enable-libspeex --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-version3 --enable-libvpx
libavutil 52. 22.100 / 52. 22.100
libavcodec 55. 1.100 / 55. 1.100
libavformat 55. 0.100 / 55. 0.100
libavdevice 55. 0.100 / 55. 0.100
libavfilter 3. 48.100 / 3. 48.100
libswscale 2. 2.100 / 2. 2.100
libswresample 0. 17.102 / 0. 17.102
libpostproc 52. 2.100 / 52. 2.100
[avi @ 0x9fff660] non-interleaved AVI
Guessed Channel Layout for Input Stream #0.1 : mono
Input #0, avi, from 'myfile.avi':
Metadata:
encoder : Lavf52.64.2
Duration: 00:00:10.40, start: 0.000000, bitrate: 409 kb/s
Stream #0:0: Video: h264 (Baseline) (H264 / 0x34363248), yuvj420p, 640x480, 10 fps, 10 tbr, 10 tbn, 30 tbc
Stream #0:1: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 8000 Hz, mono, s16, 128 kb/s
Output #0, mp4, to 'myfile.mp4':
Metadata:
encoder : Lavf55.0.100
Stream #0:0: Video: h264 ([33][0][0][0] / 0x0021), yuvj420p, 640x480, q=2-31, 10 fps, 10240 tbn, 10 tbc
Stream #0:1: Audio: aac ([64][0][0][0] / 0x0040), 8000 Hz, mono, s16, 128 kb/s
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Stream #0:1 -> #0:1 (pcm_s16le -> libvo_aacenc)
Press [q] to stop, [?] for help
[mp4 @ 0xa006ea0] pts has no value
Last message repeated 100 times
frame= 101 fps=0.0 q=-1.0 Lsize= 350kB time=00:00:11.06 bitrate= 259.3kbits/s
video:332kB audio:15kB subtitle:0 global headers:0kB muxing overhead 0.926809%
这会生成一个我可以使用HTML5视频播放器播放的文件，但对于旧版浏览器，我想使用Flash播放器（Flowplayer）。该文件不能与Flowplayer一起使用，实际上它会导致它崩溃。
但是，如果我使用：
./ffmpeg -i myfile.avi myfile2.mp4
ffmpeg version N-51169-gcedf276 Copyright (c) 2000-2013 the FFmpeg developers
built on Mar 21 2013 05:12:00 with gcc 4.6 (Debian 4.6.3-1)
configuration: --prefix=/root/ffmpeg-static/32bit --arch=x86_32 --extra-cflags='-m32 -I/root/ffmpeg-static/32bit/include -static' --extra-ldflags='-m32 -L/root/ffmpeg-static/32bit/lib -static' --extra-libs='-lxml2 -lexpat -lfreetype' --enable-static --disable-shared --disable-ffserver --disable-doc --enable-bzlib --enable-zlib --enable-postproc --enable-runtime-cpudetect --enable-libx264 --enable-gpl --enable-libtheora --enable-libvorbis --enable-libmp3lame --enable-gray --enable-libass --enable-libfreetype --enable-libopenjpeg --enable-libspeex --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-version3 --enable-libvpx
libavutil 52. 22.100 / 52. 22.100
libavcodec 55. 1.100 / 55. 1.100
libavformat 55. 0.100 / 55. 0.100
libavdevice 55. 0.100 / 55. 0.100
libavfilter 3. 48.100 / 3. 48.100
libswscale 2. 2.100 / 2. 2.100
libswresample 0. 17.102 / 0. 17.102
libpostproc 52. 2.100 / 52. 2.100
[avi @ 0x9b02660] non-interleaved AVI
Guessed Channel Layout for Input Stream #0.1 : mono
Input #0, avi, from 'myfile.avi':
Metadata:
encoder : Lavf52.64.2
Duration: 00:00:10.40, start: 0.000000, bitrate: 409 kb/s
Stream #0:0: Video: h264 (Baseline) (H264 / 0x34363248), yuvj420p, 640x480, 10 fps, 10 tbr, 10 tbn, 30 tbc
Stream #0:1: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 8000 Hz, mono, s16, 128 kb/s
No pixel format specified, yuvj420p for H.264 encoding chosen.
Use -pix_fmt yuv420p for compatibility with outdated media players.
[libx264 @ 0x9b065a0] using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle SSE4.1 Cache64
[libx264 @ 0x9b065a0] profile High, level 2.2
[libx264 @ 0x9b065a0] 264 - core 129 r2230 1cffe9f - H.264/MPEG-4 AVC codec - Copyleft 2003-2012 - 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=1 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=10 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, mp4, to 'myfile2.mp4':
Metadata:
encoder : Lavf55.0.100
Stream #0:0: Video: h264 ([33][0][0][0] / 0x0021), yuvj420p, 640x480, q=-1--1, 10240 tbn, 10 tbc
Stream #0:1: Audio: aac ([64][0][0][0] / 0x0040), 8000 Hz, mono, s16, 128 kb/s
Stream mapping:
Stream #0:0 -> #0:0 (h264 -> libx264)
Stream #0:1 -> #0:1 (pcm_s16le -> libvo_aacenc)
Press [q] to stop, [?] for help
frame= 47 fps=0.0 q=25.0 size= 21kB time=00:00:04.40 bitrate= 39.9kbits/s dup=3 dropframe= 59 fps= 56 q=25.0 size= 56kB time=00:00:05.68 bitrate= 80.2kbits/s dup=3 dropframe= 71 fps= 45 q=25.0 size= 89kB time=00:00:06.84 bitrate= 106.9kbits/s dup=3 dropframe= 83 fps= 40 q=25.0 size= 124kB time=00:00:08.12 bitrate= 124.9kbits/s dup=3 dropframe= 94 fps= 36 q=25.0 size= 157kB time=00:00:09.14 bitrate= 140.4kbits/s dup=4 dropframe= 105 fps= 23 q=25.0 Lsize= 309kB time=00:00:11.06 bitrate= 228.8kbits/s dup=4 drop=0
video:291kB audio:15kB subtitle:0 global headers:0kB muxing overhead 1.108651%
[libx264 @ 0x9b065a0] frame I:1 Avg QP:17.65 size: 12772
[libx264 @ 0x9b065a0] frame P:94 Avg QP:19.46 size: 2868
[libx264 @ 0x9b065a0] frame B:10 Avg QP:21.58 size: 1464
[libx264 @ 0x9b065a0] consecutive B-frames: 82.9% 13.3% 0.0% 3.8%
[libx264 @ 0x9b065a0] mb I I16..4: 16.6% 66.3% 17.1%
[libx264 @ 0x9b065a0] mb P I16..4: 4.2% 6.3% 0.5% P16..4: 27.0% 9.5% 5.1% 0.0% 0.0% skip:47.4%
[libx264 @ 0x9b065a0] mb B I16..4: 0.8% 1.0% 0.0% B16..8: 39.1% 4.6% 0.5% direct: 2.4% skip:51.7% L0:39.8% L1:56.4% BI: 3.9%
[libx264 @ 0x9b065a0] 8x8 transform intra:58.0% inter:74.7%
[libx264 @ 0x9b065a0] coded y,uvDC,uvAC intra: 47.3% 0.0% 0.0% inter: 16.6% 0.0% 0.0%
[libx264 @ 0x9b065a0] i16 v,h,dc,p: 29% 19% 10% 42%
[libx264 @ 0x9b065a0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 31% 21% 29% 2% 3% 4% 4% 3% 3%
[libx264 @ 0x9b065a0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 39% 28% 18% 2% 3% 3% 3% 2% 2%
[libx264 @ 0x9b065a0] i8c dc,h,v,p: 100% 0% 0% 0%
[libx264 @ 0x9b065a0] Weighted P-Frames: Y:5.3% UV:0.0%
[libx264 @ 0x9b065a0] ref P L0: 67.9% 12.0% 12.6% 6.8% 0.6%
[libx264 @ 0x9b065a0] ref B L0: 76.9% 23.1%
[libx264 @ 0x9b065a0] ref B L1: 99.7% 0.3%
[libx264 @ 0x9b065a0] kb/s:226.31
这很有效。但是时间差异很大，更不用说CPU周期了。第一个命令以毫秒为单位测量，而第二个命令则需要相当长的时间（~5-40秒）。
还有另一种方法可以快速将avi转换为mp4容器吗？理想情况下，通过重新复用而不是重新编码。
编辑
我现在正在使用它，我发现它是重新编码最快的。但我再次不愿意这样做。我只是想重新编写代码。
ffmpeg -loglevel quiet -i myfile.avi -vcodec libx264 -profile:v baseline -preset ultrafast myfile.mp4
答案 0 :(得分：6)
我不会以你做过的方式做得与众不同。我尝试在OS X 10.7上用ffmpeg-1.2重新启动文件：
ffmpeg --info
ffmpeg version 1.2 Copyright (c) 2000-2013 the FFmpeg developers
built on Apr 8 2013 02:39:03 with Apple LLVM version 4.2 (clang-425.0.27) (based on LLVM 3.2svn)
我尝试了你的命令并明确地
ffmpeg -i myfile.avi -vcodec copy -acodec copy out.mp4
但我总是遇到以下错误：
ffmpeg -i myfile.avi -vcodec copy -acodec copy out.mp4
ffmpeg version 1.2 Copyright (c) 2000-2013 the FFmpeg developers
built on Apr 8 2013 02:39:03 with Apple LLVM version 4.2 (clang-425.0.27) (based on LLVM 3.2svn)
configuration: --prefix=/usr/local/Cellar/ffmpeg/1.2 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-nonfree --enable-hardcoded-tables --enable-avresample --enable-vda --cc=cc --host-cflags= --host-ldflags= --enable-libx264 --enable-libfaac --enable-libmp3lame --enable-libxvid
libavutil 52. 18.100 / 52. 18.100
libavcodec 54. 92.100 / 54. 92.100
libavformat 54. 63.104 / 54. 63.104
libavdevice 54. 3.103 / 54. 3.103
libavfilter 3. 42.103 / 3. 42.103
libswscale 2. 2.100 / 2. 2.100
libswresample 0. 17.102 / 0. 17.102
libpostproc 52. 2.100 / 52. 2.100
[avi @ 0x7f9ef981ae00] non-interleaved AVI
Guessed Channel Layout for Input Stream #0.1 : mono
Input #0, avi, from 'myfile.avi':
Metadata:
encoder : Lavf52.64.2
Duration: 00:00:10.40, start: 0.000000, bitrate: 409 kb/s
Stream #0:0: Video: h264 (Baseline) (H264 / 0x34363248), yuvj420p, 640x480, 10 fps, 10 tbr, 10 tbn, 30 tbc
Stream #0:1: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 8000 Hz, mono, s16, 128 kb/s
[mp4 @ 0x7f9ef991ac00] Tag [1][0][0][0]/0x00000001 incompatible with output codec id '65536' ([0][0][0][0])
Output #0, mp4, to 'out.mp4':
Metadata:
encoder : Lavf52.64.2
Stream #0:0: Video: h264 ([33][0][0][0] / 0x0021), yuvj420p, 640x480, q=2-31, 10 fps, 90k tbn, 10 tbc
Stream #0:1: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 8000 Hz, mono, 128 kb/s
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Stream #0:1 -> #0:1 (copy)
Could not write header for output file #0 (incorrect codec parameters ?): Invalid data found when processing input
所以我对错误编号进行了快速研究，发现pcm_s16le与mp4不兼容。请参阅此bug report on the ffmpeg tracker。
这可能会解释两个命令的不同结果 - 虽然奇怪的是它没有在你的情况下产生错误（旧的ffmpeg快照？）。
所以我想解决方案可能是/将会从一开始就提供不同的音频编解码器，或者将音轨转换为不同的编解码器。作为一个快速测试我试过：
ffmpeg -i myfile.avi -vcodec copy -acodec mp2 out.mp4
输出文件立即写入磁盘 - 没有产生任何错误。不幸的是，我没有办法用flash播放器验证结果。