用ffmpeg从mp4或flv中提取h264原始视频流，生成无效的流 [英] extracting h264 raw video stream from mp4 or flv with ffmpeg generate an invalid stream
问题描述
我正在使用ffmpeg从mp4或flv h264视频（YouTube视频）中提取视频流。原始视频（test.flv）播放ffplay没有麻烦，ffprobe会出现如下错误：
I'm trying to extract the video stream from an mp4 or flv h264 video (youtube video) using ffmpeg. The original video (test.flv) play without trouble with ffplay , ffprobe gives an error as follow:
ffprobe version N-55515-gbbbd959 Copyright (c) 2007-2013 the FFmpeg developers
built on Aug 13 2013 18:06:32 with gcc 4.7.3 (GCC)
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-av
isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
le-iconv --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetyp
e --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --ena
ble-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-l
ibopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libsp
eex --enable-libtheora --enable-libtwolame --enable-libvo-aacenc --enable-libvo-
amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --
enable-libxvid --enable-zlib
libavutil 52. 42.100 / 52. 42.100
libavcodec 55. 27.100 / 55. 27.100
libavformat 55. 13.102 / 55. 13.102
libavdevice 55. 3.100 / 55. 3.100
libavfilter 3. 82.100 / 3. 82.100
libswscale 2. 4.100 / 2. 4.100
libswresample 0. 17.103 / 0. 17.103
libpostproc 52. 3.100 / 52. 3.100
[flv @ 000000000031ea80] Stream discovered after head already parsed
Input #0, flv, from 'test.flv':
Metadata:
starttime : 0
totalduration : 142
totaldatarate : 692
bytelength : 12286492
canseekontime : true
sourcedata : B42B95507HH1381414522145462
purl :
pmsg :
Duration: 00:02:22.02, start: 0.000000, bitrate: 692 kb/s
Stream #0:0: Video: h264 (Main), yuv420p, 640x268, 568 kb/s, 23.98 tbr, 1k t
bn, 47.95 tbc
Stream #0:1: Audio: aac, 44100 Hz, stereo, fltp, 131 kb/s
Stream #0:2: Data: none
Unsupported codec with id 0 for input stream 2
除去额外的流（我只需要视频）我使用以下ffmpeg命令行：
to get rid of the extra streams ( I only needs the video) I used the following ffmpeg command line:
ffmpeg -i test.flv -map 0:0 -vcodec copy -an -f h264 test.h264
新的流无法读取包含ffplay的任何播放器，并给出ffprobe错误：
test.h264：处理inputq = 0B时发现的无效数据f = 0/0
The new stream is unreadable by any player including ffplay and gives an error with ffprobe : test.h264: Invalid data found when processing inputq= 0B f=0/0
任何身体都有一个想法，我做错了什么？
Any body have an idea about what am I doing wrong?
我也尝试了更简单的youtube命令行：
I also tried simpler youtube command line:
ffmpeg -i test.flv -vcodec copy -an test.h264
如果我使用其他格式（例如avi）：
if I use another format (avi for example):
ffmpeg -i test.flv -vcodec copy -an test.avi
如果我转码视频
ffmpeg -i test.flv -an test.h264
输出也有效
任何建议？
推荐答案
要从MP4或FLV容器中提取原始视频，您应该指定 -bsf：v h264_mp4toannexb 或 -vbfs h264_mp4toannexb 选项。
To extract a raw video from an MP4 or FLV container you should specify the -bsf:v h264_mp4toannexb or -vbfs h264_mp4toannexb option.
ffmpeg -i test.flv -vcodec copy -an -bsf:v h264_mp4toannexb test.h264
没有 H264附件B / NAL 的原始流不能由播放器解码。使用该选项，ffmpeg在NAL单元中执行每个h264样本的简单mux。
The raw stream without H264 Annex B / NAL cannot be decode by player. With that option ffmpeg perform a simple "mux" of each h264 sample in a NAL unit.
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