Extracting h264 raw video stream from mp4 or flv with ffmpeg generates invalid stream

Question

I am trying to extract a video stream from mp4 or flv h264 video (youtube video) using ffmpeg. The original video (test.flv) plays without problems with ffplay, ffprobe produces the following error:

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 

to get rid of extra streams (I only need video) I used the following ffmpeg command line:

 ffmpeg -i test.flv -map 0:0 -vcodec copy -an -f h264 test.h264 

The new stream is not read by any player, including ffplay, and gives an error with ffprobe: test.h264: Invalid data found during processing inputq = 0B f = 0/0

Does any body have an idea of ​​what I'm doing wrong?

I also tried the simplified youtube command line:

 ffmpeg -i test.flv -vcodec copy -an test.h264 

if I use another format (e.g. avi):

 ffmpeg -i test.flv -vcodec copy -an test.avi 

the output video is valid.

If I recode a video

 ffmpeg -i test.flv -an test.h264 

the conclusion is also valid

Any suggestions?

Answer 1

To extract raw video from an MP4 or FLV container, you must specify the -bsf:v h264_mp4toannexb option -bsf:v h264_mp4toannexb or -vbfs h264_mp4toannexb .

 ffmpeg -i test.flv -vcodec copy -an -bsf:v h264_mp4toannexb test.h264 

Raw stream without H264 The B / NAL application cannot be decoded by the player. With this option, ffmpeg performs a simple “multiplex” of each h264 sample in the NAL block.