Nsryjdtyk

From FFMPEG's GitHub, I use the encode_video.c to generate a 1 second video. Here is the example in question: https://github.com/FFmpeg/FFmpeg/blob/master/doc/examples/encode_video.c

I compile with: gcc -Wall -o ffencode encode_video.c -lavcodec -lavutil -lz -lm

Clean compile, zero warnings.

I test the program by running: ./ffencode video.mp4 libx264

Lots of stats printed out (expected based on source code) as well as ffmpeg logs, but ultimately no errors or warnings.

However, then the generated output video.mp4, can only be played by ffplay, and VLC Player (as well as Google Chrome) fail to play the video.

Playing it via vlc command line actually prints:

[00007ffd3550fec0] main libvlc: Running vlc with the default interface. Use 'cvlc' to use vlc without interface.

TagLib: MP4: Invalid atom size

TagLib: MP4: Invalid atom size

TagLib: MP4: Invalid atom size

Looking at ffprobe output, the bitrate and duration fields are empty:

Input #0, h264, from 'video.mp4':

  Duration: N/A, bitrate: N/A

    Stream #0:0: Video: h264 (High), yuv420p(progressive), 352x288, 25 fps, 25 tbr, 1200k tbn, 50 tbc

I am using ffmpeg 4.1 with the following configuration:

ffprobe version 4.1 Copyright (c) 2007-2018 the FFmpeg developers

  built with Apple LLVM version 10.0.0 (clang-1000.11.45.5)

  configuration: --prefix=/usr/local/Cellar/ffmpeg/4.1 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-gpl --enable-libmp3lame --enable-libopus --enable-libsnappy --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-opencl --enable-videotoolbox

  libavutil      56. 22.100 / 56. 22.100

  libavcodec     58. 35.100 / 58. 35.100

  libavformat    58. 20.100 / 58. 20.100

  libavdevice    58.  5.100 / 58.  5.100

  libavfilter     7. 40.101 /  7. 40.101

  libavresample   4.  0.  0 /  4.  0.  0

  libswscale      5.  3.100 /  5.  3.100

  libswresample   3.  3.100 /  3.  3.100

  libpostproc    55.  3.100 / 55.  3.100

Any ideas how to fix this? It is pretty surprising to see an API's official example to be lacking such basic information.

The example generates a raw bitstream - it is not a MP4. The example is only meant to demonstrate encoding, not muxing (the term for packaging one or more streams into a container file format like MP4).

Rename extension to .h264 and test with VLC. No idea if Chrome supports raw .h264 files.

To generate MP4 from this output, run

ffmpeg -i video.mp4 -c copy actually.mp4

You will need to perform muxing of your video stream into video container, such as .mp4. Muxing stuff is kept in libavformat. Algorithm should go like this:

• Initialize format library by invoking av_register_all or manually registering formats of interests.


• Create muxing context by invoking avformat_alloc_context
  


• Create one or more media streams by invoking avformat_new_stream
  


• Write header by invoking avformat_write_header
  


• Write media data by invoking av_write_frame
  


• Write trailer by invoking av_write_trailer
  


• Destroy muxing context by invoking avformat_free_context