无法播放Libavcodec(ffmpeg)编码示例的视频输出

问题描述

在FFMPEG的GitHub上，我使用 encode_video.c 生成1秒的视频.这是有问题的示例: https://github.com/FFmpeg/FFmpeg/blob/master/doc/examples/encode_video.c

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

我使用以下代码进行编译: gcc -Wall -o ffencode encode_video.c -lavcodec -lavutil -lz -lm

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

干净编译，零警告.

我通过运行以下代码来测试程序: ./ffencode video.mp4 libx264

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

打印出许多统计信息(根据源代码预期)以及ffmpeg日志，但最终没有错误或警告.

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

但是，生成的输出 video.mp4 只能由 ffplay 播放，并且VLC Player(以及Google Chrome)无法播放视频.

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.

通过 vlc 命令行播放它实际上会打印:

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

查看 ffprobe 输出，比特率和持续时间字段为空:

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

我使用具有以下配置的ffmpeg 4.1:

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

有什么办法解决此问题吗?看到API的官方示例缺少此类基本信息，这真是令人惊讶.

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

推荐答案

您将需要将视频流混合到视频容器中，例如 .mp4 .木星的东西保存在libavformat中.算法应该像这样:

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:

• 通过调用 av_register_all 或手动注册感兴趣的格式来初始化格式库.
• 通过调用 avformat_alloc_context
创建混合环境
• 通过调用 avformat_new_stream
创建一个或多个媒体流
• 通过调用 avformat_write_header
编写标题
• 通过调用 av_write_frame
写入媒体数据
• 通过调用 av_write_trailer
编写预告片
• 通过调用 avformat_free_context
破坏混合环境

• 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

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