video - 将 'timeout' 标志添加到 ffprobe/ffmpeg 会导致它立即失败

Question

如果我运行 ffprobe -timeout 20 -v trace -print_format json -show_format -show_streams 'http://www.sample-videos.com/video/mp4/720/big_buck_bunny_720p_2mb.mp4' ，即使我将超时设置为 20 秒，该命令也会立即失败并出现 Connection timed out 错误。它不会等待接近 20 秒，而是立即退出，退出代码为 1。这是跟踪输出。

ffprobe version 3.2.2 Copyright (c) 2007-2016 the FFmpeg developers
  built with gcc 6.2.1 (GCC) 20160830
  configuration: --prefix=/usr --disable-debug --disable-static --disable-stripping --enable-avisynth --enable-avresample --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl --enable-ladspa --enable-libass --enable-libbluray --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libiec61883 --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-netcdf --enable-shared --enable-version3 --enable-x11grab
  libavutil      55. 34.100 / 55. 34.100
  libavcodec     57. 64.101 / 57. 64.101
  libavformat    57. 56.100 / 57. 56.100
  libavdevice    57.  1.100 / 57.  1.100
  libavfilter     6. 65.100 /  6. 65.100
  libavresample   3.  1.  0 /  3.  1.  0
  libswscale      4.  2.100 /  4.  2.100
  libswresample   2.  3.100 /  2.  3.100
  libpostproc    54.  1.100 / 54.  1.100
{
[http @ 0x5598e7df1e20] Setting default whitelist 'http,https,tls,rtp,tcp,udp,crypto,httpproxy'
[http @ 0x5598e7df1e20] request: GET /video/mp4/720/big_buck_bunny_720p_2mb.mp4 HTTP/1.1
User-Agent: Lavf/57.56.100
Accept: */*
Range: bytes=0-
Connection: close
Host: www.sample-videos.com
Icy-MetaData: 1


http://www.sample-videos.com/video/mp4/720/big_buck_bunny_720p_2mb.mp4: Connection timed out

}

如果我删除 -timeout 20 标志，该命令可以正常工作。如何让 ffprobe 处理超时？

Answer 1

-timeout的单位在各个协议(protocol)中是不同的。

在 HTTP 中，单位是微秒。