audio - 如何仅选择视频中的两个音频流并将其馈送到ffmpeg中的ebur128过滤器？

Question

我想使用FFmpeg分析MXF视频文件的响度。
我有一个包含8个单声道音频流的MXF文件。我只想通过ebur128过滤器提供前两个流。但是我找不到办法。 FFmpeg文档对我来说还不清楚，因为我对FFmpeg相当陌生。

我尝试了几件事:

ffmpeg -i source.mxf -nostats -filter_complex ebur128=dualmono=true:panlaw=-3.01dB -f null -

我敢肯定，只是我没有正确的过滤语法。但是，嘿...我是新手...

ffmpeg -i myVideo.mxf -nostats -filter_complex [0:a:0][0:a:1]amerge; ebur128=dualmono=true:panlaw=-3.01 -f null -

这是结果控制台输出:

ffmpeg version 2.8.6 Copyright (c) 2000-2016 the FFmpeg developers
built with llvm-gcc 4.2.1 (LLVM build 2336.11.00)
configuration: --prefix=/Volumes/Ramdisk/sw --enable-gpl --enable-        pthreads --enable-version3 --enable-libspeex --enable-libvpx --disable-decoder=libvpx --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libx264 --enable-avfilter --enable-libopencore_amrwb --enable-libopencore_amrnb --enable-filters --enable-libgsm --enable-libvidstab --enable-libx265 --disable-doc --arch=x86_64 --enable-runtime-cpudetect
libavutil      54. 31.100 / 54. 31.100
libavcodec     56. 60.100 / 56. 60.100
libavformat    56. 40.101 / 56. 40.101
libavdevice    56.  4.100 / 56.  4.100
libavfilter     5. 40.101 /  5. 40.101
libswscale      3.  1.101 /  3.  1.101
libswresample   1.  2.101 /  1.  2.101
libpostproc    53.  3.100 / 53.  3.100

Guessed Channel Layout for  Input Stream #0.1 : mono
Guessed Channel Layout for  Input Stream #0.2 : mono
Guessed Channel Layout for  Input Stream #0.3 : mono
Guessed Channel Layout for  Input Stream #0.4 : mono
Guessed Channel Layout for  Input Stream #0.5 : mono
Guessed Channel Layout for  Input Stream #0.6 : mono
Guessed Channel Layout for  Input Stream #0.7 : mono
Guessed Channel Layout for  Input Stream #0.8 : mono
Input #0, mxf, from 'myVideo.mxf':
Metadata:
uid             : a727a381-1f5a-11e7-bdc8-18af61b92a5a
generation_uid  : a727a382-1f5a-11e7-9a04-18af61b92a5a
company_name    : Adobe Systems Incorporated
product_name    : Adobe Media Encoder
product_version : 11.0.2
application_platform: Mac OS X
product_uid     : 0c3919fe-46e8-11e5-a151-feff819cdc9f
modification_date: 2017-04-12 08:33:07
material_package_umid: 0x060A2B340101010501010D1113000000A0C9D501557805A5DF7018AF61B92A5A
timecode        : 00:00:00:00
Duration: 00:05:24.08, start: 0.000000, bitrate: 59986 kb/s
Stream #0:0: Video: mpeg2video (4:2:2), yuv422p(tv, unknown/bt709/bt709), 1920x1080 [SAR 1:1 DAR 16:9], 50000 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc
Metadata:
  file_package_umid: 0x060A2B340101010501010D12133A5D15A0C9D501557805A5B09318AF61B92A5A
  file_package_name: Source Package
Stream #0:1: Audio: pcm_s24le, 48000 Hz, 1 channels, s32 (24 bit), 1152 kb/s
Metadata:
  file_package_umid: 0x060A2B340101010501010D12133A5D15A0C9D501557805A5B09318AF61B92A5A
  file_package_name: Source Package
Stream #0:2: Audio: pcm_s24le, 48000 Hz, 1 channels, s32 (24 bit), 1152 kb/s
Metadata:
  file_package_umid: 0x060A2B340101010501010D12133A5D15A0C9D501557805A5B09318AF61B92A5A
  file_package_name: Source Package
Stream #0:3: Audio: pcm_s24le, 48000 Hz, 1 channels, s32 (24 bit), 1152 kb/s
Metadata:
  file_package_umid: 0x060A2B340101010501010D12133A5D15A0C9D501557805A5B09318AF61B92A5A
  file_package_name: Source Package
Stream #0:4: Audio: pcm_s24le, 48000 Hz, 1 channels, s32 (24 bit), 1152 kb/s
Metadata:
  file_package_umid: 0x060A2B340101010501010D12133A5D15A0C9D501557805A5B09318AF61B92A5A
  file_package_name: Source Package
Stream #0:5: Audio: pcm_s24le, 48000 Hz, 1 channels, s32 (24 bit), 1152 kb/s
Metadata:
  file_package_umid: 0x060A2B340101010501010D12133A5D15A0C9D501557805A5B09318AF61B92A5A
  file_package_name: Source Package
Stream #0:6: Audio: pcm_s24le, 48000 Hz, 1 channels, s32 (24 bit), 1152 kb/s
Metadata:
  file_package_umid: 0x060A2B340101010501010D12133A5D15A0C9D501557805A5B09318AF61B92A5A
  file_package_name: Source Package
Stream #0:7: Audio: pcm_s24le, 48000 Hz, 1 channels, s32 (24 bit), 1152 kb/s
Metadata:
  file_package_umid: 0x060A2B340101010501010D12133A5D15A0C9D501557805A5B09318AF61B92A5A
  file_package_name: Source Package
Stream #0:8: Audio: pcm_s24le, 48000 Hz, 1 channels, s32 (24 bit), 1152 kb/s
Metadata:
  file_package_umid: 0x060A2B340101010501010D12133A5D15A0C9D501557805A5B09318AF61B92A5A
  file_package_name: Source Package
Filter amerge has a unconnected output

bash: -f: command not found

我将视频的名称更改为myVideo.mxf。

Answer 1

假设您需要两个单声道输入的立体声输出:

ffmpeg -i input -filter_complex "[0:a:0][0:a:1]amerge,ebur128" -f null -