我无法通过ffmpeg将mp4文件转换为mp3。我尝试了以下命令，但它们不起作用并显示相同的错误：
输出文件＃0不包含任何流
这些是命令：
ffmpeg -i input.mp4 -c copy -f mpegts output.mp3
ffmpeg -i input.mp4 -acodec libmp3lame output.mp3
ffmpeg -i input.mp4 -vn -f mp3 -ab 192k output.mp3
ffmpeg -i input.mp4 -vn -f wav - | \
lame -V 3 - output.mp3
请帮助我。
这是日志-> ffmpeg -i input.mp4 -c copy -vn output.mp3
ffmpeg version 2.8.8 Copyright (c) 2000-2016 the FFmpeg developers
built with gcc 4.8.5 (GCC) 20150623 (Red Hat 4.8.5-28)
configuration: --disable-static --enable-gpl --enable-version3 --enable-nonfree --enable-shared --enable-libmp3lame --enable-libx264 --enable-libvpx --enable-libvorbis --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopencore-amrnb --enable-libtheora --enable-libxvid --enable-libfdk_aac --enable-libopus --enable-libfreetype --enable-libfaac
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
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.mp4':
Metadata:
major_brand : dash
minor_version : 0
compatible_brands: iso6avc1mp41
creation_time : 2018-05-11 00:18:13
Duration: 00:44:01.47, start: 0.000000, bitrate: 61 kb/s
Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 320x240 [SAR 1:1 DAR 4:3], 0 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc (default)
Metadata:
creation_time : 2018-05-11 00:18:13
handler_name : VideoHandler
Output #0, mp3, to 'output.mp3':
Output file #0 does not contain any stream