我看过几个类似的问题，但对我来说，这些问题都没有帮助。
尝试加入1个性质和分辨率不同的音频和4个视频文件时遇到此错误。
ffmpeg -i 0.mp3 -i 1.mp4 -i 2.mkv -i 3.mkv -i 4.webm \
-filter_complex [0:a:0][1:v:0][2:v:0][3:v:0][4:v:0]concat=n=5:v=1:a=1[outv][outa] \
-map "[outv]" -map "[outa]" output.mp4
所有这些都会产生以下错误：
Stream specifier ':a:0' in filtergraph description [0:a:0][1:v:0][2:v:0][3:v:0][4:v:0]concat=n=5:v=1:a=1[outv][outa] matches no streams.
由于不同的分辨率和视频格式，直接串联-i "concat:0.mp3|1.mp4..."也无法正常工作。所有方法的语法均取自official documentation，但这里应该缺少一些我想念的东西。
完整的输出日志：
ffmpeg version 3.4.4-0ubuntu0.18.04.1 Copyright (c) 2000-2018 the FFmpeg developers
built with gcc 7 (Ubuntu 7.3.0-16ubuntu3)
configuration: --prefix=/usr --extra-version=0ubuntu0.18.04.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-librsvg --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
libavutil 55. 78.100 / 55. 78.100
libavcodec 57.107.100 / 57.107.100
libavformat 57. 83.100 / 57. 83.100
libavdevice 57. 10.100 / 57. 10.100
libavfilter 6.107.100 / 6.107.100
libavresample 3. 7. 0 / 3. 7. 0
libswscale 4. 8.100 / 4. 8.100
libswresample 2. 9.100 / 2. 9.100
libpostproc 54. 7.100 / 54. 7.100
Input #0, mp3, from 'mp3/10.mp3':
Metadata:
album_artist : artist
title : title
artist : 10
album : 12
track : 1
VideoKind : 2
date : 2009
Duration: 00:06:00.44, start: 0.025056, bitrate: 64 kb/s
Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16p, 64 kb/s
Metadata:
encoder : LAME3.98r
Stream #0:1: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 200x200 [SAR 72:72 DAR 1:1], 90k tbr, 90k tbn, 90k tbc
Metadata:
comment : Cover (front)
Input #1, matroska,webm, from '1.mp4':
Metadata:
MINOR_VERSION : 0
COMPATIBLE_BRANDS: iso6avc1mp41
MAJOR_BRAND : dash
ENCODER : Lavf57.83.100
Duration: 00:01:53.05, start: 0.007000, bitrate: 2292 kb/s
Stream #1:0: Video: h264 (High), yuv420p(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 24 fps, 24 tbr, 1k tbn, 48 tbc (default)
Metadata:
HANDLER_NAME : VideoHandler
DURATION : 00:01:53.048000000
Input #2, matroska,webm, from '2.mkv':
Metadata:
MINOR_VERSION : 0
COMPATIBLE_BRANDS: iso6avc1mp41
MAJOR_BRAND : dash
ENCODER : Lavf57.83.100
Duration: 00:02:08.09, start: 0.007000, bitrate: 1607 kb/s
Stream #2:0: Video: h264 (High), yuv420p(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 24 fps, 24 tbr, 1k tbn, 48 tbc (default)
Metadata:
HANDLER_NAME : VideoHandler
DURATION : 00:02:08.090000000
Input #3, matroska,webm, from '3.mkv':
Metadata:
MINOR_VERSION : 0
COMPATIBLE_BRANDS: iso6avc1mp41
MAJOR_BRAND : dash
ENCODER : Lavf57.83.100
Duration: 00:01:37.05, start: 0.007000, bitrate: 3525 kb/s
Stream #3:0: Video: h264 (High), yuv420p(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 24 fps, 24 tbr, 1k tbn, 48 tbc (default)
Metadata:
HANDLER_NAME : VideoHandler
DURATION : 00:01:37.048000000
Input #4, matroska,webm, from '4.webm':
Metadata:
MINOR_VERSION : 0
COMPATIBLE_BRANDS: iso6avc1mp41
MAJOR_BRAND : dash
ENCODER : Lavf57.83.100
Duration: 00:01:45.13, start: 0.007000, bitrate: 3685 kb/s
Stream #4:0: Video: h264 (High), yuv420p(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 24 fps, 24 tbr, 1k tbn, 48 tbc (default)
Metadata:
HANDLER_NAME : VideoHandler
DURATION : 00:01:45.131000000
Stream specifier ':a:0' in filtergraph description [0:a:0][1:v:0][2:v:0][3:v:0][4:v:0]concat=n=5:v=1:a=1[outv][outa] matches no streams.