我正在尝试连接视频和音频文件，用黑框或相应的静音填充它们之间的空间。
我使用以下命令：
ffmpeg -i test/v/1.mkv -i test/v/2.mkv -i test/v/1.mka -i test/v/2.mka -filter_complex 'color=c=black:s=640x480:d=12ms[black0];
color=c=black:s=640x480:d=207725ms[black2];
aevalsrc=0:d=257495ms[silence1];
aevalsrc=0:d=114833ms[silence2];
[black0][0][black2][1][2][silence1][3][silence2]concat=n=8:v=1:a=1[v_out][a_out]' \
-map [v_out] -map [a_out] -c:v libvpx -c:a libopus result.webm
但我收到以下错误：
Stream specifier '' in filtergraph description matches no streams.
完整的 ffmpeg 输出：
ffmpeg version 4.3.1 Copyright (c) 2000-2020 the FFmpeg developers
built with Apple clang version 11.0.0 (clang-1100.0.33.17)
configuration: --prefix=/usr/local/Cellar/ffmpeg/4.3.1_9 --enable-shared --enable-pthreads --enable-version3 --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libdav1d --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-libsoxr --enable-videotoolbox --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack
libavutil 56. 51.100 / 56. 51.100
libavcodec 58. 91.100 / 58. 91.100
libavformat 58. 45.100 / 58. 45.100
libavdevice 58. 10.100 / 58. 10.100
libavfilter 7. 85.100 / 7. 85.100
libavresample 4. 0. 0 / 4. 0. 0
libswscale 5. 7.100 / 5. 7.100
libswresample 3. 7.100 / 3. 7.100
libpostproc 55. 7.100 / 55. 7.100
Input #0, matroska,webm, from 'test/v/1.mkv':
Metadata:
encoder : GStreamer matroskamux version 1.8.1.1
creation_time : 2021-02-05T16:54:38.000000Z
Duration: 00:00:52.24, start: 0.637000, bitrate: 1922 kb/s
Stream #0:0(eng): Video: vp8, yuv420p(progressive), 640x480, SAR 1:1 DAR 4:3, 29.83 tbr, 1k tbn, 1k tbc (default)
Metadata:
title : Video
Input #1, matroska,webm, from 'test/v/2.mkv':
Metadata:
encoder : GStreamer matroskamux version 1.8.1.1
creation_time : 2021-02-05T16:58:58.000000Z
Duration: 00:02:07.19, start: 260.603000, bitrate: 1966 kb/s
Stream #1:0(eng): Video: vp8, yuv420p(progressive), 640x480, SAR 1:1 DAR 4:3, 29.83 tbr, 1k tbn, 1k tbc (default)
Metadata:
title : Video
Input #2, matroska,webm, from 'test/v/1.mka':
Metadata:
encoder : GStreamer matroskamux version 1.8.1.1
creation_time : 2021-02-05T16:55:58.000000Z
Duration: 00:00:02.44, start: 0.624000, bitrate: 80 kb/s
Stream #2:0(eng): Audio: opus, 48000 Hz, stereo, fltp (default)
Metadata:
title : Audio
Input #3, matroska,webm, from 'test/v/2.mka':
Metadata:
encoder : GStreamer matroskamux version 1.8.1.1
creation_time : 2021-02-05T16:59:01.000000Z
Duration: 00:00:12.40, start: 260.561000, bitrate: 43 kb/s
Stream #3:0(eng): Audio: opus, 48000 Hz, stereo, fltp (default)
Metadata:
title : Audio
Stream specifier '' in filtergraph description color=c=black:s=640x480:d=12ms[black0];
color=c=black:s=640x480:d=207725ms[black2];
aevalsrc=0:d=257495ms[silence1];
aevalsrc=0:d=114833ms[silence3];
[black0][0][black2][1][2][silence1][3][silence3]concat=n=8:v=1:a=1[v_out][a_out] matches no streams.
视频文件不包含音频。 我做错了什么？请帮忙。