我正在尝试添加 xfade 过滤器并且该命令正在运行，但输出视频中缺少第二个视频的音频。
命令是 -
ffmpeg -i 1.mp4 -i 1.mp4 -filter_complex "[0:v]scale=480:360:force_original_aspect_ratio=decrease,pad=480:360:-1:-1,setsar=1,fps=30,format=yuv420p[v0];[1:v]scale=480:360:force_original_aspect_ratio=decrease,pad=480:360:-1:-1,setsar=1,fps=30,format=yuv420p[v1];
[v0][v1]xfade=transition=pixelize:duration=1:offset=7,format=yuv420p" -c:v libvpx-vp9 -crf 30 -b:v 0 -b:a 128k -c:a libopus -deadline good -cpu-used 8 output.webm
完整日志如下-
ffmpeg version n4.3.1 Copyright (c) 2000-2020 the FFmpeg developers
built with gcc 7 (Ubuntu 7.5.0-3ubuntu1~18.04)
configuration: --prefix= --prefix=/usr --disable-debug --disable-doc -
-disable-static --enable-cuda --enable-cuda-sdk --enable-cuvid --
enable-libdrm --enable-ffplay --enable-gnutls --enable-gpl --enable-
libass --enable-libfdk-aac --enable-libfontconfig --enable-libfreetype
--enable-libmp3lame --enable-libnpp --enable-libopencore_amrnb --
enable-libopencore_amrwb --enable-libopus --enable-libpulse --enable-
sdl2 --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libv4l2 --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxvid --enable-nonfree --enable-nvenc --enable-omx --enable-openal --enable-opencl --enable-runtime-cpudetect --enable-shared --enable-vaapi --enable-vdpau --enable-version3 --enable-xlib
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
libswscale 5. 7.100 / 5. 7.100
libswresample 3. 7.100 / 3. 7.100
libpostproc 55. 7.100 / 55. 7.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '1.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf58.29.100
Duration: 00:00:09.12, start: 0.000000, bitrate: 702 kb/s
Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 474x360, 568 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(und): Audio: mp3 (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 127 kb/s (default)
Metadata:
handler_name : SoundHandler
Input #1, mov,mp4,m4a,3gp,3g2,mj2, from '2.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf58.29.100
Duration: 00:00:08.75, start: 0.000000, bitrate: 2546 kb/s
Stream #1:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 640x360, 2416 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #1:1(und): Audio: mp3 (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 127 kb/s (default)
Metadata:
handler_name : SoundHandler
Stream mapping:
Stream #0:0 (h264) -> scale (graph 0)
Stream #1:0 (h264) -> scale (graph 0)
format (graph 0) -> Stream #0:0 (libvpx-vp9)
Stream #0:1 -> #0:1 (mp3 (mp3float) -> opus (libopus))
Press [q] to stop, [?] for help
[libvpx-vp9 @ 0x561afcf3a280] v1.7.0
Output #0, webm, to 'output.webm':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf58.45.100
Stream #0:0: Video: vp9 (libvpx-vp9), yuv420p, 480x360 [SAR 1:1 DAR 4:3], q=-1--1, 30 fps, 1k tbn, 30 tbc (default)
Metadata:
encoder : Lavc58.91.100 libvpx-vp9
Side data:
cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
Stream #0:1(und): Audio: opus (libopus), 48000 Hz, stereo, flt, 128 kb/s (default)
Metadata:
handler_name : SoundHandler
encoder : Lavc58.91.100 libopus
frame= 87 fps=0.0 q=0.0 size= 1kB time=00:00:03.19 bitrate= 2.1kbits/sframe= 157 fps=156 q=0.0 size= 171kB time=00:00:05.51 bitrate= 254.3kbits/sframe= 227 fps=150 q=0.0 size= 171kB time=00:00:07.85 bitrate= 178.5kbits/sframe= 265 fps=131 q=0.0 size= 171kB time=00:00:08.31 bitrate= 168.7kbits/sframe= 303 fps=120 q=0.0 size= 256kB time=00:00:09.30 bitrate= 225.5kbits/sframe= 341 fps=113 q=0.0 size= 256kB time=00:00:10.56 bitrate= 198.4kbits/sframe= 379 fps=107 q=0.0 size= 256kB time=00:00:11.83 bitrate= 177.2kbits/sframe= 416 fps=103 q=0.0 size= 256kB time=00:00:13.06 bitrate= 160.5kbits/sframe= 454 fps=100 q=0.0 size= 256kB time=00:00:14.33 bitrate= 146.3kbits/sframe= 472 fps= 93 q=0.0 Lsize= 1168kB time=00:00:15.73 bitrate= 608.2kbits/s speed=3.09x
video:1036kB audio:125kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.629681%
使用没有音频的在线网址时出现此错误- 收到此错误-
ffmpeg version n4.3.1 Copyright (c) 2000-2020 the FFmpeg developers
built with gcc 7 (Ubuntu 7.5.0-3ubuntu1~18.04)
configuration: --prefix= --prefix=/usr --disable-debug --disable-doc --disable-static --enable-cuda --enable-cuda-sdk --enable-cuvid --enable-libdrm --enable-ffplay --enable-gnutls --enable-gpl --enable-libass --enable-libfdk-aac --enable-libfontconfig --enable-libfreetype --enable-libmp3lame --enable-libnpp --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopus --enable-libpulse --enable-sdl2 --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libv4l2 --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxvid --enable-nonfree --enable-nvenc --enable-omx --enable-openal --enable-opencl --enable-runtime-cpudetect --enable-shared --enable-vaapi --enable-vdpau --enable-version3 --enable-xlib
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
libswscale 5. 7.100 / 5. 7.100
libswresample 3. 7.100 / 3. 7.100
libpostproc 55. 7.100 / 55. 7.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'https://player.vimeo.com/external/183300180.sd.mp4?s=8d9b1561f39df586af49fe5ab105f57f5873854b&profile_id=164':
Metadata:
major_brand : mp42
minor_version : 0
compatible_brands: mp42mp41isomavc1
creation_time : 2016-09-19T12:39:02.000000Z
Duration: 00:00:10.00, start: 0.000000, bitrate: 489 kb/s
Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt470bg/smpte170m/bt470bg), 640x360 [SAR 1:1 DAR 16:9], 486 kb/s, 30 fps, 30 tbr, 30 tbn, 60 tbc (default)
Metadata:
creation_time : 2016-09-19T12:39:02.000000Z
handler_name : L-SMASH Video Handler
encoder : AVC Coding
Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'https://player.vimeo.com/external/166335878.sd.mp4?s=828bf6e8594fab383d7ee6bac40d3f247cc40af9&profile_id=164':
Metadata:
major_brand : mp42
minor_version : 0
compatible_brands: mp42mp41isomavc1
creation_time : 2016-05-12T09:34:11.000000Z
Duration: 00:00:10.01, start: 0.000000, bitrate: 479 kb/s
Stream #1:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt470bg/smpte170m/bt470bg), 474x360 [SAR 1:1 DAR 79:60], 345 kb/s, 30 fps, 30 tbr, 30 tbn, 60 tbc (default)
Metadata:
creation_time : 2016-05-12T09:34:11.000000Z
handler_name : L-SMASH Video Handler
encoder : AVC Coding
Stream #1:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
Metadata:
creation_time : 2016-05-12T09:34:11.000000Z
handler_name : L-SMASH Audio Handler
Stream specifier ':a' in filtergraph description [0:v]scale=614:360:force_original_aspect_ratio=decrease,pad=614:360:-1:-1,setsar=1,fps=30,format=yuv420p[v0];[1:v]scale=614:360:force_original_aspect_ratio=decrease,pad=614:360:-1:-1,setsar=1,fps=30,format=yuv420p[v1];[v0][v1]xfade=transition=pixelize:duration=1:offset=8,format=yuv420p;[0:a][1:a]acrossfade=d=0 matches no streams.
答案 0 :(得分：0)
您没有告诉 ffmpeg 如何处理音频，因此它只是从第一个输入中选择音频（请参阅 stream selection）。
因为您使用的是 xfade，所以您可能想要使用 acrossfade，如 Merging multiple video files with ffmpeg and xfade filter 所示：
ffmpeg -i 1.mp4 -i 1.mp4 -filter_complex "[0:v]scale=480:360:force_original_aspect_ratio=decrease,pad=480:360:-1:-1,setsar=1,fps=30,format=yuv420p[v0];[1:v]scale=480:360:force_original_aspect_ratio=decrease,pad=480:360:-1:-1,setsar=1,fps=30,format=yuv420p[v1];[v0][v1]xfade=transition=pixelize:duration=1:offset=7,format=yuv420p;[0:a][1:a]acrossfade=d=1" -c:v libvpx-vp9 -crf 30 -b:v 0 -b:a 128k -c:a libopus -deadline good -cpu-used 8 output.webm
对于没有音频的输入，一种方法是添加 adelay 过滤器：
ffmpeg -i noaudio -i input1 -filter_complex "[0:v]scale=614:360:force_original_aspect_ratio=decrease,pad=614:360:-1:-1,setsar=1,fps=30,format=yuv420p[v0];[1:v]scale=614:360:force_original_aspect_ratio=decrease,pad=614:360:-1:-1,setsar=1,fps=30,format=yuv420p[v1];[v0][v1]xfade=transition=pixelize:duration=1:offset=8,format=yuv420p;[1:a]adelay=8s:all=1" output
其他方法包括使用 anullsrc + concat 或 apad（如果 noaudio 不是第一个输入）。