ffmpeg - 视频对话的背景音乐音量较低
ffmpeg - Lower volume of background music for dialog in a video
我有一个视频，里面有一些背景音乐。
我想在视频中的特定位置添加一段语音对话，以便在整个对话音频期间降低背景音乐。
我使用 sidechaincompress 找到了一个类似的解决方案，它只适用于 mp3。我对其进行了一些更改，以便它也包含视频 (-map 0:v)。但是，现在对话一结束，音频就被切断了。
ffmpeg -i video-with-bg-music.mp4 -i dialogue.mp3 -c:v libx264 -filter_complex "[1:a]asplit=2[sc][mix];[0:a][sc]sidechaincompress=threshold=0.003:ratio=20[bg];[bg][mix]amerge[final]" -map 0:v -map [final] final.mp4
我不是 ffmpeg 的专家，可能不知道 filter_complex 是怎么回事。请帮帮我。
编辑：
@kesh 建议的解决方案的输出日志
ffmpeg -i video_bg.mp4 -i dialogues.mp3 -filter_complex "[1:a]adelay=0,apad,asplit=2[sc][mix];[0:a][sc]sidechaincompress=threshold=0.003:ratio=20[bg];[bg][mix]amix=duration=shortest[out]" -map 0:v -map [out] video_bg_speech.mp4
ffmpeg version 4.2.4-1ubuntu0.1 Copyright (c) 2000-2020 the FFmpeg developers
built with gcc 9 (Ubuntu 9.3.0-10ubuntu2)
configuration: --prefix=/usr --extra-version=1ubuntu0.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
libavutil 56. 31.100 / 56. 31.100
libavcodec 58. 54.100 / 58. 54.100
libavformat 58. 29.100 / 58. 29.100
libavdevice 58. 8.100 / 58. 8.100
libavfilter 7. 57.100 / 7. 57.100
libavresample 4. 0. 0 / 4. 0. 0
libswscale 5. 5.100 / 5. 5.100
libswresample 3. 5.100 / 3. 5.100
libpostproc 55. 5.100 / 55. 5.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'video_bg.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf58.29.100
Duration: 00:01:50.12, start: 0.000000, bitrate: 157 kb/s
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 720x1280 [SAR 1:1 DAR 9:16], 146 kb/s, 24 fps, 24 tbr, 12288 tbn, 48 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)
Metadata:
handler_name : SoundHandler
[mp3 @ 0x5577fa3b6740] Estimating duration from bitrate, this may be inaccurate
Input #1, mp3, from 'dialogue.mp3':
Duration: 00:00:17.33, start: 0.000000, bitrate: 32 kb/s
Stream #1:0: Audio: mp3, 24000 Hz, mono, fltp, 32 kb/s
File 'video_bg_speech.mp4' already exists. Overwrite ? [y/N] y
Stream mapping:
Stream #0:1 (aac) -> sidechaincompress:main (graph 0)
Stream #1:0 (mp3float) -> adelay (graph 0)
Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
amix (graph 0) -> Stream #0:1 (aac)
Press [q] to stop, [?] for help
[libx264 @ 0x5577fa446040] using SAR=1/1
[libx264 @ 0x5577fa446040] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0x5577fa446040] profile High, level 3.1
[libx264 @ 0x5577fa446040] 264 - core 155 r2917 0a84d98 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=18 lookahead_threads=3 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=24 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
[Parsed_sidechaincompress_3 @ 0x5577faed3f00] No channel layout for input 1
Output #0, mp4, to 'video_bg_speech.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf58.29.100
Stream #0:0(und): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p(progressive), 720x1280 [SAR 1:1 DAR 9:16], q=-1--1, 24 fps, 12288 tbn, 24 tbc (default)
Metadata:
handler_name : VideoHandler
encoder : Lavc58.54.100 libx264
Side data:
cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
Stream #0:1: Audio: aac (LC) (mp4a / 0x6134706D), 24000 Hz, mono, fltp, 69 kb/s (default)
Metadata:
encoder : Lavc58.54.100 aac
frame= 480 fps=325 q=-1.0 Lsize= 517kB time=00:00:19.87 bitrate= 213.0kbits/s speed=13.5x
video:353kB audio:152kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 2.388190%
[libx264 @ 0x5577fa446040] frame I:2 Avg QP:15.99 size:136135
[libx264 @ 0x5577fa446040] frame P:121 Avg QP:16.86 size: 603
[libx264 @ 0x5577fa446040] frame B:357 Avg QP:26.34 size: 43
[libx264 @ 0x5577fa446040] consecutive B-frames: 0.6% 0.4% 0.6% 98.3%
[libx264 @ 0x5577fa446040] mb I I16..4: 2.3% 65.7% 32.1%
[libx264 @ 0x5577fa446040] mb P I16..4: 0.0% 0.1% 0.1% P16..4: 1.1% 0.1% 0.1% 0.0% 0.0% skip:98.5%
[libx264 @ 0x5577fa446040] mb B I16..4: 0.0% 0.0% 0.0% B16..8: 0.2% 0.0% 0.0% direct: 0.0% skip:99.8% L0:55.5% L1:44.5% BI: 0.0%
[libx264 @ 0x5577fa446040] 8x8 transform intra:62.5% inter:56.6%
[libx264 @ 0x5577fa446040] coded y,uvDC,uvAC intra: 89.6% 89.0% 78.7% inter: 0.0% 0.1% 0.0%
[libx264 @ 0x5577fa446040] i16 v,h,dc,p: 37% 5% 8% 50%
[libx264 @ 0x5577fa446040] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 24% 16% 6% 6% 9% 9% 9% 10% 9%
[libx264 @ 0x5577fa446040] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 25% 18% 7% 6% 11% 9% 9% 7% 7%
[libx264 @ 0x5577fa446040] i8c dc,h,v,p: 42% 22% 20% 15%
[libx264 @ 0x5577fa446040] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 @ 0x5577fa446040] ref P L0: 46.3% 2.9% 19.3% 31.5%
[libx264 @ 0x5577fa446040] ref B L0: 45.6% 54.0% 0.4%
[libx264 @ 0x5577fa446040] ref B L1: 97.0% 3.0%
[libx264 @ 0x5577fa446040] kb/s:144.26
[aac @ 0x5577fa3b9940] Qavg: 307.060
试试这个（在 3 秒标记处插入的短片）：
[1:a]aresample=44100,adelay=3000,apad,asplit=2[sc][mix];\
[0:a][sc]sidechaincompress=threshold=0.003:ratio=20[bg];\
[bg][mix]amix=duration=shortest[out]
aresample 使对话的采样率与视频的采样率相匹配。adelay 将剪辑放在正确的位置（注意延迟以毫秒为单位）apad 无限延长短流并保持沉默amix合并2个流并在视频音频结束时停止
附录：
如果mp4没有音频，试试：
ffmpeg -i video-with-bg-music.mp4 -i dialogue.mp3 \
-af [1:a]adelay=3000,apad \
-shortest final.mp4
音频过滤图中的apad扩展音频流，-shortest输出选项在视频流结束时将其切断。
调试示例
ffmpeg -filter_complex \
[1:a]aresample=44100,apad,asplit=2[sc][mix];\
[0:a][sc]sidechaincompress=threshold=0.003:ratio=20[bg];\
[bg][mix]amix=duration=shortest[out] \
-f lavfi -i anoisesrc=d=60:c=pink:r=44100:a=0.5 \
-f lavfi -i sine=220:4:d=5 \
-map [out] output.mp3
我有一个视频，里面有一些背景音乐。
我想在视频中的特定位置添加一段语音对话，以便在整个对话音频期间降低背景音乐。
我使用 sidechaincompress 找到了一个类似的解决方案，它只适用于 mp3。我对其进行了一些更改，以便它也包含视频 (-map 0:v)。但是，现在对话一结束，音频就被切断了。
ffmpeg -i video-with-bg-music.mp4 -i dialogue.mp3 -c:v libx264 -filter_complex "[1:a]asplit=2[sc][mix];[0:a][sc]sidechaincompress=threshold=0.003:ratio=20[bg];[bg][mix]amerge[final]" -map 0:v -map [final] final.mp4
我不是 ffmpeg 的专家，可能不知道 filter_complex 是怎么回事。请帮帮我。
编辑：
@kesh 建议的解决方案的输出日志
ffmpeg -i video_bg.mp4 -i dialogues.mp3 -filter_complex "[1:a]adelay=0,apad,asplit=2[sc][mix];[0:a][sc]sidechaincompress=threshold=0.003:ratio=20[bg];[bg][mix]amix=duration=shortest[out]" -map 0:v -map [out] video_bg_speech.mp4
ffmpeg version 4.2.4-1ubuntu0.1 Copyright (c) 2000-2020 the FFmpeg developers
built with gcc 9 (Ubuntu 9.3.0-10ubuntu2)
configuration: --prefix=/usr --extra-version=1ubuntu0.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
libavutil 56. 31.100 / 56. 31.100
libavcodec 58. 54.100 / 58. 54.100
libavformat 58. 29.100 / 58. 29.100
libavdevice 58. 8.100 / 58. 8.100
libavfilter 7. 57.100 / 7. 57.100
libavresample 4. 0. 0 / 4. 0. 0
libswscale 5. 5.100 / 5. 5.100
libswresample 3. 5.100 / 3. 5.100
libpostproc 55. 5.100 / 55. 5.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'video_bg.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf58.29.100
Duration: 00:01:50.12, start: 0.000000, bitrate: 157 kb/s
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 720x1280 [SAR 1:1 DAR 9:16], 146 kb/s, 24 fps, 24 tbr, 12288 tbn, 48 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)
Metadata:
handler_name : SoundHandler
[mp3 @ 0x5577fa3b6740] Estimating duration from bitrate, this may be inaccurate
Input #1, mp3, from 'dialogue.mp3':
Duration: 00:00:17.33, start: 0.000000, bitrate: 32 kb/s
Stream #1:0: Audio: mp3, 24000 Hz, mono, fltp, 32 kb/s
File 'video_bg_speech.mp4' already exists. Overwrite ? [y/N] y
Stream mapping:
Stream #0:1 (aac) -> sidechaincompress:main (graph 0)
Stream #1:0 (mp3float) -> adelay (graph 0)
Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
amix (graph 0) -> Stream #0:1 (aac)
Press [q] to stop, [?] for help
[libx264 @ 0x5577fa446040] using SAR=1/1
[libx264 @ 0x5577fa446040] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0x5577fa446040] profile High, level 3.1
[libx264 @ 0x5577fa446040] 264 - core 155 r2917 0a84d98 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=18 lookahead_threads=3 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=24 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
[Parsed_sidechaincompress_3 @ 0x5577faed3f00] No channel layout for input 1
Output #0, mp4, to 'video_bg_speech.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf58.29.100
Stream #0:0(und): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p(progressive), 720x1280 [SAR 1:1 DAR 9:16], q=-1--1, 24 fps, 12288 tbn, 24 tbc (default)
Metadata:
handler_name : VideoHandler
encoder : Lavc58.54.100 libx264
Side data:
cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
Stream #0:1: Audio: aac (LC) (mp4a / 0x6134706D), 24000 Hz, mono, fltp, 69 kb/s (default)
Metadata:
encoder : Lavc58.54.100 aac
frame= 480 fps=325 q=-1.0 Lsize= 517kB time=00:00:19.87 bitrate= 213.0kbits/s speed=13.5x
video:353kB audio:152kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 2.388190%
[libx264 @ 0x5577fa446040] frame I:2 Avg QP:15.99 size:136135
[libx264 @ 0x5577fa446040] frame P:121 Avg QP:16.86 size: 603
[libx264 @ 0x5577fa446040] frame B:357 Avg QP:26.34 size: 43
[libx264 @ 0x5577fa446040] consecutive B-frames: 0.6% 0.4% 0.6% 98.3%
[libx264 @ 0x5577fa446040] mb I I16..4: 2.3% 65.7% 32.1%
[libx264 @ 0x5577fa446040] mb P I16..4: 0.0% 0.1% 0.1% P16..4: 1.1% 0.1% 0.1% 0.0% 0.0% skip:98.5%
[libx264 @ 0x5577fa446040] mb B I16..4: 0.0% 0.0% 0.0% B16..8: 0.2% 0.0% 0.0% direct: 0.0% skip:99.8% L0:55.5% L1:44.5% BI: 0.0%
[libx264 @ 0x5577fa446040] 8x8 transform intra:62.5% inter:56.6%
[libx264 @ 0x5577fa446040] coded y,uvDC,uvAC intra: 89.6% 89.0% 78.7% inter: 0.0% 0.1% 0.0%
[libx264 @ 0x5577fa446040] i16 v,h,dc,p: 37% 5% 8% 50%
[libx264 @ 0x5577fa446040] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 24% 16% 6% 6% 9% 9% 9% 10% 9%
[libx264 @ 0x5577fa446040] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 25% 18% 7% 6% 11% 9% 9% 7% 7%
[libx264 @ 0x5577fa446040] i8c dc,h,v,p: 42% 22% 20% 15%
[libx264 @ 0x5577fa446040] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 @ 0x5577fa446040] ref P L0: 46.3% 2.9% 19.3% 31.5%
[libx264 @ 0x5577fa446040] ref B L0: 45.6% 54.0% 0.4%
[libx264 @ 0x5577fa446040] ref B L1: 97.0% 3.0%
[libx264 @ 0x5577fa446040] kb/s:144.26
[aac @ 0x5577fa3b9940] Qavg: 307.060
试试这个（在 3 秒标记处插入的短片）：
[1:a]aresample=44100,adelay=3000,apad,asplit=2[sc][mix];\
[0:a][sc]sidechaincompress=threshold=0.003:ratio=20[bg];\
[bg][mix]amix=duration=shortest[out]
aresample使对话的采样率与视频的采样率相匹配。adelay将剪辑放在正确的位置（注意延迟以毫秒为单位）apad无限延长短流并保持沉默amix合并2个流并在视频音频结束时停止
附录：
如果mp4没有音频，试试：
ffmpeg -i video-with-bg-music.mp4 -i dialogue.mp3 \
-af [1:a]adelay=3000,apad \
-shortest final.mp4
apad扩展音频流，-shortest输出选项在视频流结束时将其切断。
调试示例
ffmpeg -filter_complex \
[1:a]aresample=44100,apad,asplit=2[sc][mix];\
[0:a][sc]sidechaincompress=threshold=0.003:ratio=20[bg];\
[bg][mix]amix=duration=shortest[out] \
-f lavfi -i anoisesrc=d=60:c=pink:r=44100:a=0.5 \
-f lavfi -i sine=220:4:d=5 \
-map [out] output.mp3