问题描述
ffmpeg -f concat -i mylist.txt -c copy output.mp4
由上述命令生成的组合视频为 17 分钟。我认为这是因为帧率。有没有办法获得正确的输出。
请看下面的文字以查看两个视频的配置。
ffmpeg version 4.4-full_build-www.gyan.dev copyright (c) 2000-2021 the FFmpeg developers
built with gcc 10.2.0 (Rev6,Built by MSYS2 project)
configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-lzma --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2 --enable-libdav1d --enable-libzvbi --enable-librav1e --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-libglslang --enable-vulkan --enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libilbc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint
libavutil 56. 70.100 / 56. 70.100
libavcodec 58.134.100 / 58.134.100
libavformat 58. 76.100 / 58. 76.100
libavdevice 58. 13.100 / 58. 13.100
libavfilter 7.110.100 / 7.110.100
libswscale 5. 9.100 / 5. 9.100
libswresample 3. 9.100 / 3. 9.100
libpostproc 55. 9.100 / 55. 9.100
Input #0,mov,mp4,m4a,3gp,3g2,mj2,from 'Full.mp4':
Metadata:
major_brand : mp42
minor_version : 0
compatible_brands: mp41isom
creation_time : 2021-06-01T10:57:14.000000Z
Duration: 00:08:57.08,start: 0.000000,bitrate: 2527 kb/s
Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661),yuv420p,1920x1080 [SAR 1:1 DAR 16:9],2526 kb/s,30.30 fps,30.30 tbr,30k tbn,60 tbc (default)
Metadata:
creation_time : 2021-06-01T10:57:14.000000Z
handler_name : VideoHandler
vendor_id : [0][0][0][0]
encoder : AVC Coding
Input #1,from '1.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf58.29.100
Duration: 00:00:11.93,bitrate: 20939 kb/s
Stream #1:0(und): Video: h264 (High) (avc1 / 0x31637661),20973 kb/s,30 fps,30 tbr,15360 tbn,60 tbc (default)
Metadata:
handler_name : VideoHandler
vendor_id : [0][0][0][0]
Stream #1:1(und): Audio: aac (LC) (mp4a / 0x6134706D),48000 Hz,stereo,fltp,2 kb/s (default)
Metadata:
handler_name : SoundHandler
vendor_id : [0][0][0][0]
File 'output.mp4' already exists. Overwrite? [y/N] y
Output #0,to 'output.mp4':
Metadata:
major_brand : mp42
minor_version : 0
compatible_brands: mp41isom
encoder : Lavf58.76.100
Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661),q=2-31,30k tbc (default)
Metadata:
creation_time : 2021-06-01T10:57:14.000000Z
handler_name : VideoHandler
vendor_id : [0][0][0][0]
encoder : AVC Coding
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D),2 kb/s (default)
Metadata:
handler_name : SoundHandler
vendor_id : [0][0][0][0]
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Stream #1:1 -> #0:1 (copy)
Press [q] to stop,[?] for help
frame=16275 fps=0.0 q=-1.0 Lsize= 165734kB time=00:08:57.04 bitrate=2528.1kbits/s speed=3.02e+03x
video:165653kB audio:3kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.047347%
解决方法
连接分离器
您可以使用 concat demuxer。它将需要多个命令,但 concat 分离器可以通过 stream copy 模式保持主视频的质量。
但两个文件都必须有 same attributes。
-
Full.mp4
比1.mp4
长,所以让1.mp4
像Full.mp4
:ffmpeg -i 1.mp4 -c:v libx264 -profile:v baseline -video_track_timescale 30k -c:a copy 1_new.mp4
-
Full.mp4
没有音频,但1.mp4
有。因此,使用 anullsrc 过滤器将静音/空白/虚拟/填充音频添加到Full.mp4
:ffmpeg -i Full.mp4 -f lavfi -i anullsrc=cl=stereo:r=48000 -c:v copy -c:a aac -shortest Full_new.mp4
-
使
mylist.txt
包含:file 'Full_new.mp4' file '1_new.mp4'
-
连接:
ffmpeg -f concat -i mylist.txt -c copy output.mp4
连接过滤器
或者您可以使用 concat filter 在一个命令中完成所有操作。这将重新编码所有输入。
请参阅 How to concatenate videos in ffmpeg with different attributes? 以获取多个示例。