video - 使用 ffmpeg 组合两个具有不同帧率的视频

Question

ffmpeg -f concat -i mylist.txt -c copy output.mp4

上述命令生成的组合视频为 17 分钟。我认为是因为帧率。有没有办法获得正确的输出。
有没有一种工具可以用来更改一个视频的帧速率以匹配另一个视频。
请参阅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, mov,mp4,m4a,3gp,3g2,mj2, from '1.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.29.100
  Duration: 00:00:11.93, start: 0.000000, bitrate: 20939 kb/s
  Stream #1:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 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, mp4, 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), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 2526 kb/s, 30.30 fps, 30.30 tbr, 30k tbn, 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), 48000 Hz, stereo, fltp, 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%

Answer 1

连接分路器
您可以使用 concat demuxer .它需要多个命令，但 concat demuxer 可以通过 stream copy 保留主视频的质量模式。
但是两个文件都必须有 same attributes .

Full.mp4长于 1.mp4 ，所以使 1.mp4喜欢 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，但是1.mp4做。因此，将静音/空白/虚拟/填充音频添加到 Full.mp4与 anullsrc筛选:

ffmpeg -i Full.mp4 -f lavfi -i anullsrc=cl=stereo:r=48000 -c:v copy -c:a aac -shortest Full_new.mp4

制作 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。
见 How to concatenate videos in ffmpeg with different attributes?举几个例子。