ffmpeg - 为什么在使用此 ffmpeg 命令进行 2 遍时出现错误？

Question

F:\Project>ffmpeg -y -i 2.mp4 -b:v 18M -pass 1 -an -f null NUL && ^
更多的？ ffmpeg -i 2.mp4 -b:v 18M -pass 2 -c:a aac -b:a 128k brdown1.mp4
使用此命令并收到以下错误。为什么？请有任何帮助

ffmpeg version 4.3.2-2021-02-02-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-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2 --enable-libdav1d --enable-libzvbi --enable-librav1e --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-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. 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 '2.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2mp41
    encoder         : Lavf58.45.100
  Duration: 10:00:36.00, start: 0.000000, bitrate: 40408 kb/s
    Stream #0:0(eng): Video: hevc (Main) (hev1 / 0x31766568), yuv420p(tv, progressive), 3840x2160, 40405 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 29.97 tbc (default)
    Metadata:
      handler_name    : ?Mainconcept Video Media Handler
Stream mapping:
  Stream #0:0 -> #0:0 (hevc (native) -> wrapped_avframe (native))
Press [q] to stop, [?] for help
Output #0, null, to 'NUL':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2mp41
    encoder         : Lavf58.45.100
    Stream #0:0(eng): Video: wrapped_avframe, yuv420p, 3840x2160, q=2-31, 18000 kb/s, 29.97 fps, 29.97 tbn, 29.97 tbc (default)
    Metadata:
      handler_name    : ?Mainconcept Video Media Handler
      encoder         : Lavc58.91.100 wrapped_avframe
frame=1080000 fps= 36 q=-0.0 Lsize=N/A time=10:00:36.00 bitrate=N/A speed=1.19x
video:565312kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
ffmpeg version 4.3.2-2021-02-02-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-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2 --enable-libdav1d --enable-libzvbi --enable-librav1e --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-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. 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 '2.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2mp41
    encoder         : Lavf58.45.100
  Duration: 10:00:36.00, start: 0.000000, bitrate: 40408 kb/s
    Stream #0:0(eng): Video: hevc (Main) (hev1 / 0x31766568), yuv420p(tv, progressive), 3840x2160, 40405 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 29.97 tbc (default)
    Metadata:
      handler_name    : ?Mainconcept Video Media Handler
Stream mapping:
  Stream #0:0 -> #0:0 (hevc (native) -> h264 (libx264))
Press [q] to stop, [?] for help
[libx264 @ 000002831478e040] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 000002831478e040] ratecontrol_init: can't open stats file
Error initializing output stream 0:0 -- Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height
Conversion failed!

Answer 1

如果使用 null muxer，则必须指定编码器，因为 null muxer 的默认编码器与 MP4 muxer 的编码器不匹配。ffmpeg -y -i 2.mp4 -c:v libx264 -b:v 18M -pass 1 -an -f null NUL或者，使用 MP4 多路复用器，但确保始终将输出定向到 NUL。ffmpeg -y -i 2.mp4 -b:v 18M -pass 1 -an -f mp4 NUL