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• ffmpeg : precisely cut a video

  19 octobre 2019, par Santhosh Yedidi

  I am tring to cut a video in linux OS

  $ ffmpeg -i dhol.mkv 
  
  ffmpeg version n4.1.2 Copyright (c) 2000-2019 the FFmpeg developers
  
    built with gcc 8.2.1 (GCC) 20181127
  
    configuration: --prefix=/usr --disable-debug --disable-static --disable-stripping --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libdrm --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libiec61883 --enable-libjack --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxml2 --enable-libxvid --enable-nvdec --enable-nvenc --enable-omx --enable-shared --enable-version3
  
    libavutil      56. 22.100 / 56. 22.100
  
    libavcodec     58. 35.100 / 58. 35.100
  
    libavformat    58. 20.100 / 58. 20.100
  
    libavdevice    58.  5.100 / 58.  5.100
  
    libavfilter     7. 40.101 /  7. 40.101
  
    libswscale      5.  3.100 /  5.  3.100
  
    libswresample   3.  3.100 /  3.  3.100
  
    libpostproc    55.  3.100 / 55.  3.100
  
  Input #0, matroska,webm, from 'dhol.mkv':
  
    Metadata:
  
      ENCODER         : Lavf58.20.100
  
    Duration: 00:03:56.18, start: -0.007000, bitrate: 2688 kb/s
  
      Stream #0:0(eng): Video: vp9 (Profile 0), yuv420p(tv, bt709/unknown/unknown), 1920x1080, SAR 1:1 DAR 16:9, 30 fps, 30 tbr, 1k tbn, 1k tbc (default)
  
      Metadata:
  
        DURATION        : 00:03:56.167000000
  
      Stream #0:1(eng): Audio: opus, 48000 Hz, stereo, fltp (default)
  
      Metadata:
  
        DURATION        : 00:03:56.181000000

  I was trying to precisely cut the video file :

  But using ffmpeg I was not successfull. It cuts from the nearest key frames to the given start time

  ffmpeg -y -i dhol.mkv -ss $shift   -t $duration -c:v copy -an output.mkv

  ONE OF THE REASONS HERE IS H.264 Video format (YUV420p vs YUV420sp). I am using -c:v copy so it has to use the same format YUV420p, so it has to start from nearest keyframe

  Now the only reliable software that i can fully depend if avidemux.

  Even in that i have to select

  video-codec: MJPEG
  
  audio-codec: vorbis

  But the cut video size will be large.

  I tried in avidemux

  video-codec: copy
  
  audio-codec: copy

  It will cut from nearest keyframe than precisely.

  One conclusion :
  So irrespective of ffmpeg or avidemux, the output video format yuv420p will not allow precise formatting

  Only option currently possible :

  Using avidemux and with

  video-codec: MJPEG
  
  audio-codec: vorbis

  Cons :

  1) bigger video size.
  
  2) no proper command line examples available for avidemux to do the same as gui does

  I tried command line in avidemux :

  avidemux3_cli --video-codec MJPEG --audio-codec AAC --output-format AVI --load dhol.mkv --begin 137.633 --end 141.334 --save dhol2.mkv

  It tries to convert the whole file rather than from the start to end time

  My requirement :
  I want to do it command line.

  I didnt try with ffmpeg (with video codec : MJPEG and audio : vorbis). I never saw any example

  How to precisely cut a video (even the output format can be different (like MJPEG instead of yuv420p, and also bigger sizes, its ok) using command line

• FFmpeg raw video size parameter

  3 novembre 2019, par Yanick Salzmann

  I am using libavformat in my library to read a stream of raw i420 images and transform them into an mp4 video. I’ve found CLI commands that perform this but since I am using the library in my program I need to reconstruct the same thing.

  Currently the code that is having a problem is looking like this :

          const auto raw_format = av_find_input_format("rawvideo");
  
          if (raw_format == nullptr) {
  
              log->error("Could not find RAW input parser in FFmpeg");
  
              throw std::runtime_error("RAW not found");
  
          }
  
  
  
          _format_context->pb = _io_context.get();
  
  
  
          AVDictionary *input_options = nullptr;
  
          av_dict_set(&input_options, "framerate", std::to_string(fps).c_str(), 0);
  
          av_dict_set(&input_options, "pix_fmt", "yuv420p", 0);
  
          av_dict_set(&input_options, "s:v", fmt::format("{}x{}", width, height).c_str(), 0);
  
          av_dict_set(&input_options, "size", fmt::format("{}x{}", width, height).c_str(), 0);
  
  
  
          auto formatPtr = _format_context.get();
  
          auto res = avformat_open_input(&formatPtr, "(memory file)", raw_format, &input_options);

  Finding the rawvideo is no problem, but it fails in avformat_open_input with the error : [2019-11-03 15:03:22.953] [11599:11663] [ffmpeg] [error] Picture size 0x0 is invalid

  I assumed the sizes are something I can insert using the input options, since in the CLI version it is passed using -s:v 1920x1080, however this does not seem to be true.

  Where do I have to specify the dimensions of my raw input stream ?

• ffmpeg convert cdg/mp3 to mp4 but cdg track is always sped up by a second

  4 mai 2021, par Carver S

  I've tried this :

  



  "C:\Program Files\ffmpeg-4.2.1-win64-static\bin\ffmpeg" -i %1 -i %2 -b:v 1M -y -speed 2 "%~dpn1.mp4"

"C:\Program Files\ffmpeg-4.2.1-win64-static\bin\ffmpeg" -i %1 -i %2 -pix_fmt yuv420p -vcodec libx264 -async 1 -speed 2 "%~dpn1.mp4"


  



  Always same result. The file and quality are great, but obv since its karaoke... the lyrics need to match the timing and the converted files lyrics track is always about a full second or so ahead from when I play the original in a Karaoke program. Any ideas on what settings I could play with to help with this ?

  



  Both the original and the converted have the same play length at the end though. so the mp3 track seems to be ok.

  



  EDIT : Added cmd output

  



  "C:\Program Files\ffmpeg-4.2.1-win64-static\bin\ffmpeg" -i "A:\25 Karaoke\English\Linkin Park - In The End [SF Karaoke].cdg" -i "A:\25 Karaoke\English\Linkin Park - In The End [SF Karaoke].mp3" -b:v 1M -y -speed 2 "LP_inTheEnd.mp4"
ffmpeg version 4.2.1 Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 9.1.1 (GCC) 20190807
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt
  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
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
Input #0, cdg, from 'A:\25 Karaoke\English\Linkin Park - In The End [SF Karaoke].cdg':
  Duration: 00:03:56.21, start: 0.480000, bitrate: 57 kb/s
    Stream #0:0: Video: cdgraphics, pal8, 300x216, 300 fps, 300 tbr, 300 tbn, 300 tbc
[mp3 @ 000001bb3c14bb40] Estimating duration from bitrate, this may be inaccurate
Input #1, mp3, from 'A:\25 Karaoke\English\Linkin Park - In The End [SF Karaoke].mp3':
  Metadata:
    title           : In The End [SF Karaoke]
    artist          : Linkin Park
    comment         : http://www.otslabs.com/
  Duration: 00:03:56.26, start: 0.000000, bitrate: 128 kb/s
    Stream #1:0: Audio: mp3, 44100 Hz, stereo, fltp, 128 kb/s
Codec AVOption speed () specified for output file #0 (LP_inTheEnd.mp4) has not been used for any stream. The most likely reason is either wrong type (e.g. a video option with no video streams) or that it is a private option of some encoder which was not actually used for any stream.
Stream mapping:
  Stream #0:0 -> #0:0 (cdgraphics (native) -> h264 (libx264))
  Stream #1:0 -> #0:1 (mp3 (mp3float) -> aac (native))
Press [q] to stop, [?] for help
[libx264 @ 000001bb3c13bc00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 000001bb3c13bc00] profile High 4:4:4 Predictive, level 3.1, 4:4:4, 8-bit
[libx264 @ 000001bb3c13bc00] 264 - core 158 r2984 3759fcb - H.264/MPEG-4 AVC codec - Copyleft 2003-2019 - 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=4 threads=7 lookahead_threads=1 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=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=abr mbtree=1 bitrate=1000 ratetol=1.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'LP_inTheEnd.mp4':
  Metadata:
    encoder         : Lavf58.29.100
    Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuv444p(progressive), 300x216, q=-1--1, 1000 kb/s, 300 fps, 19200 tbn, 300 tbc
    Metadata:
      encoder         : Lavc58.54.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/1000000 buffer size: 0 vbv_delay: -1
    Stream #0:1: Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s
    Metadata:
      encoder         : Lavc58.54.100 aac
More than 1000 frames duplicated
More than 10000 frames duplicated   2048kB time=00:00:42.16 bitrate= 397.9kbits/s dup=9625 drop=0 speed=11.5x
frame=59170 fps=3226 q=-1.0 Lsize=   11887kB time=00:03:56.26 bitrate= 412.2kbits/s dup=43525 drop=0 speed=12.9x
video:7749kB audio:3340kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 7.203599%
[libx264 @ 000001bb3c13bc00] frame I:242   Avg QP: 0.26  size: 17214
[libx264 @ 000001bb3c13bc00] frame P:16651 Avg QP: 0.14  size:   164
[libx264 @ 000001bb3c13bc00] frame B:42277 Avg QP: 0.25  size:    25
[libx264 @ 000001bb3c13bc00] consecutive B-frames:  2.7%  4.9%  3.8% 88.6%
[libx264 @ 000001bb3c13bc00] mb I  I16..4: 73.7%  1.6% 24.7%
[libx264 @ 000001bb3c13bc00] mb P  I16..4:  0.1%  0.0%  0.1%  P16..4:  0.4%  0.0%  0.0%  0.0%  0.0%    skip:99.4%
[libx264 @ 000001bb3c13bc00] mb B  I16..4:  0.0%  0.0%  0.0%  B16..8:  0.3%  0.0%  0.0%  direct: 0.0%  skip:99.7%  L0:44.2% L1:55.6% BI: 0.2%
[libx264 @ 000001bb3c13bc00] final ratefactor: -19.48
[libx264 @ 000001bb3c13bc00] 8x8 transform intra:1.5% inter:14.0%
[libx264 @ 000001bb3c13bc00] coded y,u,v intra: 14.1% 14.8% 14.9% inter: 0.0% 0.0% 0.0%
[libx264 @ 000001bb3c13bc00] i16 v,h,dc,p: 90%  0%  9%  0%
[libx264 @ 000001bb3c13bc00] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 23% 14% 63%  0%  0%  0%  0%  0%  1%
[libx264 @ 000001bb3c13bc00] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 55% 15% 16%  1%  2%  3%  3%  2%  2%
[libx264 @ 000001bb3c13bc00] Weighted P-Frames: Y:0.2% UV:0.2%
[libx264 @ 000001bb3c13bc00] ref P L0: 97.9%  0.9%  1.0%  0.2%
[libx264 @ 000001bb3c13bc00] ref B L0: 99.6%  0.4%  0.0%
[libx264 @ 000001bb3c13bc00] ref B L1: 99.9%  0.1%
[libx264 @ 000001bb3c13bc00] kb/s:321.80
[aac @ 000001bb3c172e40] Qavg: 6813.878