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• After using ffmpeg to remove some streams in mkv file, it takes much longer to open the media file in potplayer in Windows

  31 mars 2024, par r ne

  It is well known that ffmpeg command line can be used to remove some streams in mkv or mp4 files, and I have no problem in doing so.

  


  ffmpeg -i input.mp4 -map 0 -map -0:a:3 -map -0:a:6 -c copy output.mp4


  


  The only issue I meet sometimes is, the result media files in mkv or mp4 are much much slower to be opened by player. I cannot figure out the real reason and bypass it.

  


  Any hint or help on solving this issue ? Thanks !

  


• Unable to open mp4 video file with VideoCapture with OpenCV 3.0 before and after recompiling with ffmpeg

  19 août 2015, par ricardo_8990

  When running

  VideoCapture cap;
  
  cap.open("GOPR3252.mp4");
  
  
  
  if(!cap.isOpened())
  
  {
  
      return -1;
  
  }

  I couldn’t open the video, even though I tried to manually add the codec CV_FOURCC(’A’, ’V’, ’C’, ’1’). I read that this may be due to the link with ffmpeg. So I compiled and installed ffmpeg using this guide and this one.

  Later, I uninstalled OpenCV, downloaded and compiled using CMake as :

  cmake -D CMAKE_SHARED_LINKER_FLAGS=-Wl,-Bsymbolic -D WITH_FFMPEG=ON -D WITH_QT=ON -D BUILD_EXAMPLES=ON CMAKE_BUILD_TYPE=Release /route_to_software/opencv/

  However, all the time I get this in the resume at the video section :

  --   Video I/O:
  
  --     DC1394 1.x:                  NO
  
  --     DC1394 2.x:                  NO
  
  --     FFMPEG:                      NO
  
  --       codec:                     NO
  
  --       format:                    NO
  
  --       util:                      NO
  
  --       swscale:                   NO
  
  --       resample:                  NO
  
  --       gentoo-style:              NO
  
  --     GStreamer:                   NO
  
  --     OpenNI:                      NO
  
  --     OpenNI PrimeSensor Modules:  NO
  
  --     OpenNI2:                     NO
  
  --     PvAPI:                       NO
  
  --     GigEVisionSDK:               NO
  
  --     UniCap:                      NO
  
  --     UniCap ucil:                 NO
  
  --     V4L/V4L2:                    NO/YES
  
  --     XIMEA:                       NO
  
  --     Xine:                        NO
  
  --     gPhoto2:                     NO
  
  --

  I have no problem making and installing OpenCV, but I still can’t open that video.

  Then, I tried to convert the video from mp4 to avi and got this error when reading the video file :

  Unexpected list type. Expected : hdrl. Got : movi.

  I tried with different formats as 3gp, wmv with any luck.

  I am running out of ideas. Any clue what I am doing wrong ?

  EDIT
  After uninstalling again ffmpeg and OpenCV. Then I installed ffmpeg from the packman repositories with libffmpeg-dev, compile and install OpenCV. I can play the video in the avi format but I still get this message :

  Unexpected list type. Expected : hdrl. Got : movi.

  I am using OpenSUSE 13.2

  Thanks in advance,

• FFmpeg error : ratecontrol_init : can't open stats file

  18 décembre 2015, par oldo.nicho

  I’ve setup an AWS EC2 instance running Ubuntu 14.04 and have installed FFmpeg so that I can compress and transcode video.

  I’m trying to do a two pass conversion with the following code :

  ffmpeg -i input-file.avi -codec:v libx264 -profile:v high -preset slow -b:v 500k -maxrate 500k -bufsize 1000k -vf scale=702:-1 -threads 0 -pass 1 -an -f mp4 ~/encoded/null

  and second pass :

  ffmpeg -i input-file.avi -codec:v libx264 -profile:v high -preset slow -b:v 500k -maxrate 500k -bufsize 1000k -vf scale=702:-1 -threads 0 -pass 2 -codec:a libfdk_aac -b:a 128k -f mp4 output-file.mp4

  However I get the following error :

  ffmpeg version N-77283-g91c2a33 Copyright (c) 2000-2015 the FFmpeg developers
  
    built with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04)
  
    configuration: --prefix=/home/ubuntu/ffmpeg_build --pkg-config-flags=--static --extra-cflags=-I/home/ubuntu/ffmpeg_build/include --extra-ldflags=-L/home/ubuntu/ffmpeg_build/lib --bindir=/home/ubuntu/bin --enable-gpl --enable-libass --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libx264 --enable-nonfree
  
    libavutil      55. 11.100 / 55. 11.100
  
    libavcodec     57. 17.100 / 57. 17.100
  
    libavformat    57. 20.100 / 57. 20.100
  
    libavdevice    57.  0.100 / 57.  0.100
  
    libavfilter     6. 21.100 /  6. 21.100
  
    libswscale      4.  0.100 /  4.  0.100
  
    libswresample   2.  0.101 /  2.  0.101
  
    libpostproc    54.  0.100 / 54.  0.100
  
  Input #0, avi, from 'input-file.avi':
  
    Duration: 01:18:05.29, start: 0.000000, bitrate: 2025 kb/s
  
      Stream #0:0: Video: mpeg4 (Simple Profile) (XVID / 0x44495658), yuv420p, 720x480 [SAR 1:1 DAR 3:2], 1789 kb/s, 29.97 fps, 29.97 tbr, 29.97 tbn, 29.97 tbc
  
      Stream #0:1: Audio: ac3 ([0] [0][0] / 0x2000), 48000 Hz, stereo, fltp, 224 kb/s
  
  [libx264 @ 0x1e04240] using SAR=1/1
  
  [libx264 @ 0x1e04240] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX AVX2 FMA3 LZCNT BMI2
  
  [libx264 @ 0x1e04240] ratecontrol_init: can't open stats file
  
  Output #0, mp4, to '/home/ubuntu/encoded/null':
  
      Stream #0:0: Video: h264, none, q=2-31, 128 kb/s, SAR 1:1 DAR 0:0, 29.97 fps
  
      Metadata:
  
        encoder         : Lavc57.17.100 libx264
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (mpeg4 (native) -> h264 (libx264))
  
  Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

  The command as written above works fine on my local computer (running OSX). Would anyone have any suggestions as to how to fix this problem ?