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• opencv and ffmpeg multipart avi files > 2GB

  8 février 2016, par jlarsch

  Is there a way OpenCV can read large (>2GB) .avi video files ?

  I am using openCV 3.0 and python 2.7 on Windows 7 64 bit.

  I have mpeg4 compressed .avi files, often > 2GB. These are created using ffmpeg.
  Such files read fine up to some point using the following commands :

  import cv2
  
  #avi_path is full path to avi
  
  cap = cv2.VideoCapture(avi_path)
  
  img1=cap.read()

  but at some frame number, read() returns ’false’

  Using Gspot, I found that such problematic videos are ’Multipart OpenDML AVI’ and read() seems to only be able to read the first part. Doing some google searches, it seems other people are having similar issues but no obvious solution.

  apparently, openCV VideoWriter is also limited to 2 GB videos :
  openCV documentation
  Is the limitation in VideoCapture by design also ?

  Is there a workaround perhaps to read large video files ?
  Alternatively, can I avoid creating multipart avi files in ffmpeg ?

• ffmpeg with libopenh264 to get profile high422

  24 juillet 2023, par Андрей Тернити

  I have raw MJPEG video file. 3840x2160, 25fps, YUYV 4:2:2. I want use ffmpeg with encoder libopenh264. Why I can't use profile high422 ?

  


  ffmpeg -framerate 25 -i inFile.yuvj422p -profile:v high422 -c:v libopenh264 -q 2 -b 2500000 -allow_skip_frames 1 -maxrate 3500000 outFile.mkv


  


  Log

  


  ...
[libopenh264enc @ 0x56077580ed80] [Eval @ 0x7ffe78457230] Undefined constant or missing '(' in 'high422'


  


  Let's know encoder's capability

  


  # ffmpeg -h encoder=libopenh264&#xA;Encoder libopenh264 [OpenH264 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10]:&#xA;    General capabilities: threads &#xA;    Threading capabilities: other&#xA;    Supported pixel formats: yuv420p&#xA;libopenh264enc AVOptions:&#xA;  -slice_mode        <int>        E..V......P set slice mode, use slices/max_nal_size (from 0 to 4) (default fixed)&#xA;     fixed           1            E..V....... a fixed number of slices&#xA;     dyn             3            E..V....... Size limited (compatibility name)&#xA;     sizelimited     3            E..V....... Size limited&#xA;  -loopfilter        <int>        E..V....... enable loop filter (from 0 to 1) (default 1)&#xA;  -profile           <int>        E..V....... set profile restrictions (from -99 to 65535) (default -99)&#xA;     constrained_baseline 578          E..V.......&#xA;     main            77           E..V.......&#xA;     high            100          E..V.......&#xA;  -max_nal_size      <int>        E..V....... set maximum NAL size in bytes (from 0 to INT_MAX) (default 0)&#xA;  -allow_skip_frames <boolean>    E..V....... allow skipping frames to hit the target bitrate (default false)&#xA;  -cabac             <int>        E..V......P Enable cabac(deprecated, use coder) (from 0 to 1) (default 0)&#xA;  -coder             <int>        E..V....... Coder type (from -1 to 1) (default default)&#xA;     default         -1           E..V.......&#xA;     cavlc           0            E..V.......&#xA;     cabac           1            E..V.......&#xA;     vlc             0            E..V.......&#xA;     ac              1            E..V.......&#xA;  -rc_mode           <int>        E..V....... Select rate control mode (from -1 to 3) (default quality)&#xA;     off             -1           E..V....... bit rate control off&#xA;     quality         0            E..V....... quality mode&#xA;     bitrate         1            E..V....... bitrate mode&#xA;     buffer          2            E..V....... using buffer status to adjust the video quality (no bitrate control)&#xA;     timestamp       3            E..V....... bit rate control based on timestamp&#xA;</int></int></int></boolean></int></int></int></int>

  


  Looks like there is no high422 profile in libopenh264. But I can find
PRO_HIGH422 in several places of source code...

  


  ffmpeg version

  


  # ffmpeg -v
ffmpeg version N-111611-g5b11ee9429 Copyright (c) 2000-2023 the FFmpeg developers
  built with gcc 11 (Ubuntu 11.4.0-1ubuntu1~22.04)
  configuration: --prefix=/home/a/Downloads/myGitHub/FFmpeg_fixing/ffmpeg_openh264/ffmpeg_build/ --pkg-config-flags=--static --extra-cflags=-I/home/a/Downloads/myGitHub/FFmpeg_fixing/ffmpeg_openh264/ffmpeg_build/include --extra-ldflags=-L/home/a/Downloads/myGitHub/FFmpeg_fixing/ffmpeg_openh264/ffmpeg_build/lib --extra-libs='-lpthread -lm' --ld=g++ --bindir=/home/a/bin --enable-gpl --enable-libopenh264


  


  Why I can't use profile high422 ?

  


• FLV to MP4 conversion keeping PTS consistent

  16 janvier 2019, par M.Do

  The input file has the following video settings but playsback in media player at 29.97 FPS

  Video
  
  Format                      : AVC
  
  Format/Info                 : Advanced Video Codec
  
  Format profile              : Baseline@L2.1
  
  Format settings             : 2 Ref Frames
  
  Format settings, CABAC      : No
  
  Format settings, ReFrames   : 2 frames
  
  Codec ID                    : 7
  
  Duration                    : 1 min 30 s
  
  Width                       : 480 pixels
  
  Height                      : 360 pixels
  
  Display aspect ratio        : 4:3
  
  Frame rate mode             : Constant
  
  Frame rate                  : 14.985 (15000/1001) FPS
  
  Color space                 : YUV
  
  Chroma subsampling          : 4:2:0
  
  Bit depth                   : 8 bits
  
  Scan type                   : Progressive
  
  Color range                 : Limited
  
  Color primaries             : BT.601 NTSC
  
  Transfer characteristics    : BT.709
  
  Matrix coefficients         : BT.601

  However, another coded application will not accept the file as a valid file frame rates are only NTSC or PAL
  How can I force the frame rate to be presented as 29.97 without changing the duration of the clip ?