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• Opencv Won't compile due to "cap_ffmpeg_impl.hpp" and "ffmpeg_codecs.hpp"

  13 octobre 2022, par AmberGraph41161

  I am new to opencv and linux. I am trying to install opencv or build opencv from source to use the library with c++. When building or trying to use "make" to build all the files, everything is fine until around 50% (I've tried to redo the entire installation process multiple times over because I have no idea what I am doing and keep getting the same errors). At around the 50% mark, I get the same two errors :

  


  make[2]: *** [modules/videoio/CMakeFiles/opencv_videoio.dir/build.make:244: modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_ffmpeg.cpp.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:5218: modules/videoio/CMakeFiles/opencv_videoio.dir/all] Error 2
make: *** [Makefile:166: all] Error 2


  


  I get these two errors as well as a ton of build error messages containing errors about 2 files in particular (I get a bunch of errors and all of them deal with 2 files).

  


  /home/jinwoo_k/opencv/opencv-4.6.0/modules/videoio/src/ffmpeg_codecs.hpp:96:27: error: ‘CODEC_ID_LJPEG’ was not declared in this scope; did you mean ‘AV_CODEC_ID_LJPEG’?
   96 | #define AV_CODEC_ID_LJPEG CODEC_ID_LJPEG
      |                           ^~~~~~~~~~~~~~
/home/jinwoo_k/opencv/opencv-4.6.0/modules/videoio/src/cap_ffmpeg_impl.hpp:215:26: note: in expansion of macro ‘AV_CODEC_ID_LJPEG’
  215 | #  define CV_CODEC(name) AV_##name
      |                          ^~~
/home/jinwoo_k/opencv/opencv-4.6.0/modules/videoio/src/cap_ffmpeg_impl.hpp:2842:10: note: in expansion of macro ‘CV_CODEC’
 2842 |     case CV_CODEC(CODEC_ID_LJPEG):
      |          ^~~~~~~~
/home/jinwoo_k/opencv/opencv-4.6.0/modules/videoio/src/ffmpeg_codecs.hpp:100:30: error: ‘CODEC_ID_RAWVIDEO’ was not declared in this scope; did you mean ‘AV_CODEC_ID_RAWVIDEO’?
  100 | #define AV_CODEC_ID_RAWVIDEO CODEC_ID_RAWVIDEO
      |                              ^~~~~~~~~~~~~~~~~



  


  ^^^These are just a couple of the error messages, I get hundreds of them.

  


  I read another stackoverflow post about opencv and ffmpeg : OpenCV 3.0.0 make error with FFMPEG
but I don't think that this is the same error that I have. I don't believe that I have made a mistake in the installation or build process or anything with cmake - I have followed and redone the process of following mutliple video and forum guides on how to install opencv. What am I doing wrong ?

  


• FFmpeg command line vs programatically

  10 avril 2018, par John

  How do I reproduce the ffmpeg rtsp streaming/codec copying/audio disabling command line entry

  ffmpeg -i rtsp://abcd:123456@1.2.3.4/rtspvideostream -vcodec copy -an /home/pc/video.avi

  within ffmpeg library referencing code ? Currently I use (along with all the necessary av_find_stream_info / avcodec_find_decoder etc. commands)

  numBytes = av_open_input_file(&pFormatCtx,"rtsp://abcd:123456@1.2.3.4/rtspvideostream", NULL, 0, NULL))

  which to me appears to reproduce the command line entry

  ffmpeg -i rtsp://abcd:123456@1.2.3.4/rtspvideostream /home/pc/video.avi

  without the hugely CPU saving flags of ’-vcodec copy -an’.

• How to join two video files using Python ?

  1er juillet 2013, par rash

  Here I tried to cut first and second 30sec long video file from "path/connect.webm" to the strings out and out1. It works. But what I need to do is to concatenate these two strings and write that to a file "path/final.webm". So that I get a 60sec long video file "final.webm" at the end. But now i get first 30sec long video only as the output. Please help me. Thanks a lot in advance.

  Code in python :

  import subprocess,os
  
  
  
  fname = "/home/xincoz/test/final.webm"
  
  
  
  fp = open(fname,'wb')
  
  
  
  ffmpeg_command = ["ffmpeg", "-i", "/home/xincoz/test/connect.webm", "-acodec", "copy",   "-ss", "00:00:00", "-t", "00:00:30","-f", "webm", "pipe:1"]
  
  
  
  p = subprocess.Popen(ffmpeg_command,stdout=subprocess.PIPE)
  
  
  
  out, err = p.communicate()
  
  
  
  ffmpeg_command1 = ["ffmpeg", "-i", "/home/xincoz/test/connect.webm", "-acodec", "copy",   "-ss", "00:00:31", "-t", "00:00:30","-f", "webm", "pipe:1"]
  
  
  
  p1 = subprocess.Popen(ffmpeg_command1,stdout=subprocess.PIPE)
  
  
  
  out1, err1 = p1.communicate()
  
  
  
  string = out + out1
  
  
  
  print len(out)
  
  
  
  print len(out1)
  
  
  
  print len(string)
  
  
  
  fp.write(string)
  
  
  
  fp.close()

  Please help me.