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• How to set the value of an arbitrary pixel in ffmpeg ?

  14 mai 2017, par Neb

  I want to modify the rgb value of each pixel inside ffmpeg.

  I need to implement the following function :

  A[x + expr_1][y] = expr_2

  where x and y are the current sampled pixel, A is the input frame whose pixel need to be modified and expr_1, expr_2 are two independent expressions.

  I tried using the geq filter but it seems there no way to set the value of a pixel other than from that currently sampled. For istance, the function p(x,y) only returns the value of the pixel at the specified location, but doesn’t allow to set a value for that pixel. In other word, ffmpeg seems allowing only something like :

  A[x][y] = expr

  Is there a way to tell ffmpeg to set the value of a specific pixel ?

  Thanks for your time.

• How to specify a non default type when calling a FFmpeg library using ctypes

  1er août 2013, par Jim Ramberg

  I am calling an FFMPEG library called avformat_alloc_context() that returns a pointer to type AVFormatContext. The structure AVFormatContext is defined in the avformat library.

  Obviously ; this is not one ctypes default types and results in an error when I try to pass a reference to it to another ffmpeg library further down in my code.

  Is there a way to add in the the classes defined inside of the library ? I read through what documentation I could find online and was not able to find a good answer to this question.

• android ffmpeg halfninja Could not find input stream matching output stream

  2 octobre 2013, par Nguyen

  I need your help about Android FFMPEG .

  I tried to run halfninja's projectTest but some errors are occurred.

  First error is occurred and it has been fixed by following suggestion : android ffmpeg halfninja av_open_input_file returns -2 (no such file or directory)

  Then after run again, I have this error :

  10-03 00:38:48.070 : E/Videokit(10474) : Could not find input stream matching output stream #0.0

  Full error :

  10-03 00:38:47.340 : E/Videokit(10474) : ffmpeg version N-30996-gf925b24, Copyright (c) 2000-2011 the FFmpeg developers
  10-03 00:38:47.340 : E/Videokit(10474) : built on Oct 2 2013 10:32:27 with gcc 4.4.3
  10-03 00:38:47.340 : E/Videokit(10474) : configuration : —enable-cross-compile —arch=arm5te —enable-armv5te —target-os=linux —disable-stripping —prefix=../output —disable-neon —enable-version3 —disable-shared —enable-static —enable-gpl —enable-memalign-hack —cc=arm-linux-androideabi-gcc —ld=arm-linux-androideabi-ld —extra-cflags='-fPIC -DANDROID -D_thumb_ -mthumb -Wfatal-errors -Wno-deprecated' —disable-everything —enable-decoder=mjpeg —enable-demuxer=mjpeg —enable-parser=mjpeg —enable-demuxer=image2 —enable-muxer=mp4 —enable-encoder=libx264 —enable-libx264 —enable-decoder=rawvideo —enable-protocol=file —enable-hwaccels —disable-ffmpeg —disable-ffplay —disable-ffprobe —disable-ffserver —disable-network —enable-filter=buffer —enable-filter=buffersink —disable-demuxer=v4l —disable-demuxer=v4l2 —disable-indev=v4l —disable-indev=v4l2 —extra-cflags='-I../x264 -Ivideokit' —extra-ldflags=-L../x264
  10-03 00:38:48.070 : E/Videokit(10474) : Could not find input stream matching output stream #0.0
  10-03 00:38:48.070 : E/Videokit(10474) : ffmpeg_exit(1) called !

  please help me.Thanks so much