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• avcodec/proresenc_aw : use for frame flag in the header the same value than the offic...

  8 octobre 2018, par Martin Vignali

  avcodec/proresenc_aw : use for frame flag in the header the same value than the official encoder
  

  • [DH] libavcodec/proresenc_anatoliy.c
  • [DH] tests/ref/vsynth/vsynth1-prores
  • [DH] tests/ref/vsynth/vsynth2-prores
  • [DH] tests/ref/vsynth/vsynth3-prores
  • [DH] tests/ref/vsynth/vsynth_lena-prores

• FFmpeg API example (encode_video.c) does not work correctly

  30 janvier 2023, par NewbieCoder

  I am using the official encode_video.c example to test if FFmpeg works correctly for me. 
I got the pre-built windows edition from ffmpeg.zeranoe.com/builds. It is built already with libx264 and other external libraries. I got both dev and shared editions and added the DLLs, header files and libs accordingly in Visual Studio.

  



  Now the encode_video.c example does not work correctly.

  



  



  What I tried :

  



  I compiled the example and run it on many different file formats and codecs such as the following.

  



  First I tried all of these file formats (.mp4, .m4v, .h264, .x264, .avi, .flv) with codec name as libx264. The code executed without errors but the output video file did not play in VLC or Windows 10 default player.

  



  Next, I tried all of those above file formats but with codec name as mpeg4. The code executed without errors but the output video file played only for .m4v in VLC.

  



  



  What is expected :

  



  All of those combinations should have produced a video file which could be played in VLC. None of them worked except for .m4v as file format and mpeg4 as codec name.

  



  



  Please tell me how to make this work for h264. I mainly want it to work for h264 as that is only important for now.

  



  I am running the code like ./encode_video.exe test.mp4 libx264 where first argument is output filename and second argument is codec name.

  



  This is the output for test.mp4 and libx264 as command line arguments https://imgur.com/a/AHLQwuK

  



  It seems that in the encode function, it goes over the below code and returns because of AVERROR(EAGAIN) or AVERROR_EOF. Please tell me what is happening.

  



  while (ret >= 0) {
        ret = avcodec_receive_packet(enc_ctx, pkt);
        if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
            return;
        else if (ret < 0) {
            fprintf(stderr, "Error during encoding\n");
            exit(1);
        }

        printf("Write packet %3"PRId64" (size=%5d)\n", pkt->pts, pkt->size);
        fwrite(pkt->data, 1, pkt->size, outfile);
        av_packet_unref(pkt);
    }


  



  I used DepenciesGUI to find out the DLLs linked and it shows that the DLLs are correctly linked. Please help me figure out what the problem is now !!

  


• Building ffmpeg libraries for third party usage

  23 mars 2023, par mikeProgrammer

  I am trying to create bindings for FFmpeg in Elixir programming language and would love to handle FFmpeg binaries for users of my library.

  


  The whole flow is as follows :

  


  

  1. Write some function definition in Elixir

  


  2. Implement it in in C using ffmpeg libs

  


  3. Compile C code as shared library

  


  4. When running application, Erlang Virtual Machine will load my dynamic library

  


  


  The question is how to compile and include ffmpeg libs in my shared lib so that users of my Elixir lib don't have to install any native dependencies.

  


  Here is what I was trying :

  


  


  1. Compile ffmpeg libs as shared ones. When my Elixir lib is compiling, it downloads precompiled ffmpeg archive, extracts its content and links to it when compiling native functions. I realized that this still won't work as ffmpeg shared libs depend on other shared libs that user has to install on their own.

     


  


  2. Compile ffmpeg libs as static ones and include them in my native shared library using —whole-archive linker option. Here I am getting

     


  


  


  /usr/bin/ld : ffmpeg_build/lib/libavcodec.a(vp9lpf_16bpp.o) : warning : relocation against ff_pw_1' in read-only section .text'
/usr/bin/ld : ffmpeg_build/lib/libavcodec.a(cavsdsp.o) : relocation R_X86_64_PC32 against symbol `ff_pw_5' can not be used when making a shared object ; recompile with -fPIC
/usr/bin/ld : final link failed : bad value
collect2 : error : ld returned 1 exit status

  


  The command I am using

  


  cc -fPIC -I/home/michal/.asdf/installs/erlang/25.1/erts-13.1/include -Iffmpeg_build/include -Ic_src/xav -shared -DXAV_DEBUG=1 c_src/xav/xav_nif.c c_src/xav/reader.c c_src/xav/utils.c -o /home/michal/Repos/xav/_build/test/lib/xav/priv/libxav.so -Lffmpeg_build/lib -Wl,--whole-archive -lavcodec -lswscale -lavutil -lavformat -Wl,--no-whole-archive


  


  FFmpeg configuration

  


  ./configure \
--prefix="$PWD/ffmpeg_build" \
--extra-cflags="-fPIC -I$PWD/ffmpeg_build/include" \
--extra-ldflags="-L$PWD/ffmpeg_build/lib" \
--enable-pic
--disable-programs


  


  Does anything that I am trying to do make sense to you ?

  


  When I am installing ffmpeg-libs package on Fedora, it depends on other shared libs that are automatically downlaoded but what I would love to achieve is to provide self-contained ffmpeg build that can be used in other shared libraries.