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• FFmpeg Has A Native VP8 Decoder

  24 juin 2010, par Multimedia Mike — VP8

  Thanks to David Conrad and Ronald Bultje who committed their native VP8 video decoder to the FFmpeg codebase yesterday. At this point, it can decode 14/17 of the VP8 test vectors that Google released during the initial open sourcing event. Work is ongoing on those 3 non-passing samples (missing bilinear filter). Meanwhile, FFmpeg’s optimization-obsessive personalities are hard at work optimizing the native decoder. The current decoder is already profiled to be faster than Google/On2’s official libvpx.

  Testing
  So it falls to FATE to test this on the ridiculous diversity of platforms that FFmpeg supports. I staged individual test specs for each of the 17 test vectors : vp8-test-vector-001 ... vp8-test-vector-017. After the samples have propagated through to the various FATE installations, I’ll activate the 14 test specs that are currently passing.

  Initial Testing Methodology
  Inspired by Ronald Bultje’s idea, I built the latest FFmpeg-SVN with libvpx enabled. Then I selected between the reference and native decoders as such :

  $ for i in 001 002 003 004 005 006 007 008 009 \
   010 011 012 013 014 015 016 017
  do
    echo vp80-00-comprehensive-$i.ivf
    ffmpeg -vcodec libvpx -i \
      /path/to/vp8-test-vectors-r1/vp80-00-comprehensive-$i.ivf \
      -f framemd5 - 2> /dev/null
  done > refs.txt
  $ for i in 001 002 003 004 005 006 007 008 009 \
  
   010 011 012 013 014 015 016 017
  
  do
  
    echo vp80-00-comprehensive-$i.ivf
  
    ffmpeg -vcodec vp8 -i \
  
      /path/to/vp8-test-vectors-r1/vp80-00-comprehensive-$i.ivf \
  
      -f framemd5 - 2> /dev/null
  
  done > native.txt
  $ diff -u refs.txt native.txt
  

  That reveals precisely which files differ.

• FFmpeg realtime volume changing with C API

  9 janvier 2019, par Tank2006

  My environment is FFmpeg 4.1(Prebuild package from an official site) on Windows 10/Visual Studio 2017.

  I want to change an audio volume as realtime according to a volume button operation from media player apps.

  Think simply, it will update if AVFilter parameters changes, but it seems doesn’t work.

  const char src[] = "C:\\sample.mp3";
  
  
  
  AVFilterGraph *graph = NULL;
  
  AVFilterContext *ctx_src, *ctx_sink;
  
  AVFilter *ctx_vol;
  
  
  
  int main()
  
  {
  
      int res;
  
      AVPacket *packet = av_packet_alloc();
  
      AVFrame *frame = av_frame_alloc();
  
      AVFrame *fframe = av_frame_alloc();
  
  
  
      AVCodec *codec = avcodec_find_decoder(AV_CODEC_ID_MP3);
  
      AVCodecParser *parser = av_parser_init(codec->id);
  
  
  
      AVCodecContext *cc = avcodec_alloc_context3(codec);
  
      avcodec_open2(cc, codec, NULL);
  
  
  
  
  
      FILE *fp; uint8_t buffer[1024]; int filterinit = 0;
  
      fopen_s(&fp, src, "rb");
  
      while (feof(fp) == 0) {
  
          int read = fread(buffer, 1, 1024, fp);
  
  
  
          res = av_parser_parse2(parser, cc, &packet->data, &packet->size,
  
              buffer, read, AV_NOPTS_VALUE, AV_NOPTS_VALUE, 0);
  
          if (packet->size) {
  
              res = avcodec_send_packet(cc, packet);
  
  
  
              while (res >= 0) {
  
                  res = avcodec_receive_frame(cc, frame);
  
  
  
                  if (res == AVERROR(EAGAIN) || res == AVERROR_EOF) {
  
                      break;
  
                  } else if (res < 0) {
  
                      fprintf(stderr, "Error during decoding\n");
  
                      exit(1);
  
                  }
  
  
  
                  if (filterinit == 0) {
  
                      // Create a volume filter, links and graph from AVCodecContext's parameter
  
                      if(init_filters(cc)) filterinit = 1;
  
                  }
  
  
  
                  if (filterinit == 1) {
  
                      res = av_buffersrc_add_frame(ctx_src, frame);
  
                      if(av_buffersink_get_frame(ctx_sink, frame) >= 0) {
  
  
  
                          // Change the volume realtime
  
                          av_opt_set(ctx_vol, "volume", AV_STRINGIFY(1.2), AV_OPT_SEARCH_CHILDREN);
  
  
  
  
  
                          int datasize = av_get_bytes_per_sample(cc->sample_fmt);
  
                          for (int i = 0; i < frame->nb_samples; i++) {
  
                              for (int ch = 0; ch < cc->channels; ch++) {
  
                                  //fwrite(frame->data[ch] + data_size * i, 1, data_size, outfile);
  
                              }
  
                          }
  
                      }
  
                  }
  
              }
  
          }
  
      }
  
  
  
      fclose(fp);
  
  
  
      avcodec_free_context(&cc);
  
      av_parser_close(parser);
  
      av_frame_free(&frame);
  
      av_frame_free(&fframe);
  
      av_packet_free(&packet);
  
  
  
      avfilter_graph_free(&graph);
  
  
  
      return 0;
  
  }

  Can I change the filter value in realtime with FFmpeg’s C API or I need to create a new filter link each time when it requires to update ?

• x264 configure linking and building problems

  16 janvier 2014, par Pie

  I am trying to build x264 from source on Ubuntu 32bit in order to convert a sequence of jpg or png images into mp4 video : x264 site, sample images

  The downloaded binaries is able to convert the sequence into an mkv video (or few other formats) when I run this command :

  ./x264dist ~/Dev/x264emp/img/FLYOVER%4d.JPG -o abc.mkv

  x264dist is the renamed name of the binary I download from the site.

  However, when I grab the source and compile with simple configure :

  $ ./configure --enable-shared --enable-static --enable-pic

  platform:      X86
  
  system:        LINUX
  
  cli:           yes
  
  libx264:       internal
  
  shared:        yes
  
  static:        yes
  
  asm:           yes
  
  interlaced:    yes
  
  avs:           avxsynth
  
  lavf:          no
  
  ffms:          no
  
  mp4:           no
  
  gpl:           yes
  
  thread:        posix
  
  opencl:        yes
  
  filters:       crop select_every 
  
  debug:         no
  
  gprof:         no
  
  strip:         no
  
  PIC:           yes
  
  bit depth:     8
  
  chroma format: all

  then $ make. Then I use the binaries to run the exactly same command as above but there is this error :

  ./x264 ~/Dev/x264emp/img/FLYOVER%4d.JPG -o abc.mkv
  
  raw [error]: raw input requires a resolution.
  
  x264 [error]: could not open input file `/home/tmd/Dev/x264emp/img/FLYOVER%4d.JPG' via any method!

  It seems like it can’t read any input at all. But at least I am still able to run --help on that binaries.

  Then I realized that the downloaded binaries is 3.5Mb while my custom compilation results in 1.5Mb binaries.

  So I just want to know what are the build configurations used by the official build, and/or is there any dependency I am missing that leads to this problem.

  The reason I am trying to build myself because I want to port the x264 lib into Javascript using Emscripten. There has been a solution using FFmpeg but it seems like I don’t need the whole video processing library but only a simple H264 codec. So I need to solve the configure/compile/linking problem to port it rightly.

  Possibly similar How to configure X264 build before running make on OS X