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• Rolling back _isUndefined() and _isFunction() changes, using typeof x === ’function’ / ’undefined’ as previously. At most, this saved 80 bytes in the -nodebug-jsmin version when served with gzip and isn’t worth potential function call overhead.

  27 mai 2012, par Scott Schiller

  m script/soundmanager2-jsmin.js m script/soundmanager2-nodebug-jsmin.js m script/soundmanager2-nodebug.js m script/soundmanager2.js Rolling back _isUndefined() and _isFunction() changes, using typeof x === ’function’ / ’undefined’ as previously. At most, this saved 80 bytes in the (...)

• Decoding m4a and dumping PCM data gives back noise

  7 décembre 2013, par lynnard

  I'm using the code below (modified from the examples given in libavcodec) to decode audio files

  int main(int argc, char **argv)
  
  {
  
      av_register_all();
  
      avcodec_register_all();
  
  
  
      char *filename = argv[1];
  
      char *outfilename = argv[2];
  
  
  
      FILE *outfile;
  
  
  
      AVCodec *codec;
  
      AVCodecContext *c= NULL;
  
      AVPacket avpkt;
  
      AVFrame *frame = av_frame_alloc();
  
  
  
      printf("Decode audio file %s to %s\n", filename, outfilename);
  
  
  
      outfile = fopen(outfilename, "wb");
  
      if (!outfile) {
  
          fprintf(stderr, "Could not write to %s\n", outfilename);
  
          av_free(c);
  
          exit(1);
  
      }
  
  
  
      AVFormatContext *format_context = NULL;
  
      avformat_open_input(&format_context, filename, NULL, NULL);
  
      printf("Opened format input\n");
  
  
  
      int find_result = avformat_find_stream_info(format_context, NULL);
  
      if (find_result < 0) {
  
          fprintf(stderr, "Cannot find stream info\n");
  
          avformat_close_input(&format_context);
  
          exit(-1);
  
      }
  
  
  
      int audio_stream_idx = av_find_best_stream(format_context, AVMEDIA_TYPE_AUDIO, -1, -1, &codec, 0);
  
  
  
      if (audio_stream_idx < 0) {
  
          fprintf(stderr,"Couldn't find stream information\n");
  
          exit(-1);
  
      }
  
  
  
      // Get a pointer to the codec context for the audio stream
  
      c = format_context->streams[audio_stream_idx]->codec;
  
      av_opt_set_int(c, "refcounted_frames", 1, 0);
  
  
  
      if (avcodec_open2(c, codec, NULL) < 0) {
  
          fprintf(stderr, "Could not open codec\n");
  
          exit(-1);
  
      }
  
  
  
      // read the audio frames
  
      int ret, got_frame;
  
      while (1) {
  
          if ((ret = av_read_frame(format_context, &avpkt)) < 0)
  
              break;
  
          if (avpkt.stream_index == audio_stream_idx) {
  
              avcodec_get_frame_defaults(frame);
  
              got_frame = 0;
  
              ret = avcodec_decode_audio4(c, frame, &got_frame, &avpkt);
  
              if (ret < 0) {
  
                  fprintf(stderr, "Error decoding audio\n");
  
                  continue;
  
              }
  
  
  
              if (got_frame) {
  
                  // write to disk
  
                  fwrite(frame->extended_data[0], 1, frame->linesize[0], outfile);
  
              }
  
          }
  
          av_free_packet(&avpkt);
  
      }
  
  
  
      fclose(outfile);
  
  
  
      printf("Finished\n");
  
      if (c) 
  
          avcodec_close(c);
  
      avformat_close_input(&format_context);
  
      av_frame_free(&frame);
  
  }

  I tried .mp3 and .m4a files ; .mp3 files work fine but not for .m4a files. Any help ?

• Looking to play back non-encoded video upload then export gif from selection point via FFMPEG

  10 novembre 2019, par Christopher Neil

  We’ve been trying to crack this code all week, reaching out to everyone to see if you have any solutions ?

  1. We want the user to upload a video and in the next step he will select a small 5 second loop of the video which will be made as a gif.
  2. Old developer was able to do this by splicing the video at 10 seconds instead of 5 but not re-encoding it meant that it would sometimes be beyond 12 seconds and in some cases less than 7.
  3. We changed the code to force keyframes with re encoding so that it splices the video at exactly 5 seconds to show the loop.
  4. These slices are shown to the user using html5 video player.
  5. Upon selection of the loop that sliced video is converted to gif.

  Everything is working in the vice order. The issue is when the user uploads a large sized and length video this slicing and re-encoding takes forever and that cause the user to feel the site is not working properly.

  What we want is very simple :

  1. Show 5 second portion of the video on loop.
  2. If user wants to select another loop he/she clicks the next button and is taken to the next 5 second loop which would be either at 25% of the video or some other
  3. On selection of that portion it converts it into gif.