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• seeking with av_seek_frame returns invalid data

  27 juin 2016, par mtadmk

  Based on dranger tutorial I’m trying to implement seeking in video file. Problem is with seeking to beginning milliseconds - it always returns 0 when seeking backward, or some place in file (based on file format).

  I.e. with this video file and seeking forward to 500 pts there is always 6163 pts returned. Seeking backward to 500 is always returning 0. I have no idea why.

  Code to do this :

  import java.util.Arrays;
  
  import java.util.List;
  
  import org.bytedeco.javacpp.BytePointer;
  
  import org.bytedeco.javacpp.DoublePointer;
  
  import org.bytedeco.javacpp.PointerPointer;
  
  import org.bytedeco.javacpp.avcodec;
  
  import org.bytedeco.javacpp.avformat;
  
  import org.bytedeco.javacpp.avutil;
  
  import org.bytedeco.javacpp.swscale;
  
  
  
  import static org.bytedeco.javacpp.avcodec.av_free_packet;
  
  import static org.bytedeco.javacpp.avcodec.avcodec_close;
  
  import static org.bytedeco.javacpp.avcodec.avcodec_decode_video2;
  
  import static org.bytedeco.javacpp.avcodec.avcodec_find_decoder;
  
  import static org.bytedeco.javacpp.avcodec.avcodec_flush_buffers;
  
  import static org.bytedeco.javacpp.avcodec.avcodec_open2;
  
  import static org.bytedeco.javacpp.avcodec.avpicture_fill;
  
  import static org.bytedeco.javacpp.avcodec.avpicture_get_size;
  
  import static org.bytedeco.javacpp.avformat.AVSEEK_FLAG_BACKWARD;
  
  import static org.bytedeco.javacpp.avformat.av_dump_format;
  
  import static org.bytedeco.javacpp.avformat.av_read_frame;
  
  import static org.bytedeco.javacpp.avformat.av_register_all;
  
  import static org.bytedeco.javacpp.avformat.av_seek_frame;
  
  import static org.bytedeco.javacpp.avformat.avformat_close_input;
  
  import static org.bytedeco.javacpp.avformat.avformat_find_stream_info;
  
  import static org.bytedeco.javacpp.avformat.avformat_open_input;
  
  import static org.bytedeco.javacpp.avutil.AVMEDIA_TYPE_VIDEO;
  
  import static org.bytedeco.javacpp.avutil.AV_PIX_FMT_RGB24;
  
  import static org.bytedeco.javacpp.avutil.AV_TIME_BASE;
  
  import static org.bytedeco.javacpp.avutil.av_frame_alloc;
  
  import static org.bytedeco.javacpp.avutil.av_frame_get_best_effort_timestamp;
  
  import static org.bytedeco.javacpp.avutil.av_free;
  
  import static org.bytedeco.javacpp.avutil.av_make_q;
  
  import static org.bytedeco.javacpp.avutil.av_malloc;
  
  import static org.bytedeco.javacpp.avutil.av_q2d;
  
  import static org.bytedeco.javacpp.avutil.av_rescale_q;
  
  import static org.bytedeco.javacpp.swscale.SWS_BILINEAR;
  
  import static org.bytedeco.javacpp.swscale.sws_getContext;
  
  import static org.bytedeco.javacpp.swscale.sws_scale;
  
  
  
  public class SeekTest1 {
  
      private avformat.AVFormatContext videoFile;
  
      private final avcodec.AVPacket framePacket = new avcodec.AVPacket();
  
      private avcodec.AVCodecContext videoCodec;
  
      private avutil.AVFrame yuvFrame;
  
      private swscale.SwsContext scalingContext;
  
      private avutil.AVFrame rgbFrame;
  
      private int streamId;
  
      private long lastTime;
  
  
  
      public static void main(String[] args) {
  
          if (args.length > 0) {
  
              new SeekTest1().start(args[0]);
  
          } else {
  
              new SeekTest1().start("/path/to/file");
  
          }
  
  
  
      }
  
  
  
      private void start(String path) {
  
          init(path);
  
          //test for forward
  
  //        List<integer> seekPos = Arrays.asList(0, 100, 0, 200, 0, 300, 0, 400, 0, 500, 0, 600, 0, 700);
  
          //test for backward
  
          List<integer> seekPos = Arrays.asList(10000, 8000, 10000, 7000, 10000, 6000, 10000, 4000, 10000, 2000, 10000, 1000, 10000, 200);
  
          seekPos.forEach(seekPosition -> {
  
              readFrame();
  
              seek(seekPosition);
  
          });
  
          readFrame();
  
          cleanUp();
  
      }
  
  
  
      long seek(long seekPosition) {
  
          final avutil.AVRational timeBase = fetchTimeBase();
  
          long timeInBaseUnit = fetchTimeInBaseUnit(seekPosition, timeBase);
  
  
  
          //changing flag to AVSEEK_FLAG_ANY does not change behavior
  
          int flag = 0;
  
          if (timeInBaseUnit &lt; lastTime) {
  
              flag = AVSEEK_FLAG_BACKWARD;
  
              System.out.println("seeking backward to " + timeInBaseUnit);
  
          } else {
  
              System.out.println("seeking forward to " + timeInBaseUnit);
  
          }
  
          avcodec_flush_buffers(videoCodec);
  
          av_seek_frame(videoFile, streamId, timeInBaseUnit, flag);
  
          return timeInBaseUnit;
  
      }
  
  
  
      private long fetchTimeInBaseUnit(long seekPositionMillis, avutil.AVRational timeBase) {
  
          return av_rescale_q((long) (seekPositionMillis / 1000.0 * AV_TIME_BASE), av_make_q(1, AV_TIME_BASE), timeBase);
  
      }
  
  
  
      private void readFrame() {
  
          while (av_read_frame(videoFile, framePacket) >= 0) {
  
              if (framePacket.stream_index() == streamId) {
  
                  // Decode video frame
  
                  final int[] frameFinished = new int[1];
  
                  avcodec_decode_video2(this.videoCodec, yuvFrame, frameFinished, framePacket);
  
  
  
                  if (frameFinished[0] != 0) {
  
                      av_free_packet(framePacket);
  
                      long millis = produceFinishedFrame();
  
                      System.out.println("produced time " + millis);
  
                      break;
  
                  }
  
              }
  
              av_free_packet(framePacket);
  
          }
  
      }
  
  
  
      private long produceFinishedFrame() {
  
          sws_scale(scalingContext, yuvFrame.data(), yuvFrame.linesize(), 0,
  
              videoCodec.height(), rgbFrame.data(), rgbFrame.linesize());
  
          final long pts = av_frame_get_best_effort_timestamp(yuvFrame);
  
          final double timeBase = av_q2d(fetchTimeBase());
  
          final long foundMillis = (long) (pts * 1000 * timeBase);
  
          lastTime = foundMillis;
  
          return foundMillis;
  
      }
  
  
  
      private avutil.AVRational fetchTimeBase() {
  
          return videoFile.streams(streamId).time_base();
  
      }
  
  
  
      private void init(String videoPath) {
  
          final avformat.AVFormatContext videoFile = new avformat.AVFormatContext(null);
  
  
  
          av_register_all();
  
          if (avformat_open_input(videoFile, videoPath, null, null) != 0) throw new RuntimeException("unable to open");
  
          if (avformat_find_stream_info(videoFile, (PointerPointer) null) &lt; 0) throw new RuntimeException("Couldn't find stream information");
  
  
  
          av_dump_format(videoFile, 0, videoPath, 0);
  
  
  
          final int streamId = findFirstVideoStream(videoFile);
  
  
  
          final avcodec.AVCodecContext codec = videoFile.streams(streamId).codec();
  
  
  
          final avcodec.AVCodec pCodec = avcodec_find_decoder(codec.codec_id());
  
          if (pCodec == null) throw new RuntimeException("Unsupported codec");
  
  
  
          if (avcodec_open2(codec, pCodec, (avutil.AVDictionary) null) &lt; 0) throw new RuntimeException("Could not open codec");
  
  
  
          final avutil.AVFrame yuvFrame = av_frame_alloc();
  
  
  
          final avutil.AVFrame rgbFrame = av_frame_alloc();
  
          if (rgbFrame == null) throw new RuntimeException("Can't allocate avframe");
  
  
  
          final int numBytes = avpicture_get_size(AV_PIX_FMT_RGB24, codec.width(), codec.height());
  
          final BytePointer frameBuffer = new BytePointer(av_malloc(numBytes));
  
  
  
          final swscale.SwsContext swsContext = sws_getContext(codec.width(), codec.height(), codec.pix_fmt(), codec.width(), codec.height(),
  
              AV_PIX_FMT_RGB24, SWS_BILINEAR, null, null, (DoublePointer) null);
  
  
  
          avpicture_fill(new avcodec.AVPicture(rgbFrame), frameBuffer, AV_PIX_FMT_RGB24, codec.width(), codec.height());
  
  
  
          this.videoFile = videoFile;
  
          this.videoCodec = codec;
  
          this.yuvFrame = yuvFrame;
  
          this.scalingContext = swsContext;
  
          this.rgbFrame = rgbFrame;
  
          this.streamId = streamId;
  
      }
  
  
  
      private static int findFirstVideoStream(avformat.AVFormatContext videoFile) {
  
          int videoStream = -1;
  
          for (int i = 0; i &lt; videoFile.nb_streams(); i++) {
  
              if (videoFile.streams(i).codec().codec_type() == AVMEDIA_TYPE_VIDEO) {
  
                  videoStream = i;
  
                  break;
  
              }
  
          }
  
          if (videoStream == -1) throw new RuntimeException("Didn't find video stream");
  
          return videoStream;
  
      }
  
  
  
      private void cleanUp() {
  
          av_free(this.rgbFrame);
  
          av_free(yuvFrame);
  
          avcodec_close(videoCodec);
  
          avformat_close_input(videoFile);
  
      }
  
  }
  
  </integer></integer>

  As input arg should be provided file from above.

• combine Scheduled audio ffmpeg

  5 septembre 2018, par Erfan Esmaeilzadeh

  I am developing a music making application for Android. I need to create a system that can extract MP3s from the user’s music project.

  I can save the name of every file per second of music in a string, as in the following example :

  a.mp3-b.mp3-c.mp3|| d.mp3-e.mp3-f.mp3|| g.mp3-h.mp3-i.mp3
  
  
  
  => final.mp3

  Between "||" is equivalent to one second and the audio within this parameter must be combined. After that, the combinations are put together.

  The most important thing is the timing of each sound. Some sounds must be combined at one time and some sounds at other times.

• Flutter FFMPEG - Getting the same waveform output image for different audio files

  28 novembre 2020, par mtkguy

  I'm trying to generate waveform images for different audio files but no matter what i do, i keep getting the same waveform image for every audio. The first audio file returns the correct waveform image but subsequent files also return that same image as output. Yes, i already set the overwrite flag to my command but it doesn't change anything. Here's my code.

  


  class RecordController extends GetxController {&#xA;Rx<file> cachedAudioFile = Rx<file>();&#xA;  RxString waveFormImagePath = "".obs;&#xA;&#xA;Future<int> getWaveForm(String url) async {&#xA;    final FlutterFFmpeg _flutterFFmpeg = FlutterFFmpeg();&#xA;    final FlutterFFmpegConfig _flutterFFmpegConfig = FlutterFFmpegConfig();&#xA;    // clear out path for new wave form&#xA;    if (waveFormImagePath.value != "") {&#xA;      File(waveFormImagePath.value).delete();&#xA;    }&#xA;    waveFormImagePath.value = "";&#xA;    Directory appDocumentDir = await getApplicationDocumentsDirectory();&#xA;    String rawDocumentPath = appDocumentDir.path;&#xA;    waveFormImagePath.value = [rawDocumentPath, &#x27;/audioWaveForm.png&#x27;].join();&#xA;&#xA;    cachedAudioFile.value = await DefaultCacheManager().getSingleFile(url);&#xA;    String inputFilePath = cachedAudioFile.value.path;&#xA;    String commandToExecute = [&#xA;      &#x27;-y -i $inputFilePath -filter_complex "compand,aformat=channel_layouts=mono,showwavespic=s=4000x2000:colors=white" -frames:v 1 &#x27;,&#xA;      waveFormImagePath.value&#xA;    ].join();&#xA;    _flutterFFmpeg&#xA;        .execute(commandToExecute)&#xA;        .then((rc) => print("FFmpeg process exited with rc $rc"));&#xA;    int returnCode = await _flutterFFmpegConfig.getLastReturnCode();&#xA;    var output = await _flutterFFmpegConfig.getLastCommandOutput();&#xA;    print(output);&#xA;    print(waveFormImagePath.value);&#xA;&#xA;    return returnCode;&#xA;  }&#xA;}&#xA;</int></file></file>

  


  I'm using the Getx package to manage state and as such i can use the waveFormImagePath anywhere in my UI plus it's reactive. So somewhere in my UI i have this

  


  FileImage(File(recordController?.waveFormImagePath?.value))


  


  Any help would be appreciated.