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• movenc-test : Add tests for negative cts offsets

  23 septembre 2017, par Martin Storsjö

  movenc-test : Add tests for negative cts offsets
  Signed-off-by : Martin Storsjö <martin@martin.st>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavformat/tests/movenc.c
  • [DH] tests/ref/fate/movenc

• movenc : Add an option for enabling negative CTS offsets

  26 septembre 2017, par Martin Storsjö

  movenc : Add an option for enabling negative CTS offsets
  This reduces the need for an edit list ; streams that start with
  
  e.g. dts=-1, pts=0 can be encoded as dts=0, pts=0 (which is valid
  
  in mov/mp4) by shifting the dts values of all packets forward.
  
  This avoids the need for edit lists for such streams (while they
  
  still are needed for audio streams with encoder delay).
  This eases conformance with the DASH-IF interoperability guidelines.
  Signed-off-by : Martin Storsjö <martin@martin.st>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] doc/muxers.texi
  • [DH] libavformat/movenc.c
  • [DH] libavformat/movenc.h

• Java FFmpeg decoding AVPacket result of avcodec_decode_video2 negative

  19 octobre 2017, par nh_

  I’m new to ffmpeg. I’m using FFmpegFrameGrabber and JavaCPP (version 1.3.3) to grab packets of an mp4-video-file. I would like to save the packet’s bytestream in a database in order to decode the packets at the time the data is requested and to process the image.

  public static void saveVideoToDB(String pathToVideo){
  
  FFmpegFrameGrabber grabber = new FFmpegFrameGrabber(pathToVideo);
  
  grabber.start();
  
  AVPacket pkt;
  
  while ((pkt = grabber.grabPacket()) != null) {
  
      BytePointer data = pkt.data();
  
      data.capacity(pkt.size());
  
      byte[] arr = data.getStringBytes();  
  
      //arr = [0, 0, 0, 62, 39, 100, 0, 40, -83, -124.....]
  
       if (pkt.stream_index() == AVMEDIA_TYPE_VIDEO) {
  
          //ToDo: save arr to database
  
           testDecode(arr);
  
       }
  
  
  
  
  
  }
  
  grabber.close();
  
  logger.info("Import video finished.");
  
  }   

  In my code I first tried to decode a packet’s data for a proof-of-concept, but I’m not sure if it’s working like this :

   public static void testDecode(byte[] data){
  
      AVCodec avCodec = avcodec_find_decoder(AV_CODEC_ID_H264);
  
      AVCodecContext avCodecContext = avcodec_alloc_context3(avCodec);
  
      AVDictionary opts = new AVDictionary();
  
      avcodec_open2(avCodecContext, avCodec, opts);
  
      av_dict_free(opts);
  
      AVFrame avFrame = av_frame_alloc();
  
      AVPacket avPacket = new AVPacket();
  
      av_init_packet(avPacket);
  
      Frame frame = new Frame();
  
      avPacket.pts(AV_NOPTS_VALUE);
  
      avPacket.dts(AV_NOPTS_VALUE);
  
      BytePointer bp = new BytePointer(data);
  
      bp.capacity(data.length);
  
      avPacket.data(bp);
  
      avPacket.size(data.length);
  
      avPacket.pos(-1);
  
  
  
      IntBuffer gotPicture = IntBuffer.allocate(1);
  
      boolean doVideo = true;
  
      boolean keyFrames = false;
  
      boolean processImage = true;
  
      AVPacket pkt = avPacket; 
  
      if (doVideo) {
  
        int len = avcodec_decode_video2(avCodecContext, avFrame, gotPicture, avPacket);
  
        if (len >= 0 && gotPicture.get(0) != 0
  
            && (!keyFrames || avFrame.pict_type() == AV_PICTURE_TYPE_I)) {
  
          //ToDo: process image
  
          logger.info("decode success");
  
        }else{
  
          logger.info("decode failed");
  
        }
  
      }
  
    }

  The result of avcodec_decode_video2 is always negative (-1094995529 => Invalid data found when processing input) and I receive following errors :

  [h264 @ 00000000214d11a0] No start code is found.

  [h264 @ 00000000214d11a0] Error splitting the input into NAL units.

  Here are some metadata from the input :

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'C:\Users\user01\Documents\fullstream.mp4':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 0
  
      compatible_brands: mp42mp41isomiso2
  
      creation_time   : 2017-07-27T11:17:19.000000Z
  
    Duration: 00:55:55.48, start: 0.000000, bitrate: 5126 kb/s
  
      Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x1080, 4996 kb/s, 25 fps, 25 tbr, 2500 tbn, 5k tbc (default)
  
      Metadata:
  
        creation_time   : 2017-07-27T11:17:19.000000Z
  
        handler_name    : VideoHandler
  
      Stream #0:1(eng): Audio: mp3 (mp4a / 0x6134706D), 24000 Hz, mono, s16p, 125 kb/s (default)
  
      Metadata:
  
        creation_time   : 2017-07-27T11:17:19.000000Z
  
        handler_name    : SoundHandler