Recherche avancée

Sur d’autres sites (11186)

• avformat/aiffenc : Add deinit function

  25 octobre 2019, par Andreas Rheinhardt

  avformat/aiffenc : Add deinit function
  Prevents memleaks if the trailer is never written.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavformat/aiffenc.c

• Saving frames from a network camera (RTSP) to a mp4 file

  24 novembre 2015, par Dídac Pérez

  I am quite confused about how to save a video stream into a mp4 file. I am using ffmpeg. Let me explain the problem :

  1. I connect to a network camera via RTSP (H.264 stream) with avformat_open_input(), avformat_find_stream_info(), av_read_play(), and I get frames with av_read_frame().
  2. Each time I get a frame with av_read_frame(), I store the corresponding AVPacket in a circular buffer.
  3. In some points in my application, a range of this circular buffer is selected. I find a key frame used to start from.
  4. Once I have a list of AVPacket’s starting from a key frame, I write header, frames, and tail, as I described below in the code.

  The problem is that the resulting mp4 video has artifacts if I try to watch it using VLC, Windows Media Player, or another one.

  I have also realized that the pts of that packets are not continuous, while dts are continuous. I know about B frames, but is this a problem in my case ?

  // Prepare the output
  
  AVFormatContext* oc = avformat_alloc_context();
  
  oc->oformat = av_guess_format(NULL, "video.mp4", NULL);
  
  
  
  // Must write header, packets, and trailing
  
  avio_open2(&oc->pb, "video.mp4", AVIO_FLAG_WRITE, NULL, NULL);
  
  
  
  // Write header
  
  AVStream* stream = avformat_new_stream(oc, (AVCodec*) context->streams[video_stream_index]->codec->codec);
  
  avcodec_copy_context(stream->codec, context->streams[video_stream_index]->codec);
  
  stream->sample_aspect_ratio = context->streams[video_stream_index]->codec->sample_aspect_ratio;
  
  avformat_write_header(oc, NULL);
  
  
  
  // FOR EACH FRAME...
  
  ... av_write_frame(oc, circular[k]); ...
  
  
  
  // Write trailer and close the file
  
  av_write_trailer(oc);
  
  avcodec_close(stream->codec);
  
  avio_close(oc->pb);
  
  avformat_free_context(oc);

  Thank you so much,

• Unable to find/write moov atom in the mp4 recorded stream

  11 juillet 2014, par AnilJ

  I have written the following code to write the webcam feed into a file (.mp4) on disk. The program is successful, but when I try to play the file using player, it says "moov atom not found" and player is not showing anything. The file however is a valid mp4 file according to ffmpeg command.

  This is my main thread where I encode a picture every 30ms.

  public void run() {        
  
  
  
      // Set the thread rolling.
  
      mRunning = true;
  
  
  
      while (mRunning) {
  
          // and display it on the Java Swing window
  
          Record();
  
      }
  
  
  
      // clean up resources
  
      cleanup();
  
  }
  
  
  
  private void Record() {
  
  
  
      IVideoPicture picture = null;
  
      BufferedImage image = null;
  
  
  
      picture = GetNextPicture();
  
      image = Utils.videoPictureToImage(picture);
  
  
  
      if (picture != null) {  
  
          // If recording is enabled, record the webcam stream.
  
          if (mRecordStream) {
  
  
  
              // convert to the right image type
  
              BufferedImage bgrScreen = ConvertToType(image, BufferedImage.TYPE_3BYTE_BGR);
  
  
  
              // encode the image to stream #0
  
              mWriter.encodeVideo(0, bgrScreen, System.nanoTime() - mStartTime, TimeUnit.NANOSECONDS);
  
          }
  
  
  
          try {
  
              Thread.sleep(30);
  
          } catch (InterruptedException e) {
  
              return;
  
          }
  
      }
  
  }

  From the main thread, I do this when I want to stop the recording and close this recording thread. The cleanup() method is eventually called by the main thread to close the writer. The comment does says about writing the trailer (I guess moov atom), but it does not do it. Can someone please help me find where the problem is ?

  public void stopRecording() {      
  
      // Stop the thread loop.
  
      mRunning = false;
  
  }
  
  
  
  private void cleanup() {
  
  
  
      // tell the writer to close and write the trailer if  needed
  
      if (mWriter != null) {
  
          mWriter.close();
  
          mWriter = null;
  
      }
  
  
  
      if (mVideoCoder != null) {
  
          mVideoCoder.close();
  
          mVideoCoder = null;
  
      }
  
  
  
      if (mContainer != null) {
  
          mContainer.close();
  
          mContainer = null;
  
      }
  
  }