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• Error to encode audio though out the video in FFmpegFrameRecorder

  28 mars 2016, par Ragghwendra Suryawanshi

  Hello Stack World,

  I am trying to crate video from images in android using FFMpeg and
  javacv. I am able to crate video from images with out audio, when i try
  the same thing with audio video is crated but audio is just for 1
  sec of the video

          FFmpegFrameRecorder myFFmpegFrameRecorder = new FFmpegFrameRecorder(new StringBuilder(String.valueOf(strPath)).append("/").append(this.FileName).toString(), 640, 480, frameGrabber.getAudioChannels());
  
          myFFmpegFrameRecorder.setVideoCodec(13);
  
          myFFmpegFrameRecorder.setFormat("mp4");
  
          myFFmpegFrameRecorder.setPixelFormat(0);
  
          myFFmpegFrameRecorder.setSampleFormat(frameGrabber.getSampleFormat());
  
          myFFmpegFrameRecorder.setSampleRate(44100);
  
          myFFmpegFrameRecorder.setFrameRate(1.0d);
  
          myFFmpegFrameRecorder.setVideoBitrate(AccessibilityEventCompat.TYPE_TOUCH_INTERACTION_START);
  
          myFFmpegFrameRecorder.setAudioCodec(avcodec.AV_CODEC_ID_MP3);
  
          boolean isAudioFinish = false;
  
          try {
  
              frameGrabber.start();
  
              IplImage iplimage = new IplImage();
  
              myFFmpegFrameRecorder.start();
  
              for (int i = 0; i <= imgname - 1; i++) {
  
                  for (int j = 0; j <= 6; j++) {
  
                      Frame frame = frameGrabber.grabFrame();
  
                      if (frame != null) {
  
                          myFFmpegFrameRecorder.record(frame);
  
                      }
  
                      long l1 = 1000L * (System.currentTimeMillis() - l);
  
                      if (l1 < myFFmpegFrameRecorder.getTimestamp()) {
  
                          l1 = 1000L + myFFmpegFrameRecorder.getTimestamp();
  
                      }
  
                      myFFmpegFrameRecorder.setTimestamp(l1);
  
                  }
  
  
  
                  iplimage = opencv_highgui.cvLoadImage(myObjects.get(i).toString());
  
                  myFFmpegFrameRecorder.record(iplimage);
  
                  opencv_core.cvReleaseImage(iplimage);
  
              }
  
              myFFmpegFrameRecorder.stop();
  
              frameGrabber.stop();
  
          } catch (Exception e) {
  
              e.printStackTrace();
  
          }

  Please help me to solve it. I am missing something due to which it not working out here. I have read doc of the FFmpegFrameRecorder but unable to find my error.

• How can I get start time of rtsp-sesson via ffmpeg (C++) ? start_time_realtime always equal -9223372036854775808

  5 août 2019, par chuchuchu

  I’m trying to get a frame by rtsp and calculate its real-world timestamp. I previously used Live555 for this (presentationTime).

  As far as I understand, ffmpeg does not provide such functionality, but provides the ability to read the relative time of each frame and the start time of the stream. In my case, the frame timestamps (pts) works correctly, but the stream start time (start_time_realtime) is always -9223372036854775808.

  I’m trying to use simple example from this Q : https://stackoverflow.com/a/11054652/5355846

  Value does not change. regardless of the position in the code

  int main(int argc, char** argv) {
  
      // Open the initial context variables that are needed
  
      SwsContext *img_convert_ctx;
  
      AVFormatContext* format_ctx = avformat_alloc_context();
  
      AVCodecContext* codec_ctx = NULL;
  
      int video_stream_index;
  
  
  
      // Register everything
  
      av_register_all();
  
      avformat_network_init();
  
  
  
      //open RTSP
  
      if (avformat_open_input(&format_ctx, "path_to_rtsp_stream",
  
                              NULL, NULL) != 0) {
  
          return EXIT_FAILURE;
  
      }
  
      ...
  
  }

  while (av_read_frame(format_ctx, &packet) >= 0 && cnt < 1000) { //read ~ 1000 frames
  
  
  
          //// here!
  
          std::cout<< " ***** "
  
          << std::to_string(format_ctx->start_time_realtime) 
  
          << " | "<start_time
  
          << " | "<best_effort_timestamp;
  
  
  
  ...
  
  }

  ***** -9223372036854775808 | 0 | 4120 | 40801 Frame : 103

  What am I doing wrong ?

• How to write a text in a frame using ffmpeg

  21 février 2024, par Jorge Augusto Wilchen

  I need to write a text in every frame before write in the video file, this text will be passed as a argument (std::string or char, whatever you want to best solution). For example, write "Hello World" 24px, color yellow, position 30x30.

  


  How can i do this ?

  


  This is my function that read frames to a AVPacket and write in the video file :

  


  bool VideoRecorder::record_video()
{
    if (recording) {
        AVPacket packet;

        while (recording && av_read_frame(inputFormatContext, &packet) >= 0) {
            AVStream* in_stream = inputFormatContext->streams[packet.stream_index];
            AVStream* out_stream = outputFormatContext->streams[0];

            // Adjustment of DTS and PTS to ensure increasing monoticity
            if (packet.pts != AV_NOPTS_VALUE) {
                packet.pts = av_rescale_q_rnd(packet.pts, in_stream->time_base, out_stream->time_base, AVRounding(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX));
            }

            if (packet.dts != AV_NOPTS_VALUE) {
                packet.dts = av_rescale_q_rnd(packet.dts, in_stream->time_base, out_stream->time_base, AVRounding(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX));
            }

            packet.duration = av_rescale_q(packet.duration, in_stream->time_base, out_stream->time_base);

            packet.stream_index = 0;

            av_interleaved_write_frame(outputFormatContext, &packet);

            av_packet_unref(&packet);
        }


        return true;
    }

    std::cerr << "Error recording video. Recording not started or already stopped." << std::endl;
    return false;
}