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• FFmpeg - get and play audio data from frames

  22 avril 2019, par AscendCode

  I have an project that use FFmpeg to play video. I was able to step frames from the video and display image gotten from those. But don’t know how to get audio data from those frames and play it.
  Did any one experience with FFmpeg and audio processing ?
  Please help.
  Thanks in advance

  // Here is a piece of the code written in Objective C

  FFDecoder.m

  -(id)initWithVideo:(NSString *)moviePath{
  
  self = [super init];
  
  if (self == nil) {
  
      return nil;
  
  }
  
  pFormatCtx = avformat_alloc_context();
  
  AVCodec * pCodec = NULL;
  
  
  
  
  
  
  
  if(avformat_open_input(&pFormatCtx, [moviePath cStringUsingEncoding:NSUTF8StringEncoding], NULL, NULL) != 0){
  
      av_log(NULL, AV_LOG_ERROR, "Couldn't open file\n");
  
      goto initError;
  
  }
  
  
  
  if (avformat_find_stream_info(pFormatCtx, NULL) < 0) {
  
      avformat_close_input(&pFormatCtx);
  
      av_log(NULL, AV_LOG_ERROR, "Couldn't find stream information\n");
  
      goto  initError;
  
  }
  
  av_dump_format(pFormatCtx, 0, [moviePath.lastPathComponent cStringUsingEncoding:NSUTF8StringEncoding], false);
  
  
  
  videoStream = -1;
  
  
  
  for (int i = 0 ; i < pFormatCtx->nb_streams; ++i ) {
  
      if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO && videoStream < 0) {
  
          videoStream = i;
  
      }
  
  }
  
  if (videoStream == -1) {
  
      av_log(NULL, AV_LOG_ERROR, "Didn't find a video stream");
  
      goto initError;
  
  }
  
  pCodecCtx = pFormatCtx->streams[videoStream]->codec;
  
  pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
  
  if (!pCodec) {
  
      av_log(NULL, AV_LOG_ERROR, "unsupported codec\n");
  
      goto initError;
  
  }
  
  
  
  if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0) {
  
      av_log(NULL, AV_LOG_ERROR, "Can't open video decoder\n");
  
      goto initError;
  
  }
  
  
  
  pFrame = av_frame_alloc();
  
  outputWidth = pCodecCtx->width;
  
  outputHeight = pCodecCtx->height;
  
  return self;
  
  
  
  initError:
  
   return nil;
  
  }
  
  - (void)seekTime:(double)seconds {
  
  AVRational timeBase = pFormatCtx->streams[videoStream]->time_base;
  
  int64_t targetFrame = (int64_t)((double)timeBase.den / timeBase.num * seconds);
  
  avformat_seek_file(pFormatCtx, videoStream, targetFrame, targetFrame, targetFrame, AVSEEK_FLAG_FRAME);
  
  avcodec_flush_buffers(pCodecCtx); 
  
  }
  
  
  
  - (BOOL)stepFrame {
  
  int frameFinished = 0;
  
  while (!frameFinished && av_read_frame(pFormatCtx, &pPacket) >= 0) {
  
      if (pPacket.stream_index == videoStream) {
  
          //decode video frame
  
          avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &pPacket);
  
      }
  
  }
  
  return frameFinished != 0;
  
  }

  And here is code for updating UI of viewcontroller, but don’t know how to play audio

  - (IBAction)playButtonAction:(id)sender {
  
  [[self playButton] setEnabled:NO];
  
  [video seekTime:0.0];
  
  double preferredFramesPerSecond = 30.0f;
  
  [NSTimer scheduledTimerWithTimeInterval:1.0/preferredFramesPerSecond
  
                                   target:self
  
                                 selector:@selector(displayNextFrame:)
  
                                 userInfo:nil
  
                                  repeats:YES];
  
  }
  
  
  
  #define LERP(A,B,C) ((A)*(1.0-C)+(B)*C)
  
  
  
  -(void)displayNextFrame:(NSTimer *)timer {
  
  NSTimeInterval startTime = [NSDate timeIntervalSinceReferenceDate];
  
  if (![video stepFrame]) {
  
      [timer invalidate];
  
      [_playButton setEnabled:YES];
  
      [video closeAudio];
  
      return;
  
  }
  
  _imageView.image = video.currentImage;
  
  
  
  float frameTime = 1.0/([NSDate timeIntervalSinceReferenceDate]-startTime);
  
  if (lastFrameTime<0) {
  
      lastFrameTime = frameTime;
  
  } else {
  
      lastFrameTime = LERP(frameTime, lastFrameTime, 0.8);
  
  }
  
  [_label setText:[NSString stringWithFormat:@"%.0f",lastFrameTime]];
  
  }

• How to decrypt hls video content

  16 mai 2019, par SHAH MD MONIRUL ISLAM

  My requirement is to play the encrypted hls video files from local storage in android. I have used NanoHTTPD to create and run the local server. From there I am serving the .ts an .m3u8 files. To play this video ExoPlayer need a key to decrypt the files and thus I made a url : http://localhost:4990/dataKey.

  Here is my local server class :

  import android.os.Environment;
  
  import android.util.Log;
  
  
  
  import java.io.File;
  
  import java.io.FileInputStream;
  
  import java.io.FileNotFoundException;
  
  import java.util.Map;
  
  
  
  import fi.iki.elonen.NanoHTTPD;
  
  
  
  public class LocalStreamingServer extends NanoHTTPD{
  
      public LocalStreamingServer(int port){
  
          super(port);
  
  
  
      }
  
  
  
      @Override
  
      public Response serve(IHTTPSession session){
  
          Log.e("req", session.getUri());
  
  
  
          if(session.getUri().equalsIgnoreCase("/dataKey")){
  
  
  
              return newFixedLengthResponse(Response.Status.OK, "txt", "what is the key?");
  
          }
  
  
  
          if(session.getUri().contains("m3u8")){
  
              String path = Environment.getExternalStorageDirectory().toString() + "/s3" + session.getUri();
  
  
  
              FileInputStream fis = null;
  
              File f = new File(path);
  
              try {
  
                  fis = new FileInputStream(f);
  
              } catch (FileNotFoundException e) {
  
              }
  
              return newFixedLengthResponse(Response.Status.OK, "m3u8", fis, f.length());
  
          }
  
  
  
          if(session.getUri().endsWith("ts")){
  
              String path = Environment.getExternalStorageDirectory().toString() + "/s3" + session.getUri();
  
  
  
              FileInputStream fis = null;
  
              File f = new File(path);
  
              try {
  
                  fis = new FileInputStream(f);
  
              } catch (FileNotFoundException e) {
  
  
  
              }
  
              return newFixedLengthResponse(Response.Status.OK, "ts", fis, f.length());
  
          }
  
  
  
          String path = Environment.getExternalStorageDirectory().toString() + "/s3/master.m3u8";
  
  
  
          FileInputStream fis = null;
  
          File f = new File(path);
  
          try {
  
              fis = new FileInputStream(f);
  
          } catch (FileNotFoundException e) {
  
          }
  
          return newFixedLengthResponse(Response.Status.OK, "m3u8", fis, f.length());
  
      }
  
  }

  I have transcoded the video using ffmpeg. I need to know that which data or key need to be returned when the dataKey url is called. I have the encrypted the video using these key :

  key=617D8A125A284DF48E3C6B1866348A3F
  
  IV=5ff82ce11c7e73dcdf7e73cacd0ef98

  I can not understand which of them are need to be returned from the datakey url. Both of them are not working. Exoplayer is sending the error message :java.security.InvalidKeyException: Unsupported key size

  can Any one help me about this ?

• avcodec/nvenc : only unregister input resources when absolutely needed

  24 avril 2019, par Timo Rothenpieler

  avcodec/nvenc : only unregister input resources when absolutely needed
  This reverts nvenc to old behaviour, which in some super rare edge cases
  
  performs better.
  
  The implication of this is that any potential API user who relies on
  
  nvenc cleaning up every frames device resources after it's done using
  
  them will have to change their usage pattern.
  That should not be a problem, since pretty much every normal usage
  
  pattern automatically implies that surfaces are reused from a common
  
  pool, since constant re-allocation is also very expensive.
  

  • [DH] libavcodec/nvenc.c