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• Ffmpeg : how to keep orientation when trimming video file ?

  7 mars 2013, par Alex

  I have a video file which I capture from my Android program and save as an mp4 video.

  In this my Android program I use

  setOrientationHint(90)

  call to indicate to a videoplayer that my camera has been rotated 90 degrees.

  I'm not really sure what setOrientationHint(90) does but with it I can see the file properly oriented when it plays in the video player. If not, then a video player orients my file incorrectly.

  Now I trim this file using FFMPEG command (here in.mp4, out.mp4, 1000 and 2000 are just for example)

  ffmpeg -i in.mp4 -ss 1000 -t 2000 -vcodec copy -acodec

  However, the resulting file is again wrongly oriented in the player.

  I wonder what should I do to keep the orientation hint in the trimmed video file ?

• FFmpeg memory leak

  10 septembre 2015, par Spamdark

  I have developed just a simple library modifing a library that I found on the internet.

  What scares me, is that, when I play an avi, it plays and free the memory when the video ends, but when I play the video, it’s like a memory leak ! It grows to 138mb although the video has ended and the FreeAll method (A function that deletes the context, etc...) has been called.

  Here is the code of the method that is causing the memory leak :

  int VideoGL::NextVideoFrame(){
  
  int frameDone = 0;
  
  int result = 0;
  
  double pts = 0;
  
  
  
  if(!this->ended){
  
  
  
  if (!_started) return 0;
  
  AVPacket* packet;
  
  
  
  // Get the number of milliseconds passed and see if we should display a new frame
  
  int64_t msPassed = (1000 * (clock() - _baseTime)) / CLOCKS_PER_SEC;
  
  if (msPassed >= _currentPts)
  
  {
  
      // If this is not the current frame, copy it to the buffer
  
      if (_currentFramePts != _currentPts){
  
          _currentFramePts = _currentPts;
  
          memcpy(buffer_a,buffer, 3 * _codec_context_video->width * _codec_context_video->height);
  
          result = 1;
  
      }
  
  
  
      // Try to load a new frame from the video packet queue
  
      bool goodop=false;
  
      AVFrame *_n_frame = avcodec_alloc_frame();
  
      while (!frameDone && (packet = this->DEQUEUE(VIDEO)) != NULL)
  
      {
  
          if (packet == (AVPacket*)-1) return -1;
  
  
  
          goodop=true;
  
  
  
          _s_pts = packet->pts;
  
          avcodec_decode_video2(_codec_context_video, _n_frame, &frameDone, packet);
  
          av_free_packet(packet);
  
  
  
          if (packet->dts == AV_NOPTS_VALUE)
  
          {
  
              if (_n_frame->opaque && *(uint64_t*)_n_frame->opaque != AV_NOPTS_VALUE) pts = (double) *(uint64_t*)_n_frame->opaque;
  
              else pts = 0;
  
          }
  
          else pts = (double) packet->dts;
  
  
  
          pts *= av_q2d(_codec_context_video->time_base);
  
  
  
      }
  
  
  
      if (frameDone)
  
      {
  
          // if a frame was loaded scale it to the current texture frame buffer, but also set the pts so that it won't be copied to the texture until it's time
  
          sws_scale(sws_ctx,_n_frame->data, _n_frame->linesize, 0, _codec_context_video->height, _rgb_frame->data, _rgb_frame->linesize);
  
  
  
  
  
          double nts = 1.0/av_q2d(_codec_context_video->time_base);
  
          _currentPts = (uint64_t) (pts*nts);
  
  
  
      }
  
  
  
      avcodec_free_frame(&_n_frame);
  
      av_free(_n_frame);
  
  
  
      if(!goodop){
  
          ended=true;
  
      }
  
  }
  
  }
  
  
  
  return result;
  
  }

  I’ll be waiting for answers, thanks.

• Android how to increase ffmpeg mp4 perfromance ?

  4 janvier 2013, par testCoder

  I have detected that function avcodec_decode_audio3 works slow with mp4 format, here my code cycle for decoding audio :

  while (av_read_frame(av_format_context, &packet) >= 0 && is_play == 1) {
  
          if (av_codec_context->codec_type == AVMEDIA_TYPE_AUDIO
  
                  && is_play == 1) {
  
              int out_size = AVCODEC_MAX_AUDIO_FRAME_SIZE;
  
              int size = packet.size;
  
              int n;
  
              int dataLength = size;
  
              int decoded = 0;
  
              while (size > 0) {
  
  
  
                  //start measure time
  
                  gettimeofday(&tvBegin, NULL);
  
  
  
                  int len = avcodec_decode_audio3(av_codec_context,
  
                          (int16_t *) pAudioBuffer, &out_size, &packet);
  
  
  
                  //stop measure time
  
                  gettimeofday(&tvEnd, NULL);
  
                  timeval_subtract(&tvDiff, &tvEnd, &tvBegin);
  
  
  
                  LOGI("%d", tvDiff.tv_usec / 1000);
  
                  LOGI("len='%d'", len);
  
                  LOGI("out_size='%d'", out_size);
  
  
  
                  if (len < 0) {
  
                      break;
  
                      return 1;
  
                  }
  
                  if (out_size > 0) {
  
  
  
  
  
  
  
                      jbyte *bytes = (*env)->GetByteArrayElements(env, array,
  
                              NULL);
  
                      memcpy(bytes, (int16_t *) pAudioBuffer, out_size);
  
                      (*env)->ReleaseByteArrayElements(env, array, bytes, 0);
  
                      (*env)->CallVoidMethod(env, obj, play, array, out_size,
  
                              is_play);
  
  
  
                  }
  
                  size -= len;
  
              }
  
  
  
          }
  
          if (packet.data)
  
              av_free_packet(&packet);
  
  
  
      }

  But with other formats like flac and mp3 it works fine. avcodec_decode_audio3 take about 1-2 milisecounds for decoding mp3 frame with out_size = 4608 but with the same frame size in mp4 decoding take about 6-7 millisecounds. I got my build script from here.

  Does it normal behavior ? Is any way to increase performance of decoding mp4 ?