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• ffmpeg fixed video noise reduction

  19 mars 2024, par leo

  I have a camera with a fixed noise (video sample). Is it possible to remove this noise completely using ffmpeg ?

  


  I tried ffmpeg "-vf" noise reduction but didn't find any way to remove the noise by supplying a noise mask.

  


• rtsp : Fix infinite loop in listen mode with UDP transport

  30 septembre 2020, par Martin Storsjö

  rtsp : Fix infinite loop in listen mode with UDP transport
  In listen mode with UDP transport, once the sender has sent
  
  the TEARDOWN and closed the connection, poll will indicate that
  
  one can read from the connection (indicating that the socket has
  
  reached EOF and should be closed by the receiver as well). In this
  
  case, parse_rtsp_message won't try to parse the command (because
  
  it's no longer in state STREAMING), but previously just returned
  
  zero.
  Prior to f6161fccf8c5720ceac1ed1df8ba60ff8fed69f5, this caused
  
  udp_read_packet to return zero, which is treated as EOF by
  
  read_packet. But after that commit, udp_read_packet would continue
  
  if parse_rtsp_message didn't return an explicit error code.
  To keep the original behaviour from before that commit, more
  
  explicitly return an error in parse_rtsp_message when in the wrong
  
  state.
  Fixes : #8840
  
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] libavformat/rtsp.c

• Libav and xaudio2 - audio not playing

  25 août 2013, par siz

  I am trying to get audio playing with libav using xaudio2. The xaudio2 code I am using works with an older ffmpeg using avcodec_decode_audio2, but that has been deprecated for avcodec_decode_audio4. I have tried following various libav examples, but can't seem to get the audio to play. Video plays fine (or rather it just plays right fast now, as I haven't coded any sync code yet).

  Firstly audio gets init, no errors, video gets init, then packet :

  while (1) {
  
      //is this packet from the video or audio stream?
  
      if (packet.stream_index == player.v_id) {
  
          add_video_to_queue(&packet);
  
      } else if (packet.stream_index == player.a_id) { 
  
          add_sound_to_queue(&packet);
  
      } else {
  
          av_free_packet(&packet);
  
      }
  
  }

  Then in add_sound_to_queue :

  int add_sound_to_queue(AVPacket * packet) {
  
  AVFrame *decoded_frame = NULL;
  
  int done = AVCODEC_MAX_AUDIO_FRAME_SIZE;
  
  int got_frame = 0;
  
  
  
  if (!decoded_frame) {
  
      if (!(decoded_frame = avcodec_alloc_frame())) {
  
          printf("[ADD_SOUND_TO_QUEUE] Out of memory\n");
  
          return -1;
  
      }
  
  } else {
  
      avcodec_get_frame_defaults(decoded_frame);
  
  }
  
  
  
  if (avcodec_decode_audio4(player.av_acodecctx, decoded_frame, &got_frame, packet) < 0)  {
  
      printf("[ADD_SOUND_TO_QUEUE] Error in decoding audio\n");
  
      av_free_packet(packet);
  
      //continue;
  
      return -1;
  
  }
  
  if (got_frame) {
  
      int data_size;
  
      if (packet->size > done) {
  
          data_size = done;
  
      } else {
  
          data_size = packet->size;
  
      }
  
      BYTE * snd = (BYTE *)malloc( data_size * sizeof(BYTE));
  
  
  
      XMemCpy(snd,
  
          AudioBytes, 
  
          data_size * sizeof(BYTE)
  
      );
  
  
  
      XMemSet(&g_SoundBuffer,0,sizeof(XAUDIO2_BUFFER));
  
  
  
      g_SoundBuffer.AudioBytes = data_size;
  
      g_SoundBuffer.pAudioData = snd;
  
      g_SoundBuffer.pContext = (VOID*)snd;
  
  
  
      XAUDIO2_VOICE_STATE state;
  
      while( g_pSourceVoice->GetState( &state ), state.BuffersQueued > 60 ) {
  
          WaitForSingleObject( XAudio2_Notifier.hBufferEndEvent, INFINITE );
  
      }
  
  
  
      g_pSourceVoice->SubmitSourceBuffer( &g_SoundBuffer );
  
  }
  
  return 0;
  
  }

  I can't seem to figure out the problem, I have added error messages in init, opening video, codec handling etc. As mentioned before the xaudio2 code is working with an older ffmpeg, so maybe I have missed something with the avcodec_decode_audio4 ?

  If this snappet of code isn't enough, I can post the whole code, these are just the places in the code I think the problem would be :(