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• FFMPEG - Recursive mp3 bitrate-conversion (Windows)

  3 avril 2018, par ShroomPow

  I am looking for a way to convert every mp3-file in a directory (including sub-directories) to 128kbps using ffmpeg and preferably batch on windows.
  Either by replacing the original files or "cloning" the whole directory-structure.

  I am trying to cut down the size of my musiclibrary for my phone. Is this easily achievable ?

• Using ffMPEG on Windows with only the DLL's ?

  7 novembre 2012, par Nav

  What I actually want is to store frames of a video into a char array, using ffMPEG.
  Constraint is to use only MSVC. Not allowed to use the Windows building tweak due to maintainability issues.

  So considered using the shared build to accomplish the task. It consists of only DLL's. No lib files, so I tried loading one of the DLL's using HINSTANCE hInstLibrary = LoadLibrary("avcodec-54.dll"); and it works. But I couldn't find the interfaces of this DLL published anywhere. Could anyone help with this ? How do I know which functions of the DLL I can call and what parameters I can pass it so that I can get the video frames ?

• FFmpeg recording h264 to a circular buffer "Packet header not contained in global..."

  25 novembre 2015, par user15941

  I’ve made a class which captures a RTSP h264 stream and stores its Packets in a circular buffer. On demand the content of the buffer is dumped to a file with header and trailer. I based the code mainly on : this question example, but by trial and error I came up with three modifications :

  1. I use wrapping object for AVPacket not to bother with memory deallocation.
  2. I convert the data with a filter : "h264_mp4toannexb", so the result file is in .ts format.
  3. I wait in a loop to get a key-frame before any push_back() to circular buffer.

  However something’s wrong with the framerate. The only player, that opens my videos correctly is mplayer. VLC and other players I tested show all the frames in one second.

  ffmpeg lib also reports a lot of error messages : "Packet header is not contained in global metadata", but I don’t know whether the information is held in that header or in some other place ?

  With this code I assign consecutive pts and dts. Then every packet is stored in the circular buffer.

  packet.pts = idx++;
  
  packet.dts = packet.pts;
  
  if (cbuf_mutex.try_lock()) {
  
      cbuf.push_back(PACKET(&packet));
  
      captured_frames++;
  
      if (captured_frames > CBUF_SIZE)
  
          captured_frames = CBUF_SIZE;
  
      cbuf_mutex.unlock();
  
  }
  
  else {
  
      syslog(LOG_ERR, "Buffer mutex was locked - packet skipped");
  
  }

  PACKET class implements copying of the data.
  Is there something missing, which may cause the errors ?

  PACKET::PACKET(const PACKET& rhs)
  
  {
  
      av_new_packet(&packet, rhs.packet.size);
  
      av_copy_packet(&packet, &rhs.packet);
  
  }
  
  
  
  PACKET& PACKET::operator=(const PACKET& rhs)
  
  {
  
      if (&rhs == this)
  
          return *this;
  
      av_free_packet(&packet);
  
      av_new_packet(&packet, rhs.packet.size);
  
      av_copy_packet(&packet, &rhs.packet);
  
      return *this;
  
  }