如何在Delphi中使用FFMPEG

uses
  FFmpeg;

av_register_all;
avformat_network_init;

var
  pFormatContext: PAVFormatContext;
  videoStreamIndex: Integer;
  pCodecContext: PAVCodecContext;
  pCodec: PAVCodec;
  pFrame: PAVFrame;
  packet: TAVPacket;
begin
  avformat_open_input(@pFormatContext, 'path/to/video/file', nil, nil);
  avformat_find_stream_info(pFormatContext, nil);
  
  videoStreamIndex := av_find_best_stream(pFormatContext, AVMEDIA_TYPE_VIDEO, -1, -1, nil, 0);
  
  pCodecContext := pFormatContext^.streams[videoStreamIndex]^.codec;
  pCodec := avcodec_find_decoder(pCodecContext^.codec_id);
  avcodec_open2(pCodecContext, pCodec, nil);
  
  pFrame := av_frame_alloc;
  
  while av_read_frame(pFormatContext, @packet) >= 0 do
  begin
    if packet.stream_index = videoStreamIndex then
    begin
      avcodec_decode_video2(pCodecContext, pFrame, @frameFinished, @packet);
      
      // 处理视频帧
      
      av_free_packet(@packet);
    end;
  end;
  
  av_frame_free(@pFrame);
  avcodec_close(pCodecContext);
  avformat_close_input(@pFormatContext);
end;