RtspClient简易音视频解码

namespace RtspClient_Decode
{
    public partial class MainFrom : Form
    {
        // 视频
        Dispatcher _dispatcher = Dispatcher.CurrentDispatcher;
        Bitmap _videoBitmap;
        TransformParameters _transformParameters;
        Dictionary<FFmpegVideoCodecId, FFmpegVideoDecoder> _videoDecodersMap = new Dictionary<FFmpegVideoCodecId, FFmpegVideoDecoder>();

        // 音频
        BufferedWaveProvider _audioOut;
        WaveOut _waveOut;
        Dictionary<FFmpegAudioCodecId, FFmpegAudioDecoder> _audioDecodersMap = new Dictionary<FFmpegAudioCodecId, FFmpegAudioDecoder>();
       
        // 连接 
        CancellationTokenSource _cancellationTokenSource;

        int _msgLine = 1;
        bool _checkVideo;
        bool _checkAudio;

        public MainFrom()
        {
            InitializeComponent();

            cbxProtocol.SelectedIndex = 0;
        }

        void btnControl_Click(object sender, EventArgs e)
        {
            _checkVideo = chbVideo.Checked;
            _checkAudio = chbAudio.Checked;

            switch (btnControl.Text)
            {
                case "播放":
                    btnControl.Text = "停止";
                    Connect();
                    break;
                case "停止": 
                    _cancellationTokenSource.Cancel(); 
                    //_connectTask.Wait(CancellationToken.None);
                    //
                    btnControl.Text = "播放";
                    break;
            }
        }

        void Connect()
        {
            if (_checkVideo)
            {
                _videoBitmap = new Bitmap(video.Width, video.Height);
                _transformParameters = _videoBitmap.GetTransformParameters();
            }

            var serverUri = new Uri(txtAddress.Text);
            var credentials = new NetworkCredential(txtUsername.Text, txtPassword.Text);

            var connectionParameters = new ConnectionParameters(serverUri, credentials); connectionParameters.RtpTransport = (RtpTransportProtocol)(cbxProtocol.SelectedIndex);
            _cancellationTokenSource = new CancellationTokenSource();

            var _connectTask = ConnectAsync(connectionParameters, _cancellationTokenSource.Token); 
        }

        async Task ConnectAsync(ConnectionParameters connectionParameters, CancellationToken token)
        {
            try
            {
                TimeSpan delay = TimeSpan.FromSeconds(5);

                using (var rtspClient = new RtspClient(connectionParameters))
                {
                    rtspClient.FrameReceived += RtspClient_FrameReceived;

                    while (true)
                    {
                        UpdateMessage("[Info] Connecting...");

                        try
                        {
                            await rtspClient.ConnectAsync(token);
                        }
                        catch (OperationCanceledException e)
                        {
                            UpdateMessage("[Error] ConnectAsync,Canceled1:" + e.ToString());
                            return;
                        }
                        catch (RtspClientException e)
                        {
                            UpdateMessage("[Error] ConnectAsync,Errmsg:" + e.ToString());
                            await Task.Delay(delay, token);
                            continue;
                        }

                        UpdateMessage("[Info] Connected.");

                        try
                        {
                            await rtspClient.ReceiveAsync(token);
                        }
                        catch (OperationCanceledException e)
                        {
                            UpdateMessage("[Error] ReceiveAsync,Canceled:" + e.ToString());
                            return;
                        }
                        catch (RtspClientException e)
                        {
                            UpdateMessage("[Error] ReceiveAsync,Errmsg:" + e.ToString());
                            await Task.Delay(delay, token);
                        }
                    }
                }
            }
            catch (OperationCanceledException e)
            {
                UpdateMessage("[Error] ConnectAsync Task,Canceled:" + e.ToString());
            }
        } 
      
        void RtspClient_FrameReceived(object sender, RtspClientSharp.RawFrames.RawFrame rawFrame)
        {
            //UpdateMessage($"[Info] New frame {rawFrame.Timestamp}: {rawFrame.GetType().Name}");

            switch (rawFrame.Type)
            {
                case FrameType.Video: 
                    {
                        // 视频解码
                        if (!_checkVideo) return;
                        if (!(rawFrame is RawVideoFrame rawVideoFrame)) return;

                        FFmpegVideoDecoder decoder = GetVideoDecoderForFrame(rawVideoFrame);

                        IDecodedVideoFrame decodedFrame = decoder.TryDecode(rawVideoFrame);

                        _dispatcher.Invoke(() =>
                        {
                            _videoBitmap.UpdateBitmap(decodedFrame, _transformParameters);
                            video.Image = _videoBitmap;
                        }, DispatcherPriority.Send);
                    }
                    break;
                case FrameType.Audio: 
                    {
                        // 音频解码 G711A
                        if (!_checkAudio) return;
                        if (!(rawFrame is RawAudioFrame rawAudioFrame)) return;

                        FFmpegAudioDecoder decoder = GetAudioDecoderForFrame(rawAudioFrame);

                        if (!decoder.TryDecode(rawAudioFrame)) return;

                        IDecodedAudioFrame decodedFrame = decoder.GetDecodedFrame(new AudioConversionParameters() { OutBitsPerSample = 16 });

                        if (_audioOut == null)
                        {
                            _audioOut = new BufferedWaveProvider(new WaveFormat(decodedFrame.Format.SampleRate, decodedFrame.Format.BitPerSample, decodedFrame.Format.Channels));
                            _audioOut.BufferLength = 2560 * 16;
                            _audioOut.DiscardOnBufferOverflow = true;

                            _waveOut = new WaveOut();
                            _waveOut.Init(_audioOut);
                            _waveOut.Volume = 1.0f;
                        }

                        _audioOut.AddSamples(decodedFrame.DecodedBytes.Array, decodedFrame.DecodedBytes.Offset, decodedFrame.DecodedBytes.Count);

                        if (_waveOut.PlaybackState != PlaybackState.Playing)
                        {
                            _waveOut.Play();
                        }
                    }
                    break;
            }
        } 
       
        FFmpegAudioDecoder GetAudioDecoderForFrame(RawAudioFrame audioFrame)
        {
            FFmpegAudioCodecId codecId = DetectAudioCodecId(audioFrame);

            if (!_audioDecodersMap.TryGetValue(codecId, out FFmpegAudioDecoder decoder))
            {
                int bitsPerCodedSample = 0;

                if (audioFrame is RawG726Frame g726Frame)
                    bitsPerCodedSample = g726Frame.BitsPerCodedSample;

                decoder = FFmpegAudioDecoder.CreateDecoder(codecId, bitsPerCodedSample);
                _audioDecodersMap.Add(codecId, decoder);
            }

            return decoder;
        }

        FFmpegAudioCodecId DetectAudioCodecId(RawAudioFrame audioFrame)
        {
            if (audioFrame is RawAACFrame)
                return FFmpegAudioCodecId.AAC;
            if (audioFrame is RawG711AFrame)
                return FFmpegAudioCodecId.G711A;
            if (audioFrame is RawG711UFrame)
                return FFmpegAudioCodecId.G711U;
            if (audioFrame is RawG726Frame)
                return FFmpegAudioCodecId.G726;

            throw new ArgumentOutOfRangeException(nameof(audioFrame));
        }

        FFmpegVideoDecoder GetVideoDecoderForFrame(RawVideoFrame videoFrame)
        {
            FFmpegVideoCodecId codecId = DetectVideoCodecId(videoFrame);
            if (!_videoDecodersMap.TryGetValue(codecId, out FFmpegVideoDecoder decoder))
            {
                decoder = FFmpegVideoDecoder.CreateDecoder(codecId);
                _videoDecodersMap.Add(codecId, decoder);
            }

            return decoder;
        }

        FFmpegVideoCodecId DetectVideoCodecId(RawVideoFrame videoFrame)
        {
            if (videoFrame is RawJpegFrame)
                return FFmpegVideoCodecId.MJPEG;
            if (videoFrame is RawH264Frame)
                return FFmpegVideoCodecId.H264;

            throw new ArgumentOutOfRangeException(nameof(videoFrame));
        }

        void UpdateMessage(string msg)
        {
            this.BeginInvoke((EventHandler)(delegate
            {
                msg = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss") + msg;
                if (_msgLine ++ > 30)
                {
                    rtbMsg.Clear();
                }
                rtbMsg.AppendText(msg + "\n");
                Console.WriteLine(msg);
            }));
        }
    }
}