如何在Unity3d平臺下低延遲播放RTMP或RTSP流

隨着VR類、遊戲類場景的快速發展，開發者對Unity3d低延遲的直播需求量越來越大，前兩年，大牛直播SDK發佈了Windows平臺、Android平臺和iOS平臺的Unity3d RTMP和RTSP的播放，好多公司用起來體驗都非常好，以下介紹大概實現流程。

本文以Android平臺爲例，我們的實現：基於大牛直播SDK現有非常成熟的native RTMP和RTSP播放模塊，回調解碼後的原始數據，傳遞給Unity3d，實現相應的繪製即可，對應demo，可以參考 Github。

具體步驟如下：

1. Native RTSP或RTSP直播播放SDK回調RGB/YUV420/NV12等其中的一種未壓縮的圖像格式；

2. Unity3D創建相應的RGB/YUV420等Shader；

3.Unity3D從各個平臺獲取圖像數據來填充紋理即可。

以Android平臺爲例，我們在原有接口基礎上，做了橋接接口，供Unity平臺使用：

    /// <summary>
    /// Init
    /// </summary>
    public int NT_U3D_Init()
    {
        return DANIULIVE_RETURN_OK;
    }

    /// <summary>
    /// 開始
    /// 返回播放句柄
    /// </summary>
    public long NT_U3D_Open()
    {
        if ( 0 != player_obj_.Call<int>("Init", java_obj_cur_activity_) )
        {
            return 0;
        }

        return player_obj_.Call<long>("Open");
    }

    /// <summary>
    /// Register Game Object,用於消息傳遞
    /// </summary>
    public int NT_U3D_Set_Game_Object(long handle, string gameObjectName)
    {
        return player_obj_.Call<int>("SetGameObject", handle, gameObjectName);
    }

    /// <summary>
    /// 設置H.264解碼方式 false 軟件解碼 true 硬件解碼 默認爲false
    /// </summary>
    /// <param name="isHwDecoder"></param>
    public int NT_U3D_SetVideoDecoderMode(long handle, int isHwDecoder)
    {
        return player_obj_.Call<int>("SetPlayerVideoHWDecoder", handle, isHwDecoder);
    }

    /// <summary>
    /// 設置H.265 解碼方式 false 軟件解碼 true 硬件解碼 默認爲false
    /// </summary>
    /// <param name="isHevcHwDecoder"></param>
    public int NT_U3D_SetVideoHevcDecoderMode(long handle, int isHevcHwDecoder)
    {
        return player_obj_.Call<int>("SetPlayerVideoHevcHWDecoder", handle, isHevcHwDecoder);
    }

    /// <summary>
    /// 設置音頻輸出模式: if 0: 自動選擇; if with 1: audiotrack模式
    /// </summary>
    /// <param name="use_audiotrack"></param>
    public int NT_U3D_SetAudioOutputType(long handle, int use_audiotrack)
    {
        return player_obj_.Call<int>("SetAudioOutputType", handle, use_audiotrack);
    }

    /// <summary>
    /// 設置播放端緩存大小, 默認200毫秒
    /// </summary>
    /// <param name="buffer"></param>
    public int NT_U3D_SetBuffer(long handle, int buffer)
    {
        return player_obj_.Call<int>("SetBuffer", handle, buffer);
    }

    /// <summary>
    /// 接口可實時調用：設置是否實時靜音，1：靜音; 0: 取消靜音
    /// </summary>
    /// <param name="is_mute"></param>
    public int NT_U3D_SetMute(long handle, int is_mute)
    {
        return player_obj_.Call<int>("SetMute", handle, is_mute);
    }

    /// <summary>
    /// 設置RTSP TCP模式, 1: TCP; 0: UDP
    /// </summary>
    /// <param name="is_using_tcp"></param>
    public int NT_U3D_SetRTSPTcpMode(long handle, int is_using_tcp)
    {
        return player_obj_.Call<int>("SetRTSPTcpMode", handle, is_using_tcp);
    }

    /// <summary>
    /// 設置RTSP超時時間, timeout單位爲秒，必須大於0
    /// </summary>
    /// <param name="timeout"></param>
    public int NT_U3D_SetRTSPTimeout(long handle, int timeout)
    {
        return player_obj_.Call<int>("SetRTSPTimeout", handle, timeout);
    }

    /// <summary>
    /// 設置RTSP TCP/UDP自動切換
    /// NOTE: 對於RTSP來說，有些可能支持rtp over udp方式，有些可能支持使用rtp over tcp方式.
    /// 爲了方便使用，有些場景下可以開啓自動嘗試切換開關, 打開後如果udp無法播放，sdk會自動嘗試tcp, 如果tcp方式播放不了,sdk會自動嘗試udp.
    /// </summary>
    /// <param name="timeout"></param>
    /// timeout：如果設置1的話, sdk將在tcp和udp之間嘗試切換播放，如果設置爲0，則不嘗試切換.
    public int NT_U3D_SetRTSPAutoSwitchTcpUdp(long handle, int is_auto_switch_tcp_udp)
    {
        return player_obj_.Call<int>("SetRTSPAutoSwitchTcpUdp", handle, is_auto_switch_tcp_udp);
    }

    /// <summary>
    /// 設置快速啓動該模式，
    /// </summary>
    /// <param name="is_fast_startup"></param>
    public int NT_U3D_SetFastStartup(long handle, int is_fast_startup)
    {
        return player_obj_.Call<int>("SetFastStartup", handle, is_fast_startup);
    }

    /// <summary>
    /// 設置超低延遲模式 false不開啓 true開啓 默認false
    /// </summary>
    /// <param name="mode"></param>
    public int NT_U3D_SetPlayerLowLatencyMode(long handle, int mode)
    {
        return player_obj_.Call<int>("SetPlayerLowLatencyMode", handle, mode);
    }

    /// <summary>
    /// 設置視頻垂直反轉
    /// is_flip： 0: 不反轉, 1: 反轉
    /// </summary>
    /// <param name="is_flip"></param>
    public int NT_U3D_SetFlipVertical(long handle, int is_flip)
    {
        return player_obj_.Call<int>("SetFlipVertical", handle, is_flip);
    }

    /// <summary>
    /// 設置視頻水平反轉
    /// is_flip： 0: 不反轉, 1: 反轉
    /// </summary>
    /// <param name="is_flip"></param>
    public int NT_U3D_SetFlipHorizontal(long handle, int is_flip)
    {
        return player_obj_.Call<int>("SetFlipHorizontal", handle, is_flip);
    }

    /// <summary>
    /// 設置順時針旋轉, 注意除了0度之外， 其他角度都會額外消耗性能
    /// degress： 當前支持 0度，90度, 180度, 270度 旋轉
    /// </summary>
    /// <param name="degress"></param>
    public int NT_U3D_SetRotation(long handle, int degress)
    {
        return player_obj_.Call<int>("SetRotation", handle, degress);
    }

    /// <summary>
    /// 設置是否回調下載速度
    /// is_report: if 1: 上報下載速度, 0: 不上報.
    /// report_interval: 上報間隔，以秒爲單位，>0.
    /// </summary>
    /// <param name="is_report"></param>
    /// <param name="report_interval"></param>
    public int NT_U3D_SetReportDownloadSpeed(long handle, int is_report, int report_interval)
    {
        return player_obj_.Call<int>("SetReportDownloadSpeed", handle, is_report, report_interval);
    }

    /// <summary>
    /// 設置是否需要在播放或錄像過程中快照
    /// </summary>
    /// <param name="is_save_image"></param>
    public int NT_U3D_SetSaveImageFlag(long handle, int is_save_image)
    {
        return player_obj_.Call<int>("SetSaveImageFlag", handle, is_save_image);
    }

    /// <summary>
    /// 播放或錄像過程中快照
    /// </summary>
    /// <param name="imageName"></param>
    public int NT_U3D_SaveCurImage(long handle, string imageName)
    {
        return player_obj_.Call<int>("SaveCurImage", handle, imageName);
    }

    /// <summary>
    /// 播放或錄像過程中，快速切換url
    /// </summary>
    /// <param name="uri"></param>
    public int NT_U3D_SwitchPlaybackUrl(long handle, string uri)
    {
        return player_obj_.Call<int>("SwitchPlaybackUrl", handle, uri);
    }

    /// <summary>
    /// 創建錄像存儲路徑
    /// </summary>
    /// <param name="path"></param>
    public int NT_U3D_CreateFileDirectory(string path)
    {
        return player_obj_.Call<int>("CreateFileDirectory", path);
    }

    /// <summary>
    /// 設置錄像存儲路徑
    /// </summary>
    /// <param name="path"></param>
    public int NT_U3D_SetRecorderDirectory(long handle, string path)
    {
        return player_obj_.Call<int>("SetRecorderDirectory", handle, path);
    }

    /// <summary>
    /// 設置單個錄像文件大小
    /// </summary>
    /// <param name="size"></param>
    public int NT_U3D_SetRecorderFileMaxSize(long handle, int size)
    {
        return player_obj_.Call<int>("SetRecorderFileMaxSize", handle, size);
    }

    /// <summary>
    /// 設置錄像時音頻轉AAC編碼的開關
    /// aac比較通用，sdk增加其他音頻編碼(比如speex, pcmu, pcma等)轉aac的功能.
    /// 注意: 轉碼會增加性能消耗
    /// </summary>
    /// <param name="is_transcode"></param>
    /// is_transcode：設置爲1的話，如果音頻編碼不是aac，則轉成aac，如果是aac，則不做轉換. 設置爲0的話，則不做任何轉換. 默認是0.
    public int NT_U3D_SetRecorderAudioTranscodeAAC(long handle, int is_transcode)
    {
        return player_obj_.Call<int>("SetRecorderAudioTranscodeAAC", handle, is_transcode);
    }

    /// <summary>
    /// 設置播放路徑
    /// </summary>
    public int NT_U3D_SetUrl(long handle, string url)
    {
        return player_obj_.Call<int>("SetUrl", handle, url);
    }

    /// <summary>
    /// 開始播放
    /// </summary>
    public int NT_U3D_StartPlay(long handle)
    {
        return player_obj_.Call<int>("StartPlay", handle);
    }

    /// <summary>
    /// 獲取YUV數據
    /// </summary>
    public AndroidJavaObject NT_U3D_GetVideoFrame(long handle)
    {
        return player_obj_.Call<AndroidJavaObject>("GetVideoFrame", handle);
    }

    /// <summary>
    /// 停止播放
    /// </summary>
    public int NT_U3D_StopPlay(long handle)
    {
        return player_obj_.Call<int>("StopPlay", handle);
    }

    /// <summary>
    /// 開始錄像
    /// </summary>
    public int NT_U3D_StartRecorder(long handle)
    {
        return player_obj_.Call<int>("StartRecorder", handle);
    }

    /// <summary>
    /// 停止錄像
    /// </summary>
    public int NT_U3D_StopRecorder(long handle)
    {
        return player_obj_.Call<int>("StopRecorder", handle);
    }

    /// <summary>
    /// 關閉播放
    /// </summary>
    public int NT_U3D_Close(long handle)
    {
        return player_obj_.Call<int>("Close", handle);
    }

    /// <summary>
    /// UnInit Player
    /// </summary>
    public int NT_U3D_UnInit()
    {
        return DANIULIVE_RETURN_OK;
    }

Event傳遞，我們在unity3d裏面解析相應的字串即可：

   /// <summary>
    /// android 傳遞過來 code
    /// </summary>
    /// <param name="code"></param>
    public void onNTSmartEvent(string param)
    {
        if (!param.Contains(","))
        {
            Debug.Log("[onNTSmartEvent] android傳遞參數錯誤");
            return;
        }

       string[] strs = param.Split(',');

       string player_handle =strs[0];
       string code = strs[1];
       string param1 = strs[2];
       string param2 = strs[3];
       string param3 = strs[4];
       string param4 = strs[5];
        
       Debug.Log("[onNTSmartEvent] code: 0x" + Convert.ToString(Convert.ToInt32(code), 16));

        switch (Convert.ToInt32(code))
        {
            case EVENTID.EVENT_DANIULIVE_ERC_PLAYER_STARTED:
                Debug.Log("開始。。");
                break;
            case EVENTID.EVENT_DANIULIVE_ERC_PLAYER_CONNECTING:
                Debug.Log("連接中。。");
                break;
            case EVENTID.EVENT_DANIULIVE_ERC_PLAYER_CONNECTION_FAILED:
                Debug.Log("連接失敗。。");
                break;
            case EVENTID.EVENT_DANIULIVE_ERC_PLAYER_CONNECTED:
                Debug.Log("連接成功。。");
                break;
            case EVENTID.EVENT_DANIULIVE_ERC_PLAYER_DISCONNECTED:
                Debug.Log("連接斷開。。");
                break;
            case EVENTID.EVENT_DANIULIVE_ERC_PLAYER_STOP:
                Debug.Log("停止播放。。");
                break;
            case EVENTID.EVENT_DANIULIVE_ERC_PLAYER_RESOLUTION_INFO:
                Debug.Log("分辨率信息: width: " + Convert.ToInt32(param1) + ", height: " + Convert.ToInt32(param2));
                break;
            case EVENTID.EVENT_DANIULIVE_ERC_PLAYER_NO_MEDIADATA_RECEIVED:
                Debug.Log("收不到媒體數據，可能是url錯誤。。");
                break;
            case EVENTID.EVENT_DANIULIVE_ERC_PLAYER_SWITCH_URL:
                Debug.Log("切換播放URL。。");
                break;

            case EVENTID.EVENT_DANIULIVE_ERC_PLAYER_CAPTURE_IMAGE:
                Debug.Log("快照: " + param1 + " 路徑：" + param3);

                if (Convert.ToInt32(param1) == 0)
                {
                    Debug.Log("截取快照成功。.");
                }
                else
                {
                    Debug.Log("截取快照失敗。.");
                }
                break;

            case EVENTID.EVENT_DANIULIVE_ERC_PLAYER_RECORDER_START_NEW_FILE:
                Debug.Log("[record]開始一個新的錄像文件 : " + param3);
                break;
            case EVENTID.EVENT_DANIULIVE_ERC_PLAYER_ONE_RECORDER_FILE_FINISHED:
                Debug.Log("[record]已生成一個錄像文件 : " + param3);
                break;

            case EVENTID.EVENT_DANIULIVE_ERC_PLAYER_START_BUFFERING:
                Debug.Log("Start_Buffering");
                break;

            case EVENTID.EVENT_DANIULIVE_ERC_PLAYER_BUFFERING:
                Debug.Log("Buffering: " + Convert.ToInt32(param1));
                break;

            case EVENTID.EVENT_DANIULIVE_ERC_PLAYER_STOP_BUFFERING:
                Debug.Log("Stop_Buffering");
                break;

            case EVENTID.EVENT_DANIULIVE_ERC_PLAYER_DOWNLOAD_SPEED:
                Debug.Log("download_speed:" + param1 + "Byte/s" + ", "
                        + (Convert.ToInt32(param1) * 8 / 1000) + "kbps" + ", " + (Convert.ToInt32(param1) / 1024)
                        + "KB/s");
                break;
        }

    }

開始播放：

    public void Play()
    {
        if (is_running)
        {
            Debug.Log("已經在播放。。");   
            return;
        }

        //獲取輸入框的url
        string url = input_url_.text.Trim();

        if (!url.StartsWith("rtmp://") && !url.StartsWith("rtsp://"))
        {
            videoUrl = "rtmp://202.69.69.180:443/webcast/bshdlive-pc";
        }
        else
        {
            videoUrl = url;
        }

        OpenPlayer();

        if ( player_handle_ == 0 )
            return;

        NT_U3D_Set_Game_Object(player_handle_, game_object_);

        NT_U3D_SetUrl(player_handle_, videoUrl);

        /* ++ 播放前參數配置可加在此處 ++ */
        int is_using_tcp = 0;        //TCP/UDP模式設置
        NT_U3D_SetRTSPTcpMode(player_handle_, is_using_tcp);

        int is_report = 0;
        int report_interval = 1;
        NT_U3D_SetReportDownloadSpeed(player_handle_, is_report, report_interval);  //下載速度回調

        NT_U3D_SetBuffer(player_handle_, play_buffer_time_);                        //設置buffer time

        NT_U3D_SetPlayerLowLatencyMode(player_handle_, is_low_latency_ ? 1 : 0);    //設置是否啓用低延遲模式

        NT_U3D_SetMute(player_handle_, is_mute_ ? 1 : 0);                           //是否啓動播放的時候靜音

        NT_U3D_SetVideoDecoderMode(player_handle_, is_hw_decode_ ? 1 : 0);          //設置H.264軟硬解模式

        NT_U3D_SetVideoHevcDecoderMode(player_handle_, is_hw_decode_ ? 1 : 0);          //設置H.265軟硬解模式

        int is_fast_startup = 1;
        NT_U3D_SetFastStartup(player_handle_, is_fast_startup);                     //設置快速啓動模式

        int rtsp_timeout = 10;
        NT_U3D_SetRTSPTimeout(player_handle_, rtsp_timeout);                        //設置RTSP超時時間

        int is_auto_switch_tcp_udp = 1;
        NT_U3D_SetRTSPAutoSwitchTcpUdp(player_handle_, is_auto_switch_tcp_udp);    //設置TCP/UDP模式自動切換
        /* -- 播放前參數配置可加在此處 -- */

        int flag = NT_U3D_StartPlay(player_handle_);

        if (flag  == DANIULIVE_RETURN_OK)
        {
            is_need_get_frame_ = true;
            Debug.Log("播放成功");
        }
        else
        {
            is_need_get_frame_ = false;
            Debug.LogError("播放失敗");
        }

        is_running = true;  
    }

開始播放後，native模塊，回調yuv/rgb數據，unity3d模塊，做相應的繪製處理即可。

    private void Update()
    {
        if (!is_need_get_frame_)
            return;

        if (player_handle_ == 0)
            return;

        AndroidJavaObject u3d_video_frame_obj = NT_U3D_GetVideoFrame(player_handle_);

        if (u3d_video_frame_obj == null)
            return;

        VideoFrame converted_video_frame = ConvertToVideoFrame(u3d_video_frame_obj);

        if (converted_video_frame == null)
            return;

        if ( !is_need_init_texture_)
        {
            if (converted_video_frame.width_ != video_width_
                || converted_video_frame.height_ != video_height_
                || converted_video_frame.y_stride_ != y_row_bytes_
                || converted_video_frame.u_stride_ != u_row_bytes_
                || converted_video_frame.v_stride_ != v_row_bytes_)
            {
                is_need_init_texture_ = true;
            }
        }

        if (is_need_init_texture_)
        {
            if (InitYUVTexture(converted_video_frame))
            {
                is_need_init_texture_ = false;
            }
        }

        UpdateYUVTexture(converted_video_frame);

        converted_video_frame = null;
    }

關閉播放：

    private void ClosePlayer()
    {
        is_need_get_frame_ = false;
        is_need_init_texture_ = false;
 
        int flag = NT_U3D_StopPlay(player_handle_);
        if (flag == DANIULIVE_RETURN_OK)
        {
            Debug.Log("停止成功");
        }
        else
        {
            Debug.LogError("停止失敗");
        }

        flag = NT_U3D_Close(player_handle_);
        if (flag == DANIULIVE_RETURN_OK)
        {
            Debug.Log("關閉成功");
        }
        else
        {
            Debug.LogError("關閉失敗");
        }

        player_handle_ = 0;

        NT_U3D_UnInit();

        is_running = false;
    }

以上是大概的實現流程，Unity環境下，實際測試時延，和 native直播模塊相差無幾，都是毫秒級延遲。Windows平臺和iOS平臺也是如此。

如何在Unity3d平臺下低延遲播放RTMP或RTSP流

Android投屏（屏幕共享）設計需要考慮的關鍵因素

海康攝像機rtsp地址格式(官方最新版)

RTSP/RTMP播放端錄像不可忽視的幾個設計要點

D3D還是GDI? Windows平臺播放RTSP或RTMP渲染模式比較

跨平臺RTSP/RTMP轉RTMP轉發SDK

https://yachay.unat.edu.pe/blog/index.php?comment_area=format_blog&comment_component=blog&comment_co

linux以太網驅動總結