背景

盡管Windows平臺(tái)有諸多優(yōu)勢(shì)，Linux平臺(tái)的發(fā)展還是勢(shì)不可擋，特別實(shí)在傳統(tǒng)行業(yè)，然而Linux生態(tài)構(gòu)建，總是差點(diǎn)意思，特別是有些常用的組件，本文基于已有的Linux平臺(tái)RTSP、RTMP播放模塊，構(gòu)建Unity下的RTSP和RTMP直播播放。

技術(shù)實(shí)現(xiàn)

實(shí)際上，Unity層面這塊沒(méi)什么好介紹的，和Windows、Android、iOS平臺(tái)一樣，調(diào)用原生的播放模塊，回調(diào)解碼后的數(shù)據(jù)，在Unity繪制，主要的技術(shù)難點(diǎn)，還在原生的處理，也就是拉流、解碼、回調(diào)數(shù)據(jù)這塊。

先上個(gè)只管感受圖，本視頻以Windows平臺(tái)采集秒表計(jì)時(shí)器窗體，然后編碼打包傳輸?shù)絉TMP服務(wù)，Unity3D的Linux平臺(tái)RTMP播放器拉流播放，整體延遲毫秒級(jí)。

Linux平臺(tái)，我們是回調(diào)的YUV的數(shù)據(jù)，也就是 NT_SP_E_VIDEO_FRAME_FROMAT_I420：

/*定義視頻幀圖像格式*/public enum NT_SP_E_VIDEO_FRAME_FORMAT : uint{NT_SP_E_VIDEO_FRAME_FORMAT_RGB32 = 1, // 32位的rgb格式, r, g, b各占8, 另外一個(gè)字節(jié)保留, 內(nèi)存字節(jié)格式為: bb gg rr xx, 主要是和windows位圖匹配, 在小端模式下，按DWORD類型操作，最高位是xx, 依次是rr, gg, bbNT_SP_E_VIDEO_FRAME_FORMAT_ARGB = 2, // 32位的argb格式，內(nèi)存字節(jié)格式是: bb gg rr aa 這種類型，和windows位圖匹配NT_SP_E_VIDEO_FRAME_FROMAT_I420 = 3, // YUV420格式, 三個(gè)分量保存在三個(gè)面上}

開(kāi)始播放之前，把回調(diào)設(shè)置下去：

//video frame callback (YUV/RGB)videoctrl[sel].video_frame_call_back_ = new SP_SDKVideoFrameCallBack(NT_SP_SetVideoFrameCallBack);NTSmartPlayerSDK.NT_SP_SetVideoFrameCallBack(videoctrl[sel].player_handle_, (Int32)NT.NTSmartPlayerDefine.NT_SP_E_VIDEO_FRAME_FORMAT.NT_SP_E_VIDEO_FRAME_FROMAT_I420, window_handle_, videoctrl[sel].video_frame_call_back_);

視頻幀結(jié)構(gòu)：

/*定義視頻幀結(jié)構(gòu).*/[StructLayoutAttribute(LayoutKind.Sequential)]public struct NT_SP_VideoFrame{public Int32 format_; // 圖像格式, 請(qǐng)參考NT_SP_E_VIDEO_FRAME_FORMATpublic Int32 width_; // 圖像寬public Int32 height_; // 圖像高public Int64 timestamp_; // 時(shí)間戳, 一般是0,不使用, 以ms為單位的//具體的圖像數(shù)據(jù), argb和rgb32只用第一個(gè), I420用前三個(gè)public IntPtr plane0_;public IntPtr plane1_;public IntPtr plane2_;public IntPtr plane3_;// 每一個(gè)平面的每一行的字節(jié)數(shù)，對(duì)于argb和rgb32，為了保持和windows位圖兼容，必須是width_*4// 對(duì)于I420, stride0_ 是y的步長(zhǎng), stride1_ 是u的步長(zhǎng), stride2_ 是v的步長(zhǎng),public Int32 stride0_;public Int32 stride1_;public Int32 stride2_;public Int32 stride3_;}

具體回調(diào)處理：

private void SDKVideoFrameCallBack(UInt32 status, IntPtr frame, int sel){//這里拿到回調(diào)frame，進(jìn)行相關(guān)操作NT_SP_VideoFrame video_frame = (NT_SP_VideoFrame)Marshal.PtrToStructure(frame, typeof(NT_SP_VideoFrame));VideoFrame u3d_frame = new VideoFrame();u3d_frame.width_ = video_frame.width_;u3d_frame.height_ = video_frame.height_;u3d_frame.timestamp_ = (UInt64)video_frame.timestamp_;int d_y_stride = video_frame.width_;int d_u_stride = (video_frame.width_ + 1) / 2;int d_v_stride = d_u_stride;int d_y_size = d_y_stride * video_frame.height_;int d_u_size = d_u_stride * ((video_frame.height_ + 1) / 2);int d_v_size = d_u_size;int u_v_height = ((u3d_frame.height_ + 1) / 2);u3d_frame.y_stride_ = d_y_stride;u3d_frame.u_stride_ = d_u_stride;u3d_frame.v_stride_ = d_v_stride;u3d_frame.y_data_ = new byte[d_y_size];u3d_frame.u_data_ = new byte[d_u_size];u3d_frame.v_data_ = new byte[d_v_size];CopyFramePlane(u3d_frame.y_data_, d_y_stride,video_frame.plane0_, video_frame.stride0_, u3d_frame.height_);CopyFramePlane(u3d_frame.u_data_, d_u_stride,video_frame.plane1_, video_frame.stride1_, u_v_height);CopyFramePlane(u3d_frame.v_data_, d_v_stride,video_frame.plane2_, video_frame.stride2_, u_v_height);lock (videoctrl[sel].frame_lock_ ){videoctrl[sel].cur_video_frame_ = u3d_frame;}}

Unity層拿到video frame后，刷新即可：

private void UpdateProc(int sel){VideoFrame video_frame = null;lock (videoctrl[sel].frame_lock_){video_frame = videoctrl[sel].cur_video_frame_;videoctrl[sel].cur_video_frame_ = null;}if ( video_frame == null )return;if (!videoctrl[sel].is_need_get_frame_)return;if (videoctrl[sel].player_handle_ == IntPtr.Zero )return;if ( !videoctrl[sel].is_need_init_texture_){if ( video_frame.width_ != videoctrl[sel].video_width_|| video_frame.height_ != videoctrl[sel].video_height_|| video_frame.y_stride_ != videoctrl[sel].y_row_bytes_|| video_frame.u_stride_ != videoctrl[sel].u_row_bytes_|| video_frame.v_stride_ != videoctrl[sel].v_row_bytes_ ){videoctrl[sel].is_need_init_texture_ = true;}}if (videoctrl[sel].is_need_init_texture_){if (InitYUVTexture(video_frame, sel)){videoctrl[sel].is_need_init_texture_ = false;}}UpdateYUVTexture(video_frame, sel);}

UpdateYUVTexture相關(guān)實(shí)現(xiàn)：

private void UpdateYUVTexture(VideoFrame video_frame, int sel){if (video_frame.y_data_ == null || video_frame.u_data_ == null || video_frame.v_data_ == null){Debug.Log("video frame with null..");return;}if (videoctrl[sel].yTexture_ != null){videoctrl[sel].yTexture_.LoadRawTextureData(video_frame.y_data_);videoctrl[sel].yTexture_.Apply();}if (videoctrl[sel].uTexture_ != null){videoctrl[sel].uTexture_.LoadRawTextureData(video_frame.u_data_);videoctrl[sel].uTexture_.Apply();}if (videoctrl[sel].vTexture_ != null){videoctrl[sel].vTexture_.LoadRawTextureData(video_frame.v_data_);videoctrl[sel].vTexture_.Apply();}}

相關(guān)Player封裝：

/** SmartPlayerLinuxMono.cs** WebSite: https://daniusdk.com* Github: https://github.com/daniulive/SmarterStreaming*/public void Play(int sel){if (videoctrl[sel].is_running){Debug.Log("已經(jīng)在播放..");return;}lock (videoctrl[sel].frame_lock_){videoctrl[sel].cur_video_frame_ = null;}OpenPlayer(sel);if (videoctrl[sel].player_handle_ == IntPtr.Zero)return;//設(shè)置播放URLNTSmartPlayerSDK.NT_SP_SetURL(videoctrl[sel].player_handle_, videoctrl[sel].videoUrl);/* ++ 播放前參數(shù)配置可加在此處 ++ */int play_buffer_time_ = 0;NTSmartPlayerSDK.NT_SP_SetBuffer(videoctrl[sel].player_handle_, play_buffer_time_); //設(shè)置buffer timeint is_using_tcp = 0; //TCP模式NTSmartPlayerSDK.NT_SP_SetRTSPTcpMode(videoctrl[sel].player_handle_, is_using_tcp);int timeout = 10;NTSmartPlayerSDK.NT_SP_SetRtspTimeout(videoctrl[sel].player_handle_, timeout);int is_auto_switch_tcp_udp = 1;NTSmartPlayerSDK.NT_SP_SetRtspAutoSwitchTcpUdp(videoctrl[sel].player_handle_, is_auto_switch_tcp_udp);Boolean is_mute_ = false;NTSmartPlayerSDK.NT_SP_SetMute(videoctrl[sel].player_handle_, is_mute_ ? 1 : 0); //是否啟動(dòng)播放的時(shí)候靜音int is_fast_startup = 1;NTSmartPlayerSDK.NT_SP_SetFastStartup(videoctrl[sel].player_handle_, is_fast_startup); //設(shè)置快速啟動(dòng)模式Boolean is_low_latency_ = false;NTSmartPlayerSDK.NT_SP_SetLowLatencyMode(videoctrl[sel].player_handle_, is_low_latency_ ? 1 : 0); //設(shè)置是否啟用低延遲模式//設(shè)置旋轉(zhuǎn)角度(設(shè)置0， 90， 180， 270度有效，其他值無(wú)效)int rotate_degrees = 0;NTSmartPlayerSDK.NT_SP_SetRotation(videoctrl[sel].player_handle_, rotate_degrees);int volume = 100;NTSmartPlayerSDK.NT_SP_SetAudioVolume(videoctrl[sel].player_handle_, volume); //設(shè)置播放音量, 范圍是[0, 100], 0是靜音，100是最大音量, 默認(rèn)是100// 設(shè)置上傳下載報(bào)速度int is_report = 0;int report_interval = 1;NTSmartPlayerSDK.NT_SP_SetReportDownloadSpeed(videoctrl[sel].player_handle_, is_report, report_interval);/* -- 播放前參數(shù)配置可加在此處 -- *///video frame callback (YUV/RGB)videoctrl[sel].video_frame_call_back_ = new SP_SDKVideoFrameCallBack(NT_SP_SetVideoFrameCallBack);NTSmartPlayerSDK.NT_SP_SetVideoFrameCallBack(videoctrl[sel].player_handle_, (Int32)NT.NTSmartPlayerDefine.NT_SP_E_VIDEO_FRAME_FORMAT.NT_SP_E_VIDEO_FRAME_FROMAT_I420, window_handle_, videoctrl[sel].video_frame_call_back_);UInt32 flag = NTSmartPlayerSDK.NT_SP_StartPlay(videoctrl[sel].player_handle_);if (flag == DANIULIVE_RETURN_OK){videoctrl[sel].is_need_get_frame_ = true;Debug.Log("播放成功");}else{videoctrl[sel].is_need_get_frame_ = false;Debug.LogError("播放失敗");}videoctrl[sel].is_running = true;}

調(diào)用到的OpenPlayer實(shí)現(xiàn)：

OpenPlayer主要是調(diào)用底層NT_SP_Open()接口，獲取播放實(shí)例句柄，然后設(shè)置Event回調(diào)等。

private void OpenPlayer(int sel){window_handle_ = IntPtr.Zero;if (videoctrl[sel].player_handle_ == IntPtr.Zero){videoctrl[sel].player_handle_ = new IntPtr();UInt32 ret_open = NTSmartPlayerSDK.NT_SP_Open(out videoctrl[sel].player_handle_, window_handle_, 0, IntPtr.Zero);if (ret_open != 0){videoctrl[sel].player_handle_ = IntPtr.Zero;Debug.LogError("調(diào)用NT_SP_Open失敗..");return;}}videoctrl[sel].event_call_back_ = new SP_SDKEventCallBack(NT_SP_SDKEventCallBack);NTSmartPlayerSDK.NT_SP_SetEventCallBack(videoctrl[sel].player_handle_, window_handle_, videoctrl[sel].event_call_back_);videoctrl[sel].sdk_video_frame_call_back_ = new VideoControl.SetVideoFrameCallBack(SDKVideoFrameCallBack);videoctrl[sel].sdk_event_call_back_ = new VideoControl.SetEventCallBack(SDKEventCallBack);}

關(guān)閉播放：

private void ClosePlayer(int sel){videoctrl[sel].is_need_get_frame_ = false;videoctrl[sel].is_need_init_texture_ = false;if (videoctrl[sel].player_handle_ == IntPtr.Zero){return;}UInt32 flag = NTSmartPlayerSDK.NT_SP_StopPlay(videoctrl[sel].player_handle_);if (flag == DANIULIVE_RETURN_OK){Debug.Log("停止成功");}else{Debug.LogError("停止失敗");}videoctrl[sel].player_handle_ = IntPtr.Zero;videoctrl[sel].is_running = false;}

總結(jié)

Unity環(huán)境下的直播播放，Windows平臺(tái)或者Android的比較多，用在Linux平臺(tái)的少之又少，一方面Linux平臺(tái)本身需求不大，另一方面，Linux平臺(tái)這塊，可參考的例程不多，實(shí)際上，如果已經(jīng)完成Windows或Android平臺(tái)下的核心功能實(shí)現(xiàn)，再移植到Linux下，非常方便。

Unity下，簡(jiǎn)單來(lái)說(shuō)就是拉流解碼回調(diào)，上層繪制，其實(shí)也沒(méi)有那么復(fù)雜，需要注意的是DllImport的寫法、之前C++結(jié)構(gòu)體或枚舉的轉(zhuǎn)換、Unity3D對(duì)Linux的版本兼容等一些細(xì)節(jié)，對(duì)熟悉C#的開(kāi)發(fā)者來(lái)說(shuō)，不具備多大的技術(shù)難度。

總結(jié)

以上是生活随笔為你收集整理的Unity3D下Linux平台播放RTSP或RTMP流的全部?jī)?nèi)容，希望文章能夠幫你解決所遇到的問(wèn)題。

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