EasyPlayerPro for Windows是基于ffmpeg進(jìn)行開發(fā)的全功能播放器，開發(fā)過程中參考了很多開源的播放器，諸如vlc和ffplay等，其中最強(qiáng)大的莫過于vlc，但是鑒于vlc框架過于龐大而其中仍存在諸多問題而舍棄了，而其他的更傾向于演示demo，只能提供部分借鑒意義；故而，EasyPlayerPro 一貫秉承Easy系列小而精，接口簡(jiǎn)單功能強(qiáng)大的宗旨從新設(shè)計(jì)了一套框架，該套框架能適應(yīng)多線程調(diào)用以及多個(gè)播放實(shí)例同時(shí)運(yùn)行，和EasyPlayer一樣Easy; 當(dāng)然，在此也鄭重的感謝各大開源播放器以及ffmpeg的作者的無私奉獻(xiàn)。

EasyPlayerPro分為三大模塊：打開模塊，讀取流數(shù)據(jù)模塊，解碼模塊和渲染模塊，其中：

(1) 打開模塊
打開流模塊很簡(jiǎn)單，教科書式的調(diào)用方法：

player->avformat_context = avformat_alloc_context();player->avformat_context->interrupt_callback.callback = interrupt_cb;player->avformat_context->interrupt_callback.opaque = player;// open input fileAVDictionary *options = NULL;//av_dict_set(&options, "rtsp_transport", "udp", 0);if (avformat_open_input(&player->avformat_context, url, fmt, &options) != 0) {goto error_handler;}// find stream infoif (avformat_find_stream_info(player->avformat_context, NULL) < 0) {goto error_handler;}// set current audio & video streamfor (i=0,idx=-1,cur=-1; i<(int)player->avformat_context->nb_streams; i++) { switch (type) {case AVMEDIA_TYPE_AUDIO:// get last codec contextif (player->acodec_context) {lastctxt = player->acodec_context;}// get new acodec_context & astream_timebaseplayer->acodec_context = player->avformat_context->streams[idx]->codec;player->astream_timebase = player->avformat_context->streams[idx]->time_base;// reopen codecif (lastctxt) avcodec_close(lastctxt);decoder = avcodec_find_decoder(player->acodec_context->codec_id);if (decoder && avcodec_open2(player->acodec_context, decoder, NULL) == 0) {player->astream_index = idx;}else {av_log(NULL, AV_LOG_WARNING, "failed to find or open decoder for audio !\n");player->astream_index = -1;}break;case AVMEDIA_TYPE_VIDEO:// get last codec contextif (player->vcodec_context) {lastctxt = player->vcodec_context;}// get new vcodec_context & vstream_timebaseplayer->vcodec_context = player->avformat_context->streams[idx]->codec;player->vstream_timebase = player->avformat_context->streams[idx]->time_base;// reopen codecif (lastctxt) avcodec_close(lastctxt);decoder = avcodec_find_decoder(player->vcodec_context->codec_id);if (decoder && avcodec_open2(player->vcodec_context, decoder, NULL) == 0) {player->vstream_index = idx;}else {av_log(NULL, AV_LOG_WARNING, "failed to find or open decoder for video !\n");player->vstream_index = -1;}break;case AVMEDIA_TYPE_SUBTITLE:return -1; // todo...}}if (idx == -1) return -1;// for audioif (player->astream_index != -1){arate = player->acodec_context->sample_rate;aformat = player->acodec_context->sample_fmt;alayout = player->acodec_context->channel_layout;//++ fix audio channel layout issueif (alayout == 0) {alayout = av_get_default_channel_layout(player->acodec_context->channels);}//-- fix audio channel layout issue}// for videoif (player->vstream_index != -1) {vrate = player->avformat_context->streams[player->vstream_index]->r_frame_rate;if (vrate.num / vrate.den >= 100) {vrate.num = 25;vrate.den = 1;}player->vcodec_context->pix_fmt = vformat;width = player->vcodec_context->width;height = player->vcodec_context->height;}

首先，avformat_open_input打開一個(gè)流，為了避免在打開流的時(shí)候出現(xiàn)阻塞，我們創(chuàng)建一個(gè)線程來執(zhí)行，同時(shí)，為了防止ffmpeg內(nèi)部出現(xiàn)持久行的阻塞，我們傳入阻塞回調(diào)函數(shù)，在關(guān)閉流或者其他必要的時(shí)候解除阻塞；avformat_find_stream_info獲取流的解碼信息，根據(jù)音視頻以及字幕的解碼信息初始化解碼器；

(2) 讀取流數(shù)據(jù)模塊

retv = av_read_frame(player->avformat_context, packet);//++ play completed ++//if (retv < 0){if (player->avformat_context->pb && player->avformat_context->pb->error){ //告知播放實(shí)時(shí)流中斷player->error_flag = 1;//創(chuàng)建斷線重連錯(cuò)誤檢測(cè)線程// [9/4/2017 swordtwelve]break;}player->player_status |= PS_D_PAUSE;pktqueue_write_post_i(player->pktqueue, packet);usleep(20*1000); continue;}//-- play completed --//player->error_flag = 0;//-1=初始化 0=正常 1-n錯(cuò)誤代碼// audioif (packet->stream_index == player->astream_index){pktqueue_write_post_a(player->pktqueue, packet);}// videoif (packet->stream_index == player->vstream_index){pktqueue_write_post_v(player->pktqueue, packet);}if ( packet->stream_index != player->astream_index&& packet->stream_index != player->vstream_index ){av_packet_unref(packet); // free packetpktqueue_write_post_i(player->pktqueue, packet);}}

讀取數(shù)據(jù)模塊超級(jí)簡(jiǎn)單，創(chuàng)建一個(gè)線程循環(huán)執(zhí)行av_read_frame，讀取到一幀就將其放入隊(duì)列，這里采用了ffplay的阻塞的方式來處理隊(duì)列的消費(fèi)者和生產(chǎn)者的問題，這塊有待優(yōu)化，后續(xù)將改成無鎖循環(huán)隊(duì)列模式，如EasyPlayer。

(3) 解碼模塊
解碼模塊分為音頻和視頻解碼模塊，音視頻的解碼流程非常相似，
主要分為三步：
a. 從隊(duì)列中讀取音視頻編碼數(shù)據(jù)；
b. 音視頻分別采用avcodec_decode_audio4和avcodec_decode_video2進(jìn)行解碼；
c. 音視頻渲染；
這里著重講解視頻的解碼后的過程，其中涉及到解碼后的原始圖像數(shù)據(jù)進(jìn)行處理，解碼出一幀圖像以后，我們需要對(duì)其進(jìn)行字幕和圖像或者其他的視頻圖像的疊加，借助ffmpeg強(qiáng)大的圖像轉(zhuǎn)換和縮放能力，借助VFX庫(kù)我們很容易實(shí)現(xiàn)：

consumed = avcodec_decode_video2(player->vcodec_context, vframe, &gotvideo, packet);if (consumed < 0) {av_log(NULL, AV_LOG_WARNING, "an error occurred during decoding video.\n");break;}if (gotvideo) {// 解碼視頻幀添加特技處理 [9/7/2017 dingshuai]// 1. 疊加圖片// 2. 疊加字母// 3. 畫框...// 對(duì)解碼幀進(jìn)行特技處理（字符，圖片疊加，添加特效） [Dingshuai 2017/08/07] #if 1WaterMarkInfo g_waterMarkInfo = player->vfxConfigInfo.warkMarkInfo;if (g_waterMarkInfo.bIsUseWaterMark){if (player->vcodec_context->width != vframe->width || player->vcodec_context->height != vframe->height || player->vfxConfigInfo.warkMarkInfo.bResetWaterMark ){//初始化水印疊加//;表示臺(tái)標(biāo)位置：1 == 左上 2 == 右上 3 == 左下 4 == 右下//eWaterMarkPos = 3//;水印頂點(diǎn)x軸坐標(biāo)，建議不小于0；不大于視頻寬度//nLeftTopX = 0//;水印頂點(diǎn)y軸坐標(biāo)，建議不小于0；不大于視頻高度//nLeftTopY = 480//;水印風(fēng)格：0 - 6//eWatermarkStyle = 3//;水印圖像文件路徑LOGO.png//strWMFilePath = .\Res\logo.pngswitch (g_waterMarkInfo.eWaterMarkPos){case POS_LEFT_TOP:g_waterMarkInfo.nLeftTopX = 0;g_waterMarkInfo.nLeftTopY = 0;break;case POS_RIGHT_TOP:g_waterMarkInfo.nLeftTopX = vframe->width;g_waterMarkInfo.nLeftTopY = 0;break;case POS_LEFT_BOTTOM:g_waterMarkInfo.nLeftTopX = 0;g_waterMarkInfo.nLeftTopY = vframe->height;break;case POS_RIGHT_BOTTOM:g_waterMarkInfo.nLeftTopX = vframe->width;g_waterMarkInfo.nLeftTopY = vframe->height;break;}player->vfxHandle->SetVideoInVideoParam( 101, 0, 0, vframe->width,vframe->height, 100, 100, 100);player->vfxHandle->SetLogoImage(g_waterMarkInfo.strWMFilePath, g_waterMarkInfo.nLeftTopX,g_waterMarkInfo.nLeftTopY, g_waterMarkInfo.bIsUseWaterMark, g_waterMarkInfo.eWatermarkStyle);player->vfxConfigInfo.warkMarkInfo.bResetWaterMark = FALSE;}}//初始化字幕信息VideoTittleInfo tittleInfo = player->vfxConfigInfo.tittleInfo;if(tittleInfo.bResetTittleInfo){// -->1、初始化創(chuàng)建字幕指針,并初始化視頻長(zhǎng)寬參數(shù) m_pVideoVfxMakerInfo->nDesWidth, m_pVideoVfxMakerInfo->nDesHeight, m_pVideoVfxMakerInfo->strDesBytesType);player->vfxHandle->CreateOverlayTitle(vframe->width, vframe->height, ("YUY2"));// -->2、設(shè)置字幕文字信息LOGFONTA inFont;inFont.lfHeight = tittleInfo.nTittleHeight;inFont.lfWidth = tittleInfo.nTittleWidth;inFont.lfEscapement = 0;inFont.lfOrientation = 0;inFont.lfWeight = tittleInfo.nFontWeight;//FW_NORMAL;inFont.lfItalic = 0;inFont.lfUnderline = 0;inFont.lfStrikeOut = 0;inFont.lfCharSet =GB2312_CHARSET;// ANSI_CHARSET;//134inFont.lfOutPrecision =3;// OUT_DEFAULT_PRECIS;inFont.lfClipPrecision = 2;//CLIP_DEFAULT_PRECIS;inFont.lfQuality = 1;//PROOF_QUALITY;inFont.lfPitchAndFamily = 0;//49;//49strcpy(inFont.lfFaceName, tittleInfo.strFontType);//"華文新魏");//"華文隸書");"隸書"POINT pointTitle;if(tittleInfo.nMoveType==0){pointTitle= tittleInfo.ptStartPosition;if(pointTitle.x<=0) pointTitle.x=1;if(pointTitle.x>=vframe->width) pointTitle.x=vframe->width/2;}else if(tittleInfo.nMoveType==1)//從左往右{pointTitle.x = -1;pointTitle.y = tittleInfo.ptStartPosition.y;}else if(tittleInfo.nMoveType==2){pointTitle.x = vframe->width+1;pointTitle.y = tittleInfo.ptStartPosition.y;}player->vfxHandle->SetOverlayTitleInfo(tittleInfo.strTittleContent, inFont, tittleInfo.nColorR, tittleInfo.nColorG,tittleInfo.nColorB, pointTitle);//-->3、設(shè)置字幕運(yùn)行抓狀態(tài)player->vfxHandle->SetOverlayTitleState(tittleInfo.nState);player->vfxConfigInfo.tittleInfo.bResetTittleInfo = FALSE;}if (player->vfxHandle && (g_waterMarkInfo.bIsUseWaterMark || tittleInfo.nState))//logo-水印 + 字幕 + ？？？{if (player->vcodec_context->width != vframe->width || player->vcodec_context->height != vframe->height ){if (pVfxBuffer){free(pVfxBuffer);pVfxBuffer = NULL;}}int nBufSize = vframe->width*vframe->height << 1;if (!pVfxBuffer){pVfxBuffer = (BYTE*)malloc(nBufSize); //緩存寫入源數(shù)據(jù) memset(pVfxBuffer, 0x00, nBufSize);}AVFrame src;av_image_fill_arrays(src.data, src.linesize, pVfxBuffer, outPixelFormat, vframe->width, vframe->height, 1);//YUV420 -> YUY2ConvertColorSpace(&src, outPixelFormat, vframe, inPixelFormat, vframe->width, vframe->height); // av_image_copy_to_buffer(pVfxBuffer, nBufSize, // vframe->data, vframe->linesize, AV_PIX_FMT_YUYV422, vframe->width, vframe->height, 1);//水印疊加if(g_waterMarkInfo.bIsUseWaterMark)player->vfxHandle->AddWaterMask(pVfxBuffer);//OSD疊加if(tittleInfo.nState)player->vfxHandle->DoOverlayTitle(pVfxBuffer);//YUY2 -> I420//ConvertColorSpace(vframe, inPixelFormat, &src, outPixelFormat, vframe->width, vframe->height);av_image_fill_arrays(vframe->data, vframe->linesize, pVfxBuffer, outPixelFormat, vframe->width, vframe->height, 1);int nPixelFmt = AV_PIX_FMT_YUYV422;player_setparam(player, PARAM_RENDER_OUTFORMAT, &nPixelFmt); }else{int nPixelFmt = AV_PIX_FMT_YUV420P;player_setparam(player, PARAM_RENDER_OUTFORMAT, &nPixelFmt); } #endif

由于視頻渲染需要一定的時(shí)間，我們也將解碼幀數(shù)據(jù)進(jìn)入隊(duì)列進(jìn)行緩存，從而保證播放的流暢性；

(4) 渲染模塊
渲染模塊分為音頻渲染和視頻渲染，音頻渲染即播放，使用waveOutOpen，waveOutWrite等waveout函數(shù)即可實(shí)現(xiàn)，下面重點(diǎn)說一下視頻渲染，視頻渲染通俗講也就是圖像繪制，Windows平臺(tái)可采用D3D,DDraw, GDI，OpenGL等多種方式進(jìn)行呈現(xiàn)，本文主要采用3種渲染方式，D3D，GDI和OpenGL；
為了保證渲染的流暢性，我們創(chuàng)建線程執(zhí)行渲染，
a. 讀取解碼圖像隊(duì)列；
b. 音視頻時(shí)間戳同步處理；
c. D3D/gdi/openGL渲染：

關(guān)于EasyPlayerPro

EasyPlayerPro是一款全功能的流媒體播放器，支持RTSP、RTMP、HTTP、HLS、UDP、RTP等多種流媒體協(xié)議播放、支持本地文件播放，支持本地抓拍、本地錄像、播放旋轉(zhuǎn)、多屏播放等多種功能特性，穩(wěn)定、高效、可靠，支持Windows、Android、iOS三個(gè)平臺(tái)，目前在多家教育、安防、行業(yè)型公司，都得到的應(yīng)用，廣受好評(píng)！

EasyPlayerPro：https://github.com/EasyDSS/EasyPlayerPro

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