EasyPlayerPro for Windows是基於ffmpeg進行開發的全功能播放器，開發過程中參考了很多開源的播放器，諸如vlc和ffplay等，其中最強大的莫過於vlc，但是鑑於vlc框架過於龐大而其中仍存在諸多問題而捨棄了，而其他的更傾向於演示demo，只能提供部分借鑑意義；故而，EasyPlayerPro 一貫秉承Easy系列小而精，接口簡單功能強大的宗旨從新設計了一套框架，該套框架能適應多線程調用以及多個播放實例同時運行，和EasyPlayer一樣Easy; 當然，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。
EasyPlayerPro分爲三大模塊：打開模塊，讀取流數據模塊，解碼模塊和渲染模塊，其中：
(1) 打開模塊
打開流模塊很簡單，教科書式的調用方法：
player->avformat_context = avformat_alloc_context();
player->avformat_context->interrupt_callback.callback = interrupt_cb;
player->avformat_context->interrupt_callback.opaque = player;
// open input file
AVDictionary *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 info
if (avformat_find_stream_info(player->avformat_context, NULL) < 0)
{
goto error_handler;
}
// set current audio & video stream
for (i=0,idx=-1,cur=-1; i<(int)player->avformat_context->nb_streams; i++) {
switch (type) {
case AVMEDIA_TYPE_AUDIO:
// get last codec context
if (player->acodec_context) {
lastctxt = player->acodec_context;
}
// get new acodec_context & astream_timebase
player->acodec_context = player->avformat_context->streams[idx]->codec;
player->astream_timebase = player->avformat_context->streams[idx]->time_base;
// reopen codec
if (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 context
if (player->vcodec_context) {
lastctxt = player->vcodec_context;
}
// get new vcodec_context & vstream_timebase
player->vcodec_context = player->avformat_context->streams[idx]->codec;
player->vstream_timebase = player->avformat_context->streams[idx]->time_base;
// reopen codec
if (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 audio
if (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 issue
if (alayout == 0) {
alayout = av_get_default_channel_layout(player->acodec_context->channels);
}
//-- fix audio channel layout issue
}
// for video
if (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打開一個流，爲了避免在打開流的時候出現阻塞，我們創建一個線程來執行，同時，爲了防止ffmpeg內部出現持久行的阻塞，我們傳入阻塞回調函數，在關閉流或者其他必要的時候解除阻塞；avformat_find_stream_info獲取流的解碼信息，根據音視頻以及字幕的解碼信息初始化解碼器；
(2) 讀取流數據模塊
retv = av_read_frame(player->avformat_context, packet);
//++ play completed ++//
if (retv < 0)
{
if (player->avformat_context->pb && player->avformat_context->pb->error)
{
//告知播放實時流中斷
player->error_flag = 1;
//創建斷線重連錯誤檢測線程
// [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錯誤代碼
// audio
if (packet->stream_index == player->astream_index)
{
pktqueue_write_post_a(player->pktqueue, packet);
}
// video
if (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 packet
pktqueue_write_post_i(player->pktqueue, packet);
}
}
讀取數據模塊超級簡單，創建一個線程循環執行av_read_frame，讀取到一幀就將其放入隊列，這裏採用了ffplay的阻塞的方式來處理隊列的消費者和生產者的問題，這塊有待優化，後續將改成無鎖循環隊列模式，如EasyPlayer。
(3) 解碼模塊
解碼模塊分爲音頻和視頻解碼模塊，音視頻的解碼流程非常相似，
主要分爲三步：
a. 從隊列中讀取音視頻編碼數據；
b. 音視頻分別採用avcodec_decode_audio4和avcodec_decode_video2進行解碼；
c. 音視頻渲染；
這裏着重講解視頻的解碼後的過程，其中涉及到解碼後的原始圖像數據進行處理，解碼出一幀圖像以後，我們需要對其進行字幕和圖像或者其他的視頻圖像的疊加，藉助ffmpeg強大的圖像轉換和縮放能力，藉助VFX庫我們很容易實現：
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...
// 對解碼幀進行特技處理（字符，圖片疊加，添加特效） [Dingshuai 2017/08/07]
#if 1
WaterMarkInfo 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
//;表示臺標位置：1 == 左上 2 == 右上 3 == 左下 4 == 右下
//eWaterMarkPos = 3
//;水印頂點x軸座標，建議不小於0；不大於視頻寬度
//nLeftTopX = 0
//;水印頂點y軸座標，建議不小於0；不大於視頻高度
//nLeftTopY = 480
//;水印風格：0 - 6
//eWatermarkStyle = 3
//;水印圖像文件路徑LOGO.png
//strWMFilePath = .\Res\logo.png
switch (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、初始化創建字幕指針,並初始化視頻長寬參數 m_pVideoVfxMakerInfo->nDesWidth, m_pVideoVfxMakerInfo->nDesHeight, m_pVideoVfxMakerInfo->strDesBytesType);
player->vfxHandle->CreateOverlayTitle(vframe->width, vframe->height, ("YUY2"));
// -->2、設置字幕文字信息
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;//134
inFont.lfOutPrecision =3;// OUT_DEFAULT_PRECIS;
inFont.lfClipPrecision = 2;//CLIP_DEFAULT_PRECIS;
inFont.lfQuality = 1;//PROOF_QUALITY;
inFont.lfPitchAndFamily = 0;//49;//49
strcpy(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、設置字幕運行抓狀態
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); //緩存寫入源數據
memset(pVfxBuffer, 0x00, nBufSize);
}
AVFrame src;
av_image_fill_arrays(src.data, src.linesize, pVfxBuffer, outPixelFormat, vframe->width, vframe->height, 1);
//YUV420 -> YUY2
ConvertColorSpace(&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由於視頻渲染需要一定的時間，我們也將解碼幀數據進入隊列進行緩存，從而保證播放的流暢性；
(4) 渲染模塊
渲染模塊分爲音頻渲染和視頻渲染，音頻渲染即播放，使用waveOutOpen，waveOutWrite等waveout函數即可實現，下面重點說一下視頻渲染，視頻渲染通俗講也就是圖像繪製，Windows平臺可採用D3D,DDraw, GDI，OpenGL等多種方式進行呈現，本文主要採用3種渲染方式，D3D，GDI和OpenGL；
爲了保證渲染的流暢性，我們創建線程執行渲染，
a. 讀取解碼圖像隊列；
b. 音視頻時間戳同步處理；
c. D3D/gdi/openGL渲染：