网站活动打造,wordpress重新生成永久链接,郑州企业建筑资质多少钱,招聘网站怎么做推广文章目录 1.FFMPEG利用命令行将mp4转yuv4202.ffmpeg将mp4解析为yuv数据2.1 核心api: 3.SDL2进行yuv绘制到屏幕3.1 核心api 4.完整代码5.效果展示6.SDL2事件响应补充6.1 处理方式-016.2 处理方式-02 本项目采用生产者消费者模型#xff0c;生产者线程#xff1a;使用ffmpeg将m… 文章目录 1.FFMPEG利用命令行将mp4转yuv4202.ffmpeg将mp4解析为yuv数据2.1 核心api: 3.SDL2进行yuv绘制到屏幕3.1 核心api 4.完整代码5.效果展示6.SDL2事件响应补充6.1 处理方式-016.2 处理方式-02 本项目采用生产者消费者模型生产者线程使用ffmpeg将mp4格式数据解析为yuv的帧消费者线程利用sdl2将解析的yuv的帧进行消费绘制到屏幕上。未完成的部分1.解析音频数据并与视频数据同步。2.增加界面暂停播放按钮支持视频前进和后退。 学习音视频的参考资料与项目 playdemo_github 雷神的csdn博客 1.FFMPEG利用命令行将mp4转yuv420 ffmpeg -i input.mp4 -c:v rawvideo -pix_fmt yuv420p output.yuv 2.ffmpeg将mp4解析为yuv数据
2.1 核心api:
av_read_frame:读取一帧数据avcodec_send_packet:将数据包发送给解码器avcodec_receive_frame:将数据包从解码器中取sws_scale:格式转换将解码后的帧数据转为yuv数据存储在data[0],data[1],data[2]中
void readFrame()
{AVPacket* avPacket av_packet_alloc();AVFrame* frame av_frame_alloc();FILE* fp fopen(F:/VS_Project/ffmpeg_demo/yuv.data,wb) ;while (av_read_frame(formatContext, avPacket) 0 fp){if (avPacket-stream_index videoStreamIndex){if (avcodec_send_packet(codecContext, avPacket) 0) {std::cerr 发送数据包到解码器失败 std::endl;break;}/*解码*/int ret avcodec_receive_frame(codecContext, frame);printf(ret:%d\n, ret);if (ret 0){ret sws_scale(swsContext, frame-data, frame-linesize, 0, codecContext-height, yuvFrame-data, yuvFrame-linesize);printf(sws_scale ret%d\n, ret);std::lock_guardstd::mutexlck(mtx);isFinished false;memcpy(yuvBuf, yuvFrame-data[0], yuvFrame-width * yuvFrame-height);memcpy(yuvBuf yuvFrame-width * yuvFrame-height, yuvFrame-data[1], yuvFrame-width * yuvFrame-height / 4);memcpy(yuvBuf yuvFrame-width * yuvFrame-height*5/4, yuvFrame-data[2], yuvFrame-width * yuvFrame-height / 4);isFinished true;condvar.notify_one();//保存y分量//fwrite(yuvFrame-data[0], 1, yuvFrame-width * yuvFrame-height, fp);//保存uv分量//fwrite(yuvFrame-data[1], 1, yuvFrame-width * yuvFrame-height/4, fp);//fwrite(yuvFrame-data[2], 1, yuvFrame-width * yuvFrame-height / 4, fp);}}}fclose(fp);av_frame_unref(yuvFrame);av_packet_free(avPacket);av_frame_unref(frame);
}3.SDL2进行yuv绘制到屏幕
3.1 核心api
SDL_InitSDL_CreateWindowSDL_CreateRendererSDL_CreateTextureSDL_UpdateTextureSDL_RenderCopySDL_RenderPresentSDL_Delay:控制帧率
int sdl_display()
{if (SDL_Init(SDL_INIT_VIDEO)) {printf(sdl init failed\n);return -1;}SDL_Window* window SDL_CreateWindow(sdl_demo, 200, 200, codecContext-width, codecContext-height, SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE);if (!window) {SDL_Quit();return -1;}SDL_Renderer* renderer SDL_CreateRenderer(window, -1, 0);if (!renderer){SDL_DestroyWindow(window);SDL_Quit();return -1;}SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);SDL_RenderClear(renderer);Uint32 pixformat SDL_PIXELFORMAT_IYUV;SDL_Texture* sdlTexture SDL_CreateTexture(renderer, pixformat, SDL_TEXTUREACCESS_STREAMING, codecContext-width, codecContext-height);//FILE* fp fopen(F:/VS_Project/ffmpeg_demo/yuv.data, rb);while (1) {//int ret fread(yuvBuf, 1, yuvlen, fp);//if (ret 0) {// break;//}std::unique_lockstd::mutexlck(mtx);if (condvar.wait_for(lck, std::chrono::seconds(1), [] {return isFinished;})){isFinished false;SDL_UpdateTexture(sdlTexture, NULL, yuvBuf, codecContext-width);SDL_RenderCopy(renderer, sdlTexture, NULL, NULL);SDL_RenderPresent(renderer);//控制帧率25fpsSDL_Delay(40);}else {printf(sdl thread exit!\n);break;}}SDL_Quit();return 0;
}4.完整代码
-使用两个线程生产者消费者模型
#include stdio.h
#include stdlib.h
#include stdbool.h
#include stdexcept
#include iostream
#include string
#include thread
#include fstream#include mutex
#include condition_variable
extern C {
#include libavcodec/avcodec.h
#include libavformat/avformat.h
#include libavutil/avutil.h
#include libswscale/swscale.h#include SDL.h
}
#undef main
#pragma warning(disable:4996)
AVFormatContext* formatContext nullptr;
AVCodecContext* codecContext nullptr;
SwsContext* swsContext nullptr;
int videoStreamIndex -1;
AVFrame* yuvFrame;
unsigned char* yuvBuf;
bool isReady false;
bool isFinished false;std::mutex mtx;
std::condition_variable condvar;
void readFrame()
{AVPacket* avPacket av_packet_alloc();AVFrame* frame av_frame_alloc();FILE* fp fopen(F:/VS_Project/ffmpeg_demo/yuv.data,wb) ;while (av_read_frame(formatContext, avPacket) 0 fp){if (avPacket-stream_index videoStreamIndex){if (avcodec_send_packet(codecContext, avPacket) 0) {std::cerr 发送数据包到解码器失败 std::endl;break;}/*解码*/int ret avcodec_receive_frame(codecContext, frame);printf(ret:%d\n, ret);if (ret 0){ret sws_scale(swsContext, frame-data, frame-linesize, 0, codecContext-height, yuvFrame-data, yuvFrame-linesize);printf(sws_scale ret%d\n, ret);std::lock_guardstd::mutexlck(mtx);isFinished false;memcpy(yuvBuf, yuvFrame-data[0], yuvFrame-width * yuvFrame-height);memcpy(yuvBuf yuvFrame-width * yuvFrame-height, yuvFrame-data[1], yuvFrame-width * yuvFrame-height / 4);memcpy(yuvBuf yuvFrame-width * yuvFrame-height*5/4, yuvFrame-data[2], yuvFrame-width * yuvFrame-height / 4);isFinished true;condvar.notify_one();//保存y分量//fwrite(yuvFrame-data[0], 1, yuvFrame-width * yuvFrame-height, fp);//保存uv分量//fwrite(yuvFrame-data[1], 1, yuvFrame-width * yuvFrame-height/4, fp);//fwrite(yuvFrame-data[2], 1, yuvFrame-width * yuvFrame-height / 4, fp);}}}fclose(fp);av_frame_unref(yuvFrame);av_packet_free(avPacket);av_frame_unref(frame);
}int sdl_display()
{if (SDL_Init(SDL_INIT_VIDEO)) {printf(sdl init failed\n);return -1;}SDL_Window* window SDL_CreateWindow(sdl_demo, 200, 200, codecContext-width, codecContext-height, SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE);if (!window) {SDL_Quit();return -1;}SDL_Renderer* renderer SDL_CreateRenderer(window, -1, 0);if (!renderer){SDL_DestroyWindow(window);SDL_Quit();return -1;}SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);SDL_RenderClear(renderer);Uint32 pixformat SDL_PIXELFORMAT_IYUV;SDL_Texture* sdlTexture SDL_CreateTexture(renderer, pixformat, SDL_TEXTUREACCESS_STREAMING, codecContext-width, codecContext-height);//FILE* fp fopen(F:/VS_Project/ffmpeg_demo/yuv.data, rb);while (1) {//int ret fread(yuvBuf, 1, yuvlen, fp);//if (ret 0) {// break;//}std::unique_lockstd::mutexlck(mtx);if (condvar.wait_for(lck, std::chrono::seconds(1), [] {return isFinished;})){isFinished false;SDL_UpdateTexture(sdlTexture, NULL, yuvBuf, codecContext-width);SDL_RenderCopy(renderer, sdlTexture, NULL, NULL);SDL_RenderPresent(renderer);//控制帧率25fpsSDL_Delay(40);}else {printf(sdl thread exit!\n);break;}}SDL_Quit();return 0;
}/*ffmpeg -i input.mp4 -c:v rawvideo -pix_fmt yuv420p output.yuv*/
int main(int argc, char* argv[])
{/*if (argc ! 2) {std::cerr 文件名未指定 std::endl;return -1;}*/std::string filename F:/VS_Project/ffmpeg_demo/1.mkv;if (avformat_open_input(formatContext, filename.c_str(), nullptr, nullptr) ! 0){std::cerr 无法打开文件 std::endl;return -1;}if (avformat_find_stream_info(formatContext, nullptr) 0) {std::cerr 无法找到视频流 std::endl;return -1;}for (int i 0; i formatContext-nb_streams; i){enum AVMediaType type AVMEDIA_TYPE_VIDEO;AVStream* st formatContext-streams[i];AVCodecParameters* codecpar st-codecpar;if (codecpar-codec_type type){videoStreamIndex i;const AVCodec* codec avcodec_find_decoder(codecpar-codec_id);codecContext avcodec_alloc_context3(codec);avcodec_parameters_to_context(codecContext, codecpar);avcodec_open2(codecContext, codec, nullptr);swsContext sws_getContext(codecContext-width, codecContext-height, codecContext-pix_fmt,codecContext-width, codecContext-height, AV_PIX_FMT_YUV420P,SWS_BILINEAR, nullptr, nullptr, nullptr);std::cout w: codecpar-width std::endl;std::cout h: codecpar-height std::endl;}}yuvFrame av_frame_alloc();yuvFrame-width codecContext-width;yuvFrame-height codecContext-height;yuvFrame-format AV_PIX_FMT_YUV420P;int yuvlen codecContext-width * codecContext-height * 3 / 2;yuvBuf new unsigned char[yuvlen];int ret av_frame_get_buffer(yuvFrame, 0);if (ret 0) {printf(分配缓冲区失败\n);return -1;}//sdl_init();std::thread th1(readFrame);std::thread th2(sdl_display);th1.join();th2.join();delete[]yuvBuf;return 0;
}
5.效果展示 6.SDL2事件响应补充
6.1 处理方式-01 起一个refresh_video线程用于产生一个自定义更新video的事件REFRESH_EVENT并且每40ms更新一次。while循环中持续等待事件的到来SDL_WaitEvent当收到事件后更新一帧画面。同时当监测到窗口改变的事件SDL_GetWindowSize对窗口进行调整。 int refresh_video(void *opaque){thread_exit0;while (thread_exit0) {SDL_Event event;event.type REFRESH_EVENT;SDL_PushEvent(event);SDL_Delay(40);}thread_exit0;//BreakSDL_Event event;event.type BREAK_EVENT;SDL_PushEvent(event);return 0;
}
SDL_Thread *refresh_thread SDL_CreateThread(refresh_video,NULL,NULL);SDL_Event event;while(1){//WaitSDL_WaitEvent(event);if(event.typeREFRESH_EVENT){if (fread(buffer, 1, pixel_w*pixel_h*bpp/8, fp) ! pixel_w*pixel_h*bpp/8){// Loopfseek(fp, 0, SEEK_SET);fread(buffer, 1, pixel_w*pixel_h*bpp/8, fp);}SDL_UpdateTexture( sdlTexture, NULL, buffer, pixel_w); //FIX: If window is resizesdlRect.x 0; sdlRect.y 0; sdlRect.w screen_w; sdlRect.h screen_h; SDL_RenderClear( sdlRenderer ); SDL_RenderCopy( sdlRenderer, sdlTexture, NULL, sdlRect); SDL_RenderPresent( sdlRenderer ); }else if(event.typeSDL_WINDOWEVENT){//If ResizeSDL_GetWindowSize(screen,screen_w,screen_h);}else if(event.typeSDL_QUIT){thread_exit1;}else if(event.typeBREAK_EVENT){break;}}SDL_Quit();6.2 处理方式-02 起一个事件循环线程SDL_PeepEvents 从事件队列中取出一个事件然后更新事件队列并进行绘制操作。 //播放控制循环
void VideoCtl::LoopThread(VideoState *cur_stream)
{SDL_Event event;double incr, pos, frac;m_bPlayLoop true;while (m_bPlayLoop){double x;refresh_loop_wait_event(cur_stream, event);switch (event.type) {case SDL_KEYDOWN:switch (event.key.keysym.sym) {case SDLK_s: // S: Step to next framestep_to_next_frame(cur_stream);break;case SDLK_a:stream_cycle_channel(cur_stream, AVMEDIA_TYPE_AUDIO);break;case SDLK_v:stream_cycle_channel(cur_stream, AVMEDIA_TYPE_VIDEO);break;case SDLK_c:stream_cycle_channel(cur_stream, AVMEDIA_TYPE_VIDEO);stream_cycle_channel(cur_stream, AVMEDIA_TYPE_AUDIO);stream_cycle_channel(cur_stream, AVMEDIA_TYPE_SUBTITLE);break;case SDLK_t:stream_cycle_channel(cur_stream, AVMEDIA_TYPE_SUBTITLE);break;default:break;}break;case SDL_WINDOWEVENT://窗口大小改变事件qDebug()SDL_WINDOWEVENT endl;switch (event.window.event) {case SDL_WINDOWEVENT_RESIZED:screen_width cur_stream-width event.window.data1;screen_height cur_stream-height event.window.data2;case SDL_WINDOWEVENT_EXPOSED:cur_stream-force_refresh 1;}break;case SDL_QUIT:case FF_QUIT_EVENT:do_exit(cur_stream);break;default:break;}}do_exit(m_CurStream);//m_CurStream nullptr;}
