FFmpeg_11_视频流自定义分辨率播放

/****************** 程序功能： 内存方式读取视频流，对视频流自定义分辨率进行播放 ******************/ #include "sdl2\SDL.h" extern "C" { #include "libavformat\avformat.h" #include "libswscale\swscale.h" }; FILE *fp = NULL; int read_buffer(void *opaque,uint8_t *buf,int buf_size) { if(!feof(fp)) { int true_size = fread(buf,1,buf_size,fp); return true_size; } else return -1; } /* 缩放一帧视频画面的分辨率（适用于YUV420P类型的视频帧）： pCodecCtx -- 保存了相应流的详细编码信息的结构体（如视频的宽、高、编码类型等） pFrame -- 用于保存数据帧的数据结构（分辨率改变前） pNewFrame -- 用于保存数据帧的数据结构（分辨率改变后） NewWidth -- 新分辨率的宽度 NewHeight -- 新分辨率的高度 */ void ResolutionChange(AVCodecContext *pCodecCtx,AVFrame *pFrame,AVFrame *pNewFrame,int pNewWidth,int pNewHeight) { pNewFrame->linesize[0] = pNewWidth; pNewFrame->linesize[1] = pNewWidth/2; pNewFrame->linesize[2] = pNewWidth/2; //用 sws_getContext函数 得到 sws_scale函数 运行的上下文，之后用 sws_scale函数 将图形缩放 struct SwsContext *pSwsCtx = NULL; pSwsCtx = sws_getContext(pCodecCtx->width,pCodecCtx->height,PIX_FMT_YUV420P,pNewWidth,pNewHeight,PIX_FMT_YUV420P,SWS_SINC,NULL,NULL,NULL); if(pSwsCtx == NULL) return ; sws_scale(pSwsCtx,pFrame->data,pFrame->linesize,0,pCodecCtx->height,pNewFrame->data,pNewFrame->linesize); sws_freeContext(pSwsCtx); } int main(int argc,char** argv) { av_register_all(); AVFormatContext *pFormatCtx = NULL; pFormatCtx = avformat_alloc_context(); char filepath[]="test.flv"; fp = fopen(filepath,"rb"); if(fp == NULL) exit(1); unsigned char *aviobuffer = (unsigned char *)av_malloc(32768);//32K AVIOContext *avio = avio_alloc_context(aviobuffer,32768,0,NULL,read_buffer,NULL,NULL); pFormatCtx->pb = avio; if(avformat_open_input(&pFormatCtx,NULL,NULL,NULL) != 0) exit(1); if(avformat_find_stream_info(pFormatCtx,NULL) < 0) exit(1); int videoIndex = -1; for(int i=0;i<pFormatCtx->nb_streams;i++) { if(pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) { videoIndex = i; break; } } if(videoIndex == -1) exit(1); AVCodecContext *pCodecCtx; pCodecCtx = pFormatCtx->streams[videoIndex]->codec; AVCodec *pCodec; pCodec = avcodec_find_decoder(pCodecCtx->codec_id); if(pCodec == NULL) exit(1); if(avcodec_open2(pCodecCtx,pCodec,NULL) < 0) exit(1); AVFrame *pFrame,*pNewFrame; pFrame = av_frame_alloc(); pNewFrame = av_frame_alloc(); if((pFrame == NULL) || (pNewFrame == NULL)) exit(1); //自定义分辨率 int NewWidth = 640,NewHeight = 480; int PictureSize = avpicture_get_size(PIX_FMT_YUV420P,NewWidth,NewHeight); uint8_t* buffer = (uint8_t *)av_malloc(PictureSize*sizeof(uint8_t)); avpicture_fill((AVPicture *)pNewFrame,buffer,PIX_FMT_YUV420P,NewWidth,NewHeight); if(SDL_Init(SDL_INIT_VIDEO|SDL_INIT_AUDIO|SDL_INIT_TIMER)) exit(1); SDL_Window *window = nullptr; window = SDL_CreateWindow("MyPlayer",SDL_WINDOWPOS_UNDEFINED,SDL_WINDOWPOS_UNDEFINED,NewWidth,NewHeight,SDL_WINDOW_OPENGL); if(!window) exit(1); SDL_Renderer *renderer = nullptr; renderer = SDL_CreateRenderer(window,-1,0); if(renderer == nullptr) exit(1); SDL_Texture *texture = nullptr; texture = SDL_CreateTexture(renderer,SDL_PIXELFORMAT_YV12,SDL_TEXTUREACCESS_STREAMING,NewWidth,NewHeight); SDL_Rect rect; SDL_Event event; AVPacket *packet=(AVPacket *)malloc(sizeof(AVPacket)); av_new_packet(packet,PictureSize); int frameFinished; while(av_read_frame(pFormatCtx,packet) >= 0) { if(packet->stream_index == videoIndex) { if(avcodec_decode_video2(pCodecCtx,pFrame,&frameFinished,packet) >= 0) { if(frameFinished) { ResolutionChange(pCodecCtx,pFrame,pNewFrame,NewWidth,NewHeight); rect.x = 0; rect.y = 0; rect.w = NewWidth; rect.h = NewHeight; SDL_UpdateYUVTexture(texture,&rect,pNewFrame->data[0],pNewFrame->linesize[0],pNewFrame->data[1],pNewFrame->linesize[1],pNewFrame->data[2],pNewFrame->linesize[2]); SDL_RenderClear(renderer); SDL_RenderCopy(renderer,texture,&rect,&rect); SDL_RenderPresent(renderer); SDL_Delay(20); } } else exit(1); } av_free_packet(packet); SDL_PollEvent(&event); switch(event.type) { case SDL_QUIT: SDL_Quit(); exit(1); break; default: break; } } SDL_DestroyTexture(texture); SDL_Quit(); av_free(buffer); av_frame_free(&pNewFrame); av_frame_free(&pFrame); avcodec_close(pCodecCtx); avformat_close_input(&pFormatCtx); return 0; }