(转载)QT+FFMPEG+SDL2.0实现视频播放QT+FFMPEG+SDL2.0实现视频播放（没有声音）

开发环境：MinGW+QT5.9+FFMPEG20190212+SDL2.0.9

一、开发环境搭建

（1）下载工具

在https://ffmpeg.zeranoe.com/builds/下载对应版本。链接方式有三种，

Static:这个版本只包含了ffmpeg.exe、ffplay.exe、ffprobe.exe三个可执行程序，没有头文件和库文件。

Shared:这个版本包含了ffmpeg.exe、ffplay.exe、ffprobe.exe三个可执行程序和相关动态库文件。

Dev:开发版，这个包含了头文件和库文件。

我们需要下载Shared和Dev两个版本，Dev有我们程序开发需要的头文件和库文件，这里面包含的库是动态调用的，所依赖的动态库在Shared这个版本里面，所以两个版本都要下载。

 

在http://www.libsdl.org/download-2.0.php下载SDL库，选择

 

（2）添加库

将下载的文件解压缩，然后新建一个QT工程，在pro添加lib目录和include目录的路径。

INCLUDEPATH +="E:\\Lib\\ffmpeg\\include"
INCLUDEPATH +="E:\\Lib\\SDL2-2.0.9\\include"

LIBS += -LE:\Lib\ffmpeg\lib -lavutil -lavformat -lavcodec -lavdevice -lavfilter -lpostproc -lswresample -lswscale
LIBS += -LE:\Lib\SDL2-2.0.9\lib\x86 -lSDL2

然后将ffmpeg的dll和SDL2.dll放到exe目录下。

 

二、代码实现：

在QT界面上放置一个widget和一个按钮，点击按钮时实现下面功能：

extern "C"{
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#include <libavutil/imgutils.h>
#include <SDL.h>
}

void MainWindow::on_btnPlay_clicked()
{
    AVFormatContext    *pFormatCtx;
    int                i, videoindex;
    AVCodecContext    *pCodecCtx;
    AVCodec            *pCodec;
    AVFrame    *pFrame, *pFrameYUV;
    unsigned char *out_buffer;
    AVPacket *packet;
    int ret, got_picture;
    struct SwsContext *img_convert_ctx;

    char filepath[] = "E:\\media\\1.avi";
    //初始化编解码库
    av_register_all();
    //已经无需使用的函数？
    //avformat_network_init();
    //创建AVFormatContext对象，与码流相关的结构。
    pFormatCtx = avformat_alloc_context();
    //初始化pFormatCtx结构
    if (avformat_open_input(&pFormatCtx, filepath, NULL, NULL) != 0){
        printf("Couldn't open input stream.\n");
        return ;
    }
    //获取音视频流数据信息
    if (avformat_find_stream_info(pFormatCtx, NULL) < 0){
        printf("Couldn't find stream information.\n");
        return ;
    }
    videoindex = -1;
    //nb_streams视音频流的个数，这里当查找到视频流时就中断了。
    for (i = 0; i < pFormatCtx->nb_streams; i++)
        if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO){
            videoindex = i;
            break;
    }
    if (videoindex == -1){
        printf("Didn't find a video stream.\n");
        return ;
    }
    //获取视频流编码结构
    pCodecCtx = pFormatCtx->streams[videoindex]->codec;
    //查找解码器
    pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
    if (pCodec == NULL){
        printf("Codec not found.\n");
        return ;
    }
    //用于初始化pCodecCtx结构
    if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0){
        printf("Could not open codec.\n");
        return ;
    }
    //创建帧结构，此函数仅分配基本结构空间，图像数据空间需通过av_malloc分配
    pFrame = av_frame_alloc();
    pFrameYUV = av_frame_alloc();
    //创建动态内存,创建存储图像数据的空间
    //av_image_get_buffer_size获取一帧图像需要的大小
    out_buffer = (unsigned char *)av_malloc(av_image_get_buffer_size(AV_PIX_FMT_YUV420P, ui->widget->width(), ui->widget->height(), 1));
    av_image_fill_arrays(pFrameYUV->data, pFrameYUV->linesize, out_buffer,
        AV_PIX_FMT_YUV420P, ui->widget->width(), ui->widget->height(), 1);

    packet = (AVPacket *)av_malloc(sizeof(AVPacket));
    //Output Info-----------------------------
    printf("--------------- File Information ----------------\n");
    //此函数打印输入或输出的详细信息
    av_dump_format(pFormatCtx, 0, filepath, 0);
    printf("-------------------------------------------------\n");
    //初始化img_convert_ctx结构
    img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt,
        ui->widget->width(), ui->widget->height(), AV_PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);
    //SDL---------------------------
    SDL_Window *screen;
    SDL_Renderer* sdlRenderer;
    SDL_Texture* sdlTexture;
    SDL_Rect sdlRect;
    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) {
        printf("Could not initialize SDL - %s\n", SDL_GetError());
        return;
    }
    screen = SDL_CreateWindowFrom((void *)ui->widget->winId());
    if(screen==NULL)
    {
        printf("Could not create window - %s\n", SDL_GetError());
        return;
    }
    sdlRenderer = SDL_CreateRenderer(screen, -1, 0);
    sdlTexture = SDL_CreateTexture(sdlRenderer, SDL_PIXELFORMAT_IYUV, SDL_TEXTUREACCESS_STREAMING, pCodecCtx->width, pCodecCtx->height);
    sdlRect.x = 0;
    sdlRect.y = 0;
    sdlRect.w = pCodecCtx->width;
    sdlRect.h = pCodecCtx->height;
    //end SDL-----------------------
    //av_read_frame读取一帧未解码的数据
    while (av_read_frame(pFormatCtx, packet) >= 0){
        //如果是视频数据
        if (packet->stream_index == videoindex){
            //解码一帧视频数据
            ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, packet);
            if (ret < 0){
                printf("Decode Error.\n");
                return ;
            }
            if (got_picture){
                sws_scale(img_convert_ctx, (const unsigned char* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height,
                    pFrameYUV->data, pFrameYUV->linesize);
                SDL_UpdateYUVTexture(sdlTexture, &sdlRect,
                    pFrameYUV->data[0], pFrameYUV->linesize[0],
                    pFrameYUV->data[1], pFrameYUV->linesize[1],
                    pFrameYUV->data[2], pFrameYUV->linesize[2]);
                SDL_RenderClear(sdlRenderer);
                SDL_RenderCopy(sdlRenderer, sdlTexture, NULL, &sdlRect);
                SDL_RenderPresent(sdlRenderer);
                SDL_Delay(40);
            }
        }
        av_free_packet(packet);
    }
    sws_freeContext(img_convert_ctx);
    av_frame_free(&pFrameYUV);
    av_frame_free(&pFrame);
    avcodec_close(pCodecCtx);
    avformat_close_input(&pFormatCtx);
}

extern "C"
{
    #include <libavcodec/avcodec.h>
    #include <libavformat/avformat.h>
    #include <libavutil/avutil.h>
    #include "libavutil/log.h"
    #include <libswscale/swscale.h>  
    #include <libavutil/avutil.h>
    #include <libavdevice/avdevice.h>
    #include <libavutil/pixfmt.h>
    #include <libavutil/imgutils.h>

    #include <SDL.h>
    #include <SDL_audio.h>
    #include <SDL_types.h>
    #include <SDL_name.h>
    #include <SDL_main.h>
    #include <SDL_config.h>
};
void FFmpegDemo::on_playerSdlBtn1_clicked()
{
    AVFormatContext    *pFormatCtx;
    int                i, videoindex;
    AVCodecContext    *pCodecCtx;
    AVCodec            *pCodec;
    AVFrame    *pFrame, *pFrameYUV;
    unsigned char *out_buffer;
    AVPacket *packet;
    int ret, got_picture;
    struct SwsContext *img_convert_ctx;

    //char filepath[] = "E:\\media\\1.avi";
    char filepath[] = ".\\1.mp4";
    //初始化编解码库
    av_register_all();
    //已经无需使用的函数？
    //avformat_network_init();
    //创建AVFormatContext对象，与码流相关的结构。
    pFormatCtx = avformat_alloc_context();
    //初始化pFormatCtx结构
    if (avformat_open_input(&pFormatCtx, filepath, NULL, NULL) != 0){
        printf("Couldn't open input stream.\n");
        return;
    }
    //获取音视频流数据信息
    if (avformat_find_stream_info(pFormatCtx, NULL) < 0){
        printf("Couldn't find stream information.\n");
        return;
    }
    videoindex = -1;
    //nb_streams视音频流的个数，这里当查找到视频流时就中断了。
    for (i = 0; i < pFormatCtx->nb_streams; i++)
    if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO){
        videoindex = i;
        break;
    }
    if (videoindex == -1){
        printf("Didn't find a video stream.\n");
        return;
    }
    //获取视频流编码结构
    pCodecCtx = pFormatCtx->streams[videoindex]->codec;
    //查找解码器
    pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
    if (pCodec == NULL){
        printf("Codec not found.\n");
        return;
    }
    //用于初始化pCodecCtx结构
    if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0){
        printf("Could not open codec.\n");
        return;
    }
    //创建帧结构，此函数仅分配基本结构空间，图像数据空间需通过av_malloc分配
    pFrame = av_frame_alloc();
    pFrameYUV = av_frame_alloc();
    //创建动态内存,创建存储图像数据的空间
    //av_image_get_buffer_size获取一帧图像需要的大小
    //==================================== 分配空间 ==================================//
    //一帧图像数据大小
    //int numBytes = avpicture_get_size(AV_PIX_FMT_YUVJ420P, pCodecCtx->width, pCodecCtx->height);

    //out_buffer = (unsigned char *)av_malloc(numBytes * sizeof(unsigned char));


    out_buffer = (unsigned char *)av_malloc(av_image_get_buffer_size(AV_PIX_FMT_YUV420P, ui.label->width(), ui.label->height(), 1));
    av_image_fill_arrays(pFrameYUV->data, pFrameYUV->linesize, out_buffer,
        AV_PIX_FMT_YUV420P, ui.label->width(), ui.label->height(), 1);

    packet = (AVPacket *)av_malloc(sizeof(AVPacket));
    //Output Info-----------------------------
    printf("--------------- File Information ----------------\n");
    //此函数打印输入或输出的详细信息
    av_dump_format(pFormatCtx, 0, filepath, 0);
    printf("-------------------------------------------------\n");
    //初始化img_convert_ctx结构
    img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt,
        ui.label->width(), ui.label->height(), AV_PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);
    //img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, //源地址长宽以及数据格式
    //    pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_YUVJ420P,    //目的地址长宽以及数据格式
    //    SWS_BICUBIC, NULL, NULL, NULL);//算法类型  AV_PIX_FMT_YUVJ420P   AV_PIX_FMT_BGR24
    //SDL---------------------------
    SDL_Window *screen;
    SDL_Renderer* sdlRenderer;
    SDL_Texture* sdlTexture;
    SDL_Rect sdlRect;
    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) {
        printf("Could not initialize SDL - %s\n", SDL_GetError());
        return;
    }
    screen = SDL_CreateWindowFrom((void *)ui.label->winId());
    if (screen == NULL)
    {
        printf("Could not create window - %s\n", SDL_GetError());
        return;
    }
    sdlRenderer = SDL_CreateRenderer(screen, -1, 0);
    sdlTexture = SDL_CreateTexture(sdlRenderer, SDL_PIXELFORMAT_IYUV, SDL_TEXTUREACCESS_STREAMING, pCodecCtx->width, pCodecCtx->height);
    sdlRect.x = 0;
    sdlRect.y = 0;
    sdlRect.w = pCodecCtx->width;
    sdlRect.h = pCodecCtx->height;
    //end SDL-----------------------
    //av_read_frame读取一帧未解码的数据
    while (av_read_frame(pFormatCtx, packet) >= 0){
        //如果是视频数据
        if (packet->stream_index == videoindex){
            //解码一帧视频数据
            ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, packet);
            if (ret < 0){
                printf("Decode Error.\n");
                return;
            }
            if (got_picture){
                sws_scale(img_convert_ctx, (const unsigned char* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height,
                    pFrameYUV->data, pFrameYUV->linesize);
                SDL_UpdateYUVTexture(sdlTexture, &sdlRect,
                    pFrameYUV->data[0], pFrameYUV->linesize[0],
                    pFrameYUV->data[1], pFrameYUV->linesize[1],
                    pFrameYUV->data[2], pFrameYUV->linesize[2]);
                SDL_RenderClear(sdlRenderer);
                SDL_RenderCopy(sdlRenderer, sdlTexture, NULL, &sdlRect);
                SDL_RenderPresent(sdlRenderer);
                SDL_Delay(40);
            }
        }
        av_free_packet(packet);
    }
    sws_freeContext(img_convert_ctx);
    av_frame_free(&pFrameYUV);
    av_frame_free(&pFrame);
    avcodec_close(pCodecCtx);
    avformat_close_input(&pFormatCtx);
}