sdl2_mmpeg.cpp

// g++ main.cpp -o video_player -lSDL2 -lavformat -lavcodec -lavutil -lswscale


#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>
extern "C" {
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
}

int main(int argc, char* argv[]) {
    if (argc != 2) {
        std::cout << "Usage: " << argv[0] << " <video_file_path>\n";
        return 1;
    }

    const char* videoFilePath = argv[1];

    // Initialize SDL
    if (SDL_Init(SDL_INIT_VIDEO) != 0) {
        std::cerr << "SDL_Init error: " << SDL_GetError() << std::endl;
        return 1;
    }

    // Create SDL window and renderer
    SDL_Window* window = SDL_CreateWindow("Video Player", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
                                          640, 480, SDL_WINDOW_SHOWN);
    if (window == nullptr) {
        std::cerr << "SDL_CreateWindow error: " << SDL_GetError() << std::endl;
        SDL_Quit();
        return 1;
    }

    SDL_Renderer* renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
    if (renderer == nullptr) {
        std::cerr << "SDL_CreateRenderer error: " << SDL_GetError() << std::endl;
        SDL_DestroyWindow(window);
        SDL_Quit();
        return 1;
    }

    // Initialize FFmpeg
    av_register_all();
    avformat_network_init();

    AVFormatContext* formatContext = nullptr;
    if (avformat_open_input(&formatContext, videoFilePath, nullptr, nullptr) != 0) {
        std::cerr << "Could not open video file" << std::endl;
        SDL_DestroyRenderer(renderer);
        SDL_DestroyWindow(window);
        SDL_Quit();
        return 1;
    }

    if (avformat_find_stream_info(formatContext, nullptr) < 0) {
        std::cerr << "Could not find stream information" << std::endl;
        avformat_close_input(&formatContext);
        SDL_DestroyRenderer(renderer);
        SDL_DestroyWindow(window);
        SDL_Quit();
        return 1;
    }

    // Find the first video stream
    int videoStreamIndex = -1;
    for (unsigned int i = 0; i < formatContext->nb_streams; i++) {
        if (formatContext->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
            videoStreamIndex = i;
            break;
        }
    }

    if (videoStreamIndex == -1) {
        std::cerr << "Could not find video stream" << std::endl;
        avformat_close_input(&formatContext);
        SDL_DestroyRenderer(renderer);
        SDL_DestroyWindow(window);
        SDL_Quit();
        return 1;
    }

    // Get video codec context
    AVCodecContext* codecContext = avcodec_alloc_context3(nullptr);
    if (codecContext == nullptr) {
        std::cerr << "Could not allocate video codec context" << std::endl;
        avformat_close_input(&formatContext);
        SDL_DestroyRenderer(renderer);
        SDL_DestroyWindow(window);
        SDL_Quit();
        return 1;
    }

    avcodec_parameters_to_context(codecContext, formatContext->streams[videoStreamIndex]->codecpar);
    AVCodec* codec = avcodec_find_decoder(codecContext->codec_id);
    if (codec == nullptr) {
        std::cerr << "Codec not found" << std::endl;
        avcodec_free_context(&codecContext);
        avformat_close_input(&formatContext);
        SDL_DestroyRenderer(renderer);
        SDL_DestroyWindow(window);
        SDL_Quit();
        return 1;
    }

    if (avcodec_open2(codecContext, codec, nullptr) < 0) {
        std::cerr << "Could not open codec" << std::endl;
        avcodec_free_context(&codecContext);
        avformat_close_input(&formatContext);
        SDL_DestroyRenderer(renderer);
        SDL_DestroyWindow(window);
        SDL_Quit();
        return 1;
    }

    // Allocate video frame and buffer
    AVFrame* frame = av_frame_alloc();
    if (frame == nullptr) {
        std::cerr << "Could not allocate video frame" << std::endl;
        avcodec_free_context(&codecContext);
        avformat_close_input(&formatContext);
        SDL_DestroyRenderer(renderer);
        SDL_DestroyWindow(window);
        SDL_Quit();
        return 1;
    }

    uint8_t* buffer = static_cast<uint8_t*>(av_malloc(av_image_get_buffer_size(
        AV_PIX_FMT_RGB24, codecContext->width, codecContext->height, 1)));
    AVFrame* rgbFrame = av_frame_alloc();
    if (buffer == nullptr || rgbFrame == nullptr) {
        std::cerr << "Could not allocate frame buffer" << std::endl;
        av_free(buffer);
        av_frame_free(&rgbFrame);
        av_frame_free(&frame);
        avcodec_free_context(&codecContext);
        avformat_close_input(&formatContext);
        SDL_DestroyRenderer(renderer);
        SDL_DestroyWindow(window);
        SDL_Quit();
        return 1;
    }

    av_image_fill_arrays(rgbFrame->data, rgbFrame->linesize, buffer, AV_PIX_FMT_RGB24, codecContext->width,
                         codecContext->height, 1);

    // Initialize SwsContext for color conversion
    SwsContext* swsContext = sws_getContext(codecContext->width, codecContext->height, codecContext->pix_fmt,
                                            codecContext->width, codecContext->height, AV_PIX_FMT_RGB24,
                                            SWS_BILINEAR, nullptr, nullptr, nullptr);
    if (swsContext == nullptr) {
        std::cerr << "Could not initialize color conversion context" << std::endl;
        av_free(buffer);
        av_frame_free(&rgbFrame);
        av_frame_free(&frame);
        avcodec_free_context(&codecContext);
        avformat_close_input(&formatContext);
        SDL_DestroyRenderer(renderer);
        SDL_DestroyWindow(window);
        SDL_Quit();
        return 1;
    }

    // Main loop to read and render video frames
    AVPacket packet;
    SDL_Texture* texture = nullptr;
    SDL_Event event;
    int quit = 0;
    while (av_read_frame(formatContext, &packet) >= 0 && !quit) {
        if (packet.stream_index == videoStreamIndex) {
            avcodec_send_packet(codecContext, &packet);
            avcodec_receive_frame(codecContext, frame);

            // Convert the frame to RGB24
            sws_scale(swsContext, frame->data, frame->linesize, 0, codecContext->height, rgbFrame->data,
                      rgbFrame->linesize);

            // Create the texture if it's not created yet
            if (texture == nullptr) {
                texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_RGB24, SDL_TEXTUREACCESS_STREAMING,
                                            codecContext->width, codecContext->height);
                if (texture == nullptr) {
                    std::cerr << "Could not create SDL texture: " << SDL_GetError() << std::endl;
                    quit = 1;
                }
            }

            // Update texture with the new frame data
            SDL_UpdateTexture(texture, nullptr, rgbFrame->data[0], rgbFrame->linesize[0]);

            // Clear the screen and render the texture
            SDL_RenderClear(renderer);
            SDL_RenderCopy(renderer, texture, nullptr, nullptr);
            SDL_RenderPresent(renderer);
        }

        // Handle quit event
        while (SDL_PollEvent(&event)) {
            if (event.type == SDL_QUIT) {
                quit = 1;
            }
        }

        av_packet_unref(&packet);
    }

    // Clean up resources
    av_free(buffer);
    av_frame_free(&rgbFrame);
    av_frame_free(&frame);
    avcodec_free_context(&codecContext);
    avformat_close_input(&formatContext);
    sws_freeContext(swsContext);
    if (texture != nullptr) {
        SDL_DestroyTexture(texture);
    }
    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(window);
    SDL_Quit();
    return 0;
}