SDL2.0 渲染 yuv4.0

SDL2.0 支持渲染 YUV4:2:0 格式的视频，需要使用 SDL_Texture 和 SDL_RenderCopy 函数来实现。

以下是一个简单的示例代码：

#include <SDL2/SDL.h>
#include <stdio.h>

const int SCREEN_WIDTH = 640;
const int SCREEN_HEIGHT = 480;

int main(int argc, char* argv[])
{
    SDL_Window* window = NULL;
    SDL_Renderer* renderer = NULL;
    SDL_Texture* texture = NULL;

    if (SDL_Init(SDL_INIT_VIDEO) < 0)
    {
        printf("SDL could not initialize! SDL_Error: %s\n", SDL_GetError());
        return 1;
    }

    window = SDL_CreateWindow("YUV4:2:0 Video", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
    if (window == NULL)
    {
        printf("Window could not be created! SDL_Error: %s\n", SDL_GetError());
        return 1;
    }

    renderer = SDL_CreateRenderer(window, -1, 0);
    if (renderer == NULL)
    {
        printf("Renderer could not be created! SDL_Error: %s\n", SDL_GetError());
        return 1;
    }

    texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_YV12, SDL_TEXTUREACCESS_STREAMING, SCREEN_WIDTH, SCREEN_HEIGHT);
    if (texture == NULL)
    {
        printf("Texture could not be created! SDL_Error: %s\n", SDL_GetError());
        return 1;
    }

    // YUV data
    Uint8* yPlane = NULL;
    Uint8* uPlane = NULL;
    Uint8* vPlane = NULL;
    int yPitch = 0;
    int uPitch = 0;
    int vPitch = 0;
    int w = 0;
    int h = 0;

    // read YUV file
    FILE* fp = fopen("video.yuv", "rb");
    if (fp == NULL)
    {
        printf("Could not open YUV file!\n");
        return 1;
    }

    // allocate memory for YUV data
    int bufferSize = SCREEN_WIDTH * SCREEN_HEIGHT * 3 / 2;
    Uint8* buffer = (Uint8*)malloc(bufferSize);

    // main loop
    SDL_Event event;
    bool quit = false;
    while (!quit)
    {
        while (SDL_PollEvent(&event))
        {
            if (event.type == SDL_QUIT)
            {
                quit = true;
            }
        }

        // read YUV data
        if (fread(buffer, 1, bufferSize, fp) != bufferSize)
        {
            // end of file
            rewind(fp);
        }

        // set YUV data
        yPlane = buffer;
        uPlane = yPlane + SCREEN_WIDTH * SCREEN_HEIGHT;
        vPlane = uPlane + SCREEN_WIDTH * SCREEN_HEIGHT / 4;
        yPitch = SCREEN_WIDTH;
        uPitch = SCREEN_WIDTH / 2;
        vPitch = SCREEN_WIDTH / 2;
        w = SCREEN_WIDTH;
        h = SCREEN_HEIGHT;

        // update texture
        SDL_UpdateYUVTexture(texture, NULL, yPlane, yPitch, uPlane, uPitch, vPlane, vPitch);

        // clear screen
        SDL_SetRenderDrawColor(renderer, 0xFF, 0xFF, 0xFF, 0xFF);
        SDL_RenderClear(renderer);

        // render texture
        SDL_RenderCopy(renderer, texture, NULL, NULL);

        // update screen
        SDL_RenderPresent(renderer);
    }

    // free memory
    free(buffer);

    // cleanup
    SDL_DestroyTexture(texture);
    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(window);
    SDL_Quit();

    return 0;
}

在代码中，我们首先创建一个 SDL 窗口和渲染器。然后，使用 SDL_CreateTexture 函数创建一个 YV12 格式的纹理。接下来，读取 YUV 文件，并将数据设置到纹理中。在主循环中，使用 SDL_RenderCopy 函数将纹理渲染到屏幕上。最后，记得在程序结束前释放所有内存和资源。