前言
SDL中內置加載BMP的API，使用起來會更加簡單，便于初學者學習使用SDL
如果需要加載JPG、PNG等其他格式的圖片，可以使用第三方庫：SDL_image
測試環境：
- ffmpeg的4.3.2自行編譯版本
- windows環境
- qt5.12
- sdl2.0.22（mingw編譯器）
顯示yuv圖片需要知道yuv圖片的尺寸和采樣格式
ffplay -video_size 564x513 -pixel_format yuv420p out.yuv
完整代碼：
SdlShowYuvThread.h
#ifndef SDLSHOWYUVTHREAD_H
#define SDLSHOWYUVTHREAD_H#include <QObject>
#include <QThread>class SdlShowYuvThread : public QThread
{Q_OBJECT
public:explicit SdlShowYuvThread(QObject *parent = nullptr);~SdlShowYuvThread();signals:// QThread interface
protected:virtual void run() override;
};#endif // SDLSHOWYUVTHREAD_H
SdlShowYuvThread.cpp
#include "sdlshowyuvthread.h"#include <SDL2/SDL.h>
#include <QDebug>
#include <QFile>#define END(judge, func) \if (judge) { \qDebug() << #func << "error" << SDL_GetError(); \goto end; \}#define FILENAME "E:/media/picture-test-yuv420p.yuv"
#define PIXEL_FORMAT SDL_PIXELFORMAT_IYUV
#define IMG_W 1928
#define IMG_H 1048SdlShowYuvThread::SdlShowYuvThread(QObject *parent) : QThread(parent)
{// 當監聽到線程結束時（finished），就調用deleteLater回收內存connect(this,&SdlShowYuvThread::finished,this,[=](){this->deleteLater();qDebug()<<"SdlShowYuvThread線程結束";});
}SdlShowYuvThread::~SdlShowYuvThread()
{// 斷開所有的連接disconnect();// 內存回收之前，正常結束線程requestInterruption();// 安全退出quit();wait();qDebug() << this << "析構（內存被回收）";
}void SdlShowYuvThread::run()
{// 窗口SDL_Window *window = nullptr;// 渲染上下文SDL_Renderer *renderer = nullptr;// 紋理（直接跟特定驅動程序相關的像素數據）SDL_Texture *texture = nullptr;// 文件QFile file(FILENAME);// 初始化子系統END(SDL_Init(SDL_INIT_VIDEO), SDL_Init);// 創建窗口window = SDL_CreateWindow(// 標題"SDL顯示YUV圖片",// xSDL_WINDOWPOS_UNDEFINED,// ySDL_WINDOWPOS_UNDEFINED,// wIMG_W,// hIMG_H,SDL_WINDOW_SHOWN);END(!window, SDL_CreateWindow);// 創建渲染上下文renderer = SDL_CreateRenderer(window, -1,SDL_RENDERER_ACCELERATED |SDL_RENDERER_PRESENTVSYNC);if (!renderer) {renderer = SDL_CreateRenderer(window, -1, 0);END(!renderer, SDL_CreateRenderer);}// 創建紋理texture = SDL_CreateTexture(renderer,PIXEL_FORMAT,SDL_TEXTUREACCESS_STREAMING,IMG_W, IMG_H);END(!texture, SDL_CreateTexture);// 打開文件if (!file.open(QFile::ReadOnly)) {qDebug() << "file open error" << FILENAME;goto end;}// 將YUV的像素數據填充到textureEND(SDL_UpdateTexture(texture, nullptr, file.readAll().data(), IMG_W),SDL_UpdateTexture);// 設置繪制顏色（畫筆顏色）END(SDL_SetRenderDrawColor(renderer,0, 0, 0, SDL_ALPHA_OPAQUE),SDL_SetRenderDrawColor);// 用繪制顏色（畫筆顏色）清除渲染目標END(SDL_RenderClear(renderer),SDL_RenderClear);// 拷貝紋理數據到渲染目標（默認是window）END(SDL_RenderCopy(renderer, texture, nullptr, nullptr),SDL_RenderCopy);// 更新所有的渲染操作到屏幕上SDL_RenderPresent(renderer);// 等待退出事件while (!isInterruptionRequested()) {SDL_Event event;SDL_WaitEvent(&event);switch (event.type) {case SDL_QUIT:goto end;}}end:file.close();SDL_DestroyTexture(texture);SDL_DestroyRenderer(renderer);SDL_DestroyWindow(window);SDL_Quit();
}
線程調用：
void MainWindow::on_pushButton_sdl_show_yuv_clicked()
{m_pSdlShowYuvThread=new SdlShowYuvThread(this);m_pSdlShowYuvThread->start();
}
注意：.h文件中提前聲明了以下全局變量
SdlShowYuvThread *m_pSdlShowYuvThread=nullptr;
注意：本文為個人記錄，新手照搬可能會出現各種問題，請謹慎使用
碼字不易，如果這篇博客對你有幫助，麻煩點贊收藏，非常感謝！有不對的地方
