音视频（42-48）

注意本人的环境为qt6.11.1 ffmpeg-5.16.2 将dll拷贝到exe文件下进行调试#include stdio.h #include SDL2/SDL.h #undef main int main() { printf(Hello World!\n); SDL_Window *window NULL; // 声明窗口 SDL_Init(SDL_INIT_VIDEO); // 初始化SDL // 创建SDL Window window SDL_CreateWindow(Basic Window, SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 640, 480, SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE); if(!window) // 检测是否创建成功 { printf(Cant create window, err:%s\n, SDL_GetError()); return 1; } SDL_Delay(10000); // 延迟10000ms SDL_DestroyWindow(window); // 消耗窗口 SDL_Quit(); // 释放资源 return 0; }#include stdio.h #include SDL2/SDL.h #undef main int main() { int run 1; SDL_Window *window NULL; SDL_Renderer *renderer NULL; SDL_Texture *texture NULL; SDL_Rect rect; // 长方形原点在左上角 rect.w 50; //方块大小 rect.h 50; SDL_Init(SDL_INIT_VIDEO);//初始化函数,可以确定希望激活的子系统 window SDL_CreateWindow(2 Window, SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 640, 480, SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE);// 创建窗口 if (!window) { return -1; } renderer SDL_CreateRenderer(window, -1, 0);//基于窗口创建渲染器 if (!renderer) { return -1; } texture SDL_CreateTexture(renderer, SDL_PIXELFORMAT_RGBA8888, SDL_TEXTUREACCESS_TARGET, 640, 480); //创建纹理 if (!texture) { return -1; } int show_count 0; while (run) { rect.x rand() % 600; rect.y rand() % 400; SDL_SetRenderTarget(renderer, texture); // 设置渲染目标为纹理 SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255); // 纹理背景为黑色 SDL_RenderClear(renderer); //清屏 SDL_RenderDrawRect(renderer, rect); //绘制一个长方形 SDL_SetRenderDrawColor(renderer, 0, 255, 255, 255); //长方形为白色 SDL_RenderFillRect(renderer, rect); SDL_SetRenderTarget(renderer, NULL); //恢复默认渲染目标为窗口 SDL_RenderCopy(renderer, texture, NULL, NULL); //拷贝纹理到CPU SDL_RenderPresent(renderer); //输出到目标窗口上 SDL_Delay(300); if(show_count 30) { run 0; // 不跑了 } } SDL_DestroyTexture(texture); SDL_DestroyRenderer(renderer); SDL_DestroyWindow(window); //销毁窗口 SDL_Quit(); return 0; }#include SDL2/SDL.h #include stdio.h #define FF_QUIT_EVENT (SDL_USEREVENT 2) // 用户自定义事件 #undef main int main(int argc, char* argv[]) { SDL_Window *window NULL; // Declare a pointer SDL_Renderer *renderer NULL; SDL_Init(SDL_INIT_VIDEO); // Initialize SDL2 // Create an application window with the following settings: window SDL_CreateWindow( An SDL2 window, // window title SDL_WINDOWPOS_UNDEFINED, // initial x position SDL_WINDOWPOS_UNDEFINED, // initial y position 640, // width, in pixels 480, // height, in pixels SDL_WINDOW_SHOWN | SDL_WINDOW_BORDERLESS// flags - see below ); // Check that the window was successfully created if (window NULL) { // In the case that the window could not be made... printf(Could not create window: %s\n, SDL_GetError()); return 1; } /* We must call SDL_CreateRenderer in order for draw calls to affect this window. */ renderer SDL_CreateRenderer(window, -1, 0); /* Select the color for drawing. It is set to red here. */ SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255); /* Clear the entire screen to our selected color. */ SDL_RenderClear(renderer); /* Up until now everything was drawn behind the scenes. This will show the new, red contents of the window. */ SDL_RenderPresent(renderer); SDL_Event event; int b_exit 0; for (;;) { SDL_WaitEvent(event); switch (event.type) { case SDL_KEYDOWN: /* 键盘事件 */ switch (event.key.keysym.sym) { case SDLK_a: printf(key down a\n); break; case SDLK_s: printf(key down s\n); break; case SDLK_d: printf(key down d\n); break; case SDLK_q: printf(key down q and push quit event\n); SDL_Event event_q; event_q.type FF_QUIT_EVENT; SDL_PushEvent(event_q); break; default: printf(key down 0x%x\n, event.key.keysym.sym); break; } break; case SDL_MOUSEBUTTONDOWN: /* 鼠标按下事件 */ if (event.button.button SDL_BUTTON_LEFT) { printf(mouse down left\n); } else if(event.button.button SDL_BUTTON_RIGHT) { printf(mouse down right\n); } else { printf(mouse down %d\n, event.button.button); } break; case SDL_MOUSEMOTION: /* 鼠标移动事件 */ printf(mouse movie (%d,%d)\n, event.button.x, event.button.y); break; case FF_QUIT_EVENT: printf(receive quit event\n); b_exit 1; break; } if(b_exit) break; } //destory renderer if (renderer) SDL_DestroyRenderer(renderer); // Close and destroy the window if (window) SDL_DestroyWindow(window); // Clean up SDL_Quit(); return 0; }45#include SDL2/SDL.h #include stdio.h SDL_mutex *s_lock NULL; SDL_cond *s_cond NULL; int thread_work(void *arg) { SDL_LockMutex(s_lock); printf( thread_work sleep\n); sleep(10); // 用来测试获取锁 printf( thread_work wait\n); // 释放s_lock资源并等待signal。之所以释放s_lock是让别的线程能够获取到s_lock SDL_CondWait(s_cond, s_lock); //另一个线程(1)发送signal和(2)释放lock后这个函数退出 printf( thread_work receive signal, continue to do ~_~!!!\n); printf( thread_work end\n); SDL_UnlockMutex(s_lock); return 0; } #undef main int main() { s_lock SDL_CreateMutex(); s_cond SDL_CreateCond(); SDL_Thread * t SDL_CreateThread(thread_work,thread_work,NULL); if(!t) { printf( %s,SDL_GetError); return -1; } for(int i 0;i 2;i) { sleep(2); printf(main execute \n); } printf(main SDL_LockMutex(s_lock) before \n); SDL_LockMutex(s_lock); // 获取锁但是子线程还拿着锁 printf(main ready send signal\n); printf(main SDL_CondSignal(s_cond) before \n); SDL_CondSignal(s_cond); // 发送信号唤醒等待的线程 printf(main SDL_CondSignal(s_cond) after \n); sleep(10); SDL_UnlockMutex(s_lock);// 释放锁让其他线程可以拿到锁 printf(main SDL_UnlockMutex(s_lock) after \n); SDL_WaitThread(t, NULL); SDL_DestroyMutex(s_lock); SDL_DestroyCond(s_cond); return 0; }#include stdio.h #include string.h #include SDL2/SDL.h //自定义消息类型 #define REFRESH_EVENT (SDL_USEREVENT 1) // 请求画面刷新事件 #define QUIT_EVENT (SDL_USEREVENT 2) // 退出事件 //定义分辨率 // YUV像素分辨率 #define YUV_WIDTH 320 #define YUV_HEIGHT 240 //定义YUV格式 #define YUV_FORMAT SDL_PIXELFORMAT_IYUV int s_thread_exit 0; // 退出标志 1则退出 int refresh_video_timer(void *data) { while (!s_thread_exit) { SDL_Event event; event.type REFRESH_EVENT; SDL_PushEvent(event); SDL_Delay(40); } s_thread_exit 0; //push quit event SDL_Event event; event.type QUIT_EVENT; SDL_PushEvent(event); return 0; } #undef main int main(int argc, char* argv[]) { //初始化 SDL if(SDL_Init(SDL_INIT_VIDEO)) { fprintf( stderr, Could not initialize SDL - %s\n, SDL_GetError()); return -1; } // SDL SDL_Event event; // 事件 SDL_Rect rect; // 矩形 SDL_Window *window NULL; // 窗口 SDL_Renderer *renderer NULL; // 渲染 SDL_Texture *texture NULL; // 纹理 SDL_Thread *timer_thread NULL; // 请求刷新线程 uint32_t pixformat YUV_FORMAT; // YUV420P即是SDL_PIXELFORMAT_IYUV // 分辨率 // 1. YUV的分辨率 int video_width YUV_WIDTH; int video_height YUV_HEIGHT; // 2.显示窗口的分辨率 int win_width YUV_WIDTH; int win_height YUV_WIDTH; // YUV文件句柄 FILE *video_fd NULL; const char *yuv_path E:/2025/ffmpeg/05-sdl-yuv/yuv420p_320x240.yuv; size_t video_buff_len 0; uint8_t *video_buf NULL; //读取数据后先把放到buffer里面 // 我们测试的文件是YUV420P格式 uint32_t y_frame_len video_width * video_height; uint32_t u_frame_len video_width * video_height / 4; uint32_t v_frame_len video_width * video_height / 4; uint32_t yuv_frame_len y_frame_len u_frame_len v_frame_len; //创建窗口 window SDL_CreateWindow(Simplest YUV Player, SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, video_width, video_height, SDL_WINDOW_OPENGL|SDL_WINDOW_RESIZABLE); if(!window) { fprintf(stderr, SDL: could not create window, err:%s\n,SDL_GetError()); goto _FAIL; } // 基于窗口创建渲染器 renderer SDL_CreateRenderer(window, -1, 0); // 基于渲染器创建纹理 texture SDL_CreateTexture(renderer, pixformat, SDL_TEXTUREACCESS_STREAMING, video_width, video_height); // 分配空间 video_buf (uint8_t*)malloc(yuv_frame_len); if(!video_buf) { fprintf(stderr, Failed to alloce yuv frame space!\n); goto _FAIL; } // 打开YUV文件 video_fd fopen(yuv_path, rb); if( !video_fd ) { fprintf(stderr, Failed to open yuv file\n); goto _FAIL; } // 创建请求刷新线程 timer_thread SDL_CreateThread(refresh_video_timer, NULL, NULL); while (1) { // 收取SDL系统里面的事件 SDL_WaitEvent(event); if(event.type REFRESH_EVENT) // 画面刷新事件 { video_buff_len fread(video_buf, 1, yuv_frame_len, video_fd); if(video_buff_len 0) { fprintf(stderr, Failed to read data from yuv file!\n); goto _FAIL; } // 设置纹理的数据 video_width 320 plane SDL_UpdateTexture(texture, NULL, video_buf, video_width); // 显示区域可以通过修改w和h进行缩放 rect.x 0; rect.y 0; float w_ratio win_width * 1.0 /video_width; float h_ratio win_height * 1.0 /video_height; // 320x240 怎么保持原视频的宽高比例 rect.w video_width * w_ratio; rect.h video_height * h_ratio; // rect.w video_width * 0.5; // rect.h video_height * 0.5; // 清除当前显示 SDL_RenderClear(renderer); // 将纹理的数据拷贝给渲染器 SDL_RenderCopy(renderer, texture, NULL, rect); // 显示 SDL_RenderPresent(renderer); } else if(event.type SDL_WINDOWEVENT) { //If Resize SDL_GetWindowSize(window, win_width, win_height); printf(SDL_WINDOWEVENT win_width:%d, win_height:%d\n,win_width, win_height ); } else if(event.type SDL_QUIT) //退出事件 { s_thread_exit 1; } else if(event.type QUIT_EVENT) { break; } } _FAIL: s_thread_exit 1; // 保证线程能够退出 // 释放资源 if(timer_thread) SDL_WaitThread(timer_thread, NULL); // 等待线程退出 if(video_buf) free(video_buf); if(video_fd) fclose(video_fd); if(texture) SDL_DestroyTexture(texture); if(renderer) SDL_DestroyRenderer(renderer); if(window) SDL_DestroyWindow(window); SDL_Quit(); return 0; }/** * SDL2播放PCM * * Darren 326873713 * 326873713qq.com * 腾讯课堂-零声学院https://ke.qq.com/course/468797 * * 本程序使用SDL2播放PCM音频采样数据。SDL实际上是对底层绘图 * APIDirect3DOpenGL的封装使用起来明显简单于直接调用底层 * API。 * 测试的PCM数据采用采样率44.1k, 采用精度S16SYS, 通道数2 * * 函数调用步骤如下: * * [初始化] * SDL_Init(): 初始化SDL。 * SDL_OpenAudio(): 根据参数存储于SDL_AudioSpec打开音频设备。 * SDL_PauseAudio(): 播放音频数据。 * * [循环播放数据] * SDL_Delay(): 延时等待播放完成。 * */ #include stdio.h #include SDL2/SDL.h // 每次读取2帧数据, 以1024个采样点一帧 2通道 16bit采样点为例 #define PCM_BUFFER_SIZE (1024*2*2*2) // 音频PCM数据缓存 static Uint8 *s_audio_buf NULL; // 目前读取的位置 static Uint8 *s_audio_pos NULL; // 缓存结束位置 static Uint8 *s_audio_end NULL; //音频设备回调函数 void fill_audio_pcm(void *udata, Uint8 *stream, int len) { SDL_memset(stream, 0, len); if(s_audio_pos s_audio_end) // 数据读取完毕 { return; } // 数据够了就读预设长度数据不够就只读部分不够的时候剩多少就读取多少 int remain_buffer_len s_audio_end - s_audio_pos; len (len remain_buffer_len) ? len : remain_buffer_len; // 拷贝数据到stream并调整音量 SDL_MixAudio(stream, s_audio_pos, len, SDL_MIX_MAXVOLUME/8); printf(len %d\n, len); s_audio_pos len; // 移动缓存指针 } // 提取PCM文件 // ffmpeg -i input.mp4 -t 20 -codec:a pcm_s16le -ar 44100 -ac 2 -f s16le 44100_16bit_2ch.pcm // 测试PCM文件 // ffplay -ar 44100 -ac 2 -f s16le 44100_16bit_2ch.pcm #undef main int main(int argc, char *argv[]) { int ret -1; FILE *audio_fd NULL; SDL_AudioSpec spec; const char *path E:/2025/ffmpeg/06-sdl-pcm/44100_16bit_2ch.pcm; // 每次缓存的长度 size_t read_buffer_len 0; //SDL initialize if(SDL_Init(SDL_INIT_AUDIO)) // 支持AUDIO { fprintf(stderr, Could not initialize SDL - %s\n, SDL_GetError()); return ret; } //打开PCM文件 audio_fd fopen(path, rb); if(!audio_fd) { fprintf(stderr, Failed to open pcm file!\n); goto _FAIL; } s_audio_buf (uint8_t *)malloc(PCM_BUFFER_SIZE); // 音频参数设置SDL_AudioSpec spec.freq 44100; // 采样频率 spec.format AUDIO_S16SYS; // 采样点格式 spec.channels 2; // 2通道 spec.silence 0; spec.samples 1024; // 23.2ms - 46.4ms 每次读取的采样数量多久产生一次回调和 samples spec.callback fill_audio_pcm; // 回调函数 spec.userdata NULL; //打开音频设备 if(SDL_OpenAudio(spec, NULL)) { fprintf(stderr, Failed to open audio device, %s\n, SDL_GetError()); goto _FAIL; } //play audio SDL_PauseAudio(0); int data_count 0; while(1) { // 从文件读取PCM数据 read_buffer_len fread(s_audio_buf, 1, PCM_BUFFER_SIZE, audio_fd); if(read_buffer_len 0) { break; } data_count read_buffer_len; // 统计读取的数据总字节数 printf(now playing %10d bytes data.\n,data_count); s_audio_end s_audio_buf read_buffer_len; // 更新buffer的结束位置 s_audio_pos s_audio_buf; // 更新buffer的起始位置 //the main thread wait for a moment while(s_audio_pos s_audio_end) { SDL_Delay(10); // 等待PCM数据消耗 } } printf(play PCM finish\n); // 关闭音频设备 SDL_CloseAudio(); _FAIL: //release some resources if(s_audio_buf) free(s_audio_buf); if(audio_fd) fclose(audio_fd); //quit SDL SDL_Quit(); return 0; }48