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【FFmpeg+SDL】使用FFmpeg捕获屏幕，SDL显示

news 2025/5/16 7:50:10

FFMpeg版本:7.1.1

SDL版本:2.32.6

直接上代码,工程文件放在最后

其中的define TT是显示窗口和屏幕像素大小的比例,如果按屏幕原本大小显示,不太好观察.
(命名不规范,define这样用也不太安全,不建议这样,我是为了方便观察随便搞的)

#include <iostream>extern "C" {
#include <libavdevice/avdevice.h>
#include <libavformat/avformat.h>
#include <libavcodec/avcodec.h>
#include <libswscale/swscale.h>
#include <libavutil/mem.h>
#include <libavutil/imgutils.h>
#include "SDL2/SDL.h"
}
#undef main#define TT *9/10int main()
{AVFormatContext *fmt_ctx = NULL;AVCodecContext *codec_ctx = NULL;int video_stream_index = -1;SDL_Window *window = NULL;SDL_Renderer *renderer = NULL;SDL_Texture *texture = NULL;struct SwsContext *sws_ctx = NULL;AVFrame *frame = NULL;AVPacket pkt;avdevice_register_all();avformat_network_init();AVDictionary *options = NULL;if (avformat_open_input(&fmt_ctx, "desktop", av_find_input_format("gdigrab"), &options) < 0){fprintf(stderr, "无法打开输入设备\n");return -1;}// 获取流信息if (avformat_find_stream_info(fmt_ctx, NULL) < 0) {fprintf(stderr, "无法获取流信息\n");avformat_close_input(&fmt_ctx);return -1;}// 查找视频流for (int i = 0; i < fmt_ctx->nb_streams; i++) {if (fmt_ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {video_stream_index = i;break;}}if (video_stream_index == -1) {fprintf(stderr, "未找到视频流\n");avformat_close_input(&fmt_ctx);return -1;}// 获取编解码参数并创建解码器上下文AVCodecParameters *codec_par = fmt_ctx->streams[video_stream_index]->codecpar;const AVCodec *codec = avcodec_find_decoder(codec_par->codec_id);if (!codec) {fprintf(stderr, "解码器未找到\n");avformat_close_input(&fmt_ctx);return -1;}printf("%s\n", avcodec_get_name(codec_par->codec_id));codec_ctx = avcodec_alloc_context3(codec);if (avcodec_parameters_to_context(codec_ctx, codec_par) < 0) {fprintf(stderr, "无法复制编解码参数\n");avcodec_free_context(&codec_ctx);avformat_close_input(&fmt_ctx);return -1;}if (avcodec_open2(codec_ctx, codec, NULL) < 0) {fprintf(stderr, "无法打开解码器\n");avcodec_free_context(&codec_ctx);avformat_close_input(&fmt_ctx);return -1;}// 初始化SDLif (SDL_Init(SDL_INIT_VIDEO) < 0) {fprintf(stderr, "SDL初始化失败: %s\n", SDL_GetError());avcodec_free_context(&codec_ctx);avformat_close_input(&fmt_ctx);return -1;}window = SDL_CreateWindow("桌面捕获", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,codec_ctx->width TT, codec_ctx->height TT, SDL_WINDOW_SHOWN);if (!window) {fprintf(stderr, "无法创建窗口: %s\n", SDL_GetError());SDL_Quit();avcodec_free_context(&codec_ctx);avformat_close_input(&fmt_ctx);return -1;}renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);if (!renderer) {fprintf(stderr, "无法创建渲染器: %s\n", SDL_GetError());SDL_DestroyWindow(window);SDL_Quit();avcodec_free_context(&codec_ctx);avformat_close_input(&fmt_ctx);return -1;}// 根据FFmpeg的像素格式设置SDL纹理格式Uint32 sdl_pix_fmt;AVPixelFormat ffmpeg_pix_fmt = codec_ctx->pix_fmt;if (ffmpeg_pix_fmt == AV_PIX_FMT_BGRA) {sdl_pix_fmt = SDL_PIXELFORMAT_ARGB8888;}else {// 需要转换到支持的格式，此处示例转换为RGB24sdl_pix_fmt = SDL_PIXELFORMAT_RGB24;sws_ctx = sws_getContext(codec_ctx->width, codec_ctx->height, ffmpeg_pix_fmt,codec_ctx->width TT, codec_ctx->height TT, AV_PIX_FMT_RGB24,SWS_BILINEAR, NULL, NULL, NULL);}texture = SDL_CreateTexture(renderer, sdl_pix_fmt,SDL_TEXTUREACCESS_STREAMING,codec_ctx->width, codec_ctx->height);if (!texture) {fprintf(stderr, "无法创建纹理: %s\n", SDL_GetError());SDL_DestroyRenderer(renderer);SDL_DestroyWindow(window);SDL_Quit();avcodec_free_context(&codec_ctx);avformat_close_input(&fmt_ctx);return -1;}frame = av_frame_alloc();if (!frame) {fprintf(stderr, "无法分配帧\n");SDL_DestroyTexture(texture);SDL_DestroyRenderer(renderer);SDL_DestroyWindow(window);SDL_Quit();avcodec_free_context(&codec_ctx);avformat_close_input(&fmt_ctx);return -1;}SDL_Event event;int quit = 0;while (!quit) {// 处理SDL事件while (SDL_PollEvent(&event)) {if (event.type == SDL_QUIT) {quit = 1;}}if (av_read_frame(fmt_ctx, &pkt) < 0) {break; // 结束读取}if (pkt.stream_index == video_stream_index) {// 发送数据包到解码器if (avcodec_send_packet(codec_ctx, &pkt) < 0) {fprintf(stderr, "发送数据包失败\n");av_packet_unref(&pkt);continue;}// 接收解码后的帧while (avcodec_receive_frame(codec_ctx, frame) == 0) {// 转换帧格式（如果需要）if (sws_ctx) {AVFrame *rgb_frame = av_frame_alloc();rgb_frame->format = AV_PIX_FMT_RGB24;rgb_frame->width = frame->width TT;rgb_frame->height = frame->height TT;av_frame_get_buffer(rgb_frame, 0);sws_scale(sws_ctx, frame->data, frame->linesize, 0, frame->height,rgb_frame->data, rgb_frame->linesize);// 更新纹理SDL_UpdateTexture(texture, NULL, rgb_frame->data[0], rgb_frame->linesize[0]);av_frame_free(&rgb_frame);}else {// 直接使用原始数据SDL_UpdateTexture(texture, NULL, frame->data[0], frame->linesize[0]);}// 渲染SDL_RenderClear(renderer);SDL_RenderCopy(renderer, texture, NULL, NULL);SDL_RenderPresent(renderer);}}av_packet_unref(&pkt);}// 清理资源av_frame_free(&frame);sws_freeContext(sws_ctx);SDL_DestroyTexture(texture);SDL_DestroyRenderer(renderer);SDL_DestroyWindow(window);SDL_Quit();avcodec_free_context(&codec_ctx);avformat_close_input(&fmt_ctx);}

链接: https://pan.baidu.com/s/1J2v6pXlkPZJ2r3psVbQX0A?pwd=c4p7 提取码: c4p7

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