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企业网站建设兴田德润地址,城乡与建设厅网站,排名优化公司哪家好,创建游戏网站FFmpeg入门：最简单的视频播放器 FFmpeg入门第一篇，制作一个简单的MP4视频播放器。整体流程话不多说，直接上流程图视频播放速率控制这里可以直接看图中的帧率同步模块，可以分为如下几步获取到当前帧的预期播放时间&…

FFmpeg入门：最简单的视频播放器

FFmpeg入门第一篇，制作一个简单的MP4视频播放器。

整体流程

话不多说，直接上流程图在这里插入图片描述

视频播放速率控制

这里可以直接看图中的帧率同步模块，可以分为如下几步

获取到当前帧的预期播放时间：根据时间基time_base和帧pts计算；time_base*pts；
解码渲染过程中，获取当前时间av_gettime，计算和预期播放时间的时间差；
使用SDL_Delay函数延迟播放时间差。

源代码

tutorial01.h

//
//  tutorial02.h
//  tutorial02
//
//  Created by chenhuaiyi on 2025/2/13.
//#ifndef tutorial02_h
#define tutorial02_h#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#include <libavutil/imgutils.h>
#include <libavutil/time.h>#include <SDL.h>
#include <SDL_thread.h>#include <stdio.h>/**宏定义*/
#define SFM_REFRESH_EVENT (SDL_USEREVENT+1)/**全局变量*/
extern int            thread_exit;/**方法声明*/
char* get_frame_type(AVFrame* frame);#endif /* tutorial02_h */

tutorial02.c

// tutorial02.c
// A pedagogical video player that will stream through every video frame as fast as it can.#ifdef __MINGW32__
#undef main /* Prevents SDL from overriding main() */
#endif#include "tutorial02.h"// 控制程序是否结束
int		thread_exit=0;/**获取帧类型*/
char* get_frame_type(AVFrame* frame) {switch (frame->pict_type) {case AV_PICTURE_TYPE_I:return "I";break;case AV_PICTURE_TYPE_P:return "P";break;case AV_PICTURE_TYPE_B:return "B";break;case AV_PICTURE_TYPE_S:return "S";break;case AV_PICTURE_TYPE_SI:return "SI";break;case AV_PICTURE_TYPE_SP:return "SP";break;case AV_PICTURE_TYPE_BI:return "BI";break;default:return "N";break;}
}int main(int argc, char *argv[]) {AVFormatContext*  pFormatCtx = NULL;int               i, videoStream;AVCodecContext*   pCodecCtx = avcodec_alloc_context3(NULL);;AVCodecParameters*  pCodecParam = NULL;const AVCodec*    pCodec = NULL;AVFrame*          pFrame = NULL;AVFrame*          pFrame2 = NULL;AVPacket          packet;AVDictionary*     optionsDict = NULL;struct SwsContext*  sws_ctx = NULL;SDL_Window*       window = NULL;SDL_Renderer*     renderer = NULL;SDL_Texture*      texture=NULL;SDL_Rect          rect;SDL_Event         event;if(argc < 2) {fprintf(stderr, "Usage: test <file>\n");exit(1);}// SDL组件创建if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) {fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError());exit(1);}// 1. 打开视频文件，获取格式上下文if(avformat_open_input(&pFormatCtx, argv[1], NULL, NULL)!=0)return -1; // Couldn't open file// 2. 对文件探测流信息if(avformat_find_stream_info(pFormatCtx, NULL)<0)return -1; // Couldn't find stream information// 打印信息av_dump_format(pFormatCtx, 0, argv[1], 0);// 3.找到对应的视频流videoStream=-1;for(i=0; i<pFormatCtx->nb_streams; i++)if(pFormatCtx->streams[i]->codecpar->codec_type==AVMEDIA_TYPE_VIDEO) {videoStream=i;break;}if(videoStream==-1){return -1; // Didn't find a video stream}// 4. 将视频流编码参数写入上下文pCodecParam = pFormatCtx->streams[videoStream]->codecpar;avcodec_parameters_to_context(pCodecCtx, pCodecParam);// 5. 查找流的编码器pCodec=avcodec_find_decoder(pCodecCtx->codec_id);if(pCodec==NULL) {fprintf(stderr, "Unsupported codec!\n");return -1; // Codec not found}// 6. 打开流的编解码器if(avcodec_open2(pCodecCtx, pCodec, &optionsDict)<0)return -1; // Could not open codec// 7.申请缩放颜色空间格式的上下文sws_ctx =sws_getContext(pCodecCtx->width,pCodecCtx->height,pCodecCtx->pix_fmt,pCodecCtx->width,pCodecCtx->height,AV_PIX_FMT_YUV420P,SWS_BILINEAR,NULL,NULL,NULL);// 8.帧分配pFrame=av_frame_alloc();pFrame2=av_frame_alloc();// 9.计算并分配frame帧所占内存空间int numBytes=av_image_get_buffer_size(AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height, 1);uint8_t* buffer=(uint8_t*)av_malloc(numBytes*sizeof(uint8_t));av_image_fill_arrays(pFrame2->data, pFrame2->linesize, buffer, AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height, 1);i=0;Uint32 start_time = SDL_GetTicks();// SDL2的最新创建和渲染窗口方式window = SDL_CreateWindow("SDL2 window", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, pCodecCtx->width, pCodecCtx->height, SDL_WINDOW_SHOWN);if (!window) {printf("SDL_CreateWindow Error: %s\n", SDL_GetError());SDL_Quit();return 1;}renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);if (!renderer) {printf("SDL_CreateRenderer Error: %s\n", SDL_GetError());SDL_DestroyWindow(window);SDL_Quit();return 1;}texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_YV12, SDL_TEXTUREACCESS_STREAMING, pCodecCtx->width, pCodecCtx->height);AVRational time_base = pFormatCtx->streams[videoStream]->time_base;int64_t av_start_time = av_gettime();								// 播放开始时间int64_t frame_delay = av_q2d(time_base) * AV_TIME_BASE;				// pts单位(ms*1000)int64_t frame_start_time = av_gettime();// 循环一：对文件上下文持续读取packetwhile(av_read_frame(pFormatCtx, &packet)>=0) {if(packet.stream_index==videoStream) {// 将packet写入编解码器int ret = avcodec_send_packet(pCodecCtx, &packet);if (ret < 0) {printf("packet resolve error!");break;}// 循环二：从解码器中不断读取帧while(!avcodec_receive_frame(pCodecCtx, pFrame)) { // 解码得到数据frame// 帧格式转化，转为YUV420Psws_scale(sws_ctx,(uint8_t const * const *)pFrame->data,pFrame->linesize,0,pCodecCtx->height,pFrame2->data,pFrame2->linesize);// 将AVFrame的数据写入到texture中，然后渲染后windows上rect.x = 0;rect.y = 0;rect.w = pCodecCtx->width;rect.h = pCodecCtx->height;// 更新纹理SDL_UpdateYUVTexture(texture, &rect,pFrame2->data[0], pFrame2->linesize[0],	// 	YpFrame2->data[1], pFrame2->linesize[1],	// 	UpFrame2->data[2], pFrame2->linesize[2]);	//  V// 渲染页面SDL_RenderClear(renderer);SDL_RenderCopy(renderer, texture, NULL, NULL);SDL_RenderPresent(renderer);int64_t pts = pFrame->pts;											// ptsint64_t actual_playback_time = av_start_time + pts * frame_delay;	// 实际播放时间int64_t current_time = av_gettime();if (actual_playback_time > current_time) {SDL_Delay((Uint32)(actual_playback_time-current_time)/1000);	// 延迟当前时间和实际播放时间}i++;printf("第%i帧 | 属于%s | pts为%d | 时长为%.2fms | 实际播放点为%.2fs | 预期播放点为%.2fs\n ",i,get_frame_type(pFrame),(int)pFrame->pts,(double)(av_gettime() - frame_start_time)/1000,(double)(av_gettime() - av_start_time)/AV_TIME_BASE,pFrame->pts * av_q2d(time_base));frame_start_time = av_gettime();}}// Free the packet that was allocated by av_read_frameav_packet_unref(&packet);SDL_PollEvent(&event);switch(event.type) {case SDL_QUIT:SDL_Quit();exit(0);break;default:break;}}Uint32 endTime = SDL_GetTicks();/**打印一些关键参数*/printf("格式: %s\n", pFormatCtx->iformat->name);printf("时长: %lld us\n", pFormatCtx->duration);printf("编码器: %s (%s)\n", pCodec->name, avcodec_get_name(pCodecCtx->codec_id));printf("分辨率: %dx%d\n", pCodecCtx->width, pCodecCtx->height);printf("帧率: %.2f\n", av_q2d(pFormatCtx->streams[videoStream]->avg_frame_rate));printf("帧数: %lld\n", pFormatCtx->streams[videoStream]->nb_frames);printf("比特率: %lld\n", pFormatCtx->bit_rate);printf("pts单位(ms*1000): %.2f\n", av_q2d(pFormatCtx->streams[videoStream]->time_base) * AV_TIME_BASE);printf("视频持续时长为 %d，视频帧总数为 %d\n", (endTime-start_time)/1000, i);// Free the YUV frameav_free(pFrame);av_free(pFrame2);// Close the codec paramavcodec_parameters_free(&pCodecParam);// Close the codecavcodec_free_context(&pCodecCtx);// Close the video fileavformat_close_input(&pFormatCtx);return 0;
}