c++调用ffmpeg api将视频文件内容进行udp推流-Toy模板网

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代码及工程见https://download.csdn.net/download/daqinzl/88156926

开发工具：visual studio 2019

播放，采用ffmpeg工具集里的ffplay.exe, 执行命令 ffplay udp://238.1.1.10:6016

主要代码如下:

#include "pch.h"
#include <iostream>
using namespace std;

#include <stdio.h>

#define __STDC_CONSTANT_MACROS

extern "C"
{
#include "include/libavcodec/avcodec.h"
#include "include/libavformat/avformat.h"
#include "include/libswscale/swscale.h"
#include "include/libavdevice/avdevice.h"
#include "include/libavutil/imgutils.h"
#include "include/libavutil/opt.h"
#include "include/libavutil/imgutils.h"
#include "include/libavutil/mathematics.h"
#include "include/libavutil/time.h"
};

#pragma comment (lib,"avcodec.lib")
#pragma comment (lib,"avdevice.lib")
#pragma comment (lib,"avfilter.lib")
#pragma comment (lib,"avformat.lib")
#pragma comment (lib,"avutil.lib")
#pragma comment (lib,"swresample.lib")
#pragma comment (lib,"swscale.lib")

int main(int argc, char* argv[])
{

   AVOutputFormat* ofmt = NULL;
   //输入对应一个AVFormatContext，输出对应一个AVFormatContext
   //（Input AVFormatContext and Output AVFormatContext）
   AVFormatContext* ifmt_ctx = NULL, * ofmt_ctx = NULL;
   AVPacket pkt;
   const char* in_filename, * out_filename;
   int ret, i;
   int videoindex = -1;
   int frame_index = 0;
   int64_t start_time = 0;

   in_filename = "udp://238.1.1.11:1234";//可以为本地文件或者其他形式的直播流、设备等
   in_filename = "d:/mv/test.mp4";
   out_filename = "udp://238.1.1.10:6016";
   av_register_all();
   //Network
   avformat_network_init();

if (true) {

   }
   else {
   end:
       avformat_close_input(&ifmt_ctx);
       /* close output */
       if (ofmt_ctx && !(ofmt->flags & AVFMT_NOFILE))
           avio_close(ofmt_ctx->pb);
       avformat_free_context(ofmt_ctx);
       if (ret < 0 && ret != AVERROR_EOF) {
           printf("Error occurred.\n");
           return -1;
       }
       return 0;
   }

AVDictionary* inputdic = NULL;

   //如果不设置的话，在输入源是直播流的时候，会花屏。单位bytes
   av_dict_set(&inputdic, "buffer_size", "10485760", 0);
   av_dict_set(&inputdic, "reuse", "1", 0);
   //输入（Input）
   if ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, &inputdic)) < 0) {
       printf("Could not open input file.");
       goto end;
   }
   if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0) {
       printf("Failed to retrieve input stream information");
       goto end;
   }

   for (i = 0; i < ifmt_ctx->nb_streams; i++)
       if (ifmt_ctx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
           videoindex = i;
           break;
       }

av_dump_format(ifmt_ctx, 0, in_filename, 0);

   //输出（Output）
   avformat_alloc_output_context2(&ofmt_ctx, NULL, "mpegts", out_filename);//UDP
   if (!ofmt_ctx) {
       printf("Could not create output context\n");
       ret = AVERROR_UNKNOWN;
       goto end;
   }
   ofmt = ofmt_ctx->oformat;
   for (i = 0; i < ifmt_ctx->nb_streams; i++) {
       //根据输入流创建输出流（Create output AVStream according to input AVStream）
       AVStream* in_stream = ifmt_ctx->streams[i];
       AVStream* out_stream = avformat_new_stream(ofmt_ctx, in_stream->codec->codec);
       if (!out_stream) {
           printf("Failed allocating output stream\n");
           ret = AVERROR_UNKNOWN;
           goto end;
       }
       //复制AVCodecContext的设置（Copy the settings of AVCodecContext）
       //tanzhenwen
       ret = avcodec_parameters_copy(out_stream->codecpar, ifmt_ctx->streams[i]->codecpar);
       if (ret < 0) {
           printf("Failed to copy parameters from input to output stream codec context\n");
           goto end;
       }
       /*   ret = avcodec_copy_context(out_stream->codec, in_stream->codec);
           if (ret < 0) {
               printf("Failed to copy context from input to output stream codec context\n");
               goto end;
           }*/
       out_stream->codec->codec_tag = 0;
       if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER)
           out_stream->codec->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
   }
   //Dump Format------------------
   av_dump_format(ofmt_ctx, 0, out_filename, 1);
   //打开输出URL（Open output URL）
   if (!(ofmt->flags & AVFMT_NOFILE)) {
       AVDictionary* dic = NULL;
       av_dict_set(&dic, "pkt_size", "1316", 0);   //Maximum UDP packet size
       //av_dict_set(&dic, "fifo_size", "18800", 0);
       //av_dict_set(&dic, "buffer_size", "1000000", 0);
       //av_dict_set(&dic, "bitrate", "11000000", 0);
       //av_dict_set(&dic, "buffer_size", "1000000", 0);//1316
       av_dict_set(&dic, "reuse", "1", 0);
       ret = avio_open2(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE, NULL, &dic);
       //ret = avio_open(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE);

       if (ret < 0) {
           printf("Could not open output URL '%s'", out_filename);
           goto end;
       }
   }

   //av_opt_set(ofmt_ctx->priv_data, "muxrate", "11000000", 0);
   av_opt_set(ofmt_ctx->priv_data, "MpegTSWrite", "1", 0);
   av_opt_set(ofmt_ctx->priv_data, "pes_payload_size", "300", 0);
   //写文件头（Write file header）
   ret = avformat_write_header(ofmt_ctx, NULL);
   if (ret < 0) {
       printf("Error occurred when opening output URL\n");
       goto end;
   }

   start_time = av_gettime();
   int64_t deltpts = 0;
   while (1) {
       AVStream* in_stream, * out_stream;
       //获取一个AVPacket（Get an AVPacket）
       ret = av_read_frame(ifmt_ctx, &pkt);
       if (ret < 0)
           break;
       //FIX：No PTS (Example: Raw H.264)
       //Simple Write PTS
       if (pkt.pts == AV_NOPTS_VALUE) {
           //Write PTS
           AVRational time_base1 = ifmt_ctx->streams[videoindex]->time_base;
           //Duration between 2 frames (us)
           int64_t calc_duration = (double)AV_TIME_BASE / av_q2d(ifmt_ctx->streams[videoindex]->r_frame_rate);
           //Parameters
           pkt.pts = (double)(frame_index * calc_duration) / (double)(av_q2d(time_base1) * AV_TIME_BASE);
           pkt.dts = pkt.pts;
           pkt.duration = (double)calc_duration / (double)(av_q2d(time_base1) * AV_TIME_BASE);
       }
       //Important:Delay
       if (pkt.stream_index == videoindex) {

           AVRational time_base = ifmt_ctx->streams[videoindex]->time_base;
           AVRational time_base_q = { 1,AV_TIME_BASE };
           int64_t pts_time = av_rescale_q(pkt.dts, time_base, time_base_q);
           int64_t now_time = av_gettime() - start_time;

           static bool first = true;
           if (first)
           {
               deltpts = pts_time;
               first = false;
           }

if (pts_time - deltpts > now_time)
av_usleep(pts_time - deltpts - now_time);

}

       in_stream = ifmt_ctx->streams[pkt.stream_index];
       out_stream = ofmt_ctx->streams[pkt.stream_index];

           //if (pkt.stream_index == videoindex) {
           //   out_stream->time_base = AVRational{ 1, 25 };
           //}

           /* copy packet */
           //转换PTS/DTS（Convert PTS/DTS）
           pkt.pts = av_rescale_q_rnd(pkt.pts, in_stream->time_base, out_stream->time_base, (AVRounding)(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX));
       pkt.dts = av_rescale_q_rnd(pkt.dts, in_stream->time_base, out_stream->time_base, (AVRounding)(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX));
       pkt.duration = av_rescale_q(pkt.duration, in_stream->time_base, out_stream->time_base);
       pkt.pos = -1;
       //Print to Screen
       if (pkt.stream_index == videoindex) {
           //printf("Send %8d video frames to output URL\n", frame_index);
           frame_index++;
       }
       //ret = av_write_frame(ofmt_ctx, &pkt);
       ret = av_interleaved_write_frame(ofmt_ctx, &pkt);

       if (ret < 0) {
           printf("Error muxing packet\n");
           break;
       }

av_free_packet(&pkt);

   }
   //写文件尾（Write file trailer）
   av_write_trailer(ofmt_ctx);
//end:
   avformat_close_input(&ifmt_ctx);
   /* close output */
   if (ofmt_ctx && !(ofmt->flags & AVFMT_NOFILE))
       avio_close(ofmt_ctx->pb);
   avformat_free_context(ofmt_ctx);
   if (ret < 0 && ret != AVERROR_EOF) {
       printf("Error occurred.\n");
       return -1;
   }
   return 0;

   }
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