基于FFmpeg的推流器 (simplest ffmpeg streamer)。推流器的作用就是将本地的视频数据推送至流媒体服务器。本文记录的推流器,可以将本地的 MOV / AVI / MKV / MP4 / FLV 等格式的媒体文件,通过流媒体协议(例如RTMP,HTTP,UDP,TCP,RTP等等)以直播流的形式推送出去。目前主要的推流器如下:TMP流媒体服务器(例如 Flash Media Server,Red5,Wowza等等),本文实现推流器后用相应的flash media server实现直播流播放
推流器代码如下:
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#include <stdio.h>
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#define __STDC_CONSTANT_MACROS
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#ifdef _WIN32
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//Windows
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extern "C"
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{
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#include "libavformat/avformat.h"
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#include "libavutil/mathematics.h"
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#include "libavutil/time.h"
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};
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#else
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//Linux...
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#ifdef __cplusplus
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extern "C"
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{
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#endif
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#include <libavformat/avformat.h>
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#include <libavutil/mathematics.h>
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#include <libavutil/time.h>
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#ifdef __cplusplus
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};
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#endif
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#endif
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int main(int argc, char* argv[])
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{
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AVOutputFormat *ofmt = NULL;
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//Input AVFormatContext and Output AVFormatContext
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AVFormatContext *ifmt_ctx = NULL, *ofmt_ctx = NULL;
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AVPacket pkt;
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const char *in_filename, *out_filename;
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int ret, i;
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int videoindex=-1;
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int frame_index=0;
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int64_t start_time=0;
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in_filename = "dakongtou.mp4";//输入URL(Input file URL)
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//in_filename = "shanghai03_p.h264";
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out_filename = "rtmp://localhost/test/livestream";//输出 URL(Output URL)[RTMP]
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av_register_all();
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//Network
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avformat_network_init();
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//Input
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if ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, 0)) < 0) {
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printf( "Could not open input file.");
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goto end;
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}
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if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0) {
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printf( "Failed to retrieve input stream information");
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goto end;
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}
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for(i=0; i<ifmt_ctx->nb_streams; i++)
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if(ifmt_ctx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO){
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videoindex=i;
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break;
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}
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av_dump_format(ifmt_ctx, 0, in_filename, 0);
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//Output
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avformat_alloc_output_context2(&ofmt_ctx, NULL, "flv", out_filename); //RTMP
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//avformat_alloc_output_context2(&ofmt_ctx, NULL, "mpegts", out_filename);//UDP
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if (!ofmt_ctx) {
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printf( "Could not create output context\n");
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ret = AVERROR_UNKNOWN;
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goto end;
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}
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ofmt = ofmt_ctx->oformat;
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for (i = 0; i < ifmt_ctx->nb_streams; i++) {
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//Create output AVStream according to input AVStream
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AVStream *in_stream = ifmt_ctx->streams[i];
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AVStream *out_stream = avformat_new_stream(ofmt_ctx, in_stream->codec->codec);
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if (!out_stream) {
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printf( "Failed allocating output stream\n");
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ret = AVERROR_UNKNOWN;
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goto end;
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}
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//Copy the settings of AVCodecContext
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ret = avcodec_copy_context(out_stream->codec, in_stream->codec);
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if (ret < 0) {
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printf( "Failed to copy context from input to output stream codec context\n");
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goto end;
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}
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out_stream->codec->codec_tag = 0;
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if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER)
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out_stream->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;
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}
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//Dump Format------------------
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av_dump_format(ofmt_ctx, 0, out_filename, 1);
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//Open output URL
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if (!(ofmt->flags & AVFMT_NOFILE)) {
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ret = avio_open(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE);
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if (ret < 0) {
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printf( "Could not open output URL '%s'", out_filename);
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goto end;
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}
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}
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//Write file header
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ret = avformat_write_header(ofmt_ctx, NULL);
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if (ret < 0) {
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printf( "Error occurred when opening output URL\n");
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goto end;
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}
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start_time=av_gettime();
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while (1) {
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AVStream *in_stream, *out_stream;
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//Get an AVPacket
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ret = av_read_frame(ifmt_ctx, &pkt);
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if (ret < 0)
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break;
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//FIX:No PTS (Example: Raw H.264)
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//Simple Write PTS
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if(pkt.pts==AV_NOPTS_VALUE){
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//Write PTS
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AVRational time_base1=ifmt_ctx->streams[videoindex]->time_base;
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//Duration between 2 frames (us)
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int64_t calc_duration=(double)AV_TIME_BASE/av_q2d(ifmt_ctx->streams[videoindex]->r_frame_rate);
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//Parameters
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pkt.pts=(double)(frame_index*calc_duration)/(double)(av_q2d(time_base1)*AV_TIME_BASE);
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pkt.dts=pkt.pts;
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pkt.duration=(double)calc_duration/(double)(av_q2d(time_base1)*AV_TIME_BASE);
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}
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//Important:Delay
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if(pkt.stream_index==videoindex){
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AVRational time_base=ifmt_ctx->streams[videoindex]->time_base;
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AVRational time_base_q={1,AV_TIME_BASE};
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int64_t pts_time = av_rescale_q(pkt.dts, time_base, time_base_q);
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int64_t now_time = av_gettime() - start_time;
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if (pts_time > now_time)
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av_usleep(pts_time - now_time);
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}
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in_stream = ifmt_ctx->streams[pkt.stream_index];
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out_stream = ofmt_ctx->streams[pkt.stream_index];
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//Convert PTS/DTS
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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));
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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));
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pkt.duration = av_rescale_q(pkt.duration, in_stream->time_base, out_stream->time_base);
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pkt.pos = -1;
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//Print to Screen
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if(pkt.stream_index==videoindex){
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printf("Send %8d video frames to output URL\n",frame_index);
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frame_index++;
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}
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//ret = av_write_frame(ofmt_ctx, &pkt);
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ret = av_interleaved_write_frame(ofmt_ctx, &pkt);
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if (ret < 0) {
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printf( "Error muxing packet\n");
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break;
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}
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av_free_packet(&pkt);
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}
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//Write file trailer
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av_write_trailer(ofmt_ctx);
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end:
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avformat_close_input(&ifmt_ctx);
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if (ofmt_ctx && !(ofmt->flags & AVFMT_NOFILE))
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avio_close(ofmt_ctx->pb);
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avformat_free_context(ofmt_ctx);
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if (ret < 0 && ret != AVERROR_EOF) {
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printf( "Error occurred.\n");
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return -1;
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}
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return 0;
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}
由代码中可以看出,视频源为dakongtou.mp4,推送出的url地址为rtmp://localhost/test/livestream