ffmpeg 推rtsp/rtmp流

参考雷神的《最简单的基于FFmpeg的推流器（以推送RTMP为例）》
以及另一位《使用ffmpeg将实时流保存为AVI》实现，然后对比两种实现方式。

1、ffmpeg读rtsp/rtmp/内存数据再推流

  这部分主要是参考雷神的，在此基础上实现了读取rtsp/rtmp流后再推rtsp/rtmp流，也实现了读取内存数据再推流。其中rtsp可推h264/h265流。flv只能推送h264，暂时265不支持拓展。
从内存读取数据时，在调用avformat_open_input(&ifmt_ctx, NULL, NULL, NULL)之前，内存数据必须到位，不然会open失败,而且第一帧必须是IDR帧。

/* 使能直接读取内存数据然后进行推流 */
#define  READ_FROME_MEM_BUFFER (1)

/* 推流测试 可推rtsp/rtmp流*/
int test_pusher_main( )
{
  AVOutputFormat *ofmt = NULL;
  //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;

#ifndef READ_FROME_MEM_BUFFER
  in_filename  = "rtsp://localhost:556/test";//输入URL（Input file URL）
#else
  Read_Data read_handle("cuc_ieschool.flv");
#endif

  out_filename = "rtmp://localhost:1936/live/livestream";//输出 URL（Output URL）[RTMP]
  //out_filename = "rtp://233.233.233.233:6666";//输出 URL（Output URL）[UDP]

  //avfilter_register_all();
  av_log_set_level(AV_LOG_DEBUG);
  avcodec_register_all();
  av_register_all();

  //Network
  avformat_network_init();

#ifdef READ_FROME_MEM_BUFFER
  ifmt_ctx = avformat_alloc_context();

  unsigned char* aviobuffer = (unsigned char *)av_malloc(32768);
  AVIOContext* avio = avio_alloc_context(aviobuffer, 32768, 0, &read_handle, Read_Data::read_buffer, NULL, NULL);

  /* Open an input stream and read the header. */
  ifmt_ctx->pb = avio;
  if (avformat_open_input(&ifmt_ctx, NULL, NULL, NULL) != 0)
  {
      printf("Couldn't open input stream.\n");
      return -1;
  }

#else
  //Input
  if ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, 0)) < 0)
  {
      printf("Could not open input file.");
      goto end;
  }
#endif

  if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0) 
  {
      printf("Failed to retrieve input stream information");
      goto end;
  }

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

  if (videoindex == -1)
  {
      printf("Didn't find a video stream.\n");
      return -1;
  }

#ifndef READ_FROME_MEM_BUFFER
  av_dump_format(ifmt_ctx, 0, in_filename, 0);
#endif

  //Output
  avformat_alloc_output_context2(&ofmt_ctx, NULL, "flv", out_filename); //RTMP
  //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++) 
  {
      //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;
      }

      //Copy the settings of AVCodecContext
      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)
      //{
          //printf("###### set AV_CODEC_FLAG_GLOBAL_HEADER ######\n");
          //out_stream->codec->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
      //}
  }

  //Dump Format------------------
  av_dump_format(ofmt_ctx, 0, out_filename, 1);

  //Open output URL
  if (!(ofmt->flags & AVFMT_NOFILE)) 
  {
      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;
      }
  }

  //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();
  while (1) 
  {
      AVStream *in_stream, *out_stream;
      //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;
          if (pts_time > now_time)
              av_usleep(pts_time - now_time);
      }

      in_stream = ifmt_ctx->streams[pkt.stream_index];
      out_stream = ofmt_ctx->streams[pkt.stream_index];
      /* copy packet */
      //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 ret = %d\n", ret);
          char buf[128];
          memset(buf, 0, 128);
          av_strerror(ret, buf, 128);
          printf("error: %s\n", buf);
          break;
      }

      av_free_packet(&pkt);
  }
  //Write file trailer
  av_write_trailer(ofmt_ctx);

  getchar();

end:

#ifdef READ_FROME_MEM_BUFFER
  av_freep(&avio->buffer);
  av_freep(&avio);
#endif

  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;
  }

  getchar();
  return 0;
}

2、直接填充ffmpeg的pack再推流

  参考第二篇博文，在参考的博文中只给出代码框架，细节需要自己实现。
这种方法实现的推流，配置的部分输出码流参数并不起效，如码率、帧率及分辨率，这些参数的实际推流输出会等于输入的。
  主要是判别h264的I帧，若此处判别失败则推流成功但是客户端无法解析出。
这种方法也适合推rtsp/rtmp流，支持h264/h265码流，暂时不支持音频。

/* 直接读buffer数据后填充AVPack结构体，然后推流 */
int test_pusher_rtmp_main2()
{
  int ret;
  char buf[1024] = "";
  AVOutputFormat *ofmt = NULL;
  AVFormatContext *ofmt_ctx = NULL;
  AVStream *out_stream = NULL;
  AVPacket pkt = { 0 };
  AVPacket in_pkt = { 0 };
   AVDictionary *dic = NULL;
  AVCodecContext *avctx = NULL;

  avcodec_register_all();
  av_register_all();
  av_log_set_level(AV_LOG_DEBUG);
  avformat_network_init();

  int frame_cnt = 0;
  //Read_Data read_handle("test.h265");
  const int buffer_size = 1024 * 1024 * 3;
  uint8_t* frame_buf = new uint8_t[buffer_size];
  memset(frame_buf, 0, buffer_size);

  //const char* in_filename = "cuc_ieschool.flv";
  const char* in_filename = "test.h264";
  //const char* in_filename = "4K.h264";
  AVFormatContext *ifmt_ctx = NULL;
  int videoindex = -1;

  //Input
  if ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, 0)) < 0)
  {
      printf("Could not open input file.");
      memset(buf, 0 ,1024);
      av_strerror(ret, buf, 1024);
      printf("Couldn't open file %s with error[%s]\n", in_filename, buf);
      return -1;
  }

  if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0)
  {
      printf("Failed to retrieve input stream information");
      return -1;
  }

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

  if (videoindex == -1)
  {
      printf("Didn't find a video stream.\n");
      return -1;
  }

  const char* out_filename = "rtmp://localhost:1936/live/livestream";
  avformat_alloc_output_context2(&ofmt_ctx, NULL, "flv", out_filename);

  //const char* out_filename = "rtsp://localhost:556/livestream";
  /* allocate the output media context */
  //avformat_alloc_output_context2(&ofmt_ctx, NULL, "rtsp", out_filename);
  if (!ofmt_ctx) 
  {
      printf("Could not deduce output format from file extension: using AVI.\n");
      //avformat_alloc_output_context2(&ofmt_ctx, NULL, "avi", out_filename);
      goto exit;
  }

  if (!ofmt_ctx) 
  {
      goto exit;
  }

  ofmt = ofmt_ctx->oformat;

  out_stream = avformat_new_stream(ofmt_ctx, NULL);
  if (!out_stream)
  {
      printf("Failed allocating output stream\n");
      ret = AVERROR_UNKNOWN;
      goto exit;
  }

  avctx = out_stream->codec;
  avctx->codec_type = AVMEDIA_TYPE_VIDEO;

  ret = av_dict_set(&dic, "qp", "0", 0);
  ret = av_dict_set(&dic, "bufsize", "1524000", 0);
  if (ret < 0)
  {
      printf("av_dict_set  bufsize fail \n");
      return -1;
  }

  ///*此处,需指定编码后的H264数据的分辨率、帧率及码率*/
  /* avctx->codec_id   = AV_CODEC_ID_H264;
   avctx->codec_type = AVMEDIA_TYPE_VIDEO;
   avctx->bit_rate = 2000000;
   avctx->width = 1280;
   avctx->height = 720;
   avctx->time_base.num = 1;
   avctx->time_base.den = 25;
   avctx->qmin = 10;
   avctx->qmax = 60;
   avctx->codec_tag = 0;
   avctx->has_b_frames = 0;*/

 /* 实际上并不起效，但是必须设置否则启动不起来  */
  out_stream->codecpar->codec_id = AV_CODEC_ID_H264;
  out_stream->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
  out_stream->codecpar->width = 1920;
  out_stream->codecpar->height = 1080;
  out_stream->codecpar->codec_tag = 0;
  out_stream->codecpar->bit_rate = 8000000;
  out_stream->codecpar->format = AV_PIX_FMT_YUV420P;
  //out_stream->r_frame_rate = (AVRational){ 25, 1 };
  
  /* print output stream information*/
  av_dump_format(ofmt_ctx, 0, out_filename, 1);
  if (!(ofmt->flags & AVFMT_NOFILE))
  {
      ret = avio_open(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE);
      if (ret < 0)
      {
          printf("Could not open output file '%s'\n", out_filename);
          goto exit;
      }
      printf("Open output file success!\n");
  }

  //写文件头（Write file header）
  ret = avformat_write_header(ofmt_ctx, NULL);
  if (ret < 0)
  {
      printf("write avi file header failed\n");
      goto exit;
  }

  while (1)
  {
      av_init_packet(&pkt);
      ret = av_read_frame(ifmt_ctx, &in_pkt);
      if (ret < 0)
      {
          av_init_packet(&pkt);
          avformat_close_input(&ifmt_ctx);
          ret = avformat_open_input(&ifmt_ctx, in_filename, NULL, NULL);
          if (ret < 0)
          {
              return -1;
          }
          if (av_read_frame(ifmt_ctx, &in_pkt) != 0)
          {
              return -1;
          }
          
      }

      memcpy(frame_buf, in_pkt.data, in_pkt.size);
      printf("size = %d \n", in_pkt.size);

       if (in_pkt.size <= 4)
      {
          continue;
          av_packet_unref(&pkt);
      }

       int frame_type = H264_GetFrameType(frame_buf, in_pkt.size, 4);
       if (frame_type == H264_FRAME_I || frame_type == H264_FRAME_SI)
      { 
          // 判断该H264帧是否为I帧
          printf("####I frame ######\n");
          pkt.flags |= AV_PKT_FLAG_KEY;
          //getchar();
      }
      else
      {
          frame_type = H264_GetFrameType((unsigned char*)frame_buf, in_pkt.size, 3);
          if (frame_type == H264_FRAME_I || frame_type == H264_FRAME_SI)
          {
              // 判断该H264帧是否为I帧
              printf("11111####I frame ######\n");
              pkt.flags |= AV_PKT_FLAG_KEY;
          }
          else
          {
              /* p frame*/
              pkt.flags = 0;
          }

          }

      //pkt.dts = pkt.pts = AV_NOPTS_VALUE;
      pkt.dts = pkt.pts = frame_cnt;

      pkt.size = in_pkt.size; /*帧大小*/
      pkt.data = frame_buf; /*帧数据*/

      if (!pkt.data) 
      {
          printf("no data\n");
          continue;
      }

      //写入（Write）
      ret = av_interleaved_write_frame(ofmt_ctx, &pkt);
      if (ret < 0) 
      {
          av_strerror(ret, buf, 1024);
      }

      if (frame_cnt % 2)
          printf("Send frame[%d] \n", frame_cnt);
      frame_cnt++;

      av_packet_unref(&pkt);

      memset(frame_buf, 0, buffer_size);

      av_usleep(40000);
  }

  av_write_trailer(ofmt_ctx);

exit:

  if (frame_buf)
  {
      delete[] frame_buf;
      frame_buf = NULL;
  }
  /* close output */
  if (ofmt_ctx && !(ofmt_ctx->oformat->flags & AVFMT_NOFILE))
      avio_close(ofmt_ctx->pb);
   avformat_free_context(ofmt_ctx);

  return 0;
}

3、demo

在ubuntu14上实现的demo。