// 抓图函数实现
int take_snapshot(char *file, int w, int h, uint8_t *buffer, AVPixelFormat Format)
{
  char              *fileext = NULL;
  enum AVCodecID     codecid = AV_CODEC_ID_NONE;
  struct SwsContext *sws_ctx = NULL;
  AVPixelFormat      swsofmt = AV_PIX_FMT_NONE;
  AVFrame            picture = {};
  int                ret     = -1;

  AVFormatContext   *fmt_ctxt   = NULL;
  AVOutputFormat    *out_fmt    = NULL;
  AVStream          *stream     = NULL;
  AVCodecContext    *codec_ctxt = NULL;
  AVCodec           *codec      = NULL;
  AVPacket           packet     = {};
  int                retry      = 8;
  int                got        = 0;

  // init ffmpeg
  av_register_all();

  fileext = file + strlen(file) - 3;
  if (_stricmp(fileext, "png") == 0) {
    codecid = AV_CODEC_ID_APNG;
    swsofmt = AV_PIX_FMT_RGB24;
  }
  else {
    codecid = AV_CODEC_ID_MJPEG;
    swsofmt = AV_PIX_FMT_YUVJ420P;
  }

  AVFrame video;
  int numBytesIn;
  numBytesIn = av_image_get_buffer_size(Format, w, h, 1);
  av_image_fill_arrays(video.data, video.linesize, buffer, Format, w, h, 1);
  video.width = w;
  video.height = h;
  video.format = Format;

  // alloc picture
  picture.format = swsofmt;
  picture.width  = w > 0 ? w : video.width;
  picture.height = h > 0 ? h : video.height;

  int numBytes = av_image_get_buffer_size(swsofmt, picture.width, picture.height , 1);

  buffer = (uint8_t *)av_malloc(numBytes * sizeof(uint8_t));

  av_image_fill_arrays(picture.data, picture.linesize, buffer, swsofmt, picture.width, picture.height, 1);

  // scale picture
  sws_ctx = sws_getContext(video.width, video.height, (AVPixelFormat)Format/*video->format*/,
    picture.width, picture.height, swsofmt, SWS_FAST_BILINEAR, NULL, NULL, NULL);
  if (!sws_ctx) {
    //av_log(NULL, AV_LOG_ERROR, "could not initialize the conversion context jpg\n");
    goto done;
  }
  sws_scale(sws_ctx, video.data, video.linesize, 0, video.height, picture.data, picture.linesize);

  // do encoding
  fmt_ctxt = avformat_alloc_context();
  out_fmt  = av_guess_format(codecid == AV_CODEC_ID_APNG ? "apng" : "mjpeg", NULL, NULL);
  fmt_ctxt->oformat = out_fmt;
  if (!out_fmt) {
    //av_log(NULL, AV_LOG_ERROR, "failed to guess format !\n");
    goto done;
  }

  if (avio_open(&fmt_ctxt->pb, file, AVIO_FLAG_READ_WRITE) < 0) {
    //av_log(NULL, AV_LOG_ERROR, "failed to open output file: %s !\n", file);
    goto done;
  }

  stream = avformat_new_stream(fmt_ctxt, 0);
  if (!stream) {
    //av_log(NULL, AV_LOG_ERROR, "failed to create a new stream !\n");
    goto done;
  }

  codec_ctxt                = stream->codec;
  codec_ctxt->codec_id      = out_fmt->video_codec;
  codec_ctxt->codec_type    = AVMEDIA_TYPE_VIDEO;
  codec_ctxt->pix_fmt       = swsofmt;
  codec_ctxt->width         = picture.width;
  codec_ctxt->height        = picture.height;
  codec_ctxt->time_base.num = 1;
  codec_ctxt->time_base.den = 25;

  codec = avcodec_find_encoder(codec_ctxt->codec_id);
  if (!codec) {
    //av_log(NULL, AV_LOG_ERROR, "failed to find encoder !\n");
    goto done;
  }

  if (avcodec_open2(codec_ctxt, codec, NULL) < 0) {
    //av_log(NULL, AV_LOG_ERROR, "failed to open encoder !\n");
    goto done;
  }

  while (retry-- && !got) {
    if (avcodec_encode_video2(codec_ctxt, &packet, &picture, &got) < 0) {
      //av_log(NULL, AV_LOG_ERROR, "failed to do picture encoding !\n");
      goto done;
    }

    if (got) {
      ret = avformat_write_header(fmt_ctxt, NULL);
      if (ret < 0) {
        //av_log(NULL, AV_LOG_ERROR, "error occurred when opening output file !\n");
        goto done;
      }
      av_write_frame(fmt_ctxt, &packet);
      av_write_trailer(fmt_ctxt);
    }
  }

  // ok
  ret = 0;

done:
  avcodec_close(codec_ctxt);
  if (fmt_ctxt)
  {
    avio_close(fmt_ctxt->pb);
  }
  avformat_free_context(fmt_ctxt);
  av_packet_unref(&packet);

  sws_freeContext(sws_ctx);
  av_free(buffer);

  return ret;
}

//抓图
          if (pThread->manuScreenshot == 0x01 )//Just support jpeg，png
          {
            unsigned int timestamp = (unsigned int)time(NULL);
            time_t tt = timestamp;
            struct tm *_time = localtime(&tt);
            char szTime[64] = {0,};
            strftime(szTime, 32, "%Y%m%d-%H%M%S", _time);
  
//            char strPath[512] = {0,};
//            sprintf(strPath , "%sch%d_%s.jpg", pThread->strScreenCapturePath, pThread->channelId, szTime) ;

            PhotoShotThreadInfo* pShotThreadInfo = new PhotoShotThreadInfo;
            sprintf(pShotThreadInfo->strPath , "%sch%d_%s.jpg", pThread->strScreenCapturePath, pThread->channelId, szTime) ;

            int nYuvBufLen = frameinfo.width*frameinfo.height*3;// most size = RGB24, we donot support RGBA Render type
            pShotThreadInfo->pYuvBuf = new unsigned char[nYuvBufLen];
            pShotThreadInfo->width = frameinfo.width;
            pShotThreadInfo->height = frameinfo.height;
            pShotThreadInfo->renderFormat = pThread->renderFormat ;

            memcpy(pShotThreadInfo->pYuvBuf, pThread->yuvFrame[pThread->decodeYuvIdx].pYuvBuf, pThread->yuvFrame[pThread->decodeYuvIdx].Yuvsize-1);
            CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)_lpPhotoShotThread, pShotThreadInfo, 0, NULL);
            pThread->manuScreenshot = 0;
          }