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• how to create applications slide show ? [on hold]

  5 avril 2018, par Mua Sao Bang

  I’m creating applications slideshow video I encountered big problem is when I want to preview, I must export the video with ffmpeg so very time please give me solution

• Multicast video captured via VLC show a gray background for first 1/2 second

  28 juillet 2014, par DavidG

  I am capturing multicast video using VLC.exe and performing some processing/converting using FFmpeg.exe. The resulting video starts with a gray background with some of the moving objects moving through the gray background. This seems to me that the video is not starting on an I-Frame, but on a B-Frame or a P-Frame. However, when I run ffprobe, it states the first frame is a key frame. After about 1/2 second, the video plays fine.

  Here is the command I’m using to capture the video :

  vlc.exe -I curses --run-time=10 "my.sdp" --sout=video.mp4

  I’m not using anything special when I convert to an mp4 file using FFmpeg :

  ffmpeg.exe -i video.mp4 -s 400x300 final.mp4

  I tried to post an image of the first frame or two, but Stackoverflow gave me an error stating I need at least 10 reputation to post images. Sorry about that, an image would have helped.

  I ran the command "ffprobe show_frames " and it looks like the first frame is a key frame. Of course I’m new to all this and I don’t know what I’m doing or seeing.

  Here is beginning of the output to the "ffprobe show_frames " command :

  [FRAME]
  
  media_type=video
  
  key_frame=1
  
  pkt_pts=0
  
  pkt_pts_time=0.000000
  
  pkt_dts=0
  
  pkt_dts_time=0.000000
  
  pkt_duration=1001
  
  pkt_duration_time=0.033367
  
  pkt_pos=48
  
  pkt_size=756
  
  width=400
  
  height=300
  
  pix_fmt=yuv420p
  
  sample_aspect_ratio=1:1
  
  pict_type=I
  
  coded_picture_number=0
  
  display_picture_number=0
  
  interlaced_frame=0
  
  top_field_first=0
  
  repeat_pict=0
  
  reference=3
  
  [/FRAME]

  Is there any way to either tell VLC.exe to start capturing on an I-Frame (This would be the best solution as I specify a duration to capture the video) or is there a way to tell FFmpeg.exe to start converting the input video starting at the first I-Frame encountered ?

  Thanks,
   David

• using X264 and librtmp to send live camera frame, but the flash can't show

  9 mai 2016, par brian_wang

  I am using X264 and librtmp to send my live camera frame, all the things seems right. but my web test flash can’t show the correct video. Sometimes it seems correct, but when I re-click play button, it doesn’t show any picture on the flash.

  Here is my X264 config code

  x264_param_default_preset(&x264param, "ultrafast", "zerolatency");
  
  x264param.i_threads = 2;
  
  x264param.i_width = width;
  
  x264param.i_height = height;
  
  x264param.i_log_level = X264_LOG_DEBUG;
  
  x264param.i_fps_num = x264param.i_timebase_num= fps;
  
  x264param.i_fps_den = x264param.i_timebase_den=1;
  
  x264param.i_frame_total = 0;
  
  
  
  x264param.i_frame_reference =1;
  
  //x264param.i_frame_reference = 2;
  
  x264param.i_keyint_min = 25;
  
  x264param.i_keyint_max = fps*3;
  
  x264param.i_scenecut_threshold = 40;
  
  
  
  x264param.b_deblocking_filter = 1;
  
  x264param.b_cabac = 0;
  
  x264param.analyse.i_trellis = 0;
  
  x264param.analyse.b_chroma_me = 1;
  
  
  
  x264param.vui.i_sar_width = 0;
  
  x264param.vui.i_sar_height = 0;
  
  x264param.i_bframe_bias = 0;
  
  x264param.b_interlaced= 0;
  
  x264param.analyse.i_subpel_refine = 6; /* 0..5 -> 1..6 */
  
  x264param.analyse.i_me_method = X264_ME_DIA;//X264_ME_HEX?X264_ME_DIA
  
  x264param.analyse.i_me_range = 16;
  
  x264param.analyse.i_direct_mv_pred = X264_DIRECT_PRED_AUTO;
  
  x264param.i_deblocking_filter_alphac0 = 0;
  
  x264param.i_deblocking_filter_beta = 0;
  
  //x264param.analyse.intra = X264_ANALYSE_I4x4;
  
  x264param.analyse.intra = X264_ANALYSE_I4x4;//  | X264_ANALYSE_PSUB16x16 | X264_ANALYSE_BSUB16x16;
  
  x264param.analyse.inter = X264_ANALYSE_I4x4 | X264_ANALYSE_PSUB16x16 | X264_ANALYSE_BSUB16x16; 
  
  //edit 2014-7-28
  
  x264param.analyse.b_transform_8x8 = 1;
  
  //x264param.analyse.b_transform_8x8 = 0;
  
  x264param.analyse.b_fast_pskip = 1;
  
  x264param.i_bframe = 0;
  
  //x264param.b_intra_refresh
  
  x264param.analyse.b_weighted_bipred = 0;
  
  
  
  //// Intra refres:
  
  x264param.i_keyint_max = 250;
  
  x264param.b_intra_refresh = 0;
  
  ////Rate control:
  
  //x264param.rc.i_rc_method = X264_RC_CRF;
  
  
  
  //Rate Control
  
  x264param.rc.f_ip_factor = 1.4f;
  
  x264param.rc.f_pb_factor = 1.3f;
  
  x264param.rc.f_qcompress = 1.0;
  
  x264param.rc.i_qp_min = 20;//20;
  
  x264param.rc.i_qp_max = 32;
  
  x264param.rc.i_qp_step = 1;
  
  
  
  switch (0)
  
  {
  
  case 0: /* 1 PASS ABR */
  
      x264param.rc.i_rc_method = X264_RC_ABR;
  
      x264param.rc.i_bitrate = 300; // max = 5000
  
      x264param.rc.b_mb_tree = 0;
  
      break;
  
  case 1: /* 1 PASS CQ */
  
      x264param.rc.i_rc_method = X264_RC_CQP;
  
      x264param.rc.i_qp_constant = 26;//10 - 51
  
      break;
  
  }
  
  
  
  //For streaming:
  
  x264param.b_repeat_headers = 1;
  
  x264param.b_annexb = 1;
  
  x264_param_apply_profile(&x264param, "baseline");
  
  encoder = x264_encoder_open(&x264param);
  
  x264_picture_init( &pic_in );
  
  x264_picture_alloc(&pic_in, X264_CSP_I420, width, height);
  
  
  
  pic_in.img.i_csp = X264_CSP_I420|X264_CSP_VFLIP;
  
  pic_in.img.i_plane = 3;
  
  pic_in.i_type = X264_TYPE_AUTO;

  Sending To RTMP :

  sws_scale(convertCtx,&a,&scribe,0,height, pic_in.img.plane, pic_in.img.i_stride);
  
  int i_nal;
  
  int i_frame_size = x264_encoder_encode( encoder, &nal, &i_nal, &pic_in, &pic_out );
  
  if(i_frame_size <= 0){
  
      printf("\t!!!FAILED encode frame \n");
  
  }else{
  
      for (int i = 0,last=0; i < i_nal;i++)  
  
      {
  
          fwrite(nal[i].p_payload, 1, i_frame_size-last, fpw1);
  
          if (nal[i].i_type == NAL_SPS) {
  
              sps_len = nal[i].i_payload-4;
  
              sps  = new unsigned char[sps_len];
  
              memcpy(sps,nal[i].p_payload+4,sps_len);
  
          } else if (nal[i].i_type == NAL_PPS) {
  
              pps_len = nal[i].i_payload-4;
  
              pps  = new unsigned char[sps_len];
  
              memcpy(pps,nal[i].p_payload+4,pps_len);
  
              send_video_sps_pps(); 
  
              free(sps);
  
              free(pps);
  
          } else {
  
              send_rtmp_video(nal[i].p_payload,i_frame_size-last);
  
              break;
  
          }
  
          last += nal[i].i_payload;
  
      }
  
  }

  Send PPS and SPS

  void send_video_sps_pps(){
  
  if(rtmp!= NULL){
  
      RTMPPacket * packet;
  
      unsigned char * body;
  
      int i;
  
  
  
      packet = (RTMPPacket *)malloc(RTMP_HEAD_SIZE+1024);
  
      memset(packet,0,RTMP_HEAD_SIZE);
  
  
  
      packet->m_body = (char *)packet + RTMP_HEAD_SIZE;
  
      body = (unsigned char *)packet->m_body;
  
      i = 0;
  
      body[i++] = 0x17;
  
      body[i++] = 0x00;
  
  
  
      body[i++] = 0x00;
  
      body[i++] = 0x00;
  
      body[i++] = 0x00;
  
  
  
      /*AVCDecoderConfigurationRecord*/
  
      body[i++] = 0x01;
  
      body[i++] = sps[1];
  
      body[i++] = sps[2];
  
      body[i++] = sps[3];
  
      body[i++] = 0xff;
  
  
  
      /*sps*/
  
      body[i++]   = 0xe1;
  
      body[i++] = (sps_len >> 8) & 0xff;
  
      body[i++] = sps_len & 0xff;
  
      memcpy(&body[i],sps,sps_len);
  
      i +=  sps_len;
  
  
  
      /*pps*/
  
      body[i++]   = 0x01;
  
      body[i++] = (pps_len >> 8) & 0xff;
  
      body[i++] = (pps_len) & 0xff;
  
      memcpy(&body[i],pps,pps_len);
  
      i +=  pps_len;
  
  
  
      packet->m_packetType = RTMP_PACKET_TYPE_VIDEO;
  
      packet->m_nBodySize = i;
  
      packet->m_nChannel = 0x04;
  
      packet->m_nTimeStamp = 0;
  
      packet->m_hasAbsTimestamp = 0;
  
      packet->m_headerType = RTMP_PACKET_SIZE_MEDIUM;
  
      packet->m_nInfoField2 = rtmp->m_stream_id;
  
  
  
      RTMP_SendPacket(rtmp,packet,TRUE);
  
      free(packet);   
  
      rtmp_start_time = GetTickCount();
  
  }else{
  
      std::cout<<"RTMP is not ready"<code>

  Send video Frame

  void send_rtmp_video(unsigned char * buf,int len){
  
  RTMPPacket * packet;
  
  long timeoffset = GetTickCount() - rtmp_start_time; 
  
  
  
  int type = buf[0]&0x1f;
  
  
  
  packet = (RTMPPacket *)malloc(RTMP_HEAD_SIZE+len+9);
  
  memset(packet,0,RTMP_HEAD_SIZE);
  
  
  
  packet->m_body = (char *)packet + RTMP_HEAD_SIZE;
  
  packet->m_nBodySize = len + 9;
  
  
  
  /*send video packet*/
  
  unsigned char *body = (unsigned char *)packet->m_body;
  
  memset(body,0,len+9);
  
  
  
  /*key frame*/
  
  body[0] = 0x27;
  
  if (type == NAL_SLICE_IDR) {
  
      body[0] = 0x17;
  
  }
  
  
  
  body[1] = 0x01;   /*nal unit*/
  
  body[2] = 0x00;
  
  body[3] = 0x00;
  
  body[4] = 0x00;
  
  
  
  body[5] = (len >> 24) & 0xff;
  
  body[6] = (len >> 16) & 0xff;
  
  body[7] = (len >>  8) & 0xff;
  
  body[8] = (len ) & 0xff;
  
  
  
  /*copy data*/
  
  memcpy(&body[9],buf,len);
  
  
  
  packet->m_hasAbsTimestamp = 0;
  
  packet->m_packetType = RTMP_PACKET_TYPE_VIDEO;
  
  if(rtmp != NULL){
  
      packet->m_nInfoField2 = rtmp->m_stream_id;
  
  }
  
  packet->m_nChannel = 0x04;
  
  packet->m_headerType = RTMP_PACKET_SIZE_LARGE;
  
  packet->m_nTimeStamp = timeoffset;
  
  
  
  if(rtmp != NULL){
  
      RTMP_SendPacket(rtmp,packet,TRUE);
  
  }
  
  free(packet);

  }