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• Libavcodec and QuickSync

  15 février 2016, par FrancescoBLT

  I’m attempting to encode in h264 format using libavcodec with and without QuickSync hardware acceleration. If I don’t use the hw acceleration is quite simple :

  ff_codec = avcodec_find_encoder(AV_CODEC_ID_H264) ;

  ff_cdctx = avcodec_alloc_context3(ff_codec) ;

  ff_cdctx->width = 1920;
  
  ff_cdctx->height = 1080;
  
  ff_cdctx->time_base.num = 1;
  
  ff_cdctx->time_base.den = 25;
  
  ff_cdctx->sample_aspect_ratio.num = 16;
  
  ff_cdctx->sample_aspect_ratio.den = 9;
  
  ff_cdctx->pix_fmt = AV_PIX_FMT_YUV420P;
  
  av_dict_set(&param,"profile","main",0);
  
  av_dict_set(&param,"preset","medium",0);
  
  av_dict_set(&param,"tune","film",0)<0);
  
  ff_cdctx->gop_size = 10;
  
  ff_cdctx->max_b_frames = 1;
  
  opres = avcodec_open2(ff_cdctx,ff_codec,&param);
  
  ff_frame = av_frame_alloc();
  
  ff_frame->format = ff_cdctx->pix_fmt;
  
  ff_frame->width  = ff_cdctx->width;
  
  ff_frame->height = ff_cdctx->height; 
  
  
  
  opres = av_image_alloc(ff_frame->data, ff_frame->linesize,ff_cdctx->width,ff_cdctx->height,ff_cdctx->pix_fmt, 32);
  
  ff_frame->linesize[0] = ff_cdctx->width;
  
  ff_frame->linesize[1] = ff_frame->linesize[2] = ff_cdctx->width>>1;
  
  
  
  ff_frame->sample_aspect_ratio.num = ff_cdctx->sample_aspect_ratio.num;
  
  ff_frame->sample_aspect_ratio.den = ff_cdctx->sample_aspect_ratio.den;
  
  av_init_packet(&pkt);
  
  enc_err = avcodec_encode_video2(ff_cdctx,&pkt,ff_frame,&got_pkt);  }

  And so on for all source frame. Problem arise when I attempt to use hardware
  acceleration. In this case I use :

  ff_codec = avcodec_find_encoder_by_name("h264_qsv") ;
  for gathering the codec. But when I attempt to open it, the result is "invalid parameter" :
  opres = avcodec_open2(ff_cdctx,ff_codec,&param) ;
  if(opres<0)
  
  if(av_strerror(opres,err_str,256)==0) OutputDebugStringA(err_str) ;
  return -6 ;
  
  Did anyone have attempted to use QuickSync from code ? In the examples there is only one file (qsvdec.c) and is for decoding, not for encoding.
  regards

• What is the commmand line to record destop screen with watermark using ffmpeg ?

  11 septembre 2020, par Yong Ju

  I tried to record screen using ffmpeg commmand line. So, I have complete it using this commmand.&#xA;ffmpeg.exe -rtbufsize 1500M -f -y -rtbufsize 100M -f gdigrab -t 00:02:00 -framerate 30 0 0 -probesize 10M 1920 1080 -draw_mouse 1 -i desktop -c:v libx264 -r 30 -preset ultrafast -tune zerolatency -crf 30 -pix_fmt yuv420p output.avi".

  &#xA;

  Now, I want to add watermark while recording video.&#xA;If you have good experience this field, Please give me good advice.&#xA;Thanks for your attention.&#xA;Sincerely.

  &#xA;

• How to create ffmpeg mosaic with empty cells ?

  7 septembre 2020, par DenVebber

  I try to create video mosaic with ffmpeg.

  &#xA;

  Two videos with horizontal stack :

  &#xA;

  ffmpeg -i vid1.mp4 -i vid2.mp4 -filter_complex "[0]scale=-1:1080[v0];[1]scale=-1:1080[v1];[v0][v1]hstack=inputs=2[vmap]" -map "[vmap]" output.mp4

  &#xA;

  How can I replace vid1.mp4 with black background and save the stack with 2 elements ?&#xA;I can add blackvideo.mp4, but it should be easier, right ?

  &#xA;