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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

• x264 on Ubuntu video bad/corrupted

  6 septembre 2013, par Ryzone

  I am trying to use command line x264 to produce a blu-ray compatible file for use in Adobe Encore. For the source file I've tried both ProRes and mpeg2, both 1080p24. Both files import into Encore fine (no transcoding needed which is great) but the ProRes version is pink and grey "static" and the mpeg2 is just a bunch of green/black lines. The exact same files and the exact same commands on my Win7 PC come out fine. I'm only doing a 10 sec sample of the complete 90min movie. I'd love for it to work on Ubuntu cause it is running a new i7 haswell that encodes much quicker than my PC (many hours difference in encoding time)

  Ubuntu 13.04
  
  
  
  x264 0.135.2 f0c1c53<br />
  
  built on Jul 24 2013, gcc: 4.7.3<br />
  
  configuration: --bit-depth=8 --chroma-format=all<br />
  
  x264 license: GPL version 2 or later
  
  
  
  command:
  
      x264 --bitrate 30000 --preset veryslow --tune film --bluray-compat --fps 24000/1001 --force-cfr --bframes 3 --ref 4 --muxer raw --no-weightb --weightp 0 --b-pyramid none --vbv-maxrate 40000 --vbv-bufsize 30000 --level 4.1 --profile high --keyint 24 --min-keyint 1 --open-gop --slices 4 --colorprim "bt709" --transfer "bt709" --colormatrix "bt709" --sar 1:1  -o output.264 --input-res 1920x1080 sample.mov

  (if it would work I'd be doing two pass encoding)

  I am able to encode the sample file with ffmpeg to h264 (if that helps).

• FFMPEG Dash with tiles of thumbnail images

  31 juillet 2020, par martyn Gilbert

  As of DASH-IF IOP version 4.2, section 6.2.6 defines the notion of image-based tracks in DASH :&#xA;https://dashif.org/docs/DASH-IF-IOP-v4.3.pdf.

  &#xA;&#xA;

  This is the ability to have an adaption set made up of mime type images that themselves are a strip of low resolution thumbnails. &#xA;A player will use these thumbnails when the user hovers their mouse over the video timeline and get a &#xA;preview of the the frame at that approximate timecode.

  &#xA;&#xA;

  Theo player website has a page dedicated to this function for playback :&#xA;https://www.theoplayer.com/blog/in-stream-thumbnail-support-dvr-dash-streams

  &#xA;&#xA;

  I need to generate a dash stream (not live) using ffmpeg that also contains these thumbnails. &#xA;I already have an ffmpeg command that will generate the film strip of jpgs which outputs a thumbnail every 5 seconds of input video and joins 5 of these together in a single jpg :

  &#xA;&#xA;

  ffmpeg -i INPUT -q:v 20 -vf "select=not(mod(n\,125)),scale=480:270,tile=5x1" -vsync vfr output%d.jpg

  &#xA;&#xA;

  and the mpeg dash itself :

  &#xA;&#xA;

  ffmpeg -i INPUT -y -map 0 -acodec aac -ac 2 -ar 48000 -s 960x540 -vcodec libx264 -f dash -preset veryfast -b:v:2 1500k -seg_duration 2 output.mpd

  &#xA;&#xA;

  But I cannot find a way in ffmpeg to include the thumbnails in the dash mpd file.

  &#xA;