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• lavfi/vf_hwupload : Add support for HW -> HW transfers

  24 octobre 2019, par Philip Langdale

  lavfi/vf_hwupload : Add support for HW -> HW transfers
  As we find ourselves wanting a way to transfer frames between
  
  HW devices (or more realistically, between APIs on the same device),
  
  it's desirable to have a way to describe the relationship. While
  
  we could imagine introducing a `hwtransfer` filter, there is
  
  almost no difference from `hwupload`. The main new feature we need
  
  is a way to specify the target device. Having a single device
  
  for the filter chain is obviously insufficient if we're dealing
  
  with two devices.
  So let's add a way to specify the upload target device, and if none
  
  is specified, continue with the existing behaviour.
  We must also correctly preserve the sw_format on such a transfer.
  

  • [DH] doc/filters.texi
  • [DH] libavfilter/vf_hwupload.c
  • [DH] libavfilter/vf_hwupload_cuda.c

• Encode HEVC/H.265/HDR Video for YouTube from 10bit Pro-Res using FFmpeg

  30 janvier 2018, par Rodrigo Polo

  I want to have an HDR YouTube video published, my source file is either an Apple ProRes or DNxHR using a chroma subsamplig 4:4:4 or full RGB, both 10bit, so the original source file has all what is needed in order to be encoded into a 10bit 4:2:0 H.265/HEVC (HDR).

  I have followed some answers listed here, reviewed lots of different approaches, tried out many different commands without success, colors aren’t right when using only FFmpeg, to much red, when using only Adobe to encode into H.264 with the recommended settings on their support page, the results is darker, here are the commands I’ve using :

  I have tried this :

  ffmpeg \
  
  -i input.mov \
  
  -c:v libx265 \
  
  -tag:v hvc1 \
  
  -crf 21 \
  
  -preset fast \
  
  -pix_fmt yuv420p10le \
  
  -x265-params "colorprim=bt2020:transfer=smpte2084:colormatrix=bt2020nc:master-display=G(13250,34500)B(7500,3000)R(34000,16000)WP(15635,16450)L(10000000,10):max-cll=1000,400" \
  
  -c:a libfdk_aac \
  
  -b:a 128k \
  
  -ac 2 \
  
  -ar 44100 \
  
  -movflags +faststart \
  
  output.mp4

  And this :

  ffmpeg \
  
  -y \
  
  -hide_banner \
  
  -i input.mov \
  
  -pix_fmt yuv420p10le \
  
  -vf "scale=out_color_matrix=bt2020:out_h_chr_pos=0:out_v_chr_pos=0,format=yuv420p10" \
  
  -c:v libx265 \
  
  -tag:v hvc1 \
  
  -crf 21 \
  
  -preset fast \
  
  -x265-params 'crf=12:colorprim=bt2020:transfer=smpte-st-2084:colormatrix=bt2020nc:master-display="G(13250,34500)B(7500,3000)R(34000,16000)WP(15635,16450)L(10000000,1)":max-cll="1000,400"' \
  
  -c:a libfdk_aac \
  
  -b:a 128k \
  
  -ac 2 \
  
  -ar 44100 \
  
  -movflags +faststart \
  
  output.mp4

  I have also tried using MKVToolNix in order to insert the metadata into the encoded HEVC/H.265 file with the following command :

  /Applications/MKVToolNix-9.7.1.app/Contents/MacOS/mkvmerge \
  
  -o output.mkv \
  
  --colour-matrix 0:9 \
  
  --colour-range 0:1 \
  
  --colour-transfer-characteristics 0:16 \
  
  --colour-primaries 0:9 \
  
  --max-content-light 0:1000 \
  
  --max-frame-light 0:300 \
  
  --max-luminance 0:1000 \
  
  --min-luminance 0:0.01 \
  
  --chromaticity-coordinates 0:0.68,0.32,0.265,0.690,0.15,0.06 \
  
  --white-colour-coordinates 0:0.3127,0.3290 \
  
  input.mp4

  But the result is the same and YouTube don’t recognize the file as an HDR file, it does only with the first FFmpeg command and with the file encoded with Adobe Premiere, but the colors don’t look well, so, maybe I’m getting some concept wrong, thanks for your help.

• Is it possible .FLV to .MP4 conversion on client side by ffmpeg-asm.js ?

  24 mars 2016, par Egor M.

  Is it possible to do .FLV to .MP4 conversion on client side by ffmpeg-asm.js ?
  The main issue lot’s of mobile video players didn’t support flash, but .FLV still popular at the internet ;(

  Have no idea how to avoid server-side conversion and storing...