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• 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.

• starting ffmpeg on an explicit frame

  15 février 2018, par resatee

  I am trying to slica a file. I want the first part to end after 1550 frames and the second one to go from frame 1551 to 3000. The first part wasn’t a problem, I used that line :

  ffmpeg.exe -i foo.hevc -c copy -frames:v 1549 -s 1920x1080 foo_1sthalf.hevc

  For the second part I tried this :

  ffmpeg.exe -ss 30 -i foo.hevc -c copy -s 1920x1080 foo_2ndhalf.hevc

  and this :

  ffmpeg.exe -ss 00:00:30 -i foo.hevc -c copy -s 1920x1080 foo_2ndhalf.hevc

  and this :

  ffmpeg.exe -start_number 1550 -i foo.hevc -c copy -s 1920x1080 foo_2ndhalf.hevc

  but nothing worked.
  Error message is always :

  could not seek to position 30.000

  Do you know a way to start at a certain frame ?
  I have ffmpeg version 3.2

• Trouble with hardware-assisted encoding/decoding via FFmpeg on Azure GPU vm's (ubuntu 16.04)

  17 avril 2018, par user3776020

  I am trying to use NVIDIA hardware acceleration with FFmpeg/libav, but can’t get it to work correctly on Azure vm’s running Ubuntu 16.04. For a sample case, I am trying to do a simple decoding of an h264 video into a raw YUV file (as detailed here : https:// developer.nvidia.com/ffmpeg).

  So far, I’ve tried it on NC-6, NC-12, and NV-6 machines (in different regions). In each of these instances, it would take about 30-45 seconds to process a single video frame. As a comparison, I also tried it on a P2.xlarge vm on AWS (which has very similar specs to the NC-6), which was able to process about 3000 frames in about 5 seconds. Has anyone else run into this issue with Azure machines, or has any idea why this would be the case ?

  Here are the commands I used to install the necessary drivers/libraries/etc (I also verified that each machine as the same NVIDIA driver version installed - 375.51) :

  CUDA_REPO_PKG=cuda-repo-ubuntu1604_8.0.61-1_amd64.deb

  wget -O /tmp/$CUDA_REPO_PKG
  http://developer.download.nvidia.com/compute/cuda/repos/ubuntu1604/x86_64/$CUDA_REPO_PKG

  sudo dpkg -i /tmp/$CUDA_REPO_PKG

  sudo apt-get update

  sudo apt-get install -y cuda-drivers

  sudo apt-get install -y cuda

  sudo apt-get install -y nvidia-cuda-toolkit

  [reboot]

  sudo apt-get update

  sudo apt-get upgrade -y

  sudo apt-get dist-upgrade -y

  [reboot]

  git clone https://github.com/FFmpeg/FFmpeg.git

  [download the latest video codec SDK from NVIDIA at : https://
  developer.nvidia.com/designworks/video_codec_sdk/downloads/v7.1]

  [unzipped codec, and copy header files from
  /Video_Codec_SDK_7.1.9/Samples/common/inc/ into /usr/include/]

  cd /FFmpeg

  ./configure —enable-nonfree —disable-shared —enable-nvenc
  —enable-cuda —enable-cuvid —enable-libnpp —extra-cflags=-Ilocal/include —extra-cflags=-I../nv_sdk —extra-ldflags=-L../nv_sdk

  sudo make && sudo make install

  For the FFmpeg command that I used to decode a sample movie file, I used the following :

  sudo ffmpeg -vsync 0 -c:v h264_cuvid -i sample_vid.mp4 -f rawvideo outputvid.yuv