NVIDIA NVENC support

[raymater]

Checklist

• I'm reporting a feature request
• I've verified that I'm running youtube-dl version 2020.03.24
• I've searched the bugtracker for similar feature requests including closed ones

Description

I've tried to pass args for NVENC FFMPEG with external-downloader-args. But it doesn't work because it's not make for encode (to H.264 MP4) but for download, as a result if I try to passed some args for hardware encode : it doesn't work when YouTube-DL try to download the video. How I can force NVENC transcode for YouTube-DL? Can you add this feature? Would like to have this feature because my CPU is used for encode.

[tripulse]

To understand what is going wrong, the full/verbose output of youtube-dl is required.
Try running with the --verbose flag and post the output of it.

[raymater]

Command : '/usr/local/bin/youtube-dl' 'my_youtube_video' '--no-playlist' '--ignore-config' '--write-info-json' '--continue' '--output=%(title)s.%(ext)s' '--cache-dir=my_cache_path' '--restrict-filenames' '--format=bestvideo+bestaudio' '--recode-video=mp4' '--external-downloader=ffmpeg' '--external-downloader-args=-hwaccel_output_format cuda -c:v h264_nvenc -preset slow'

Exit Code: 1(General error)

Result : Unknown decoder 'h264_nvenc'

My FFMPEG support h264_nvenc :
ffmpeg version N-97538-gc810a9502c Copyright (c) 2000-2020 the FFmpeg developers built with gcc 8 (Debian 8.3.0-6) configuration: --enable-nonfree --enable-nvenc --enable-libx264 --enable-gpl --enable-cuda --enable-cuvid --enable-cuda-nvcc libavutil 56. 43.100 / 56. 43.100 libavcodec 58. 82.100 / 58. 82.100 libavformat 58. 42.101 / 58. 42.101 libavdevice 58. 9.103 / 58. 9.103 libavfilter 7. 80.100 / 7. 80.100 libswscale 5. 6.101 / 5. 6.101 libswresample 3. 6.100 / 3. 6.100 libpostproc 55. 6.100 / 55. 6.100

It consider that the h264_nvenc is the decoder but how can I declare it for only encoder?

[tripulse]

This is still not a verbose log. Run this command and send the output:

'/usr/local/bin/youtube-dl' my_youtube_video --no-playlist --ignore-config --write-info-json --continue --output='%(title)s.%(ext)s' --cache-dir=my_cache_path --restrict-filenames --format='bestvideo+bestaudio' --recode-video=mp4 --external-downloader=ffmpeg --external-downloader-args='-hwaccel_output_format cuda -c:v h264_nvenc -preset slow' --verbose

[raymater]

I resolve my problem, it works !

In postprocessor-args, I had to have this : '--postprocessor-args=-c:v h264_nvenc -preset slow'.
Do not use --external-downloader-args and --external-downloader for this.

Also I had to upgrade my NVIDIA drivers because FFMPEG support NVENC on drivers v435 or more recent.

[steam3d]

Can you write the right command? I still has trouble with h264_nvenc

[raymater]

Can you write the right command? I still has trouble with h264_nvenc

'/usr/local/bin/youtube-dl' 'url_youtube_video' '--no-playlist' '--ignore-config' '--write-info-json' '--continue' '--output=%(title)s.%(ext)s' '--cache-dir=my_cache_path' '--restrict-filenames' '--format=bestvideo+bestaudio' '--recode-video=mp4' '--postprocessor-args=-c:v h264_nvenc -preset slow'

Replace url_youtube_video by your URL and my_cache_path by your folder that you want to declare like a cache directory (optional).