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I am trying to convert a 4K HEVC MKV file of 70GB into another HECV file but with less size. I am using FFmpeg with Nvidia acceleration but when I execute the following command an error appears:

ffmpeg -y -vsync 0 -hwaccel_device 0 -hwaccel cuvid -c:v hevc_cuvid -i input.mkv -c:a copy -c:v hevc_nvenc -preset slow -b:v 10M -bufsize 10M -maxrate 15M -qmin 0 -g 250 -bf 2 -temporal-aq 1 -rc-lookahead 20 -i_qfactor 0.75 -b_qfactor 1.1 output.mkv

The error is: 

[hevc_nvenc @ 0000021036b0d000] Provided device doesn't support required NVENC features
Error initializing output stream 0:0 -- Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

The video file has these details:

enter image description here

It seems that FFmpeg cannot recognize my GPU as a supported device to decode but I have read that Nvidia has support for my card with NVDEC.

I am running Windows 10 64 bits with i7 4790 and GTX 1080

genpfault
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Nestoraj
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  • It's nothing to do with nvdec here. That error message is from `hevc_nvenc` and told you your encoding arguments is not compatible with nvenc. – halfelf Jan 23 '18 at 04:13

1 Answers1

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NVENC doesn't support encoding B-frames, so -bf 0 and drop -b_qfactor 1.1.

Gyan
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  • Thanks for your reply Mulvya, how do you know that NVENC does not support these parameters? Is there any webpage where I can find what parameters support? – Nestoraj Jan 23 '18 at 21:41
  • See the comment by a Nvidia dev at https://devtalk.nvidia.com/default/topic/1011921/video-codec-sdk/-nvidia-video-codec-sdk-8-0-14-encoder-b-frames-is-do-you-support-it-/post/5189266/#5189266 – Gyan Jan 24 '18 at 16:12