[FFmpeg-user] The option of -hwaccel device doesn't works well(FFmpeg n3.4)

James Girotti james.girotti at gmail.com
Sat Nov 4 20:50:13 EET 2017

On Fri, Nov 3, 2017 at 7:48 PM, Baek Seung Hoon <seung51hoon at gmail.com>

> Hello,
> Thanks to your reply :-)
> As your mentions, Hw decoder already has resize option.
> Why I use scale_npp filter with Sw decoder is Hw decoder(=cuvid) couldn't
> read some of video files while Sw decoder(=h264) could read it.
> So I choose a decoder this way -> use the Sw decoder if Hw decoder failed
> read video file.

Like I mentioned; not really a problem to use sw-decoder. You should use
whatever you want/need.

> Your reply message is helpful to me ^^.
> But I have a problem what same as previous mail.
> In case that I use both Sw decoder and Hw encoder with below command, and
> Only GPU0 encoder have working.
> I did change option as -gpu 0 or -gpu 1, it doesn't affect.

Have you tried using sw-decoder->hw-decoder without scale-npp? Something

ffmpeg -i ./input.mp4 -c:v h264_nvenc -gpu 1 -c:a copy ./output.mp4

Does that use the correct GPU?

I assume that "hwupload_cuda" have a unknown bug because "gpu" option was
> works well when I remove "hwupload_cuda".

I think it's uploading to GPU 0 by default. There is an option 'device' for
hwupload_cuda. Could you try specifying the device for hwupload_cuda?

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