[FFmpeg-user] Ffmpeg Nvenc GPU decode , set hwaccel_device not work

Dennis Mungai dmngaie at gmail.com
Mon Dec 24 20:35:35 EET 2018

On Mon, 24 Dec 2018 at 21:23, dd <unicorok at 163.com> wrote:

> Dear my friend,
> We replace cpu with gpu to ffmpeg recently, I set the gpu device no, but
> it still use default device 0.
> As the following problem Code:
> ffmpeg -hwaccel_device 2 -hwaccel cuvid -i a.mp4 -vf
> “scale=1080:720,overlay=()” -c:v h264_nvenc out.mp4
> I found if use “scale_npp” replace  “scale” will work with device 2, but
> in that way, we will lost some filter functions
> like overlay,suntitles burning,and so on.Is there some parameters of
> scale_npp with the same functions?
> Or how can I implement add water picture on gpu platform with seted device
> number?
> Linux server has 5 NVIDIA card, i see it use device 0 always by the
> nvidia-smi tool.
> Hope your help, thank you!


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You must add the -gpu option to ffmpeg, passed to the NVENC encoder(s), as
shown below with the example you provided::

ffmpeg -hwaccel_device 2 -hwaccel cuvid -i a.mp4 -vf
“scale=1080:720,overlay=()” -c:v h264_nvenc -gpu 2 out.mp4

That should use the selected device, ie gpu 2.

Now, retest and report back.

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