[FFmpeg-user] RES: A question on the Quadro P6000 and maximum simultaneous NVENC encodes in FFmpeg

[Yang Zhang]

Yes, 25 hd1080p channels use -hwaccel cuvid options to do full hardware
acceleration transcoding. other channels use the GPU encoding only. this
should can let you transcoding more channels. and fix the stutter problem.

You can use "nvidia-smi dmon" to check the usage of NVDEC/ENC chips.

On Fri, Aug 24, 2018 at 6:02 AM Dennis Mungai <dmngaie at gmail.com> wrote:

> So, to clarify:
>
> If you were to disable hwaccel decode (and rely solely on software-based
> decoding) BUT utilize NVENC on a system with a beefy processor and adequate
> RAM, you should be able to eliminate the bottleneck, correct?
>
> Because what you're implying (by the bottleneck at decode side) would be a
> limitation in how FFmpeg handles filter performance (hwupload, to be
> exact), an issue that can be circumvented by eliminating hwaccel in decode.
>
>
>
> On Fri, 24 Aug 2018 at 00:57, Yang Zhang <yzfedora at gmail.com> wrote:
>
> > The problem is even you using the Tesla P100, and you can see it has 3
> > NVENC chips inside it. but it has only 1 NVDEC chip, this is very very
> > important. the bottleneck is at decoding side. this is why you got
> freezing
> > or stutter problem. basically, perhaps you can use Tesla P100 encoding 75
> > hd1080p channels, but you can not decoding more than 25 hd1080p channels
> on
> > it.
> >
> > On Fri, Aug 24, 2018 at 5:51 AM Dennis Mungai <dmngaie at gmail.com> wrote:
> >
> > > No.
> > >
> > > This is as tested on the Tesla P100.
> > >
> > > On Fri, 24 Aug 2018 at 00:26, Pedro Daniel Costa <
> > > portalnet2 at outlook.com.br>
> > > wrote:
> > >
> > > > Ok
> > > >
> > > > But with the TESLA models, did you have any issues over 40 streams?
> > > >
> > > > I am planning on budge project to run minimum 100channels
> > > >
> > > > -----Mensagem original-----
> > > > De: ffmpeg-user [mailto:ffmpeg-user-bounces at ffmpeg.org] Em nome de
> > > Dennis
> > > > Mungai
> > > > Enviada em: quinta-feira, 23 de agosto de 2018 13:54
> > > > Para: FFmpeg user questions
> > > > Assunto: [FFmpeg-user] A question on the Quadro P6000 and maximum
> > > > simultaneous NVENC encodes in FFmpeg
> > > >
> > > > Hello there,
> > > >
> > > > For users with this specific card (and FFmpeg installed), kindly
> > clarify
> > > > on the following:
> > > >
> > > > (a). How many simultaneous encoder sessions can you run on this card?
> > > >
> > > > (b). Have you ran into any issues, such as stuttering and dropping
> > > streams
> > > > with multiple concurrent encodes?
> > > >
> > > > I ask because of a recent case where adding more than ~40 concurrent
> > > > encodes would make the output "drop" and stutter massively, as if
> > FFmpeg
> > > > itself was hanging, despite the GPU having more than enough VRAM
> > (24GB?)
> > > > and resources (under ~11% utilization according to nvidia-smi),
> > implying
> > > > some sort of artificial limitation in effect despite the GPU support
> > > matrix
> > > > specifying otherwise:
> > > > https://developer.nvidia.com/video-encode-decode-gpu-support-matrix
> > > >
> > > > Your feedback on this is appreciated.
> > > > _______________________________________________
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