For full GPU transcoding, shouldn't -hwaccel be nvdec? FFmpeg's documentation on this is missing, but for NVENC, the decoder should be set to nvdec.
On Fri, 24 Aug 2018 at 01:24, Yang Zhang <[email protected]> wrote: > If you didn't specify -hwaccel option, then the full gpu transcoding > is disabled. for example: > > 1. full gpu transcoding. > $ ffmpeg -hwaccel cuvid -c:v h264_cuvid -i test.ts -c:v h264_nvenc ... > > 2. gpu transcoding via memory copy. > $ ffmpeg -c:v h264_cuvid -i test.ts -c:v h264_nvenc ... > > 3. cpu decoding and gpu encoding. > $ ffmpeg -i test.ts -c:v h264_nvenc ... > > > > On 8/24/18, Dennis Mungai <[email protected]> wrote: > > Is it possible to disable hwaccel decode explicitly in an FFmpeg > instance? > > > > Say, -hwaccel none such that no hardware-accelerated decoder instance is > > initialized on launch? > > > > > > > > On Fri, 24 Aug 2018 at 01:14, Yang Zhang <[email protected]> wrote: > > > >> 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 <[email protected]> > 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 <[email protected]> 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 <[email protected]> > >> wrote: > >> > > > >> > > > No. > >> > > > > >> > > > This is as tested on the Tesla P100. > >> > > > > >> > > > On Fri, 24 Aug 2018 at 00:26, Pedro Daniel Costa < > >> > > > [email protected]> > >> > > > 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:[email protected]] 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. > >> > > > > _______________________________________________ > >> > > > > ffmpeg-user mailing list > >> > > > > [email protected] > >> > > > > http://ffmpeg.org/mailman/listinfo/ffmpeg-user > >> > > > > > >> > > > > To unsubscribe, visit link above, or email > >> > > > [email protected] > >> > > > > with subject "unsubscribe". > >> > > > > _______________________________________________ > >> > > > > ffmpeg-user mailing list > >> > > > > [email protected] > >> > > > > http://ffmpeg.org/mailman/listinfo/ffmpeg-user > >> > > > > > >> > > > > To unsubscribe, visit link above, or email > >> > > > > [email protected] with subject "unsubscribe". > >> > > > _______________________________________________ > >> > > > ffmpeg-user mailing list > >> > > > [email protected] > >> > > > http://ffmpeg.org/mailman/listinfo/ffmpeg-user > >> > > > > >> > > > To unsubscribe, visit link above, or email > >> > > > [email protected] with subject "unsubscribe". > >> > > _______________________________________________ > >> > > ffmpeg-user mailing list > >> > > [email protected] > >> > > http://ffmpeg.org/mailman/listinfo/ffmpeg-user > >> > > > >> > > To unsubscribe, visit link above, or email > >> > > [email protected] with subject "unsubscribe". > >> > _______________________________________________ > >> > ffmpeg-user mailing list > >> > [email protected] > >> > http://ffmpeg.org/mailman/listinfo/ffmpeg-user > >> > > >> > To unsubscribe, visit link above, or email > >> > [email protected] with subject "unsubscribe". > >> _______________________________________________ > >> ffmpeg-user mailing list > >> [email protected] > >> http://ffmpeg.org/mailman/listinfo/ffmpeg-user > >> > >> To unsubscribe, visit link above, or email > >> [email protected] with subject "unsubscribe". > > _______________________________________________ > > ffmpeg-user mailing list > > [email protected] > > http://ffmpeg.org/mailman/listinfo/ffmpeg-user > > > > To unsubscribe, visit link above, or email > > [email protected] with subject "unsubscribe". > _______________________________________________ > ffmpeg-user mailing list > [email protected] > http://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > [email protected] with subject "unsubscribe". _______________________________________________ ffmpeg-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
