Actually, specifying -hwaccel nvdec just works. See the debug log. Tested on the current git master.
It's more of a case of missing documentation. On Fri, 24 Aug 2018 at 01:32, Yang Zhang <[email protected]> wrote: > for some reason, the developer called it cuvid, but nvidia called it > nvdec. so there is -hwaccel nvdec is a wrong option. > > On 8/24/18, Dennis Mungai <[email protected]> wrote: > > 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". > _______________________________________________ > 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".
