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".
