Jan 11, 2021, 23:27 by felix.leclair...@hotmail.com: > Hi guys and gals, first post on this mailing list, apologies for any > formatting/stylistic snafus > > TLDR; we currently have tone mapping filters (typically used to map content > from a 10bit HDR source to an 8bit SDR output) that are done on CPU with > Zscale from Zlib, or hardware implementations using VAAPI or OpenCL. Having a > version implemented in CUDA would round out the main HWaccels types. > > Context: > I'm a computer engineering student up in Canada with an interest in high > efficiency distributed processing. As a personal project I'm trying to build > a cluster of Nvidia Jetson Nano's to be able to handle a few dozen streams > (mix of SD, HD, FHD, UHD, 4kHDR) at once while drawing south of 100W at peak. > These little devices can do anywhere from 1 to 9 streams of content at a time > depending on resolution/framerate in hardware in any mix of HEVC or H.264, so > 3 of them should get me most of the way to where I want to go (this would be > a 30W package capable of ~12 2160p30@10 bit -> 1080p30 8bit streams). > > The issue is that, 4 little arm64 cores are just not going to be able to > tonemap using Zscale in real time, even with the encoder and decoders sharing > memory with the CPU (so no PCIe memcopy penalty). On the other hand, the > built in GPU and the relative simplicity of most tone mapping algorithms (say > hable) should make quick work of this. Unfortunately (or fortunately for me > to learn with?) there isn't a CUDA version of the filter. > > Question/guidance: > I've read through the doc on how to write filters, as well as looking at the > other cuda filters currently in the source and have a general idea of where > I'm going, but haven't been able to fully nail down how to access frames from > hwupload_cuda passed to vf_tonemap_cuda.c which in turn passes that frame to > vf_tonemap_cuda.cu for processing. I have a repo with everything I've been > pulling together for my project, but the piece of interest is under > */cuda_filter/ in the source tree. > <https://github.com/Camofelix/Jetson_ffmpeg_trancode_cluster/> > > Would anyone mind helping me out with how to architect this? >
The tonemap filter is just a (very old by now) copy of libplacebo's tonemapping. No one has bothered to keep it in sync. I'm working on a libplacebo wrapper currently, so once that's merged there will be up to date hardware tonemapping. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
