Very cool work explained well.
Take something like Rocket League for example. Definitely doesn't have velocity buffers.
Yes even Rocket League has it
How did you reach this conclusion? Rocket League looks like a game that definitely have velocity buffers to me. (Many fast-moving scenarios + motion blur)
Doesn't work for translucency and shader animation. The latter can be made to work if the shader can also calculate motion vectors.
- In a 3d game, a motion vector is the difference between the position of an object in 3d space from the previous to the current frame
- In H.264, the 'motion vector' is basically saying - copy this rectangular chunk of pixels from some point from some arbitrary previous frame and then encode the difference between the reference pixels and the copy with JPEG-like techniques (DCT et al)
This block copying is why H.264 video devolves into a mess of squares once the bandwidth craps out.
I haven't in a while but I used to use https://parsec.app/ on a cheap intel Air to do my STO dailies on vacation. It sends inputs, but gets a compressed stream. Im curious of any OS of something similar.
It was always shocking to me that Stadia was literally making their own games in house and the end result was just a streamed video and the latency gains were supposed to come from edge deployed gpus and a wifi-connected controller.
VR games already do something like this, so that when a game runs at below the maximum FPS of the VR headset, it can still respond to your head movements. It's not perfect because there's no parallax and it can't show anything for the region that was previously outside of your field of view, but it still makes a huge difference. (Of course, it's more important for VR because without doing this, any lag spike in a game would instantly induce motion sickness in the player. And if they wanted to, parallax could be faked using a depth map)
That's a misconception. All modern video codecs (i.e. H.264/AVC, H.265/HEVC, AV1) have explicit, first-class tools, profiles, and reference modes aimed at both low- and high-resolution low‑latency and/or low‑complexity use.
AV1: Improving RTC Video Quality at Scale: https://atscaleconference.com/av1-improving-rtc-video-qualit...
Objective metrics and tools for video encoding and source signal quality: netflix/vmaf, easyVmaf, psy-ex/metrics, ffmpeg-quality-metrics,
Ffmpeg settings for low-latency encoding:
# h264, h265
-preset ultrafast
-tune zerolatency
# AV1
-c:v libsvtav1
-preset 8
-svtav1-params tune=0:latency-mode=1
-g 60
It's possible to follow along with ffmpeg encoding for visual inspection without waiting for the whole job to complete with the tee muxer and ffplay.GPU Screen Recorder and Sunlight server expose some encoder options in GUI forms, but parameter optimization is still manual; nothing does easyVmaf with thumbnails of each rendering parameter set with IDK auto-identification of encoding artifacts.
Ardour has a "Loudness Analyzer & Normalizer" with profiles for specific streaming services.
What are good target bitrates for low-latency livestreaming 4k with h264, h265 (HDR), and AV1?
> The go-to solution here is GPU accelerated video compression
Isn't the solution usually hardware encoding?
> I think this is an order of magnitude faster than even dedicated hardware codecs on GPUs.
Is there an actual benchmark though?
I would have assumed that built-in hardware encoding would always be faster. Plus, I'd assume your game is already saturating your GPU, so the last thing you want to do is use it for simultaneous video encoding. But I'm not an expert in either of these, so curious to know if/how I'm wrong here? Like if hardware encoders are designed to be real-time, but intentionally trade off latency for higher compression? And is the proposed video encoding really is so lightweight it can easily share the GPU without affecting game performance?
Generally, you're right that these hardware blocks favor latency. One example of this is motion estimation (one of the most expensive operations during encoding). The NVENC engine on NVidia GPUs will only use fairly basic detection loops, but can optionally be fed motion hints from an external source. I know that NVidia has a CUDA-based motion estimator (called CEA) for this purpose. On recent GPUs there is also the optical flow engine (another separate block) which might be able to do higher quality detection.
It'd be interesting to see benchmarks against H.264/AVC (see example "zero‑latency" ffmpeg settings below) and JPEG XS.
-c:v libx264 -preset ultrafast -tune zerolatency \
-x264-params "keyint=1:min-keyint=1:scenecut=0:rc-lookahead=0" \
-bf 0 -b:v 8M -maxrate 8M -bufsize 1M
FWIW, there's also the non-free JPEG-XS standard [1] which also claims very low latency [2] and might be a safer choice for commercial projects, given that there is a patent pool around it.
https://www.filmlight.ltd.uk/store/press_releases/filmlight-...
We currently use the IntoPIX CUDA encoder/decoder implementation, and SRT for the low-level transport.
You can definitely achieve end-to-end latencies <16ms over decent networks.
We have customers deploying their machines in data centres and using them in their post-production facilities in the centre of town, usually over a 10GbE link. But I've had others using 1GbE links between countries, running at higher compression ratios.
Also, modern game textures are a lot of data.
I suppose the issue would be media. Faster to load locally than push it out. Could be semi solved with typical web caching approaches.
You're doing something wrong if nvenc is any slower, the llhp preset should be all you need.
https://streaminglearningcenter.com/codecs/an-interview-with...
Ultra low latency for streaming.
The two things that increase latency are more advanced processing algorithms, giving the encoder more stuff to do, and schemes that require waiting multiple frames. If you go disable those, the encoder can pretty much start working on your frame the nanosecond the GPU stops rendering to it, and have it encoded in <10ms.
For context, OP achieved 0.13 ms with his codec.
One thing to note when designing a new video codec is to carpet bomb around the idea with research projects to stake claim to any possible feature enhancements.
Anything can have an improvement patent filed against, no matter the license.
I think the main advantage is perhaps the robustness against packet drops is better.
Maybe I should try for that next weekend.
You are standing in an open field west of a white house, with a boarded front door. There is a small mailbox here.
Frame 2:
A few blades of grass sway gently in the breeze. The camera begins to drift slightly, as if under player control — a faint ambient sound begins: wind and birds.
If the author is reading this, it would be very interesting to read about the differences between this method and HTJ2K.
For those interesting in the ultra low latency space (where you’re willing to trade a bit of bandwidth to gain quality and minimise latency), VSF have a pretty good wrap up of other common options and what they each optimise for: https://static.vsf.tv/download/technical_recommendations/VSF...
Fidelix•6h ago
Can't wait until one day this gets into Moonlight or something like it.
cpeth•6h ago