Frozen History: When Temporal Losses Stop Accumulation in Learned Real-Time Supersampling
Organizations: ELLIS Institute Finland · CMVS, University of Oulu, Finland
Abstract
Learned real-time supersampling accumulates jittered low-resolution samples along motion vectors. Many methods use a temporal consistency loss to reduce flicker. We show that with accurate registration, this loss can suppress accumulation: on static content, the network copies its warped history at almost no temporal cost. Camera jitter in motion vectors raises this cost and can hide the effect. We identify four registration errors that training can conceal: jitter-carrying motion vectors, one motion field for both resolution lattices, jittered depth, and an unregistered skip path. A model-free oracle shows that correct registration makes freezing two orders of magnitude cheaper on static pixels. Controlled training shows that registration reverses the temporal weight's effect on PSNR. Under exact registration, increasing the weight reduces pixel variance at the expense of accuracy and perceived quality, with a 0.7 to 0.9 dB loss on static frames at weight 0.25. This reversal recurs across three network families and two scales; the loss also reduces accuracy on unjittered STSS data. With a small temporal weight and a normalised sample accumulator, a plain registered network improves the best published QRISP PSNR by 0.34 to 0.62 dB at 2, 3 and 4 upscaling to 1080p. At 2, its static pixel standard deviation is one quarter that of DLSS 2. Without retraining, it outperforms classical temporal upsampling by at least 4.4 dB on Arm's jittered Bistro capture. Our most accurate 4 model runs in 2.03 ms per 1080p frame on an H200. Code: https://github.com/CV-AC/Frozen_history
Figures & tables
| J: PSNR-Y | R: PSNR-Y | |||||
|---|---|---|---|---|---|---|
| Setting | static | moving | all | static | moving | all |
| Ours, 4 | +0.11 | +0.10 | +0.09 | 0.86 | 0.24 | 0.27 |
| Ours, 2 | +0.23 | +0.20 | +0.20 | 0.68 | 0.05 | 0.09 |
| QRISP-style a | +0.31 | +0.23 | +0.23 | 0.85 | 0.30 | 0.32 |
| Direct prediction | +0.12 | +0.12 | +0.11 | 0.70 | 0.29 | 0.31 |
| Ours, | +0.05 | +0.07 | +0.07 | 0.19 | 0.00 | 0.02 |
| Method | Iter. | ms | PSNR-Y | SSIM-Y | LPIPS | FLIP | JOD | tPSNR | Static PSNR | Static FLIP | Static std | JOD s |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2 (960 540 1920 1080) | ||||||||||||
| Ours (192 8) | 100k | — | 32.69 | 0.9246 | 0.091 | 0.0570 | 8.61 | 33.57 | 37.57 | 0.0458 | 0.096 | 8.26 |
| DLSS 2 (shipped frames) | — | — | 30.12 | 0.8821 | 0.151 | 0.0732 | 8.22 | 31.55 | 36.25 | 0.0546 | 0.41 | 7.96 |
| TAAU (classical) | — | — | 29.99 | 0.8740 | 0.162 | 0.0743 | 7.99 | 31.09 | 35.43 | 0.0568 | 0.67 | 7.61 |
| FSR 1.2 [ 1 ] (shipped, spatial) ¶ | — | — | 29.44 | 0.8668 | 0.160 | 0.0708 | 7.88 | 28.49 | 32.80 | 0.0585 | 0.010 | 7.08 |
| Bicubic (our harness) | — | — | 29.31 | 0.8649 | 0.217 | 0.0719 | 7.81 | 28.40 | 32.63 | 0.0593 | 0.011 | 7.01 |
| (a) Arm Bistro, jittered, zero-shot | |||||
|---|---|---|---|---|---|
| Method | PSNR-Y | SSIM-Y | LPIPS | FLIP | JOD |
| Bicubic | 22.57 | 0.7743 | 0.269 | 0.1576 | 7.22 |
| Bicubic, registered | 24.21 | 0.8283 | 0.259 | 0.1241 | 7.70 |
| Lanczos-3 | 22.41 | 0.7662 | 0.291 | 0.1575 | 7.17 |
| TAAU (classical) | 27.16 | 0.9075 | 0.111 | 0.0922 | 8.58 |
| TAAU, clamp (classical) | 27.23 | 0.9103 | 0.107 | 0.0922 | 8.61 |
| Variant | Seed | PSNR-Y | LPIPS | STD s |
|---|---|---|---|---|
| (a) Ours, 4, 45k, | ||||
| Normalised, 30 frames | 0 | 29.74 | 0.196 | 0.43 |
| Single predicted blend | 0 | 29.71 | 0.195 | 0.53 |
| Normalised, 16 frames | 0 | 29.60 | 0.208 | 0.33 |
| (b) History, 45k, , 30 frames | ||||
| 2, recurrent | — | 32.58 | 0.095 | 0.11 |
| Requirement | Measurement | Value |
|---|---|---|
| (1) history on the output lattice | copy cost ( , ) on static pixels, vs. | vs. (118 ) |
| same on the longest camera stop / on moving frames | 1304 / 2.2 | |
| held-copy PSNR ( , all frames), vs. , 4 / 3 / 2 | 35.71/25.45, 35.89/26.51, 36.09/28.30 dB | |
| (2) state on the input lattice | previous LR frame carried with (Equation 5 ) vs. with | 28.35 vs. 26.52 dB |
| (3) unjittered depth | mean reprojected depth change , static segment, jittered vs. unjittered | about |
| (4) registered skip | gain of the registered bicubic skip, moving SeaPort frames (5 frames) | to dB |
| PSNR-Y | tPSNR | Std s | JOD | FLIP | ||
| R: registered pipeline | ||||||
| 0 | 29.75 | 30.59 | 0.77 | 7.64 | 0.034 | 0.0801 |
| 0.05 | 29.74 | 30.95 | 0.43 | 7.55 | 0.0829 | |
| 0.25 | 29.48 | 31.21 | 0.17 | 7.26 | 0.0881 | |
| 1 | 28.96 | 31.32 | 0.086 | 6.70 | 0.0980 | |
| J: misregistered pipeline | ||||||
| PSNR-Y | JOD s | copy fraction | ||||
|---|---|---|---|---|---|---|
| Setting | J | R | J | R | J | R |
| Ours | +0.09 | 0.27 | +0.03 | 0.38 | 0.20 0.23 | 0.85 0.99 |
| Ours, 2 | +0.20 | 0.09 | +0.01 | 0.14 | 0.32 0.45 | 0.87 1.00 |
| QRISP-style a | +0.23 | 0.32 | +0.10 | 0.69 | 0.11 0.16 | 0.70 0.98 |
| Direct prediction | +0.11 | 0.31 | +0.01 | 0.34 | 0.21 0.31 | 0.21 0.77 |
| Unwarped term | +0.08 | +0.09 | 0.11 | 0.10 | 0.20 0.55 | 0.85 0.96 |
| Run | PSNR-Y | SSIM-Y | LPIPS | tPSNR 60 | Std s | JOD | JOD s | copy | ||
|---|---|---|---|---|---|---|---|---|---|---|
| Our network, 4 | ||||||||||
| R | 29.75 | 0.8560 | 0.177 | 30.59 | 0.769 | 7.71 | 7.64 | 0.034 | 0.855 | |
| R | 29.48 | 0.8432 | 0.221 | 31.21 | 0.174 | 7.60 | 7.26 | 0.986 | ||
| J | 29.72 | 0.8528 | 0.193 | 30.15 | 1.361 | 7.70 | 7.58 | 0.61 | 0.199 | |
| J | 29.81 | 0.8571 | 0.179 | 30.28 | 1.332 | 7.71 | 7.61 | 0.46 | 0.234 | |
| Our network, 2 | ||||||||||
| J | R | ||||||
|---|---|---|---|---|---|---|---|
| Setting | static (97) | moving (1363) | all | static (97) | moving (1363) | all | |
| Ours, 4 | +0.11 | +0.10 | +0.09 | 0.86 | 0.24 | 0.27 | |
| Ours, 4 | +0.05 | +0.07 | +0.07 | 0.19 | 0.00 | 0.02 | |
| Ours, 4 | +0.02 | +0.04 | +0.02 | 1.98 | 0.74 | 0.80 | |
| Ours, 2 | +0.23 | +0.20 | +0.20 | 0.68 | 0.05 | 0.09 | |
| Ours, 2 a | — | — | — | 0.20 | +0.04 | +0.02 | |
| (a) QRISP-style architecture, QRISP, 4, 15k | ||||||
|---|---|---|---|---|---|---|
| Pipeline | PSNR-Y | tPSNR | Std s | JOD | ||
| R | 0 | 28.73 | 29.61 | 1.25 | 7.28 | 0.031 |
| R | 0.25 | 28.41 | 30.34 | 0.22 | 6.59 | |
| J | 0 | 28.32 | 28.82 | 1.98 | 6.92 | 0.42 |
| J | 0.25 | 28.54 | 29.03 | 1.86 | 7.02 | 0.31 |
| (b) STSS Arena, 2, no jitter, 45k | ||||||
| V1. Jitter: LR reference at the sample positions | |
|---|---|
| convention used | 0.0248 |
| mirrored | 0.0455 |
| mirrored | 0.0415 |
| axes swapped | 0.0433 |
| zero jitter | 0.0385 |
| V2. Motion: warped previous reference reference | |
| Run | PSNR | SSIM | LPIPS | FLIP | JOD | tPSNR |
|---|---|---|---|---|---|---|
| R, ( 2 grid) | 31.12 | 0.9476 | 0.041 | 0.0755 | 9.22 | 32.94 |
| R, | 30.96 | 0.9490 | 0.044 | 0.0803 | 9.20 | 33.78 |
| J, , own conv. | 31.06 | 0.9491 | 0.040 | 0.0845 | 9.12 | 32.10 |
| J, , own conv. | 31.32 | 0.9517 | 0.038 | 0.0814 | 8.99 | 32.84 |
| J, , jitter-free motion | 23.93 | 0.8081 | 0.170 | 0.1503 | 7.29 | 24.28 |
| Ours, sRGB space | 30.53 | 0.9565 | 0.042 | — | 9.10 | 32.35 |
| Arena | Lewis | SunTemple | Subway | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PSNR-Y | FLIP | JOD | PSNR-Y | FLIP | JOD | PSNR-Y | FLIP | JOD | PSNR-Y | FLIP | JOD | |
| Bicubic | 33.24 | 0.0561 | 8.93 | 32.83 | 0.0665 | 8.25 | 31.42 | 0.0804 | 7.93 | 29.87 | 0.0700 | 7.36 |
| TAAU | 32.18 | 0.0714 | 8.83 | 32.90 | 0.0698 | 8.31 | 31.12 | 0.0862 | 7.86 | 30.39 | 0.0712 | 7.54 |
| TAAU, clamp | 32.11 | 0.0724 | 8.81 | 32.81 | 0.0704 | 8.29 | 31.02 | 0.0873 | 7.83 | 30.37 | 0.0719 | 7.54 |
| Ours, | 34.16 | 0.0710 | 8.99 | 37.53 | 0.0466 | 9.16 | 31.64 | 0.0866 | 7.98 | 31.08 | 0.0703 | 7.65 |
| Ours, | 33.61 | 0.0875 | 8.86 | 37.62 | 0.0476 | 9.17 | 31.61 | 0.0865 | 7.93 | 31.09 | 0.0710 | 7.68 |
| Variant | PSNR-Y | LPIPS | tPSNR | Std s | |
|---|---|---|---|---|---|
| (a) R, , 192 8, 4, 45k | |||||
| final recipe | 29.74 | — | 0.196 | 30.95 | 0.43 |
| single- blend accumulator | 29.71 | 0.02 | 0.195 | 30.95 | 0.53 |
| 16-frame training clips | 29.60 | 0.14 | 0.208 | 30.95 | 0.33 |
| (b) R minus one piece, , 192 8, 4, 15k | |||||
| control, all pieces | 29.31 | — | 0.203 | 30.19 | 0.83 |
| Variant | PSNR-Y | LPIPS | tPSNR | Std s | |
|---|---|---|---|---|---|
| control, all pieces | 29.31 | — | 0.203 | 30.19 | 0.83 |
| control, all pieces, seed 1 | 29.38 | — | 0.223 | 30.25 | 0.74 |
| sample phase | 29.22 | 0.09 | 0.208 | 30.08 | 0.81 |
| registered skip | 29.28 | 0.03 | 0.205 | 30.14 | 0.80 |
| LR re-jitter | 29.19 | 0.12 | 0.210 | 30.12 | 0.81 |
| unjittered depth | div. | div. | div. | div. | div. |
| Model | Size | Iter. | Params | GFLOP | H200 ms | PSNR-Y |
| Measurements from main Table 2 | ||||||
| QRISP-M † | f32 / m3 | 500k | 71k | 18 | 0.443 | 29.06 |
| QRISP-L † | f64 / m5 | 500k | 0.27M | 70 | 0.698 | 29.42 |
| Ours, shift-MLP | 64 6 | 200k | 0.17M | 38 | 0.201 | 29.32 |
| Ours, shift-MLP | 64 8 | 200k | 0.20M | 47 | 0.301 | 29.35 |
| Ours | 64 4 | 200k | 0.36M | 89 | 0.332 | 29.32 |
| PSNR-Y (dB) | |||||
|---|---|---|---|---|---|
| Model | GPU | Iter. | fp16 | int8 | int8, worst scene |
| 64 4 | A100 | 15k | 0.000 | 0.128 | 0.214 |
| 64 4 | H200 | 15k | 0.000 | 0.127 | 0.214 |
| 192 8 | A100 | 45k | 0.000 | 0.352 | 0.489 |
| 192 8 | H200 | 45k | 0.000 | 0.341 | 0.480 |
| Model | H200 ms | 60 Hz | 120 Hz | Break-even ∗ |
|---|---|---|---|---|
| QRISP-M | 0.443 | 3% | 5% | 2 116 fps |
| QRISP-L | 0.698 | 4% | 8% | 1 343 fps |
| Ours, shift-MLP | 0.201 | 1% | 2% | 4 664 fps |
| Ours, shift-MLP | 0.301 | 2% | 4% | 3 115 fps |
| Ours | 0.332 | 2% | 4% | 2 824 fps |
| Ours | 0.524 | 3% | 6% | 1 789 fps |
| Iter. | Seed | PSNR-Y | LPIPS | Static PSNR | Static std | Med. | |
|---|---|---|---|---|---|---|---|
| 15k | 0 | 0 | 28.73 | 0.241 | 33.59 | 1.30 | 0.031 |
| 15k | 0.05 | 0 | 28.69 | 0.261 | 33.53 | 0.64 | 1.2 |
| 15k | 0.25 | 0 | 28.41 | 0.313 | 32.66 | 0.23 | 1.1 |
| 45k | 0 | 0 | 29.05 | 0.210 | 33.89 | 1.16 | 0.024 |
| 45k | 0 | 1 | 29.04 | 0.213 | 33.89 | 1.12 | 0.024 |
| 45k | 0.05 | 0 | 28.97 | 0.233 | 33.71 | 0.59 | 6.9 |
| Tier | Trunk | Size | lr | PSNR-Y | PSNR |
|---|---|---|---|---|---|
| (a) Conventional trunks | |||||
| S | plain conv (control) | 64 4 | 6.0e-4 | 28.75 | — |
| ECB re-parameterised | 64 4 | 6.0e-4 | 28.98 | +0.24 | |
| plain conv | 64 4 | 2.0e-3 | 28.98 | +0.23 | |
| ECB re-parameterised | 64 4 | 2.0e-3 | 28.88 | +0.13 | |
| U-Net 1-2-1 | 64/128 | 6.0e-4 | 28.76 | +0.01 | |
| Method | PSNR-Y | SSIM-Y | LPIPS | FLIP | JOD | Static std | |
|---|---|---|---|---|---|---|---|
| (a) Stateless and classical temporal upsamplers, QRISP | |||||||
| 2 | |||||||
| Bicubic | 29.31 | 0.8649 | 0.217 | 0.0719 | 7.81 | 0.011 | |
| Lanczos-3 | 29.17 | 0.14 | 0.8622 | 0.233 | 0.0718 | 7.78 | 0.011 |
| Lanczos-3, jittered input | 27.95 | 1.36 | 0.8271 | 0.237 | — | — | — |
| TAAU (variance clipping) | 29.99 | 0.8740 | 0.162 | 0.0743 | 7.99 | 0.67 | |
| PSNR-Y | F LIP | JOD | pixel std (8-bit) | ||||||
| Sequence / segment | Ours | DLSS 2 | Ours | DLSS 2 | Ours | DLSS 2 | Ours | DLSS 2 | Ref. |
| whole sequences (frames 8–299) | |||||||||
| AbandonedSchool/0000 | 25.87 | 24.58 | 0.1137 | 0.1282 | 7.77 | 7.35 | — | — | — |
| AbandonedSchool/0001 | 37.92 | 35.69 | 0.0384 | 0.0486 | 9.14 | 8.80 | — | — | — |
| SeaPort/0000 | 30.04 | 27.39 | 0.0525 | 0.0694 | 8.40 | 7.92 | — | — | — |
| SpaceShipDemo/0000 | 36.83 | 33.27 | 0.0400 | 0.0533 | 9.23 | 8.80 | — | — | — |
| Abandoned- | SpaceShipDemo | ||||||
|---|---|---|---|---|---|---|---|
| School | SeaPort | all | 0000 | 0001 | Mean | ||
| 0 | R | 28.95 | 27.59 | 32.72 | 33.96 | 31.47 | 29.75 |
| J | 28.86 | 27.44 | 32.85 | 33.87 | 31.83 | 29.72 | |
| R J | +0.10 | +0.15 | 0.13 | +0.09 | 0.35 | +0.04 | |
| 0.05 | R | 28.94 | 27.55 | 32.72 | 33.81 | 31.63 | 29.74 |
| J | 28.91 | 27.49 | 32.95 | 33.99 | 31.91 | 29.78 | |
| Method | static (97) | moving (1363) | all |
|---|---|---|---|
| Ours (192 8, 100k) | 0.0458 | 0.0587 | 0.0570 |
| DLSS 2 (shipped frames) | 0.0546 | 0.0754 | 0.0732 |
| TAAU (classical) | 0.0568 | 0.0760 | 0.0743 |
| Bicubic | 0.0593 | 0.0731 | 0.0719 |
| Trunk | Clip | Seed 0 | Seed 1 | ||
|---|---|---|---|---|---|
| 96 8 | 0.05 | 30 | 29.164 | 29.168 | 0.003 |
| 192 8 | 0.25 | 16 | 28.818 | 28.827 | 0.009 |
| 192 8 | 0.05 | 16 | 29.277 | 29.266 | 0.011 |
| 192 8 b | 0.05 | 30 | 29.424 | 29.398 | 0.026 |
| 96 8, ECB | 0.05 | 30 | 29.375 | 29.346 | 0.028 |
| 192 8 | 0 | 16 | 29.312 | 29.376 | 0.064 |
Image Super-Resolution
Image super-resolution reconstructs high-resolution images from lower-resolution observations, balancing detail, fidelity, and computational cost.
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