Neural representations for videos (NeRV) have shown strong reconstruction fidelity by storing video-specific information in network weights. However, existing formulations typically require either costly per-video optimization or video-specific weight generation, making it difficult to scale to efficient amortized video representation. We propose CoANeRV, a coordinate-aware token-space framework that adapts the broader token-conditioned neural-field paradigm to amortized video representation. CoANeRV forms compact video tokens in one feed-forward pass and uses a shared coordinate-conditioned decoder to reconstruct continuous spatio-temporal queries, avoiding per-video decoder optimization or generation while retaining coordinate-level reconstruction flexibility. To make token-space reconstruction effective, CoANeRV introduces a coordinate-aware decoding architecture that aligns spatio-temporal queries with video tokens through axis-adaptive positional encoding and temperature-modulated cross-attention. Block-wise coordinate querying further reduces peak attention memory, making high-resolution reconstruction practical. Experiments on diverse video datasets show that CoANeRV consistently improves reconstruction quality over prior feed-forward NeRV and INR baselines, reduces peak memory compared with attention-based coordinate decoders, and provides efficient amortized encoding without per-video optimization. These results support the proposed video-specific combination of feed-forward token formation, spatio-temporal coordinate retrieval, and memory-bounded dense querying. The code is available at https://github.com/jialong2023/CoANeRV.
Figures & tables
Figure 1: Framework comparison and encoding speed. (a) Representative weight-space video approaches store instance-specific information in optimized, generated, or modulated decoder parameters, whereas CoANeRV stores video-specific information in compact tokens and reconstructs pixels with a shared coordinate-conditioned decoder. (b) CoANeRV enables feed-forward token inference, while the decoder-only variant freezes the shared decoder and optimizes only video tokens to isolate the cost of per-video token fitting.
Figure 2: CoANeRV framework. CoANeRV encodes each video through convolutional patch tokenization and a six-layer token former, shown as the “Transformer Encoder Block” in the schematic, and reconstructs pixels by querying the resulting compact video tokens with continuous spatio-temporal coordinates. The decoder is shared across videos, so video-specificity is stored in token space rather than decoder weight space.
Methods
F
Encoder size
INR size ↓
#θ^′↓
Epoch
GPU hrs ↓
PSNR ↑
SSIM ↑
Train
K400
SthV2
UCF101
Train
K400
SthV2
UCF101
TransINR Chen and Wang (2022)
4
48.0M
99k
25k
150
63
23.7
22.1
24.6
22.1
0.659
0.631
0.728
0.622
GINR Kim et al. (2023)
4
47.6M
139.4k
25.6k
150
65
24.5
23.2
25.9
23.1
0.685
0.66
0.744
0.66
FastNeRV Chen et al. (2024)
4
47.6M
85.6k
24.1k
150
9
26.6
26.6
29.4
26.1
0.756
0.754
0.816
0.752
CoANeRV(ours)
4
45.5M
86.4k
27k
20
5
31.4
31.5
31.9
31.5
0.924
0.922
0.925
0.923
CoANeRV(ours)
4
45.5M
86.4k
27k
150
39
35.3
34.8
36.0
35.8
0.955
0.951
0.956
0.955
Table 1: CoANeRV vs. feed-forward INR baselines. ‘F’ denotes the number of frames. “INR size” reports the size of the reconstruction network, while #θ^′ reports the video-specific representation size: generated video-specific weights for prior methods and video tokens for CoANeRV. For each frame setting, we report two CoANeRV rows: a 20-epoch checkpoint to highlight convergence speed, and the full 150-epoch result for final accuracy. Training time is measured in GPU hours.
Figure 3: Qualitative comparison. Visualizations for feed-forward INR methods: TransINR Chen and Wang (2022) (top row), GINR Kim et al. (2023) (second row), FastNeRV Chen et al. (2024) (third row), and CoANeRV (bottom row, ours). CoANeRV reconstructs finer details and cleaner structures. Best viewed digitally and zoomed in.
Methods
F
Token length N
#θ^′
Epoch
Peak memory / batch (GB) ↓
GPU hrs ↓
PSNR ↑
SSIM ↑
Train
K400
SthV2
UCF101
Train
K400
SthV2
UCF101
ANR-V-S
4
384
27k
150
18
75
31.9
29.9
32.0
31.0
0.933
0.919
0.934
0.929
CoANeRV-S
4
384
27k
150
2.6
39
35.3
34.8
36.0
35.8
0.955
0.951
0.956
0.955
ANR-V-M
4
512
36k
150
23
85
32.2
30.8
33.1
32.2
0.942
0.930
0.942
0.939
CoANeRV-M
4
512
36k
150
2.7
41
35.8
35.2
35.6
35.4
0.960
0.952
0.962
0.958
ANR-V-L
4
768
54k
150
34
132
33.6
31.2
33.4
32.9
0.947
0.934
0.946
0.946
Table 2: Comparison with video-adapted ANR. ANR-V extends ANR Zhang et al. (2024) from spatial queries (x,y) to video queries (x,y,t) using localized attention layers. CoANeRV uses temperature-modulated cross-attention with block-wise coordinate querying. Both methods are compared under matched token lengths and video-specific representation sizes. Memory is the recorded peak GPU footprint for one minibatch and is reported in GB, using 1GB=1024MiB throughout the paper.
RGB to YUV
Block Query
Convolution Tokenizer
Axis-Adaptive- Embedding
Temperature-scaled fused SDPA
Peak memory / batch (GB) ↓
GPU hrs ↓
PSNR ↑
SSIM ↑
Train
K400
SthV2
UCF101
Train
K400
SthV2
UCF101
35
178
26.9
25.3
26.3
26.2
0.668
0.579
0.612
0.602
✓
35
178
27.8
26.5
27.4
27.2
0.726
0.693
0.708
0.701
✓
✓
18
178
27.8
26.5
27.4
27.2
0.726
0.693
0.708
0.701
✓
✓
✓
18
172
28.2
27.7
28.4
28.5
0.821
0.793
0.813
0.802
✓
✓
✓
18
180
28.8
27.8
28.5
28.8
0.825
0.804
0.816
0.812
Table 3: Ablation study. Progressive analysis from an ANR-V/LAL attention decoder baseline. The temperature-attention column denotes temperature-scaled standard attention executed through fused SDPA; the reported peak memory reflects the full decoding path, including spatial block querying where enabled. All memory entries are the recorded peak GPU footprint for one minibatch and are reported in GB, using 1GB=1024MiB .
Figure 4: Attention pattern analysis. Token probability distributions for (a) pre-training and (b) post-training at the same coordinate, and (c)–(d) post-training at different coordinates from the same video. The figure illustrates the emergence of sharper and more coordinate-specific attention patterns.
AV1 CRF 60
H.264
FastNeRV
CoANeRV (ours)
CRF 35
CRF 40
CRF 45
8 bits
7 bits
6 bits
5 bits
4 bits
8 bits
7 bits
6 bits
5 bits
4 bits
Size(KB) ↓
21.9
20.4
13.1
8.7
23.7
20.7
17.7
14.7
11.6
26.9
23.6
20.2
16.9
13.5
PSNR ↑
32.4
32.8
30.0
27.3
28.4
28.3
28.1
27.5
25.6
33.0
32.9
32.5
31.2
27.8
SSIM ↑
0.910
0.912
0.860
0.788
0.808
0.807
0.802
0.784
0.712
0.938
0.937
0.933
0.919
0.866
VPS ↑
313
447
460
485
583
125
Table 4: Per-video representation-storage comparison. Rate-distortion comparison with traditional codecs and FastNeRV under a simple per-video storage protocol. For CoANeRV and FastNeRV, size reports the quantized method-specific video payload—video tokens for CoANeRV and generated video-specific parameters for FastNeRV—while excluding shared or video-agnostic weights amortized across a video collection. VPS means videos per second.
Appendix figures & tables20 assets
Supplementary material from the paper’s appendix.
Appendix
Method
New-instance path
Query domain
Retrieval/decoder
Video-specific distinction
LAG-INR
Feed-forward Transformer tokens
2D coordinates; 6D rays
Local aggregation and multi-band modulation
Temporal modeling and exact dense-video tiling not evaluated
Tokenized Neural Fields
Gradient-fitted tokens; frozen decoder
1D/2D coordinates; 6D rays
Standard cross-attention and shared MLP
No amortized encoder or evaluated temporal axis
LH-NeF
Hierarchical feed-forward tokenizer
General metric domains
Group routing, Gaussian cross-attention, and FiLM
No evaluated video temporal modeling
CoANeRV
Feed-forward video tokenizer and token former
Continuous (x,y,t)
Temperature-scaled retrieval and shared MLP
Axis-adaptive encoding and exact full-token-bank video tiling
Appendix
Table 5: Technical positioning relative to closely related token-conditioned neural fields. “Not evaluated” describes the scope of the cited paper and does not assert that the method could not be extended.
Stage
Shape
Example
Input video
T×C×H×W
4×3×256×256
After Conv2D
T×D×H′×W′
4×768×16×16
Patch tokens
Np×D
1024×768
Video tokens
N×d
384×72
Appendix
Table 6: Data shapes in the convolutional video tokenizer.
Figure 5: Encoding time comparison between CoANeRV and gradient-based NeRV optimization.
Method
Frames
Iter.
Time (s)
PSNR ↑
SSIM ↑
K400
SthV2
UCF101
K400
SthV2
UCF101
NeRV
8
300
122
24.78
24.13
24.75
0.73
0.70
0.72
NeRV
8
600
230
27.55
27.25
27.11
0.81
0.80
0.79
NeRV
8
900
373
29.82
29.89
29.29
0.85
0.87
0.86
NeRV
8
2400
942
33.64
33.73
33.17
0.90
0.91
0.89
CoANeRV
8
300
254
24.94
24.91
24.89
0.78
0.77
0.75
Appendix
Table 7: Standalone token optimization analysis under the 8-frame setting. For CoANeRV, the decoder is frozen and only randomly initialized video tokens are optimized for each test video. Time denotes per-video optimization time.
Figure 6: Temperature Coefficient. PSNR/SSIM results across training and test sets for different τ values. Both metrics peak at τ=0.4 , indicating optimal attention sharpness. Lower τ causes over-concentration; higher τ leads to diffuse attention.
Figure 7: Attention Weight Distribution with Different Temperature Parameters. Distribution of attention weights when querying spatiotemporal coordinates through video tokens before training. Red curve ( τ=0.4 ) shows a sharper distribution over tokens, while blue curve ( τ=1.0 ) exhibits smoother and more dispersed attention weights.
Figure 8: RGB vs. YUV distributions. RGB channels occupy the full normalized range, whereas the YUV chrominance channels are strongly concentrated around 0.5 .
Method
Frames
MS-SSIM ↑
LPIPS ↓
K400
SthV2
UCF101
K400
SthV2
UCF101
TransINR
4
0.787
0.868
0.843
0.565
0.361
0.411
GINR
4
0.829
0.895
0.876
0.494
0.304
0.331
FastNeRV
4
0.921
0.954
0.941
0.267
0.139
0.167
CoANeRV
4
0.981
0.983
0.984
0.052
0.044
0.034
Appendix
Table 8: Perceptual reconstruction quality under the 4-frame setting. CoANeRV consistently improves MS-SSIM and reduces LPIPS across all evaluated datasets.
Method
FLOPs (G)
MACs (G)
Architecture Type
NeRV
1.30
0.65
Convolutional
ANR-V
239.73
119.45
LAL-based attention
CoANeRV (Ours)
31.92
15.95
Temperature-modulated attention
Appendix
Table 9: Computational complexity comparison for single-frame reconstruction. FLOPs and MACs are measured in billions (G).
Figure 9: Sigma parameter. Reconstruction performance across training and test sets under different σ values.
Figure 10: Encoder depth. Performance improves as the encoder depth increases.
Figure 11: MLP depth. A deeper decoder improves the non-linear coordinate-to-signal mapping.
Figure 12: Cross-domain qualitative comparison. Ground truth (top), FastNeRV (second row), ANR-V (third row), and CoANeRV (bottom).
Dataset
Method
PSNR (dB) ↑
SSIM ↑
PSNR Gain
SSIM Gain
EchoCP
FastNeRV
20.53
0.607
-
-
ANR-V
24.40
0.784
+3.87
+0.177
CoANeRV
26.85
0.864
+6.32
+0.257
EchoNet-LVH
FastNeRV
22.88
0.684
-
-
ANR-V
27.45
0.835
+4.57
+0.151
CoANeRV
29.64
0.916
+6.76
+0.232
Appendix
Table 10: Comparative performance on medical imaging datasets.
Table 11: Speed analysis. Encoding / decoding speed (frames per second) across multiple devices.
Figure 13: Rate–distortion curves on HEVC Class D sequences.
Methods
F
Frame Resolution
#θ^′
Epoch
Peak memory / batch (GB) ↓
GPU hrs ↓
PSNR ↑
SSIM ↑
Train
K400
SthV2
UCF101
Train
K400
SthV2
UCF101
ANR-V-S
4
512
27k
50
64
275
27.9
27.2
28.0
27.0
0.833
0.819
0.834
0.829
CoANeRV-S
4
512
27k
50
5.2
62
29.3
29.5
29.0
29.8
0.855
0.846
0.856
0.855
ANR-V-M
4
512
36k
50
76
285
28.2
27.8
28.1
28.2
0.842
0.830
0.842
0.839
CoANeRV-M
4
512
36k
50
5.3
66
29.8
29.7
29.6
29.9
0.860
0.852
0.860
0.860
ANR-V-L
4
512
54k
OOM
OOM
OOM
OOM
OOM
OOM
OOM
OOM
OOM
OOM
OOM
Appendix
Table 12: CoANeRV vs. ANR-V with different resolutions. CoANeRV achieves better quality with much lower memory and training cost. Memory is the recorded peak GPU footprint for one minibatch in GB, using 1GB=1024MiB .
Bits
PSNR ↑
SSIM ↑
K400
SthV2
UCF101
K400
SthV2
UCF101
32 (Full)
33.02
33.33
33.52
0.938
0.942
0.947
8
32.99
33.30
33.49
0.938
0.942
0.947
7
32.89
33.20
33.39
0.937
0.941
0.946
6
32.51
32.82
33.01
0.933
0.937
0.942
5
31.20
31.51
31.70
0.919
0.923
0.928
Appendix
Table 13: Ablation study on token quantization. Decoder weights remain in 32-bit floating point.
Parameter
Value
CoANeRV Architecture
Video-token dimension ( d )
72
Video-token length ( N )
384
Patch-token self-encoder depth
0
Number of token-former layers ( L )
6
Token-former width ( D )
768
Appendix
Table 14: Complete Hyperparameter Settings
Dataset split
Before filtering
4F
8F
16F
K400 train
10,000
10,000
10,000
9,997
K400 validation
13,732
13,732
13,732
13,731
Something-Something V2 evaluation
20,000
20,000
20,000
19,947
UCF101 evaluation
3,500
3,500
3,500
3,500
Appendix
Table 15: Dataset split sizes before and after deterministic minimum-frame filtering.