MoCha-Stereo (fastforks)

MoCha-Stereo (Chen et al. 2024): EfficientNetV2-L features, a motif channel correlation volume next to an IGEV-style geometry volume, 3-level Mogrifier LSTM updates and a refinement step, 32 iterations. mocha-v2-sceneflow is an unofficial reconstruction (the authors released no V2 code).

This repo is the model card only: it holds no weights. fastforks downloads the authors' weights from the links below and checks them against the SHA-256 in the model card. Code: https://github.com/kleinicke/fastforks. Kernels for the kernels backend: https://huggingface.co/fastforks/kernels. Original code: https://github.com/ZYangChen/MoCha-Stereo at 78c5889c467f.

Task: stereo. Tier: experimental. Outputs: disparity. Backends: portable, kernels.

Input: a rectified left / right image pair. Output: a disparity map (pixels, left view).

Variants

Weights are the authors' files (not hosted here). SHA-256 shortened to 12 hex digits; the full hashes are in card.toml.

variant	weights (author link)	SHA-256	weights licence	commercial use
mocha-v1-sceneflow@1	mocha-stereo.pth	4d26f51d6321	MIT (assumed from code)	yes
mocha-v2-sceneflow@1	mocha-V2.pth	b7cd8969158b	MIT (assumed from code)	yes

Licence

Original-code strings, recorded as they are (research-use package; check them before any other use). Code: MIT. Files: LICENSE.

Code licence: MIT; the authors do not state a separate weights licence.

Training data: Freiburg SceneFlow (FlyingThings3D, Driving, Monkaa).

Licence evidence: https://github.com/ZYangChen/MoCha-Stereo/blob/78c5889c467fe31414c9425f1280afc0a8f6c1a0/README.md#L69

Input size

any H x W >= 32, padded to a multiple of 32 Tested up to (portable, fp16, RTX 5060 Ti 16 GB): mocha-v1-sceneflow 3000x4000 (12.2 GiB peak allocated, 15.2 reserved); mocha-v2-sceneflow 3000x4000 (12.2 GiB peak allocated, 14.8 reserved)

Speed and memory

Stereo, Middlebury 2014 half, 994x1482

model	time (ms): original fp32	original	portable	kernels	kernels speed-up: vs original	vs portable	peak memory (MiB, allocated / reserved): original	portable	kernels
mocha-v1-sceneflow	2148.5	1456.2	1057.19	455.46	3.2x	2.3x	3637 / 3982	1632 / 1770	1588 / 1730
mocha-v2-sceneflow	2054.3	1295.1	1033.49	448.12	2.9x	2.3x	3576 / 3982	1632 / 1770	1587 / 1790

Startup and first call

model	load (s): original	portable	kernels	first call (s): original	portable	kernels
mocha-v1-sceneflow	1.95 (375x1242)	0.79	0.48†	1.85 (375x1242)	1.06†	0.45†
mocha-v2-sceneflow	2.37 (375x1242)	1.30	0.45†	0.40 (375x1242)	1.03†	0.45†

Fixed-size speed and peak memory, all models

model	mode	640x480	1280x720	1920x1080	12 MP 4000x3000
mocha-v1-sceneflow	portable	231.1 ms / 500 / 662	628.3 ms / 1078 / 1438	1484.8 ms / 2164 / 2688	10361.4 ms (n=3) / 12466 / 15520
mocha-v1-sceneflow	kernels	135.4 ms / 495 / 694	317.0 ms / 1055 / 1338	718.5 ms / 2092 / 2484	4396.8 ms (n=3) / 11664 / 14958
mocha-v2-sceneflow	portable	227.0 ms / 500 / 662	613.9 ms / 1078 / 1438	1451.9 ms / 2164 / 2688	10135.5 ms (n=3) / 12464 / 15164
mocha-v2-sceneflow	kernels	133.6 ms / 494 / 654	312.9 ms / 1054 / 1456	709.3 ms / 2091 / 2482	4316.6 ms (n=3) / 11664 / 14404

Fixed-size cells: time (ms) / peak allocated / peak reserved memory (MiB).

Hardware, protocol and caveats: benchmarks (RTX 5060 Ti 16 GB, sm_120). Original = the authors' code at the precision of portable (fp16, or (fp32) where fp16 is unsupported or not finite); original fp32 = its default fp32 run. Peak memory is the torch allocator's.

Accuracy

Parity with the original code

Every variant is checked against golden outputs of the original code at its pinned commit. CPU, float32: max |diff| <= 0.002 vs the original. GPU, float16 (the default), portable and kernels: mean |diff| <= 0.02 px and p99 <= 0.25 px.

Usage

from fastforks import stereo

model = stereo.load("mocha-v1-sceneflow")  # portable PyTorch on the GPU if there is one, else the CPU
result = model("left.png", "right.png")
result.disparity  # [H, W] float32 tensor, input resolution
result.backend  # what ran, e.g. Backend(mode='portable', device='cuda:0', dtype='float16')

Install with pip install fastforks (see https://github.com/kleinicke/fastforks). Other variants: mocha-v1-sceneflow, mocha-v2-sceneflow.

Kernels backend

stereo.load("mocha-v1-sceneflow", mode="kernels") runs our CUDA kernels (igev, mocha, cutlass_conv, cudnn_hacc). It needs a prebuilt kernel for your GPU architecture (downloaded from https://huggingface.co/fastforks/kernels on first use) and a recent NVIDIA driver; if there is none it raises BackendUnavailableError with the reason and never falls back silently. mode="auto" picks kernels when it can run and logs the choice.