Denoise Ground Truth — gradient-sky
The clean reference for the gradient-sky denoise set — no noise added, encoded at CRF 14. Every noisy clip in this group was produced from these exact pixels, so PSNR, SSIM and LPIPS against this file are meaningful rather than approximate.
Browser-playable test video · 1 seconds
Specifications
- Resolution
- 640x360
- Fps
- 24
- Duration
- 1s
- Frames
- 24
- Noise
- none
- Role
- ground truth
- Crf
- 14
- Base Plate
- gradient-sky
Testing contract
Reference control- Scenario
- Use this clip as the reference term when scoring denoising output produced from any degraded input in this group.
- Expected result
- The clip carries no added noise: 24 frames of 1s at 24 fps. It is the gradient-sky base plate at 640x360, 24 fps, encoded at CRF 14 so that codec artefacts sit well below the effect being measured. Every input in this group names this file in its own specs, so a score computed against anything else is not comparable with the rest of the suite.
What is a .mp4 file?
MP4 (MPEG-4 Part 14) is the dominant container for digital video, holding video, audio, subtitle, and metadata tracks in a tree of typed boxes. `ftyp` declares the brand, `moov` carries the sample tables that make seeking possible, and `mdat` holds the media; when an encoder writes `moov` last, playback cannot begin until the file has fully downloaded, which a faststart remux fixes. It derives from Apple's QuickTime format, generalized by ISO into the ISOBMFF base that MOV, 3GP, and HEIF share.
How to use this file
Use an example MP4 to test box parsing and track detection, seeking, range-request streaming, and transcode or thumbnail pipelines: verifying that a file with a trailing `moov` box is still handled, and that codec support is checked per track rather than inferred from the extension.
How to use this file for testing
“Denoise Ground Truth — gradient-sky” is a deterministic Novus Examples fixture for Video denoise, Video QA. Clips degraded with documented noise type, sigma, and seed, each shipped beside the exact high-quality source it came from, so a denoiser's output can be scored, not eyeballed.
Documented properties for this file: ground truth · 1s · 24 fps. Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.
Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such, expect parsers to fail loudly rather than silently accept them.
Media fixtures are short and synthetic by design. Prefer waveform or transcript ground truth in the same group when measuring ASR, trim, upscale, or sync tools; do not assume broadcast-quality masters.
Code examples
<video controls preload="metadata" width="640" src="gradient-sky-clean.mp4"></video>Related files
- mp4Denoise Ground Truth — detail-chartThe clean reference for the detail-chart denoise set — no noise added, encoded at CRF 14. Every noisy clip in this group was produced from these exact pixels, so PSNR, SSIM and LPIPS against this file are meaningful rather than approximate.
- mp4Denoise Ground Truth — pan-cityThe clean reference for the pan-city denoise set — no noise added, encoded at CRF 14. Every noisy clip in this group was produced from these exact pixels, so PSNR, SSIM and LPIPS against this file are meaningful rather than approximate.
- mp4Denoise Input — detail-chart, Gaussian σ=15Gaussian σ=15 applied to the detail-chart base plate with seed 9017. Moderate Gaussian noise, roughly a mid-ISO handheld shot. The level most denoise benchmarks use. Paired with the clean ground truth in this group, so denoiser output can be scored numerically. Encoded at CRF 19, where the light noise could otherwise be confused with compression artefacts.
- mp4Denoise Input — detail-chart, Gaussian σ=30Gaussian σ=30 applied to the detail-chart base plate with seed 9034. Heavy Gaussian noise where fine detail and noise overlap in amplitude, so recovery requires temporal information rather than spatial smoothing alone. Paired with the clean ground truth in this group, so denoiser output can be scored numerically. Encoded at CRF 24 rather than 19: random noise is incompressible, and at this amplitude the codec's own artefacts sit far below the noise floor, so a coarser quantiser saves several megabytes without affecting any measurement.
- mp4Denoise Input — detail-chart, Gaussian σ=5Gaussian σ=5 applied to the detail-chart base plate with seed 9000. Light sensor noise — the level a modern camera produces at base ISO. Subtle enough that an over-aggressive denoiser does more damage than the noise did. Paired with the clean ground truth in this group, so denoiser output can be scored numerically. Encoded at CRF 19, where the light noise could otherwise be confused with compression artefacts.
- mp4Denoise Input — detail-chart, Gaussian σ=50Gaussian σ=50 applied to the detail-chart base plate with seed 9051. Severe noise approaching the signal level. Included as the failure case — most denoisers hallucinate structure here, which is exactly what the paired reference exposes. Paired with the clean ground truth in this group, so denoiser output can be scored numerically. Encoded at CRF 24 rather than 19: random noise is incompressible, and at this amplitude the codec's own artefacts sit far below the noise floor, so a coarser quantiser saves several megabytes without affecting any measurement.
Generated by generation/video_ai_suites.py. Free for any use, no attribution required, license.