Base Plate — Pan — City Skyline
A skyline scrolling at a constant 3.5 pixels per frame: pure horizontal translation with no rotation or scale change. The lit windows give sparse high-contrast features to track, and the constant velocity means the correct answer for interpolation and optical flow is known exactly. One of eight shared base plates: every AI-video suite in this library degrades one of these rather than inventing its own footage, so results across suites are comparable. Encoded at CRF 14 — well above the house CRF 30 — because a reference compressed as hard as the material under test puts the measurement floor above the effect being measured.
Browser-playable test video · 2 seconds
Specifications
- Resolution
- 640x360
- Fps
- 24
- Duration
- 2s
- Frames
- 48
- Codec
- H.264 (libx264)
- Crf
- 14
- Pixel Format
- yuv420p
- Audio
- none
- Role
- base plate
- Synthesis
- deterministic — pure function of frame index and a fixed seed
Testing contract
Reference control- Scenario
- Decode the plate and confirm its geometry, then re-run whichever AI-video suite in this library uses it as a source and compare results across suites.
- Expected result
- 48 frames of 640x360 at 24 fps (2s), H.264 at CRF 14, pixel format yuv420p, and no audio track. Synthesis is a pure function of frame index and a fixed seed, so a regenerated plate is byte-identical. The CRF 14 encode is deliberate: a reference compressed as hard as the material under test would put the measurement floor above the effect being measured.
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
“Base Plate — Pan — City Skyline” is a deterministic Novus Examples fixture for Video stabilisation, Frame interpolation, Video QA. Camera shake applied with a recorded motion path over a static original, so a stabiliser's residual motion can be measured rather than estimated.
Documented properties for this file: base plate · 2s · 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="pan-city.mp4"></video>Related files
- mp4Depth Input — Three-Layer Parallax SceneThree planes translating at 0.6, 2.4 and 6.0 pixels per frame — a 1 : 4 : 10 velocity ratio that defines their relative depth by motion alone. There are no pictorial depth cues to fall back on: no perspective convergence, no shading, no familiar object sizes. A monocular depth model that has learned pictorial cues rather than motion parallax will do poorly here, which is precisely what makes the fixture informative.
- mp4Interpolation Ground Truth — depth-layers at 24 fpsThe full-rate 24 fps reference for the depth-layers interpolation set. The decimated clips in this group drop frames from exactly this sequence, so every frame an interpolator is asked to synthesise has a true original to be scored against — which is the only way to tell invention from reconstruction.
- mp4Interpolation Ground Truth — orbit-solid at 24 fpsThe full-rate 24 fps reference for the orbit-solid interpolation set. The decimated clips in this group drop frames from exactly this sequence, so every frame an interpolator is asked to synthesise has a true original to be scored against — which is the only way to tell invention from reconstruction.
- mp4Interpolation Ground Truth — pan-city at 24 fpsThe full-rate 24 fps reference for the pan-city interpolation set. The decimated clips in this group drop frames from exactly this sequence, so every frame an interpolator is asked to synthesise has a true original to be scored against — which is the only way to tell invention from reconstruction.
- mp4Interpolation Input — depth-layers at 12 fpsThe depth-layers plate decimated to 12 fps by keeping every 2th frame, so 24 of the original 48 frames are missing. Interpolate back to 24 fps and each synthesised frame has an exact counterpart in the ground truth. Larger gaps need genuine motion understanding rather than blending.
- mp4Interpolation Input — depth-layers at 6 fpsThe depth-layers plate decimated to 6 fps by keeping every 4th frame, so 36 of the original 48 frames are missing. Interpolate back to 24 fps and each synthesised frame has an exact counterpart in the ground truth. Larger gaps need genuine motion understanding rather than blending.
Generated by generation/video_baseplates.py. Free for any use, no attribution required, license.