Crate alpha2_model

Expand description

Versioned, host-independent project model for alpha2.

This crate describes intent only. It contains no decoder handles, GPU resources, filesystem paths, or application-specific types.

Structs§

AudioEffectLoad: The most audio effect state a project holds at once.
AudioProperties: Per-clip audio presentation controls.
AudioStreamShape: An audio stream’s channel count and sample rate.
CaptionCue: Text shown over one timeline interval.
Captions: What a caption track shows: its cues, in one style.
Clip: A reference to a source over independent timeline and source ranges.
ClipComposition: A clip’s use of a Composition, and how its time maps onto it.
ClipEffect: One versioned runtime effect invocation: a composition’s effect or transition node, or a timeline transition.
ClipId: A stable timeline-clip identifier.
ClipTransition: A two-input transition over the overlap of two visual clips.
ColorPipeline: How sources’ colors come into the working space.
Composition: An acyclic graph of image operations with one selected output.
CompositionControl: A node setting a composition exposes to the group nodes that use it: an effect or transition parameter of one of its nodes.
CompositionId: A stable composition-graph identifier.
CompositionNode: One image operation in a Composition.
CompositionReads: What each composition’s output reads: the group inputs and clip nodes a walk from its output reaches, along the inputs drawing each node reads, into the compositions its group nodes draw. A group draws what its nodes would inline, so a group node needs only the ports its composition reads: a port it never reads may be left unconnected, and what a connected one reads is not drawn.
CubicBezier: A CSS cubic-bezier(x1, y1, x2, y2) timing curve.
Dash: A dash pattern.
Ducking: Sidechain ducking authored on the track that is attenuated.
EffectResource: Host-resolved, non-media data consumed by one or more visual effects.
EffectResourceId: A stable effect-resource identifier.
EllipseGeometry: The ellipse inscribed in a size, turned clockwise about its centre. Its outline starts at the top and runs clockwise.
EqBand: A single equalizer section stored independently from its DSP implementation.
GradientStop: One color of a gradient.
GridPlacement: Where a grid item lies on one axis, as grid_column writes it in CSS: 2, "1 / 3", "span 2", "2 / span 3", "auto". A missing end is auto.
ImportedCaptions: Cues read from a subtitle file.
Insets: A length on each side of a box (a padding or a margin). Missing sides are 0.
Keyframe: One timestamped control value.
LayoutBorder: A border inside the border box, as wide on every side.
LayoutInset: Where an absolute box lies in its parent’s padding box. A missing side is auto: with neither left nor right, the box keeps its place in the flow on that axis.
LayoutIssue: Where in a layout tree a problem lies, and what it is.
LayoutNode: One box of a layout tree.
LayoutOffset: A box’s offset after layout: x right, y down.
LayoutShape: A box’s shapes, drawn as a shapes generator draws its items on a picture the size of the box’s content box: positions normalized to that box, lengths fractions of its shorter side. A shape box has no size of its own.
LayoutTextStyle: A box’s text style once inherited: what its text draws with. Lengths are fractions of the picture’s shorter side.
Limiter: Final peak limiter placed at the end of the master bus.
MasterAudio: Project-wide master bus settings.
Matte: Another visual clip whose picture sets where this clip is visible.
MediaFingerprint: Evidence of a source’s media, each part recorded only when it was known.
MediaSource: A host-resolved media resource.
MergeLayer: One layer of a NodeOp::Merge.
NodeId: A stable identifier of a node within one composition graph. It has no /, which joins the IDs of the group and media nodes a step was drawn through.
Path: One or more subpaths.
PathGeometry: A path, animated as one value.
PathVertex: A path vertex and its tangents. The segment from vertex a to vertex b is the cubic Bezier through a.point, a.point + a.out_tangent, b.point + b.in_tangent, and b.point; zero tangents make it straight.
PointKeyframe: One keyframe of an AnimatedPoint.
PolystarGeometry: A regular polygon or a star, its first point straight up from the centre before rotation, the rest clockwise.
Project: A complete serializable project document.
ProjectId: A stable project identifier.
ProjectSettings: Output-wide settings independent of a renderer or encoder.
RectangleGeometry: A rectangle about its centre, turned clockwise about it. Its outline starts at the top-right corner and runs clockwise.
Rgb: An opaque color as a color picker shows it: straight, sRGB-encoded components in the inclusive unit interval.
Rgba: A straight (not premultiplied), sRGB-encoded color with alpha, each component in 0..=1.
ShapeIssue: Where in a content tree a problem lies, and what it is.
ShapeMask: A shape that limits where a clip is visible.
ShapeTransform: A group’s placement: in pixel space, translate by position, rotate, scale, and translate by minus anchor, so anchor lands on position. The default leaves its items where they are.
StreamTopology: The streams a media file carries.
StrokeItem: A stroke along geometry, centred on its outline.
Subpath: A run of vertices joined by cubic Bezier segments.
TextBackground: A box behind each line of text.
TextOutline: A band around the glyphs, drawn behind them.
TextStyle: How text looks and where it lies: a caption track’s cues, or a text crate::Generator.
TimeScale: A positive rational rate of one time against another.
Timeline: Timeline tracks ordered from back to front for visual tracks.
Track: A homogeneous visual or audio timeline lane.
TrackAudio: Per-track audio bus controls.
TrackId: A stable timeline-track identifier.
TrackList: A grid track list, as grid_template_columns writes it in CSS: "1fr 2fr 120px", "repeat(3, minmax(100px, 1fr))", "repeat(auto-fill, 160px)". Named lines are not supported.
TrimItem: Keeps a span of geometry’s length.
Vec2: A two-dimensional value in normalized output coordinates.
VideoStreamShape: A video stream’s displayed size and frame rate.
VisualProperties: Resolution-independent visual presentation controls for a clip.

Enums§

AlignContent: Where the lines of a wrapping flex container, or a grid’s rows, lie across the container.
AlignItems: Where children lie across a flex container’s main axis, or in their grid areas.
Animated: A value that is either constant or controlled by sorted keyframes.
AnimatedPoint: A position that can move along curves between its keyframes.
AudioEffect: A serializable single-input audio effect applied to a clip or track bus.
BlendSpace: The color space in which blend modes are evaluated.
CacheIntent: Whether a runtime may keep and reuse a clip’s rendered picture.
CaptionImportError: Why a file is not a subtitle file at all.
ClipBlendMode: Artistic blend operation stored independently from a renderer implementation.
Display: How a box lays its children out.
Easing: A timing curve from linear progress to eased progress, without a hold.
EffectResourceKind: Portable effect-resource categories supported by the render ABI.
EffectValue: Serializable value supplied to one runtime effect parameter.
EqBandKind: The filter shape of one equalizer band.
FadeShape: Curve applied by a clip’s fade in and fade out.
FillRule: Which regions of a path are inside it.
FlexDirection: The main axis of a flex container.
FlexWrap: Whether a flex container’s children wrap.
Generator: The picture of a generated source.
GeneratorIssue: Why a generator is invalid.
GridAutoFlow: How a grid places items that have no placement of their own.
GridEdge: One edge of a grid item’s placement.
HdrSources: What a project does with HDR sources.
Interpolation: Interpolation from one keyframe to the next.
JustifyContent: Where children lie along a container’s main axis, or a grid’s columns in it.
LayoutLength: A layout length that may be a percent: a size or an inset side.
LayoutProblem: Why a layout tree is invalid.
LayoutSize: A layout length that may not be a percent: a gap, a radius, a border width, a font size, a padding or margin side, a translation.
LineCap: How an open stroke ends.
LineJoin: How stroke segments meet at a vertex.
LinearPrimaries: Named RGB primaries linear-light media may be in, each with its own white point.
LintEdge: The end of a range a LintIssue is about.
LintIssue: Something in a project that is valid but probably not meant.
LintOwner: What a LintIssue is about.
LoopMode: How each pass of a TimeMap::Loop follows the one before.
MaskMode: How a mask combines with the coverage of the masks before it.
MatteMode: Which property of the matte clip’s picture is coverage.
MediaKind: The payload domain of a source.
MissingFrames: How an image sequence shows a frame missing from its numbering.
ModelError: A document invariant violation.
NodeInput: One named input of a node, as a node’s inputs are listed.
NodeOp: The operation of a CompositionNode.
Overflow: Whether content past a box’s padding box is drawn.
Paint: A color or gradient.
PolystarKind: What kind of figure a polystar is.
Position: Whether a box is in its parent’s flow.
ProjectLoadError: Failure while decoding a serialized project document.
ProviderSource: A source whose media an extension provider supplies, rather than the host’s video and image decoders.
RepeatCount: How often repeat() repeats its tracks.
ShapeGeometry: A geometry alone, as a mask’s outline is.
ShapeItem: One entry of a shapes generator’s content tree.
ShapeLintOwner: The shapes or layout generator a shape LintIssue is about.
ShapeOwner: What holds a shape or a layout a ModelError::InvalidShape or ModelError::InvalidLayout names.
ShapeProblem: Why a content tree or a mask outline is invalid.
Spread: What a linear or radial gradient shows outside its first and last stops.
TextAlign: How lines of text align within it.
TimeMap: How a clip plays its source range over its timeline range.
TrackBreadth: How large a grid track may be at least or at most: one side of minmax().
TrackComponent: One entry of a track list: a track, or repeat() of some.
TrackKind: The media domain accepted by a track.
TrackSize: The size of one grid track.
TrimMode: What a trim measures.

Constants§

AUDIO_EFFECT_STATE_MARGIN_MS: How long before its start, beyond the lookahead of its track’s and its own compressors, a clip’s effects are counted as holding state, in milliseconds. A mixer builds a clip’s effects for the blocks that mix the clip and drops them for the first that does not; it reads a clip early by the lookahead after it, and one block of the largest size at the lowest project rate, with the rounding of each lookahead to samples, is within this margin. A clip’s effects count until its end.
CURRENT_SCHEMA_VERSION: The newest project-document schema understood by this build.
EQ_FREQUENCY_RANGE_HZ: The frequencies an EQ band may name, in hertz: from 10 Hz to just under the Nyquist frequency of the highest project rate. A band renders at most at 0.49 times the project’s own rate, so a band above that limit of the project it is in sounds at the limit.
EQ_Q_RANGE: The resonances an EQ band renders.
HDR_PEAK_NITS_RANGE: Supported ColorPipeline::hdr_peak_nits: SDR white to PQ’s ceiling.
LAYOUT_TEXT_DEFAULTS: The initial text style: what the root inherits.
LINE_HEIGHT_RANGE: The line heights text takes, as multiples of the font size.
LOOP_FADE_SECONDS: How long sound fades out before, and in after, each wrap of a repeating loop.
MAX_AUDIO_DELAY_MS: Most audio a project’s effects hold in delay lines at once, in milliseconds, summed over the effects MAX_AUDIO_EFFECTS counts then: a compressor holds its lookahead_ms, a reverb REVERB_DELAY_MS. At the highest project rate this is under 100 MB of state.
MAX_AUDIO_EFFECTS: Most audio effects a project holds state for at once: its master’s, its tracks’, and those of the clips holding state then (see AUDIO_EFFECT_STATE_MARGIN_MS). An equalizer is one effect, whatever its bands.
MAX_CANVAS_DIMENSION: Largest canvas edge accepted by the portable project model.
MAX_CANVAS_PIXELS: Largest total canvas area accepted before quality scaling.
MAX_CAPTION_FILE_BYTES: The largest subtitle file read, in bytes: a project document’s limit. A cue’s JSON is longer than its subtitle block, so a larger file holds more cues than a project can.
MAX_CAPTION_FILE_CUES: The most cues read from one subtitle file: a day of continuous captions at a cue every 1.3 s, and far more than a feature film’s few thousand.
MAX_CAPTION_FONT_SIZE: Largest caption font size, as a fraction of the frame’s height.
MAX_CHAIN_EFFECTS: Most effects one chain holds: a clip’s, a track’s, or the master’s.
MAX_CLIPS: Maximum number of clips across one project, and of sources in it.
MAX_CLIPS_PER_TRACK: Maximum number of clips on one track.
MAX_CLIP_MASKS: Most shape masks on one clip.
MAX_COMPOSITIONS: Most compositions in one project.
MAX_COMPOSITION_CONTROLS: Most controls a composition exposes as a group.
MAX_COMPOSITION_DEPTH: Deepest nesting of compositions: a composition that draws no other has depth one, and one that draws others, through group nodes or composition-source media nodes, is one deeper than the deepest of them. Drawing a composition recurses once per level.
MAX_COMPOSITION_NODES: Most nodes in one composition.
MAX_COMPRESSOR_RATIO: Largest compressor ratio.
MAX_DASH_ENTRIES: Most entries in a stroke’s dash pattern.
MAX_EFFECT_INPUTS: The most named inputs an effect node gives its effect: what an effect definition may declare.
MAX_ENVELOPE_MS: Longest attack or release time, in milliseconds.
MAX_EQ_BANDS: Most bands one equalizer holds.
MAX_EQ_GAIN_DB: Largest peaking gain, in decibels either way, an EQ band renders.
MAX_FONT_FAMILY_BYTES: Most bytes in a text style’s font family name.
MAX_FRAME_INLINED_NODES: Most composition nodes the clips on the timeline at one instant draw together: each clip counts the nodes its composition and its composition source draw once inlined, as MAX_INLINED_NODES counts them, and a clip showing neither counts none. MAX_INLINED_NODES bounds what the compositions compile to however often they are used; this bounds what their uses draw in one frame, so a frame never draws more than one composition of the largest size the project may hold.
MAX_GAIN: Largest linear amplitude accepted by any authored gain.
MAX_GRADIENT_STOPS: Most stops in one gradient.
MAX_GRID_TRACKS: Most explicit tracks on one axis of a grid, repeat() counts expanded.
MAX_GROUP_INPUTS: Most inputs a composition takes as a group.
MAX_INLINED_NODES: Most nodes the project’s compositions draw, summed over every composition: each node counts one, except a group node or a media node reading a composition source, which counts the nodes of the composition it draws. A composition is inlined wherever it is drawn, so this bounds what compiling the compositions makes, however their uses multiply.
MAX_LAYOUT_DEPTH: Deepest nesting of one layout tree; the root is depth 1.
MAX_LAYOUT_FONT_SIZE: Largest font size of a layout’s text, as a fraction of the picture’s shorter side.
MAX_LAYOUT_ISOLATED: Most isolated nodes (with a visual field or hidden overflow) in one layout tree.
MAX_LAYOUT_NODES: Most nodes in one layout tree, the root included.
MAX_LAYOUT_TEXTS: Most nodes with text in one layout tree.
MAX_LOOKAHEAD_MS: Longest compressor lookahead, in milliseconds.
MAX_LOTTIE_DOCUMENT_BYTES: Largest Lottie animation a provider reads, in bytes: a Lottie JSON file, or the animation a dotLottie package unpacks to. A Lottie document is parsed whole, to as much as about 45 times its size at its densest (numbers alone), so a larger one is refused before it is parsed, and a host refuses a larger file before reading it. Within it, a document parses to at most about 750 MiB.
MAX_MERGE_LAYERS: Most layers in one merge node.
MAX_PATH_SUBPATHS: Most subpaths one path holds.
MAX_PATH_VERTICES: Most vertices one path holds, over all its subpaths.
MAX_POLYSTAR_POINTS: Most points a polystar has. A fractional count is valid; its fraction is dropped when drawn.
MAX_PROJECT_JSON_BYTES: Largest project document accepted by Project::from_json.
MAX_PROVIDER_DOCUMENT_BYTES: Largest dotLottie package a provider reads, in bytes. A package is read whole, and only the files a source shows are unpacked from it: its animation, within MAX_LOTTIE_DOCUMENT_BYTES, and that animation’s images. A larger file is refused before it is read.
MAX_SEQUENCE_FRAMES: Most frames an image sequence lists.
MAX_SHAPE_DEPTH: Deepest group nesting in one shapes generator.
MAX_SHAPE_ITEMS: Most items one shapes generator holds, nested groups and their items included.
MAX_SVG_DOCUMENT_BYTES: Largest SVG document a provider reads, in bytes. An SVG document is parsed whole, to as much as about 30 times its size at its densest (elements alone), so a larger one is refused before it is parsed, and a host refuses a larger file before reading it. Within it, a document parses to at most about 960 MiB.
MAX_TEXT_CONTENT_BYTES: Most bytes of text in one caption cue or text generator.
MAX_TEXT_GENERATOR_FONT_SIZE: Largest font size of a text generator, as a fraction of the canvas height.
MAX_TEXT_OUTLINE_WIDTH: Widest text outline, as a fraction of the font size.
MAX_TEXT_PADDING: Largest text background padding, as a fraction of the font size.
MAX_TRACKS: Maximum number of tracks in one project.
MAX_TRANSITIONS_PER_TRACK: Maximum number of transitions on one track.
MIN_LEVEL_DB: The quietest level a compressor threshold or a ducking depth names, in decibels; both are at most 0 dB.
MIN_POLYSTAR_POINTS: Fewest points a polystar has.
REVERB_DELAY_MS: What one reverb counts toward MAX_AUDIO_DELAY_MS: its comb and allpass lines hold about 157 ms of audio at any rate.
SAMPLE_RATE_RANGE: Supported project audio sample-rate interval.

Functions§

caption_rows: Splits cues onto rows, each row a caption track’s worth: every cue goes to the first row that has room for another cue (a track holds MAX_CLIPS_PER_TRACK) and whose last cue has ended by its start.
parse_srt: Reads SubRip (.srt) text.
parse_webvtt: Reads WebVTT (.vtt) text. NOTE, STYLE, and REGION blocks are ignored.
validate_shape_items: Checks a content tree: its limits, every value’s range, and that animated paths and paints agree in structure between keyframes.

Crate alpha2_model

Crate alpha2_model Copy item path

Structs§

Enums§

Constants§

Functions§

Crate alpha2_model