Interchange capability matrix

What each interchange format can carry, per concept. The tables below are generated from the same JSON the C++ capability tables are generated from, so a row here is the behavior, not a description of it.

The world is closed. A concept a format does not list is refused on import and reported as a loss on export -- support is something a format declares, never something it gets by default.

A row changes away from none only through a decision made on the document model's own merits. Turning rows green to widen a format's reach is not a reason to add a model feature.

Concepts

Concept	Observable in a document	Meaning
unknown	format-only	A construct the reader could not classify. No format lists it, so it always refuses.
track.flat	yes	A track holding clips directly, with no children.
track.group	format-only	A track that contains other tracks (folder/group/nested scope).
track.video	format-only	A track whose content is picture rather than audio or notes.
clip.musical	yes	A clip anchored to musical time (canonical ticks).
clip.absolute	yes	A clip anchored to absolute time (samples at a rational rate).
clip.note	yes	Clip content that is a set of note events.
clip.media	yes	Clip content that references a media asset.
clip.gain	yes	Per-clip gain applied to the clip's content.
clip.fades	yes	Per-clip fade in and fade out durations.
clip.crossfade	format-only	An overlap between two adjacent clips authored as one transition item.
clip.warp	format-only	A time-warp map deforming clip content against timeline time.
clip.launch	yes	Non-arrangement clip playback (scenes, launcher grids).
gap.explicit	format-only	A gap between clips authored as a first-class item rather than absence.
tempo.single	yes	One tempo governing the whole document.
tempo.map	yes	Tempo changing over the document at more than one point.
meter.single	yes	One time signature governing the whole document.
meter.map	yes	Time signature changing over the document at more than one point.
marker	yes	A named point or range on the timeline.
timecode.origin	yes	The wall-clock timecode the document's zero position represents.
media.provenance	format-only	Where a media asset came from: source timecode, reel or tape name, original locator.
mixer.track-gain	yes	Static per-track gain.
mixer.track-pan	yes	Static per-track pan position.
mixer.sends	format-only	Track routing to busses and auxiliary sends.
automation.device-param	yes	An automation lane targeting a device parameter.
automation.track-gain	yes	An automation lane targeting a track's gain.
automation.track-pan	yes	An automation lane targeting a track's pan.
device.placement	yes	A device occupying a slot in a track's chain, by identity.
device.payload	format-only	A device's type and saved parameter state.
effect.timewarp	format-only	An effect that remaps time rather than processing content.
take.lane	yes	An alternate recording lane holding takes alongside the arrangement.
take.comp	yes	A composite assembled by selecting segments across takes.
track.freeze	yes	A sealed offline render standing in for a track's live output.
asset.sealed-hash	yes	Media identity derived from a content hash of the actual bytes.
asset.embedded-media	yes	Media bytes carried inside the document package.
asset.referenced-media	yes	Media referenced by locator, stored outside the document.
sequence.multiple	yes	More than one sequence in the document.
sequence.nested	yes	A clip whose content is another sequence.
content.registered	yes	Typed extension clip content serialized through the schema registry.
content.opaque	yes	Uninterpreted clip content carried in a validated envelope.
edit-rate.non-audio	format-only	Positions at a rate that does not convert exactly to the document's rate.
context.chord-scale	yes	A sequence-owned lane of chord and scale statements that other items read while compiling.
context.groove	yes	A sequence-owned groove: a swing setting and a repeating table of per-step timing and accent that other items read while compiling.
clip.note-modifier	yes	Per-note playback modifiers: probability, pass condition, and ratchet.

DAWproject

Format id dawproject. Writer registered: yes.

Import

Concept	Level	Detail
unknown	none	not declared
track.flat	full
track.group	none	nested group tracks
track.video	none	not declared
clip.musical	full
clip.absolute	none	seconds-timed lanes, clips, and notes
clip.note	full
clip.media	full
clip.gain	none	per-clip gain
clip.fades	none	per-clip fades
clip.crossfade	none	not declared
clip.warp	none	warped clip content
clip.launch	none	scenes and clip-launcher content
gap.explicit	none	not declared
tempo.single	full
tempo.map	none	tempo changing after bar 1
meter.single	full
meter.map	none	time signature changing after bar 1
marker	none	arrangement markers
timecode.origin	none	not declared
media.provenance	none	not declared
mixer.track-gain	none	channel volume
mixer.track-pan	none	channel pan
mixer.sends	none	not declared
automation.device-param	none	automation lanes
automation.track-gain	none	volume automation lanes
automation.track-pan	none	pan automation lanes
device.placement	none	device chains
device.payload	none	plugin state
effect.timewarp	none	not declared
take.lane	none	not declared
take.comp	none	not declared
track.freeze	none	not declared
asset.sealed-hash	full
asset.embedded-media	none	not declared
asset.referenced-media	full	package-relative locator retained verbatim; identity sealed to the resolved bytes
sequence.multiple	none	not declared
sequence.nested	none	not declared
content.registered	none	not declared
content.opaque	none	not declared
edit-rate.non-audio	none	not declared
context.chord-scale	none	chord and scale context lanes
context.groove	none	groove templates and swing
clip.note-modifier	none	per-note probability, conditions, and ratchets

Export

Concept	Level	Becomes	Loss class	Detail
unknown	drop		dropped	not declared
track.flat	full
track.group	drop		dropped	not declared
track.video	drop		dropped	not declared
clip.musical	full
clip.absolute	degrade	clip.musical	approximated	sample-anchored clips are re-expressed in beats against the tempo map; positions that are not exact land on the nearest tick
clip.note	full
clip.media	full
clip.gain	drop		dropped	the writer does not emit a clip gain, so an authored clip gain is dropped and the clip exports at unity
clip.fades	drop		dropped	the writer does not emit clip fades, so authored fade-in and fade-out shapes are dropped and the clip exports with hard edges
clip.crossfade	drop		dropped	not declared
clip.warp	drop		dropped	not declared
clip.launch	drop		dropped	not declared
gap.explicit	drop		dropped	not declared
tempo.single	full
tempo.map	drop		dropped	not declared
meter.single	full
meter.map	drop		dropped	not declared
marker	drop		dropped	the writer does not emit markers or regions, so every named point and range on the timeline is dropped
timecode.origin	drop		dropped	the writer does not emit a session timecode origin, so the exported document starts at zero and every timecode reference shifts
media.provenance	drop		dropped	not declared
mixer.track-gain	drop		dropped	the writer does not emit a channel volume, so an authored track gain is dropped and the track exports at unity
mixer.track-pan	drop		dropped	the writer does not emit a channel pan, so an authored track pan is dropped and the track exports centred
mixer.sends	drop		dropped	not declared
automation.device-param	drop		dropped	device identity does not survive without a device payload, so its automation has no target
automation.track-gain	drop		dropped	a volume automation lane has no export target while channel volume itself is dropped
automation.track-pan	drop		dropped	a pan automation lane has no export target while channel pan itself is dropped
device.placement	drop		dropped	devices are identity-only in the document; DAWproject requires a device type to place one
device.payload	drop		dropped	not declared
effect.timewarp	drop		dropped	not declared
take.lane	degrade	clip.media	flattened	the active comp is flattened into arrangement clips; alternate takes are dropped
take.comp	degrade	clip.media	flattened	comp segment boundaries become clip boundaries; the selection is no longer editable
track.freeze	drop		dropped	DAWproject has no freeze concept; the authored track is exported and the sealed render is dropped
asset.sealed-hash	full
asset.embedded-media	drop		dropped	the writer references media by package-relative path and does not embed bytes, so an embedded asset is exported as a reference the receiving DAW must resolve
asset.referenced-media	full
sequence.multiple	degrade	track.flat	flattened	only the root sequence is written; other sequences are dropped
sequence.nested	drop		dropped	not declared
content.registered	roundtrip-only
content.opaque	roundtrip-only
edit-rate.non-audio	drop		dropped	not declared
context.chord-scale	drop		dropped	not declared
context.groove	drop		dropped	not declared
clip.note-modifier	drop		dropped	DAWproject notes carry no probability, pass condition, or ratchet; the notes are written and play unconditionally once

Adding a format

1. Write core/interchange/capabilities/<format>.json declaring an enumerator, a display_name, a writer flag, and the import and export rows the format supports.
2. Regenerate: capability_emit.py --emit concepts|tables|docs, or let the drift gate print the diff.
3. Write the reader and writer in their own target, deriving every refusal from import_supports and every loss from the export rows.

Nothing in core/interchange changes.