> ## Documentation Index
> Fetch the complete documentation index at: https://docs.tessact.ai/llms.txt
> Use this file to discover all available pages before exploring further.
# Media and layer matrix
> Compare acquisition, decoding, timeline visualization, source-time behavior, and render participation.
The editor separates three concepts that can look interchangeable at first:
1. A **source asset** is uploaded, selected from the workspace library, or returned by a supported service.
2. A **timeline layer** is one use of that source in the current draft.
3. An **evaluated frame** is what the preview and final H.264 render produce at a specific composition frame.
Changing one timeline layer does not rewrite its source asset. Duplicating a layer creates another timeline instance that may continue to reference the same media.
## Acquisition and authoring
| Kind | Bin / Library | Upload or drop | Clipboard | Draw / insert tool | AI Search |
| ----------------- | :---------------------------------------------------------------------------: | :----------------------------------------------: | :-------------------------: | :---------------------: | :--------------------: |
| Video | ✓ | ✓ | Copied Tessact layer | — | Supported video result |
| Livestream source | Library only; final MP4 or ready chunk group | — | — | — | — |
| Audio | ✓ | ✓ | Copied Tessact layer | — | Supported audio result |
| Image | ✓ | ✓ | PNG or copied Tessact layer | — | Supported image result |
| GIF | ✓ | ✓ | Copied Tessact layer | — | — |
| Text | Draft-local | Plain text creates a layer when pasted on canvas | ✓ | `T` | — |
| Solid | Draft-local | — | Copied Tessact layer | `R` | — |
| Frame | Draft-local | — | Copied Tessact layer | `F` | — |
| Captions | Draft-local, derived from a video layer with detected audio/subtitle metadata | — | Copied Tessact layer | Caption creation action | — |
## Preview and timeline behavior
| Layer | Visible on canvas | Timeline visualization | Has source-time mapping | Can carry audio | Frame-trimmable | Split at interior playhead |
| ---------------- | :-----------------------: | ----------------------------------------------------------- | :-----------------------------------------------------: | :-----------------------------------: | :-----------------------: | :--------------------------------------: |
| Video | ✓ | Filmstrip when decode succeeds | ✓ | ✓, if the source contains audio | ✓ | ✓ |
| Livestream group | ✓ | Grouped video clip and update placeholder when source grows | Chunk-aware mapping | ✓, when recorded chunks contain audio | ✓ | ✓, subject to group detachment semantics |
| Audio | — | Waveform when decode succeeds | ✓ | ✓ | ✓ | ✓ |
| Image | ✓ | Thumbnail / color-identifiable clip body | — | — | ✓ | ✓ |
| GIF | ✓ | Animated-media clip body; no filmstrip | Playback rate; verify continuity after structural edits | — | ✓, with continuity caveat | ✓, with restart caveat |
| Text | ✓ | Named text layer | — | — | ✓ | ✓ |
| Solid | ✓ | Color-identifiable layer | — | — | ✓ | ✓ |
| Frame | Container plus appearance | Frame layer with nested descendants | — | — | ✓ | ✓, subject to structural eligibility |
| Captions | ✓ when tokens are active | Caption layer | Token timestamps map from milliseconds | — | ✓ | ✓ |
All timeline layers have a composition start and frame duration. “Source-time mapping” means the layer additionally maps those composition frames into a decoded source using a source offset and, where supported, playback rate.
## Inspector capability summary
| Layer | Transform | Crop | Playback rate | Inspector volume | Typography | Layout | Effects | Shadows |
| -------- | :-------: | :--: | :-----------: | :-----------------: | :--------: | :----: | :---------------: | :-----: |
| Video | ✓ | ✓ | ✓ | If source has audio | — | — | ✓ | ✓ |
| Audio | — | — | ✓ | ✓ | — | — | — | — |
| Image | ✓ | ✓ | — | — | — | — | ✓ | ✓ |
| GIF | ✓ | ✓ | ✓ | — | — | — | ✓ | ✓ |
| Text | ✓ | ✓ | — | — | ✓ | — | Typewriter / blur | ✓ |
| Solid | ✓ | ✓ | — | — | — | — | — | ✓ |
| Frame | ✓ | ✓ | — | — | — | ✓ | ✓ | ✓ |
| Captions | ✓ | ✓ | — | — | ✓ | — | Typewriter / blur | ✓ |
For individual fields, read the [Property matrix](/editor/reference/property-matrix).
## Source mapping
For an active media layer:
```text theme={null}
source time = source in-point
+ time elapsed since the layer begins × playback rate
```
The preview evaluates a layer from its start through its last active composition frame. A left trim normally advances the video or audio source in-point; a right trim shortens the active duration. Playback rate changes how quickly source time advances without changing the draft frame rate. A trimmed or split GIF can restart at the new boundary, so review animation continuity after either edit.
Audio fade durations are authored with timeline handles rather than in the Inspector. Video and audio inspectors provide base volume where applicable.
Source metadata can use a native frame rate or time base different from the draft. The editor's public timing contract is the draft's integer composition frames; decoding chooses the best source sample for that requested time.
## Audio gain path
Audio level begins with the layer's decibel value:
```text theme={null}
base gain = 0, when dB = -60
base gain = 10^(dB / 20), otherwise
evaluated gain = base gain × fade-in multiplier × fade-out multiplier
```
Track mute and preview mute are monitoring/composition controls applied in addition to layer gain. A waveform is only a visualization; its height does not replace the numeric gain setting.
## Media formats and MIME types
Upload acceptance is broader than a single extension list and depends on browser-reported MIME type, metadata probing, and the browser's actual decode support.
| Family | Typical examples | Important caveat |
| -------------- | --------------------------------------------- | ------------------------------------------------------------------------------- |
| Video | MP4, WebM, QuickTime-compatible files | A recognized container may still contain a codec that the browser cannot decode |
| Audio | MP3, WAV, AAC/M4A, Ogg-family audio | Waveform creation and preview decode can fail independently of upload |
| Image | PNG, JPEG, WebP, common browser image formats | Very large dimensions increase decode and canvas memory |
| Animated image | GIF and supported animated formats | Duration and frame decoding depend on usable metadata |
See [Supported media formats](/editor/media/supported-formats) for the operational upload checklist.
## Remote media
Remote media needs a URL that remains readable by the browser and render path. A thumbnail URL succeeding does not prove the full-resolution asset or byte-range requests will succeed. Insert a result and verify full-resolution decoding before building dependent timing around it.
## Cache layers
The timeline can reuse decoded filmstrip frames and waveform data to avoid repeating expensive work. Cache artifacts are disposable visual accelerators:
* A missing cache should trigger regeneration, not change the layer's authored values.
* A stale filmstrip does not alter the evaluated video frame.
* Clearing browser site data can make filmstrips and waveforms rebuild.
* Export reads the actual media and draft state, not a screenshot of the timeline cache.
## H.264 render participation
| Layer | Included in final H.264 image | Included in final H.264 audio |
| ------------------------------- | :---------------------------: | :--------------------------------------------------: |
| Video | ✓ when visible at the frame | ✓ when source has audio and gain/track state permits |
| Audio | — | ✓ when active and not effectively muted |
| Image / GIF | ✓ when visible at the frame | — |
| Text / Solid / Frame / Captions | ✓ when visible at the frame | — |
Timeline guides, selection boxes, handles, the playhead, panel UI, waveform drawings, and filmstrips are editor chrome and are not rendered into the video.
Follow media discovery, upload, insertion, placement, and verification in the editor.
Diagnose metadata, decoding, proxy, waveform, and caption-source failures.