feat: Extend Lottie specification with VideoFrame asset support #149
There are no files selected for viewing
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,46 @@ | ||
| { | ||
| "$schema": "https://json-schema.org/draft/2020-12/schema", | ||
| "type": "object", | ||
| "title": "Video Frame", | ||
| "description": "Asset representing a frame from a video at a specific timestamp.", | ||
| "allOf": [ | ||
| { | ||
| "$ref": "#/$defs/assets/asset" | ||
| }, | ||
| { | ||
| "$ref": "#/$defs/helpers/slottable-object" | ||
| }, | ||
| { | ||
| "type": "object", | ||
| "properties": { | ||
|
Member
There was a problem hiding this comment. I think we should introduce a |
||
| "vsid": { | ||
|
Member
There was a problem hiding this comment. Naming bike-shed: normally How about
Contributor
Author
There was a problem hiding this comment. Agree, refId makes more sense, updated |
||
| "title": "Video Asset ID", | ||
| "description": "ID of the video asset to extract frame from", | ||
| "type": "string" | ||
| }, | ||
| "t": { | ||
| "title": "Timestamp", | ||
| "description": "Timestamp in seconds where to extract the frame from the video", | ||
|
Member
There was a problem hiding this comment. How does this interact with start-time/time-stretch/general time remapping in referencing layers? Also actual time units seem a bit odd since everything else in Lottie is expressed as frame indices (ip, op, etc).
Contributor
Author
There was a problem hiding this comment. Actually, you are right, we can define time in frames here |
||
| "type": "number", | ||
| "minimum": 0 | ||
| }, | ||
| "w": { | ||
| "title": "Width", | ||
| "description": "Width of the frame", | ||
| "type": "number" | ||
| }, | ||
| "h": { | ||
| "title": "Height", | ||
| "description": "Height of the frame", | ||
| "type": "number" | ||
| } | ||
|
Comment on lines
+33
to
+42
Member
There was a problem hiding this comment. The video asset schema also has
Contributor
Author
There was a problem hiding this comment. @mbasaglia I was thinking about extracting a frame from VideoResource, specifying width, height, x, y from the top left corner. But you are right, as a first iteration we can drop w/h from frame |
||
| }, | ||
| "if": { | ||
| "required": ["sid"] | ||
| }, | ||
| "else": { | ||
| "required": ["vsid", "t"] | ||
| } | ||
| } | ||
| ] | ||
| } | ||
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,71 @@ | ||
| { | ||
| "$schema": "https://json-schema.org/draft/2020-12/schema", | ||
| "type": "object", | ||
| "title": "Video", | ||
| "description": "Asset containing a video that can be referenced by layers or video frame assets.", | ||
| "allOf": [ | ||
| { | ||
| "$ref": "#/$defs/assets/asset" | ||
| }, | ||
| { | ||
| "$ref": "#/$defs/helpers/slottable-object" | ||
| }, | ||
| { | ||
| "type": "object", | ||
| "properties": { | ||
| "w": { | ||
| "title": "Width", | ||
| "description": "Width of the video", | ||
| "type": "number" | ||
| }, | ||
| "h": { | ||
| "title": "Height", | ||
| "description": "Height of the video", | ||
| "type": "number" | ||
| }, | ||
| "duration": { | ||
| "title": "Duration", | ||
| "description": "Duration of the video in seconds", | ||
| "type": "number", | ||
| "minimum": 0 | ||
| }, | ||
| "p": { | ||
| "title": "File Name", | ||
| "description": "Name of the video file or a data url", | ||
| "type": "string" | ||
| }, | ||
| "u": { | ||
| "title": "File Path", | ||
| "description": "Path to the video file", | ||
| "type": "string" | ||
| }, | ||
| "e": { | ||
| "title": "Embedded", | ||
| "description": "If '1', 'p' is a Data URL", | ||
| "$ref": "#/$defs/values/int-boolean" | ||
| } | ||
| }, | ||
| "allOf": [ | ||
| { | ||
| "if": { | ||
| "properties": { | ||
| "e": {"const": 1} | ||
| }, | ||
| "required": ["e"] | ||
| }, | ||
| "then": { | ||
| "properties": { | ||
| "p": {"$ref": "#/$defs/values/data-url"} | ||
| } | ||
| } | ||
| } | ||
|
Member
There was a problem hiding this comment. I'd extract this into an abstract file-asset schema so we can share the definition between image and video assets (and other future assets |
||
| ], | ||
| "if": { | ||
| "required": ["sid"] | ||
| }, | ||
| "else": { | ||
| "required": ["w", "h", "duration", "p"] | ||
| } | ||
| } | ||
| ] | ||
| } | ||
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
Is this a SHOULD or a MUST?
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
This point is up for discussion.
The advantage of using MUST is that Lottie players could extract frames on the fly, which speeds up animation initialization and reduces memory usage before playback starts. At the same time, if players don’t treat the extracted frame as a static image but instead process it in real time, it could impose constraints on the video itself - for example, requiring more keyframes to ensure fast seeking, which would increase file size.
That’s why I would vote for MUST.
In the future, if we want to support optimization for initialization we could extend videoFrame with initialization: static | dynamic param to achieve that.