iOS & Android: Thumbnail is always generated from a single frame – timestamp option is ignored

[matesbridgeapi]

Problem

On both iOS and Android, the thumbnail generation API always returns
a frame from a single fixed timestamp (usually the first frame),
even when different timestamps are requested from JS.

This makes it impossible to generate multiple thumbnails across a video timeline.

Current behavior

• JS allows passing a timeStamp / timeSec parameter
• Native code executes successfully
• BUT the generated thumbnail is always from the same frame
• Calling the method multiple times with different timestamps returns identical images

This happens on:

• iOS (AVAssetImageGenerator)
• Android (MediaMetadataRetriever / equivalent)

Expected behavior

• Native implementation should respect the requested timestamp
• Each call with a different timestamp should generate a thumbnail from that exact time
• The API should support generating multiple thumbnails for:
  • video timelines
  • trim range previews
  • cover frame selection

Why this matters

This blocks all professional video editing use cases:

• Timeline preview strips
• Video trimming UI
• Selecting a cover frame from arbitrary positions

At the moment, the library can only generate one static thumbnail per video, which severely limits usability.

Suggested fix (platform-agnostic)

• Read timeStamp (milliseconds) from JS options
• Pass it directly to the native frame extraction logic
• Do NOT hardcode or ignore the timestamp internally
• Default to 0 only if no timestamp is provided

iOS example

let timeStamp = options["timeStamp"] as? Int ?? 0
let time = CMTimeMake(value: Int64(timeStamp), timescale: 1000)

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