Feature Request: Expose decoded frame timestamp (PTS) to Flutter layer

[guoxiao0521]

Feature Request — Expose Decoded Frame Timestamp (PTS/DTS)

Expected Feature

In flutter_vlc_player, I would like to have access to the timestamp of each decoded (or soon-to-be-rendered) frame, such as PTS (presentation timestamp) or DTS (decoding timestamp).

Background / Use Cases

• Synchronizing video frames with external data sources (e.g., sensor data, subtitles, annotations).
• Performing frame-level video analysis that requires precise playback timing for each frame.
• Currently, the plugin provides playback control, screenshots, seek, and recording, but no API to obtain frame timestamps.

Suggested API Design

• Provide a frame timestamp callback (via EventChannel) that emits the timestamp each time a frame is decoded or about to be rendered.
• Alternatively, include the timestamp when fetching a frame/screenshot/texture.
• The timestamp unit could be milliseconds or microseconds, based on libVLC’s internal PTS representation.

Implementation Notes

• Android: hook into libVLC JNI frame/renderer callbacks, which contain PTS or related timing info.
• iOS: use VLCKit’s equivalent APIs to extract frame timestamps.
• Pass these timestamps back to the Dart layer using MethodChannel or EventChannel.

Difference from Existing Features

• Current flutter_vlc_player features: playback, pause, seek, screenshot, recording.
• Missing: fine-grained per-frame timing information.
• This feature would unlock new use cases involving synchronization and analysis.

Potential Considerations

• Performance cost: frequent callbacks (per frame) may introduce overhead.
• Platform differences: libVLC vs. VLCKit APIs may differ in timestamp handling.
• Consistency: need to clearly define what timestamp type is exposed (PTS, presentation time, or stream time).

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🙏 Thanks for considering this request! If maintainers are open to it, I’d be happy to help with a PoC or PR on the native layer.