docs: add timestamp synchronization best practices and HLS documentation

- Add best practices section emphasizing fixing timestamps at source in Final Cut Pro
- Document --clip-offset as fallback option with wildcard support
- Add HLS segmented output documentation with manifest file details

Author: limulus

README.md

@@ -42,3 +42,31 @@ Now that you have an export, run `tcx2webvtt` with the `--fcp` option:
 ```sh
 tcx2webvtt --fcp 'My Project Export.fcpxmld' my-workout.tcx > my-track.vtt
 ```
+
+#### Best Practices for Timestamp Synchronization
+
+For the most reliable synchronization, ensure that the "Content Created" timestamps in your Final Cut Pro project match the actual recording times of your workout clips. This creates a canonical source of timing that makes your project reproducible and easier to maintain.
+
+If you cannot modify the source project timestamps, use the `--clip-offset` option as a fallback to correct timing discrepancies:
+
+```sh
+tcx2webvtt --fcp project.fcpxmld --clip-offset GX010163,2.5 workout.tcx
+```
+
+You can also apply the same offset to all clips using the wildcard `*`:
+
+```sh
+tcx2webvtt --fcp project.fcpxmld --clip-offset '*,-1.0' workout.tcx
+```
+
+However, fixing timestamps at the source (in Final Cut Pro) is preferred over applying corrections downstream, as it ensures consistency across all exports and eliminates the need for manual offset calculations.
+
+### HTTP Live Streaming
+
+For streaming applications or web players that require segmented media, use the `--hls` option to generate segmented WebVTT output:
+
+```sh
+tcx2webvtt --hls ./output-directory my-workout.tcx
+```
+
+This creates multiple `.vtt` files and an `index.m3u8` manifest file in the specified directory, each segment containing workout data for a specific time range. This format is compatible with HLS video streams.