Lyric highlight behavior differs from Apple Music

[PuddleGH]

When a line overlaps over the next line for about a split second, the 'Preview' tab displays that first line to be highlighted for the whole duration of the next one instead of the split second that was configured.

Example:
Line 1 [Start: 00:00.00] [End: 00:01.20]
Line 2 [Start: 00:01.00] [End: 00:02.00]

Issue:
Line 1 [Start: 00:00.00] [End: 00:02.00] <----- Lasts as long as Line 2 instead of what was configured (visually)
Line 2 [Start: 00:01.00] [End: 00:02.00]

This is a visual issue with the 'Preview' tab on both the web and desktop versions.

It seems like uploading a video of the issue will continuously fail so if you still can't quite fully understand what I am talking about, feel free to ask for further clarification.

[apoint123]

Hi @PuddleGH,

Thank you for opening this issue!

This is actually the expected behavior and is intentionally designed to replicate the visual experience of Apple Music.

Why it behaves this way

In Apple Music, when two lines overlap in time:

• Both lines are highlighted simultaneously when the overlap starts.
• When the first line reaches its end time, its syllable/word progress animation stops, but it remains visually highlighted alongside the second line.
• The highlighted state of both lines will only turn off once the second line finishes.

We implemented our timeline playback logic specifically to achieve this Apple Music-like visual effect.

---

Apple Music Reference Recording

Here is a screen recording from Apple Music demonstrating this exact behavior:

output.mp4

---

(If you are interested in the implementation details, this behavior is handled in packages/core/src/lyric-player/base/timeline.ts).

Please let us know if you have any further questions!

[PuddleGH]

Hello @apoint123 ,

I just want to clarify how that isn't the case for Apple Music outside of iOS or other Apple devices.
As I own an iPhone with an Apple Music subscription, I have double-checked this with a song and what I have stated previously seems to be right.

I assume that in your screen recording, you do not seem to be using Apple Music on an Apple device and it is said that some features of Apple Music are not available outside of iOS.

I have tried to upload a video demonstrating it but I don't think it will load up.

[apoint123]

Hello @PuddleGH,

To be transparent, my screen recording was captured from the Apple Music app on Android. However, Apple Music's lyrics synchronization and rendering rules (including overlapping lines behavior) are designed to be consistent across platforms, including iOS.

To help us investigate what might be causing the difference you observed:

1. Test Song & Timestamps: Could you share the song title, artist, and timestamp of the track you tested on your iPhone?

2. Uploading the Screen Recording: The upload failed because GitHub limits attachment file sizes. You can try:

   • Compressing the video using software like ffmpeg to get it under GitHub's 10MB limit.
   • Converting the clip to an animated .gif.
   • Or uploading the video to an external hosting service (e.g., Streamable, Google Drive, or YouTube) and sharing the link here.

Looking forward to checking out the specific track with you!

[PuddleGH]

Hi again @apoint123

I have compressed the video twice.

ScreenRecording_08-17-2026.20-59-00_1.2.mp4

[apoint123]

Hi @PuddleGH,

Thank you so much for taking the time to compress and share the video! That made everything crystal clear.

There is actually a behavioral difference in Apple Music depending on the type of lyrics:

• Line-synced lyrics (as shown in your video): When two lines overlap, the first line does indeed lose its highlight immediately once its duration ends, even while the second line is still playing.
• Word-synced lyrics (as shown in my previous recording): Overlapping line remain highlighted together until the overlapping group completes.

Currently, AMLL's core timeline was primarily designed and optimized for word-synced lyrics, so it currently applies the syllable-synced grouping rule to all lyrics across the board.

We don't yet have dedicated handling for line-synced overlapping lyrics, which causes the visual behavior you noticed. We will track this and implement dedicated support for line-synced lyrics in a future update so it accurately reflects Apple Music's behavior in both modes.

Thanks again for helping us catch this detail!

[PuddleGH]

Hi @apoint123 ,

I have captured a screen recording of the same thing as the previous video but this time the lyrics are highlighted word-by-word.

ScreenRecording_08-18-2026.10-49-16_1.mp4

[apoint123]

Hi @PuddleGH,

After checking with the latest versions of Apple Music on modern iOS and macOS, I have admit that you are right. Apple has updated the highlight behavior in newer releases (probably around iOS 26 or 27) so that finished lines de-highlight as shown in your video.

My previous understanding was based on Apple Music's older implementation from a few years ago (which is also what the current Android version still uses), and AMLL was originally built around that older behavior.

Since this represents a noticeable visual change to the lyric experience, and I have previously received mixed feedback regarding this behavior (some users actually prefer the old behavior where overlapping lines remain highlighted), I need to discuss this with the team and community first before deciding on how to proceed.

Thank you so much for your patience, detailed recordings, and for helping us stay on top of Apple Music's latest design changes!

[kid141252010]

I agree with keeping the lyric line-wrapping logic consistent with the latest Apple Music on iOS. This provides a consistent visual center and prevents lines from overflowing or being truncated when there is too much text.