[Feature request] Media Overlays

[dhouck]

Describe the bug

(I donʼt know if this is the test app, or the toolkit, or just me failing to find a setting; I have a hard time disentangling all the related dependencies here)

When I open an epub with media overlays for narration, there is no option to play the audio with the media overlays. I can still use text-to-speech, but not the audio included in the file.

How to reproduce?

1. Open this A Christmas Carol book, which has audio taken from LibriVox added to the Standard Ebooks epub automatically. There are issues with the alignment but they should be irrelevant for this.
2. Go to Stave I: Marleyʼs Ghost in the book.
3. Click on the headphones button to read aloud

Expected result: Start hearing the audio aligned to chapter 1, with the appropriate text highlighted. (Because of the aforementioned alignment issues this is the text “Stave I” aligned with the entire list of readers, but after that it should highlight each sentence approximately when it is read).

Actual results: It reads the text with text-to-speech, as though there were no associated media overlay.

Readium version

3.0.2

Android API version

33 (Android 13.1)

Additional context

I tested this only in the test app, not the toolkit; for all I know this is only a test app bug and anything else using the toolkit would have this work correctly.

[qnga]

Media overlays are not supported yet, though it is something we want to do for a long time.

[dhouck]

Is it easier to add features supported by other Readium platforms, or does all the work need to basically be duplicated in Kotlin? I originally opened this as a bug because I assumed that Readium Desktop and Readium Mobile were supposed to have the same set of features.

[qnga]

Every Readium toolkit is a separate code base with different features. The mobile toolkits tend to stay close to each other but there is no hard rule. Readium Desktop is quite different and mostly goes its own way.