Enhance AudioParser

[domkm]

This adds common metadata and audio properties to Metadata and reading order Links generated by AudioParser.

I didn't see how to add the cover image here, though. Is it possible to do so?

[domkm]

All tests pass locally. How do I reproduce the CI failure?

[mickael-menu]

Hi @domkm, you can ignore the Carthage failure, it only runs properly on a local branch.

[domkm]

@mickael-menu Any thoughts on this PR? Could you share how to attach a cover image in the parser?

[mickael-menu]

Thank you for your contribution @domkm, it's much appreciated!

Regarding the cover, you can implement a CoverService or use one of the existing implementations (GeneratedCoverService) and pass it to the ServicesBuilder returned by the AudioParser. There's an example in the PDFParser:

swift-toolkit/Sources/Streamer/Parser/PDF/PDFParser.swift

Line 64 in c85d5d8

cover: document.cover.map(GeneratedCoverService.makeFactory(cover:)),

[domkm]

Hi @mickael-menu,

Sorry for the delay. I attempted to implement the solution as outlined, ran into a few stumbling blocks, and had a few realizations:

• Knowledge of readingOrder is necessary to form publication metadata, so passing all of the links and the fetcher is insufficient.
• Separating publication metadata retrieval from resource metadata retrieval is inefficient because the former requires the latter, so it's better for us to cache the results of the latter. Otherwise, we need to fetch metadata for each readingOrder link twice.
• Focusing on Manifest metadata and readingOrder exclusively precludes the possibility of easily enhancing other useful properties in the future, like tableOfContents.

Given this, I took a slightly different approach, where the configuration class processes the default manifest in its entirety, instead of processing individual fields. I’m keen to hear your thoughts on this approach. Thanks.

[mickael-menu]

Thanks for updating the PR @domkm. Doing the metadata computation in one go is fine by me, if that's necessary. 👌

In the meantime, the first 3.0.0-alpha.1 was released and develop now supports iOS 13+. Do you want to revisit the API using async/await before merging?

[domkm]

I believe the relevant async methods load and loadMetadata require iOS 15.

How do you determine what versions to support? My understanding is that iOS <15 represents a small single-digit percent of worldwide usage, at this point.

[mickael-menu]

We ask the various stakeholders what minimum version they are supporting and unfortunately it's still iOS 13 for now.

[domkm]

I noticed an issue with bitrates so I'm converting this to a draft until it's fixed.

[domkm]

I'm not sure how to correctly extract or calculate bitrate, so I'm dropping that functionality for now.

[mickael-menu]

Thank you @domkm 🙏