loadChapterMetadataGroups(bestMatchingPreferredLanguages:completionHandler:)
Loads chapter metadata with a locale that best matches the list of preferred languages.
Declaration
func loadChapterMetadataGroups(bestMatchingPreferredLanguages preferredLanguages: [String], completionHandler: @escaping @Sendable ([AVTimedMetadataGroup]?, (any Error)?) -> Void)func loadChapterMetadataGroups(bestMatchingPreferredLanguages preferredLanguages: [String]) async throws -> [AVTimedMetadataGroup]Parameters
- preferredLanguages:
An array of language identifiers in order of preference, each of which is an IETF BCP 47 (RFC 4646) language identifier. Call Preferredlanguages to retrieve the list of languates the user prefers.
- completionHandler:
A callback that the system invokes after it finishes the loading request. It passes the completion handler the following parameters:
- metadataGroups
An array of metadata groups, which may be empty if no groups exist for the specified languages. The value is
nilif an error occurs.- error
An error object if the request fails; otherwise,
nil.
Discussion
This method returns an array of AVTimedMetadataGroup objects asynchronously. Each object in the array contains an AVMetadataItem that represents the chapter’s title, and the metadata group’s timeRange value equals the time range of the chapter title item.
The metadata group contains all chapter metadata, including items with the common key commonKeyArtwork, if such items are present. The system adds an AVMetadataItem with the specified common key to an existing AVTimedMetadataGroup object if the time range (timestamp and duration) of the metadata item and the metadata group overlap. The locales of such items don’t need to match the locale of the chapter titles.
You can use the metadataItems(from:filteredAndSortedAccordingToPreferredLanguages:) method to further filter the metadata items in each group. You can also filter the returned items based on locale using the metadataItems(from:with:) method.