MNAVChapters - read chapter marks

The MNAVChapters iOS library reads chapter metadata of audiovisual assets. It reads chapters from MPEG-4 and specifically MP3 files.

Although the id3v2 standard specifies the chapter frame since 2005, I couldn't find a C or Objective-C library that parses this frame correctly. So, inspired by a post over on the auphonic blog, I started this modest Objective-C implementation.

MNAVChapter

A chapter within a media file.

Accessing Chapter Information

• title

The title of the chapter.

(nonatomic, copy) NSString *title;

• url

An URL string of the chapter.

(nonatomic, copy) NSString *url;

• time

The start time of the chapter.

(nonatomic) CMTime time;

• duration

The duration of the chapter.

(nonatomic) CMTime duration;

• artwork

An embedded chapter image.

(nonatomic) UIImage *artwork;

MNAVChapterReader

The parser which reads chapter marks from timed audiovisual media. It attempts to read chapter information from assets with "org.mp4ra" or "org.id3" meta data formats.

Reading Chapters from an Asset

• + chaptersFromAsset:

Make sense of an AVAsset object and, if possible, return an array of chapters.

+ (NSArray *)chaptersFromAsset:(AVAsset *)asset;

Here is an example of reading chapter marks from one the auphonic demo files:

AVAsset *asset = [self assetWithResource:@"auphonic_chapters_demo" ofType:@"mp3"];
NSArray *chapters = [[MNAVChapterReader chaptersFromAsset:asset];

Install

Add the MNAVChapters Xcode project to your workspace or, to create a release build and use the object files in the build directory, do:

$ make

Run tests from the command-line:

$ make test

Example

This repo contains an Xcode workspace to provide an easy to use example, written in Swift. When you are running the app for the first time, and tap on one of the episodes, be patient. It will have to download the media files, which, depending on your network might take some time. Once received, the files are copied to "/Library/Caches/", and onwardly read from there.

License

MIT License