### Manage Chapters in MP4 Files

Source: https://github.com/saecki/mp4ameta/blob/main/README.md

Handle chapters stored in either a chapter list or a chapter track. This example demonstrates reading chapter titles and times, clearing existing chapters, and adding new ones.

```rust
use mp4ameta::{Chapter, Tag};
use std::time::Duration;

let mut tag = Tag::read_from_path("audiobook.m4b").unwrap();

for chapter in tag.chapter_track() {
    let mins = chapter.start.as_secs() / 60;
    let secs = chapter.start.as_secs() % 60;
    println!("{mins:02}:{secs:02} {}", chapter.title);
}
tag.chapter_track_mut().clear();

tag.chapter_list_mut().extend([
    Chapter::new(Duration::ZERO, "first chapter"),
    Chapter::new(Duration::from_secs(3 * 60 + 42), "second chapter"),
    Chapter::new(Duration::from_secs(7 * 60 + 13), "third chapter"),
]);

tag.write_to_path("audiobook.m4b").unwrap();
```

--------------------------------

### Read and Write Basic Metadata

Source: https://github.com/saecki/mp4ameta/blob/main/README.md

Use this for straightforward reading and writing of common metadata like artist. Ensure the file exists and is accessible.

```rust
let mut tag = mp4ameta::Tag::read_from_path("music.m4a").unwrap();

println!("{}", tag.artist().unwrap());

tag.set_artist("artist");
tag.write_to_path("music.m4a").unwrap();
```

--------------------------------

### Configure Metadata Reading and Writing

Source: https://github.com/saecki/mp4ameta/blob/main/README.md

Customize which metadata is read or written to optimize performance and control data modification. Use `ReadConfig` to specify desired metadata types and `WriteConfig` to select fields for overwriting.

```rust
use mp4ameta::{ChplTimescale, ReadConfig, Tag, WriteConfig};

// Only read the metadata item list, not chapters or audio information
let read_cfg = ReadConfig {
    read_meta_items: true,
    read_image_data: false,
    read_chapter_list: false,
    read_chapter_track: false,
    read_audio_info: false,
    chpl_timescale: ChplTimescale::DEFAULT,
};
let mut tag = Tag::read_with_path("music.m4a", &read_cfg).unwrap();

println!("{tag}");

tag.clear_meta_items();

// Only overwrite the metadata item list, leave chapters intact
let write_cfg = WriteConfig {
    write_meta_items: true,
    write_chapter_list: false,
    write_chapter_track: false,
    chpl_timescale: ChplTimescale::DEFAULT,
};
tag.write_with_path("music.m4a", &write_cfg).unwrap();
```

--------------------------------

### Read and Write Metadata Using Freeform Identifiers

Source: https://github.com/saecki/mp4ameta/blob/main/README.md

Utilize Freeform Identifiers for custom metadata fields, often used by specific applications like iTunes. Ensure the identifier and namespace are correct.

```rust
use mp4ameta::{Data, FreeformIdent, Tag};

let mut tag = Tag::read_from_path("music.m4a").unwrap();
let isrc_ident = FreeformIdent::new_static("com.apple.iTunes", "ISRC");

let isrc = tag.strings_of(&isrc_ident).next().unwrap();
println!("{}", isrc);

tag.set_data(isrc_ident, Data::Utf8("isrc".to_owned()));
tag.write_to_path("music.m4a").unwrap();
```

--------------------------------

### Read and Write Metadata Using Fourcc Identifiers

Source: https://github.com/saecki/mp4ameta/blob/main/README.md

Access metadata using Fourcc identifiers for more granular control. This is useful for non-standard or specific metadata fields.

```rust
use mp4ameta::{Data, Fourcc, Tag};

let mut tag = Tag::read_from_path("music.m4a").unwrap();
let artist_ident = Fourcc(*b"\xa9ART");

let artist = tag.strings_of(&artist_ident).next().unwrap();
println!("{}", artist);

tag.set_data(artist_ident, Data::Utf8("artist".to_owned()));
tag.write_to_path("music.m4a").unwrap();
```

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