// Add background music
/// - Parameters:
///   - bgmPath: File path of the music asset
///   - startAtVideoTime: The time on the timeline when BGM starts playing (default is 0). For example, if the main track is a 10s video and you want BGM to start at the 5th second, pass the CMTime corresponding to 5s
///   - timeRange: Playback range to trim from the music asset (default is the entire track). For example, if a song is 0-90s, you can set timeRange to trim any segment within 0-90s
///  - return: Unique ID of the BGM asset
- (int)addBgm:(NSString *)bgmPath startAtVideoTime:(CMTime)startAtVideoTime timeRange:(CMTimeRange)timeRange;

/// Remove background music by unique ID
/// - Parameter bgmId: ID generated when adding background music
- (BOOL)removeBgm:(int)bgmId;

/// Remove all BGMs
- (void)removeAllBgm;

/// Adjust the BGM start position in the video. This feature is not yet active
/// - Parameters:
///   - bgmId: ID generated when adding background music
///   - startAtVideoTime: The time on the timeline when BGM starts playing. For example, if the main track is a 10s video and you want BGM to start at the 5th second, pass the CMTime corresponding to 5s
- (void)updateBgm:(int)bgmId atVideoTime:(CMTime)startAtVideoTime;

/// Set BGM playback range
/// - Parameters:
///   - bgmId: ID generated when adding background music
///   - timeRange: Playback range to trim from the music asset (default is the entire track). For example, if a song is 0-90s, you can set timeRange to trim any segment within 0-90s
- (void)updateBgm:(int)bgmId playRange:(CMTimeRange)timeRange;

/// Set BGM playback volume
/// - Parameters:
///   - bgmId: ID generated when adding background music
///   - volume: Volume (0-1f)
- (void)setBgm:(int)bgmId volume:(float)volume;

/// Set volume for all background music
/// - Parameters:
///   - volume: Volume (0-1f)
- (void)setAllBgmVolume:(float)volume;

/// Get BGM volume
/// - Parameters:
///     - bgmId: ID generated when adding background music
///    - return: Volume
- (float)getBgmVolume:(int)bgmId;


/// Adjust BGM playback speed
/// - Parameters:
///   - bgmId: ID generated when adding background music
///   - speed: Playback speed. 1 = normal, >1 = fast, <1 = slow
- (void)setBgm:(int)bgmId speed:(float)speed;

/// Get BGM playback speed
/// - Parameters:
///     - bgmID: ID generated when adding background music
///  - return: Current BGM playback speed
- (float)getBgmSpeed:(int)bgmId;