Function heif_context_get_sequence_duration 

pub unsafe extern "C" fn heif_context_get_sequence_duration(
    arg1: *const heif_context,
) -> u64

Get the total duration of the sequence in timescale clock ticks. Use heif_context_get_sequence_timescale() to get the clock ticks per second.

@return Sequence duration in clock ticks. Returns 0 if there is no sequence in the file.