Struct SampleToGroup 

pub struct SampleToGroup {
    pub grouping_type: [u8; 4],
    pub grouping_type_parameter: Option<u32>,
    pub entries: Vec<(u32, u32)>,
}

One sbgp (SampleToGroupBox) to emit on a track.

grouping_type is the four-byte selector that pairs this box with an sgpd of the same type. The common types in ISO/IEC 14496-12 are roll (audio roll-back distance), rap (random-access points), sync (sync samples), alst (alternate startup sequence), prol (audio preroll); other groupings are defined in codec-binding specs.

grouping_type_parameter selects an alternative grouping of the same type when Some(_) (version 1 of sbgp); None emits version 0.

entries is the run-length table — each pair (sample_count, group_description_index) says “the next sample_count samples belong to group group_description_index”. group_description_index = 0 means “no group of this type” for the run; an index ≥ 0x10001 is a movie-fragment-local reference and is written verbatim (the muxer does not resolve fragment-local groups). The cumulative sum(sample_count) should match the track’s total sample count per §8.9.2.1 — the builder does not validate this.

Fields

grouping_type: [u8; 4]

Four-byte grouping type (e.g. *b"roll", *b"rap ").

grouping_type_parameter: Option<u32>

grouping_type_parameter — selects an alternative grouping of the same type. Some(_) emits version 1; None emits version 0.

entries: Vec<(u32, u32)>

Run-length entries (sample_count, group_description_index). Empty is a legal “zero-entry” sbgp.

Trait Implementations

impl Clone for SampleToGroup

fn clone(&self) -> SampleToGroup

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SampleToGroup

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for SampleToGroup

fn default() -> SampleToGroup

Returns the “default value” for a type.