Trait SegmentLayout 

pub trait SegmentLayout:
    Send
    + Sync
    + 'static {
    // Required methods
    fn init_segment_range(&self) -> Range<u64>;
    fn len(&self) -> Option<u64>;
    fn segment_after_byte(&self, byte_offset: u64) -> Option<SegmentDescriptor>;
    fn segment_at_time(&self, t: Duration) -> Option<SegmentDescriptor>;
    fn segment_count(&self) -> Option<u32>;

    // Provided methods
    fn is_empty(&self) -> bool { ... }
    fn segment_at_byte(&self, _byte_offset: u64) -> Option<SegmentDescriptor> { ... }
    fn segment_at_index(&self, _segment_index: u32) -> Option<SegmentDescriptor> { ... }
}

Segment-table view exposed by segmented sources (HLS, fragmented file-mp4).

Carries the segment metadata that segment-aware decoders need to route reads — init_segment_range (ftyp+moov / EXT-X-MAP), segment_at_time, segment_after_byte, segment_count, and total len. Has no I/O surface: the byte cursor is the decoder’s Read + Seek handle, queried independently. Sources that aren’t segment-aware return None from Source::as_segment_layout.

Required Methods

fn init_segment_range(&self) -> Range<u64>

Init segment range (e.g. ftyp+moov from EXT-X-MAP) for the current layout variant. Returns an empty range (0..0) when the layout has no init segment (raw TS/AAC/MPEG-ES) or when the active variant has not yet announced one. Callers that require an init must check Range::is_empty() — distinguishing “no init” from “init at offset 0..0” is unsupported because every init we emit is non-empty by construction.

fn len(&self) -> Option<u64>

Total byte length across all segments. Used to compute total duration when the source can’t provide a direct value.

fn segment_after_byte(&self, byte_offset: u64) -> Option<SegmentDescriptor>

Next segment whose byte range starts at or after byte_offset. Used for sequential play after the current segment is consumed.

fn segment_at_time(&self, t: Duration) -> Option<SegmentDescriptor>

Locate the segment whose [decode_time, decode_time + duration) covers t. Resolves against the source’s current layout variant — same variant init_segment_range describes.

fn segment_count(&self) -> Option<u32>

Total number of segments in the current layout variant.

Provided Methods

fn is_empty(&self) -> bool

Whether the layout currently reports zero bytes. len() is Option because some segmented sources do not know their total upfront, so emptiness defaults to “len is None or Some(0)”.

fn segment_at_byte(&self, _byte_offset: u64) -> Option<SegmentDescriptor>

Segment whose byte_range covers byte_offset. Default None keeps non-segmented sources transparent.

fn segment_at_index(&self, _segment_index: u32) -> Option<SegmentDescriptor>

Descriptor for the segment at segment_index in the current layout variant. Used by demuxers to re-resolve a cursor’s byte_range against the live layout — without this, a DRM post-decrypt size shrink (PKCS7 padding stripped) between cursor setup and the actual read leaves state.range pointing past the segment’s real end and HlsSource::read_at splices bytes from the next segment onto the buffer’s tail. Returns None for non-segmented sources or for indices outside the current layout’s range.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors