Eyevinn / mp4ff / 28243513726

83%

push

github

feat: parse HEVC multilayer VPS extension and L-HEVC config record

Add parsing of the HEVC multilayer/multiview VPS extension (vps_extension(),
ISO/IEC 23008-2 Annex F.7.3.2.1.1) used by MV-HEVC and SHVC. The base VPS
struct and parsing are unchanged; the extension is exposed as an optional
hevc.VPS.Extension (*VPSExtension) carrying the scalability mask, per-layer
dimension/dependency info, layer profile-tier-levels, output layer sets and
rep_format() resolutions, with VPS.GetNumLayers/IsMultiLayer/GetNumViews/
ScalabilityMaskBits helpers.

Also add L-HEVC (lhvC) decoder configuration record support to the hevc
package: DecConfRec.DecodeLHEVCDecConfRec, EncodeLHEVC, EncodeLHEVCSW and
LHEVCSize (ISO/IEC 14496-15 Ed. 7 Sec. 9.4.3).

The output-layer-set parsing follows the normative syntax/semantics
(F-11/F-12/F-13): only OLS i>=1 read syntax elements, profile_tier_level_idx
is gated on NecessaryLayerFlag and vps_num_profile_tier_level_minus1>0, and
alt_output_layer_flag is read when required. Per-OLS state is computed in
locals so NumOutputLayerSets larger than the supported layer bound cannot
panic. VPS extensions with additional layer sets (num_add_layer_sets>0, which
need the F-6/F-9 tree-partition derivations and never occur for MV-HEVC) are
rejected with an error rather than misparsed.

307 of 382 new or added lines in 2 files covered. (80.37%)

20522 of 24789 relevant lines covered (82.79%)

0.92 hits per line