HLS SUPPLEMENTAL-CODECS (e.g. Dolby Vision dvh1) creates duplicate
variant tags with different codecs but the same media playlist URI. Due
to lazy-loading, only one variant gets its drmInfos populated via
createSegmentIndex(). The other variant remains with empty drmInfos and
is treated as unencrypted by getDecodingConfigs_().
In the preferredKeySystems loop, the filter rejected these unencrypted
configs (undefined !== preferredKeySystem), leaving the variant with no
decodingInfo and causing it to be dropped.
Fix: allow unencrypted configs (!keySystem) to pass through, matching
the pattern already used in the second (fallback) loop.
Propagating drmInfos in HLS parser would be more correct but is complex
because stream duplication happens at the tag level with separate cache
keys (URI + codecs) in createStreamInfoFromVariantTags_.
dong-heun
0f322b08bb