A tag with a region (en-US, es-419) matches only that variant and reports a miss instead of taking another region. A bare tag takes the variant it means (pt -> pt-BR, es -> es-ES) and falls back to any variant only when that one is missing. `orig` prefers the title's own tag, `-sl orig` resolves, forced and SDH subtitles are picked from their own pools, and the track name no longer strips the region from the cached language.
BREAKING CHANGE: -l es-419 no longer selects es-ES, and language_priority, language_tags and muxing.default_language treat a regional tag as exact.
sort_subtitles resolved only the all token, while the video and audio sorts
resolved all and best. by_language now asks matching_languages rather than
repeating the RFC 4647 preference, with no behaviour change.
subtitle.language_priority and audio.language_priority prepend to the CLI
languages, so the named languages sort first and nothing is filtered.
--exact-lang now applies to the sorts too, through matching_languages, which
follows the same RFC 4647 rule as Tracks.by_language and ignores invalid tags.
sort_subtitles applied the language sort before the type sort. Python sorts
are stable, so the last pass wins and type became the major key: every forced
track, then every normal, then every SDH, each block ordered by language. In a
title with many languages this put a track far from its own SDH version, for
example Finnish at track 5 and Finnish SDH at track 42.
Add a group_by parameter that selects the major key. "type" is the default and
keeps the current order byte for byte. "language" swaps the two passes so each
language stays next to its own variants. Read it from the new subtitle.group_by
config key.
Also correct the docs: type_priority was described as sorting the variants
within each language, which was never true. It ranks the types across all
languages.
Optional ranking of forced/normal/sdh per language, mirroring audio.codec_priority; first track gets the default flag, so this also picks the default subtitle. Unset = existing behavior.
imSp4rky