Genre tags: read multi-value frames correctly, and repair existing rows

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Author	SHA1	Message	Date
bvandeusen	fd27819cdd	style(scanner): tagged switch on ID3 major version — #2499 test-go / test (push) Successful in 55s Details test-go / integration (push) Successful in 4m55s Details	2026-08-05 21:22:53 -04:00
bvandeusen	37b396a7e4	fix(scanner): read multi-value genre frames correctly — #2499 test-go / test (push) Failing after 41s Details test-go / integration (push) Canceled after 4m46s Details dhowden/tag's readTFrame splits ID3v2 null-separated multi-value text frames and rejoins them with the EMPTY string, so a file tagged "Alternative Rock" + "Rock" was stored as "Alternative RockRock". It also leaves bare numeric ID3v1 references unresolved, which is why the library showed genres like "4017" and "526617". This corrupted more than the browse axis added in #367: taste_profile.sql reads tracks.genre directly, so the welded tokens were entering the taste profile's tag vocabulary, and recommendation.sql/discover.sql were comparing them as single opaque tags. Genre counts were wrong everywhere. ffprobe is not a fix — ffmpeg's read_ttag calls decode_str once with no loop, keeping only the first value. Truncating multi-genre tags would blunt the similarity signal genre mainly feeds. So the TCON frame is now parsed directly (ID3v2.2/2.3/2.4, all four text encodings, per-frame and tag-level unsynchronisation, numeric and parenthesised ID3v1 references); everything else still comes from dhowden/tag. Values are stored ";"-delimited, which the read side already splits on, so no query changes. Existing rows are repaired without an operator-run rebuild: migration 0054 adds tracks.tag_read_version DEFAULT 0, below the scanner's current tagReadVersion, so the next scan re-reads tags it would otherwise skip on mtime. Such a re-read reuses the stored duration instead of re-running ffprobe, keeping a repair pass tag-read-bound rather than one fork+exec per file. Bumping the constant is how a future extraction fix reaches an existing library. Only ID3v2 is in scope — dhowden welds nowhere else. The Vorbis/MP4 repeated-field question is #2500, unproven and deliberately not built.	2026-08-05 21:17:59 -04:00

Author

SHA1

Message

Date

bvandeusen

fd27819cdd

style(scanner): tagged switch on ID3 major version — #2499

test-go / test (push) Successful in 55s

Details

test-go / integration (push) Successful in 4m55s

Details

2026-08-05 21:22:53 -04:00

bvandeusen

37b396a7e4

fix(scanner): read multi-value genre frames correctly — #2499

test-go / test (push) Failing after 41s

Details

test-go / integration (push) Canceled after 4m46s

Details

dhowden/tag's readTFrame splits ID3v2 null-separated multi-value text
frames and rejoins them with the EMPTY string, so a file tagged
"Alternative Rock" + "Rock" was stored as "Alternative RockRock". It also
leaves bare numeric ID3v1 references unresolved, which is why the
library showed genres like "4017" and "526617".

This corrupted more than the browse axis added in #367: taste_profile.sql
reads tracks.genre directly, so the welded tokens were entering the taste
profile's tag vocabulary, and recommendation.sql/discover.sql were
comparing them as single opaque tags. Genre counts were wrong everywhere.

ffprobe is not a fix — ffmpeg's read_ttag calls decode_str once with no
loop, keeping only the first value. Truncating multi-genre tags would
blunt the similarity signal genre mainly feeds. So the TCON frame is now
parsed directly (ID3v2.2/2.3/2.4, all four text encodings, per-frame and
tag-level unsynchronisation, numeric and parenthesised ID3v1 references);
everything else still comes from dhowden/tag. Values are stored
";"-delimited, which the read side already splits on, so no query changes.

Existing rows are repaired without an operator-run rebuild: migration
0054 adds tracks.tag_read_version DEFAULT 0, below the scanner's current
tagReadVersion, so the next scan re-reads tags it would otherwise skip on
mtime. Such a re-read reuses the stored duration instead of re-running
ffprobe, keeping a repair pass tag-read-bound rather than one fork+exec
per file. Bumping the constant is how a future extraction fix reaches an
existing library.

Only ID3v2 is in scope — dhowden welds nowhere else. The Vorbis/MP4
repeated-field question is #2500, unproven and deliberately not built.

2026-08-05 21:17:59 -04:00

Genre tags: read multi-value frames correctly, and repair existing rows #120