[Bug] Error when changing from tmdb to tvdb

[alexkiddddd]

Hi there!

I have added my tmdb and tvdb api keys to scrob, and I'm changing the animes to tvdb, but some of them show the following error:

No TMDB episodes could be matched to TVDB

Also, the anime name is in Japanese.

[alexkiddddd]

I investigated this further and found two issues affecting TMDB to TVDB episode matching.

Affected series: Kimagure Orange Road
TMDB series ID: 9103
TVDB series ID: 78923
Error: “No TMDB episodes could be matched to TVDB”

I ran read-only tests using Scrob’s own fetching and matching functions, without saving mappings or changing watch history.

Results:

• TMDB returned 56 episodes with English titles.
• TVDB without an explicit language returned 61 episodes with Japanese titles. The matcher raised the error above.
• TVDB with language="eng" returned 61 episodes with English titles. The matcher found 30 matches.

Changing the metadata language to English in the UI did not resolve the switch error.

FIRST ISSUE: LANGUAGE USED FOR MATCHING

In backend/core/episode_order.py, the TVDB call inside _fetch_show_episodes() does not specify a language.

Adding language="eng" to that tvdb.get_series_episodes() call would make it request English titles, consistent with the TMDB titles returned in this matching flow. This should be independent of the user’s display-language preference.

The diagnostic test confirms that requesting English enables 30 matches. However, this is only a partial fix.

SECOND ISSUE: DIFFERENT TITLES AND SPECIALS NUMBERING

The remaining 26 unmatched episodes are 18 regular episodes and all 8 TMDB specials.

Some regular episodes have different English translations despite matching episode numbers and air dates.

Example: S01E19, aired 1987-08-10

• TMDB: “The Couple's Experience / Forbidden Island of Love!”
• TVDB: “An Experience for Two! An Island of Forbidden Love”

These fail the exact normalized-title comparison.

Specials also have a series-name prefix and different numbering.

Example: aired 1989-03-01

• TMDB S00E01: “White Lovers”
• TVDB S00E06: “Kimagure Orange Road: White Lovers”

Example: aired 1989-04-01

• TMDB S00E02: “Hawaiian Suspense”
• TVDB S00E07: “Kimagure Orange Road: Hawaiian Suspense”

Date alone is not enough to identify every episode. “An Unexpected Situation” and “Message in Rouge” both aired on 1991-04-01. They are S00E07 and S00E08 on TMDB, but S00E12 and S00E13 on TVDB.

SUGGESTED IMPROVEMENTS

• Request a consistent language from both providers during matching.
• Keep external episode IDs as the preferred matching method.
• Account for a series-name prefix when comparing titles.
• Consider a conservative fallback using corroborating air dates and episode ordering when translations differ.
• Reject ambiguous candidates and expose unmatched episodes to the user. Neither matching dates alone nor matching raw episode numbers alone is sufficient.

The English-language test is confirmed. The additional matching improvements are suggestions, not a tested complete fix.

I can provide the diagnostic script and full list of unmatched episodes if useful.

[alexkiddddd]

I found another related issue involving ratings when switching a show between TMDB and TVDB episode order.

Reproduction example: Attack on Titan

• TMDB series ID: 1429
• TVDB series ID: 267440
• The Scrob export already contained a show-level rating of 10.
• I imported AniDB ratings through a Yamtrack CSV.
• TMDB seasons 1 and 2 were imported with a rating of 9.

Behaviour:

1. With the show set to TMDB episode order, the ratings are visible.
2. Switching the same show to TVDB episode order makes the ratings disappear from the UI.
3. Switching back to TMDB makes the ratings reappear.

The ratings are therefore not deleted. They remain in the database but are hidden depending on the selected episode order.

The import path appears to create season ratings without an episode order. _apply_imported_rating() creates a Rating with season_number, but does not set episode_order, so it remains NULL.

The TMDB season view looks for ratings where:

Rating.episode_order.is_(None)

The TVDB season view instead looks for:

Rating.episode_order == "tvdb"

This explains why season ratings imported from Yamtrack are visible in TMDB order but not in TVDB order.

There may also be a related display issue with show-level ratings. A show-level rating should not depend on episode order, but the existing Attack on Titan rating also appears to disappear from the UI when TVDB order is selected and returns when switching back to TMDB.

A possible approach would be:

• Keep imported Yamtrack season ratings as TMDB-order ratings by default.
• When displaying TVDB seasons, translate a TMDB season rating to the corresponding TVDB season only when the episode-order mapping gives an unambiguous result.
• Continue showing the show-level rating regardless of the selected episode order.
• Avoid assuming that TMDB and TVDB season numbers are identical, because anime season structures frequently differ.

This may be connected to the episode-matching issue reported above, but the ratings are not lost. It appears to be an episode-order-specific display/mapping problem.