[zibaone]

Summary

YouTube playback in SendToKodi failed intermittently with HTTP 403. Two
contributing causes were identified:

1. Removed progressive formats: YouTube has removed progressive (muxed)
   formats (itag 18/22) for many videos. SendToKodi fell back to
   raw format 18, whose URL no longer exists → immediate 403.

2. CDN soft block on fresh URLs: YouTube applies a short soft block
   (HTTP 403, ~5-8 s) on freshly generated googlevideo.com/videoplayback
   URLs. The DASH builder probes URLs immediately after extraction, landing
   inside that window → manifest build fails. A Kodi restart added enough delay
   for the URL to warm up, which is why the issue appeared intermittent.

Both are addressed by this PR.

Changes

1. core/dash_builder.py — _fetch_range now retries on HTTP 403 with
   backoff (3 s, 6 s, 9 s, 3 attempts). Other HTTP errors are re-raised
   immediately. This absorbs the soft block for both the init/index range probe
   and subsequent segment fetches.

2. core/playback_selection.py — evaluate_raw_format_candidate skips
   progressive (muxed) formats (itag 18/22) when DASH streams are available,
   since YouTube has removed those formats for many videos.

3. Tests — added coverage for the retry-on-403 path (success after retry,
   immediate propagation of non-403 errors) and for the progressive-format skip.

Test plan

• pytest — 344 passed, 1 skipped (no regressions)
• Manual: 6 consecutive YouTube playbacks over ~18 h (including cold URLs after expiry) — 0 errors 403 in log. Patch active and working.
• Manual: replay after URL expiry (~6 h) — cold-URL case passed (playback at 02:11, ~18 h after deploy, no 403).

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Codecov Report

❌ Patch coverage is 87.87879% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.45%. Comparing base (4aa2a6e) to head (1e61f82).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
core/dash_builder.py	87.09%	4 Missing ⚠️
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Additional details and impacted files

@@            Coverage Diff             @@
##           master     #196      +/-   ##
==========================================
- Coverage   84.48%   84.45%   -0.03%     
==========================================
  Files          14       14              
  Lines        2591     2612      +21     
==========================================
+ Hits         2189     2206      +17     
- Misses        402      406       +4     

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[firsttris]

Thanks a lot for tracking this down, @zibaone, and for the detailed analysis and the long-running manual test! 🙏

Merged. I added a small follow-up on top in #197:

• 403 retry: _fetch_range now retries only on HTTP 403 and waits 3 s, then 6 s (the third delay was never reached). The other error paths stay as they were. Note: the retry covers the init/index range probe when the manifest is built. The media segments themselves are fetched by inputstream.adaptive directly from googlevideo, not through our server.
• Skipping itag 18/22: now limited to YouTube results, and only when the DASH builder can actually play the video (DASH builder enabled and ISA supports mpd). Users without the DASH builder or inputstream.adaptive keep the muxed fallback, and other sites that use numeric format ids like "18"/"22" are no longer affected.
• Added tests for a persistent 403 and for the narrower 18/22 skip.

Thanks again for the contribution!

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Generated by Claude Code

[zibaone]

Thanks for merging our PR so quick, and for your SponsorBlock feature — great addition! 🙏