Fix #13: use picture frame rate for field-coded interlaced sources#44
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DVB-T PAL rips stored as "separated fields" (field-coded H.264) report ffprobe r_frame_rate as the *field* rate (50 for 25fps PAL, 59.94 for 29.97fps NTSC), while avg_frame_rate carries the true picture rate. VapourBox read r_frame_rate everywhere, so it treated the source as 50p: the deinterlace panel showed 50i and — because the pipe-source template forces the clip to the detected fps — QTGMC double-rate targeted 100fps with a doubled, desynced frame count. Add FieldOrderDetector.selectFrameRate(r, avg): when r is ~2x avg (the field-coded signature, ratio 1.8-2.2) trust avg, otherwise keep r so CFR progressive and frame-coded interlaced are unaffected. Wire it into getVideoInfo and the preview generator's probe. Tests: - 6 unit tests for selectFrameRate (PAL/NTSC field-coded, 50p, 25i, null). - A real-clip test on the issue's DVB-T2 sample (trimmed, stream-copied to preserve the field-coded bitstream) asserting 25fps, interlaced, TFF. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Problem
Issue #13: a DVB-T2 PAL rip deinterlaces to 100fps instead of 50fps.
The source is 25fps interlaced H.264 stored as "separated fields" (field-coded). ffprobe reports its
r_frame_rateas the field rate (50/1), whileavg_frame_ratecarries the true picture rate (25/1) — a well-known ffprobe quirk for field-coded streams. VapourBox readr_frame_rateeverywhere, so it treated the source as 50p:fps_num={{INPUT_FPS_NUM}}), QTGMC double-rate targeted 100fps, with a doubled, desynced frame count.The owner's own files aren't affected because they're frame-coded (
r_frame_rate=avg_frame_rate= 25).Fix
Add
FieldOrderDetector.selectFrameRate(r, avg): whenris ~2×avg(the field-coded signature, ratio 1.8–2.2) trustavg; otherwise keeprso true 50p progressive and frame-coded 25i are untouched — no regression to working workflows. Wired intogetVideoInfo(fixes display,inputFrameRate→clip fps, andframeCount) and the preview generator's probe (seek accuracy).Tests
selectFrameRate(PAL/NTSC field-coded, true 50p, frame-coded 25i, null fallbacks).Tests/TestResources/pal-dvbt-fieldcoded-25i.ts, trimmed with stream copy to preserve the field-coded bitstream — assertinggetVideoInforesolves to 25fps,interlaced, TFF.🤖 Generated with Claude Code