LE Nightly 20231031 - not able to deinterlace i25 to p50 on Raspberry Pi 5

  • Have just got a Pi 5 - trialling h264 1080i25 file replay in the latest nightly (20231031) - and the only software deinterlace option I have is 'deinterlace' which deinterlaces native i25 to p25 rather than p50 - so halving the temporal resolution. Thought I'd report it.

    (Apologies if this is already known about).

  • Kodi always outputs progressive so you need to enable adjust-refresh and rate doubling, and set the mode whitelist to NOT include 1080p @ 30/29.97/25 modes. Kodi will then switch to 1080@50 with each interlaced half-frame rendered in a single frame. Normal PAL content will be output at 1080@50 too (each frame is rendered twice).

  • Kodi always outputs progressive so you need to enable adjust-refresh and rate doubling, and set the mode whitelist to NOT include 1080p @ 30/29.97/25 modes. Kodi will then switch to 1080@50 with each interlaced half-frame rendered in a single frame. Normal PAL content will be output at 1080@50 too (each frame is rendered twice).

    Ah - I hadn't realised that frame doubling was used as the term to signify i25->p50 deinterlacing vs i25->p25 deinterlacing in settings (for some reason I thought this was a way of implementing 2:2 pulldown for replay of p25/p30 stuff in 50/60Hz output modes as it talks about enabling it for compatibility reasons).

    I'd assumed denterlacing was always at field rate by default (why would anyone do it at frame rate other than if their CPU/GPU couldn't keep up?) I suspect I've always enabled that setting without thinking about it in the past. (I only ever enable 23.976/24/50/59.94/60Hz refresh modes in my Whitelist.)


    *** EDIT - should add that this was, indeed, the issue. h.264 1080i25 native 50Hz interlaced stuff is now replaying fine with full 50Hz motion deinterlaced to 1080p50. BWDIF is the deinterlacer used it seems - which is a good choice. None of my CPU cores were >40% loaded in playback - most were less than this by quite a lot. The Active Cooler PWM fan didn't kick in for the few minutes I tested. ***

    Edited once, last by noggin (November 1, 2023 at 10:22 AM).

  • It's not an obvious configuration and sadly does catch a few people out. I'm not sure what we could really do to improve though.

    Is the setting actually serving two use cases ?

    1. Displays that can't accept p25 modes and only p50 (though EDID and/or whitelisting may catch this anyway?)

    2. Chosing to deinterlace i25 to p50 rather than p25

    The two don't fully overlap - but currently one setting covers both use cases?

    Personally I'd argue that defaulting to on rather than off would be the better default?