Posts by grackle

  • HDR10 fallback from Dolby Vision - I want to better understand when it does or doesn't happen

    Quote

    No, because it depends on how the media was created?

    In this case I'm exclusively concerned about what makemkv creates from a physical 4k blu ray disk with dolby vision. It looks like the mkv files it creates are all "Profile 7, Level 6".

    The linked thread mentions

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    the "Green and Purple" issue when playing DV Profile 5 files on non-DV hardware but still get DV on licensed hardrware

    Is Profile 7 going to have the same problem?

    Looking at Dolby's official documentation it indicates some of the DV profiles will fall back to HDR10, but doesn't say which ones.

    Quote

    Certain Dolby Vision profiles support a cross-compatible base layer based on video elementary stream
    metadata, such as video usability information (VUI). Such bitstreams:
    • Can be played by a decoder system that is unaware of Dolby Vision, using only the base layer
    • Result in a standards-based base-layer video signal, such as HDR10, hybrid log-gamma (HLG), or
    BT.709 standard dynamic range (SDR), using video elementary stream metadata (for example, HEVC
    VUI ...

    I guess the question becomes "is Profile 7, Level 6" one of those with a "cross-compatible base layer" that can "be played by a decoder that is unaware of Dolby Vision" and falls back to HDR10? Or is it going to have a failure mode similar to what they're talking about with Profile 5? I can't tell.

  • HDR10 fallback from Dolby Vision - I want to better understand when it does or doesn't happen

    Question: Will LibreELEC on a pi5 always fall back to HDR10 when playing Dolby Vision / HDR10+ videos? Will connecting that box to a display that *does* support DV/HDR10+ cause issues? I understand that due to licensing there probably won't be mainline Linux support for either DV or HDR10+ for a long time, if ever. I'm perfectly fine with HDR10.

    Context: most of my 4k BD rips are HDR10, but some of them are Dolby Vision. Looks like they're all profile 6, level 7. (I guess this is the default?) Assuming I'm correctly reading the ffprobe output:

    Code
    Stream #0:0(eng): Video: hevc (Main 10), yuv420p10le(tv, bt2020nc/bt2020/smpte2084), 3840x2160 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 1k tbn
    Metadata:
		[remove stuff related to video length]
	Side data:
      DOVI configuration record: version: 1.0, profile: 7, level: 6, rpu flag: 1, el flag: 1, bl flag: 1, compatibility id: 6

    I'm using LibreELEC on a Pi5 with three different TVs/monitors.

    Monitor #1 is an MSI MAG-323. Documentation simply states "VESA DisplayHDR 600" which is apparently only somewhat even remotely related to HDR10 / HDR10+ / DV? But all 4k videos play as expected. I assume this monitor only supports the "default" / most common standard which would be HDR10? I assume something in the chain is just falling back to HDR10 here since the display doesn't support DV? Either way, both HDR10 and DV files seem to work fine.

    TV #1 is a TCL something or other that doesn't support HDR. All 4k videos have the colors looking washed out, which is expected.

    TV #2 is TBD. What I want to understand here is that if I go with a newer TV that supports DV, will my pi5 w/ LibreELEC box still fall back to HDR10 when playing these profile 6, level 7 videos?

    Or is this a thing that's dependent on the TV's handling of that DV metadata? If that's the case, should I just look for a TV that only supports HDR10? Re-ripping or transcoding to remove DV and have the file itself only include the "base" HDR10 static metadata looks like another option I'm still trying to get a handle on. But before dealing with that, I'm wondering if this pi5/LibreELEC setup is still going to "just work" and keep playing HDR10 content using DV files on a newer TV w/ Dolby Vision.