Hi there, thanks for the answer.
Everything is ticked, I get DTS MA from other files. What's weird is this DTS X file completely limits the MA and plays the standard DTS core.
Something might be up with my rip, I'll keep looking.
Posts by silentsound
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It's connected RPi4 -> Soundbar -> TV. I updated to the latest nightly but that made no difference. eARC is on, Atmos works so it's either the file or something up with Libreelec.
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Hi all, little investigation here into DTS pass through.
I have a new soundbar which now supports Dolby Atmos and DTS:X. Atmos content plays without an issue but DTS:X, it reverts back to the standard DTS core (not even DTS MA).
Any idea what could be the cause? MediaInfo confirms the audio track is DTS MA, with DTS X metadata. I'm currently on a nightly release (20240917, 12.0.1), perhaps a newer one has this ironed out?
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Awesome, I'll keep an eye out and try a nightly sometime soon.
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Which hardware?
Thanks for moving the post.
I'm on raspi 4. I split the audio/video between the hdmi slots (older soundbar, TV doesn't passthrough DTS etc) -
I'm looking for some CEC related help.
Ever since upgrading to 12.0.1, I have two CEC adopters in the Input > Peripherials menu, and they just don't co-oporate. I tried disable on of them in the menu, reboot and both are back active. How can I disable one of them? -
Two things :
1. You can use the second HDMI output from your Pi to carry audio to your Soundbar, and the first HDMI output to carry the picture directly to your TV if you have a spare HDMI port on your TV (removing your sound bar from the video path)
2. If you are watching an HDR10 video without your TV in HDR10 (aka PQ/ST.2084) HDR mode, and thus watching it in SDR (but still in Rec 2020) - you will see very nasty pictures indeed - and instantly know something is wrong.
If you are watching an HLG HDR video in SDR mode but still Rec 2020 - you will notice no major differences until you get in to the highlights of the picture - which will just look less bright. However there is very little HLG out there (BBC iPlayer uses it, as does Sky Q)
1. That is what I have been doing but CEC is not working correctly when using both HDMI ports at once (10.0.2)
2. I've re-encoded on film and compared the output: they dont seem to be very different to my eyes but it could just be the opening scene. The HDR one triggers to the TV to Rec 2020 mode, the redone one does not. The HDR one stutters a lot (bandwidth or perhaps HDR10+?) where as the other plays smoothly.
Regardless, I've learnt a lot!
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Afraid it's not just stripping metadata off - it's a case of transcoding and tone mapping from Rec 2020 PQ (aka HDR1) to Rec 709 SDR at the same time.
HDR10 content is almost always in a new, wider gamut, Rec 2020 colour-space (i.e. based around different Red, Green and Blue primary colours that are redder, greener and bluer), whereas most SDR UHD content is in the same colour space as HD (Rec 709), and HDR10 has a totally different way of handling video levels from black to the brightest whites to SDR (that's what gives it the HDR-ness). Because conversion of HDR Rec 2020 to SDR Rec 709 requires converting colours that can't be shown in Rec 709, it requires some reasonably complex processing to reduce the visibility of the lost content in the conversion process (so that hues don't change and highlights and lowlights don't get totally lost)
This requires a process called Tone Mapping - which means the h265 UHD video needs to be decoded, tone mapped, and then re-encoded to h265 (the Pi 4B won't play UHD h264) for playback in UHD SDR on a Pi 4B.
If your SDR UHD display supports Rec 2020 then you only need to convert the dynamic range (or EOTF) not the colour space - but I think most SDR UHD displays are usually also Rec 709 only.
I believe ffmpeg includes some functionality that may help with this : https://forum.doom9.org/showthread.php?t=175125 is a thread detailing some approaches - I've not tried them.
You'll need a pretty beefy CPU and/or hardware GPU acceleration on an x86 platform to do this transcoding at a reasonable speed I suspect.
Thank you for the detailed write-up, this is far more complex than I imagined! My PC is nowhere near powerful enough for this to be done in a relatively decent amount of time.
Currently I have my rpi4 connected via the soundbar which is 4K compatiable but not HDR. When I play 4K HDR files naturally HDR tag is not active but the BT.2020 one is. Is it fair to assume that the soundbar is passing over an accurate image?
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Hi there. A few other people and I have a similar issue. Some seem to have solved it but I can confirm at 10.0.1 CEC worked fine for me, at 10.0.2 with two HDMI outputs, it won't.
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The best way to avoid HDR > SDR issues is to handle the conversation at the ripping stage, then you have SDR files.
Do you have any recommendations on that? I've only ever used Handbrake, not sure if it can strip HDR meta data off a file.
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I've got a rpi4, tv on hdmi0, and an av receiver on hdmi1.
I've had a CEC problem, so I'm going to tell you as much as I can about the problem I experienced, so maybe it will help you.
I'm using the TV remote to drive LibreELEC. It was working on 10.0.0, and stopped working on 10.0.2 (skipped 10.0.1)
The AV has a remote too, but I haven't tried it.
I've got it working again, so here's the relevant info:
- It was working on reboot, and if I turned the TV off and on within 10 seconds
- Stopped working after the TV was off in excess of 10 seconds
- The TV is a Samsung
- Samsung's label for CEC is Anynet+
- Samsung's default Anynet+ settings were CEC on, but CEC power off/on was off. That means when the TV powered off, it didn't tell the rpi4
- Changed the TV's setting to send power off-on signals to the rpi4
Related, didn't change:
- LibreELEC has a Interface/Input CEC setting about power on/off too, to ignore, suspend, hibernate or poweroff. The default (in 10.0.2) is suspend. I left mine on suspend.
Related:
- turning the TV on, now results in a few seconds of CEC not working. I presume that previously the rpi4 never suspended because it never got a power signal, and so it never had to wake up, and the CEC worked immediately.
Thank you for sharing your experience. I had some free time yesterday and today to play around with this but no luck; something CEC related in 10.0.2 and using 2 HDMI outputs just does not work. I currently run my Libreelec machine through the soundbar. Its an older one so no HDR for me but I rather do that than curse at the remote not working every few minutes!
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Updated to 10.0.2, rpi EPPROM too via ssh. All smooth and all but CEC decided to stop working sadly. I use both HDMI ports, one directly to TV, the other to soundbar. Interstingly, if I switch over to just single HDMI throguh the soundbar, CEC functionality is back no problem. How would I provide more info on this for you guys?
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Did you also used direct USB (blue port) connection for this test?
NAS: Both DTS/DTS-HD go out of sync within a minute or two
Directly via USB: Both DTS/DTS-HD play smoothly. -
Here's the latest:
- Playing just DTS (rather than DTS-HD) still doesn't play smoothly
- Playing DTS-HD from a drive directly connected to the device, success!
So I guess a bandwidth problem with my NAS/nfs?
I don't know the specifics between DTS and Dolby but Dolby True HD 4K files play from the NAS without any issues.
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Hi again, thanks for the suggestion. I've got a new set of cables but... it's still happening. Do you see anything new in the log?
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Thanks again for stopping by and looking at this, much apprichiated!
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The "display reset" is weired. Maybe your HDMI cable doesn't support high data rate, which is definitely the case when playing 4K / dtsHD. Make sure your HDMI cable is conform to HDMI 2.0 / 2.1 standard.
Thanks for that. I checked, both cables are marked as 'High Speed'. As I use both HDMI outputs, I swapped the two cables around, tried using one directly into the soundbar but the issue still persits in some way or another
. I have lowered the UI resolution from 1080 to 720 and... it feels a bit better? Could placebo though.
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I think I managed to get a more detailed one:
