Posts by noggin

Quote from doubleP

My Sony is not switching .... as long as I tell him to do so.

<snip>

This leads, in my case, to normal videos with colour space 'auto' and HDR videos with bt.2020.

Yes - this is a known issue.

At the moment the Pi 4B builds correctly send the HDR EOTF (HLG/ARIB B-67 or HDR10/ST.2084) signal to switch the TV from SDR mode into the right HDR mode.

However the other requirement for most HDR material (and all HDR10 material) is to switch from Rec 709 to Rec 2020 colour gamut (which is the Wide Colour Gamut used for all HDR10 and most other HDR content). The Rec 2020 colour gamut can be manually forced on your Sony TV, as it can be on mine.

That gets the colour into the right gamut for HDR10.

The two other issues are that the output is still RGB 8-bit not 10-bit - so banding is more likely to be an issue - and if the gamut is flagged as Rec 709 then there is no guarantee that the YCbCr->RGB colour matrices used to generate the RGB won't also still be the Rec 709 ones (which are slightly different to the Rec 2020 ones)

Rec 709 : Y = 0.2126 x R + 0.7152 x G + 0.0722 x B

Rec 2020 : Y = 0.2627 x R + 0.678 x G + 0.0593 x B

UHD TVs don't automatically assume all UHD inputs are Rec 2020 though - as some (most?) SDR UHD content is often still in Rec 709 gamut (the same gamut used for HD)

(For reference the SD Rec 601 RGB->YCbCr matrix is also different - Y = 0.299 x R + 0.587 x G + 0.114 x B)

Quote from CarlG314

That link was great. I stumbled across it yesterday when trying to fix HDR on my AVR X4200. The step which worked for me was:

"Disable the video conversion in the AVR."

Something as simple as that (default) setting was killing HDR, resulting in washed-out colors.

Now to see if my new RPi 4 with LE can reliably play 4K content for entire movies (my S912 with CoreElec struggled).

Cheers, Carl

I believe you may still be getting sub-par colours in the current Pi 4 HDR builds - as I don't believe Rec 2020 gamut (which is the gamut HDR10 and the 'in the wild' HLG uses) is being flagged, so whilst the colours look less washed-out than when the HDR EOTF was being blocked (and your PQ ST.2084 content was being displayed in SDR), the Pi 4 still outputs Rec 2020 as Rec 709.

Some TVs may switch to Rec 2020 when they detect an HDR EOTF I guess (though that's a bit of an 'out of spec' guess), but certainly my Sony TV will display Rec 709 gamut stuff in Rec 709 with an HDR EOTF (which means the colours will be less vibrant than if correctly flagged as Rec 2020 - which I can manually force and which brings things closer to what they should look like) (*)

(*) The YCbCr->RGB matrixes used for Rec 709 and Rec 2020 are slightly different - but the differences between them will be harder to tell. (The difference between Rec 601 SD and Rec 709 HD are more marked ISTR)

Quote from smp

I was talking about 50/60Hz 4K modes. 12-bit works with 2160p/24/30Hz.

That's good progress - ISTR that in the earlier days it was 8-bit + dither for <50Hz 2160p modes too. I guess this is with RGB or YCbCr 4:4:4? (And not 4:2:2 ?)

For 2160p50 and above, if 4:2:2 isn't supported, then 4:2:0 will be the only HDMI 2.0 option for >8 bit output I guess (as 4:4:4/YCbCr is 8-bit only at 2160p50 and above in the specs - you have to use 4:2:0 or 4:2:2 for >8-bit output at 2160p50 and above)

Quote from pletopia

chewitt .. quick question, i saw this on the LE blog "We are pretty confident RPi4 users will like the update since it brings HBR audio and initial HDR video support" .. what exactly does initial support mean?

So has anyone done "proper" passthru audio testing of the build in 502? Like does it finally fix the split second audio drop that occurs every few mintues?

Off topic - but the initial support I've seen for HDR on the Pi 4B means that it detects an ST.2084/PQ or ARIB-B67/HLG EOTF flagged (i.e. HDR10 or HLG) in a video file and correctly flags this over HDMI.

However at the moment it doesn't correctly detect and/or flag Rec 2020 video - so Rec 2020 content is output flagged as Rec 709 (or not flagged as Rec 2020). I've not been able to check whether a Rec 2020 or Rec 709 YCbCr->RGB conversion matrix is used for Rec 2020 video (They aren't the same)

At the moment I believe video output is restricted to RGB 8-bit too - so no 10-bit replay path yet.

So you get the correct EOTF flagged, but not the correct Colour Gamut, and with 8-bit not 10-bit or 12-bit output.

It's very early days - and the Pi Developers work through things methodically to deliver the best results they can with their available effort.

Quote from smp

On Gemini Lake 2160p60Hz is only possible with RGB 8-bit (default), YCbCr 4:4:4 8-bit (with a driver hack).

I'm not sure if YCbCr 4:2:0 12-bit could be enabled with a hack or otherwise. 4:2:2 is not supported by the driver.

It is possible to enable GPU dithering for 8-bit modes (with a driver hack). It certainly eliminates the banding on my test videos and looks ok to me.

Good news that 2160p60 is now supported.

YCbCr in 4:2:0 10-bit or 12-bit would be a good route to full 10-bit HDR output I guess. Dithering is a compromise that adds noise to hide banding. (Is the dithering done at output frame rate or source frame rate?)

Is there any update on a 10-bit replay path, 2160p60Hz output and/or 4:2:2 or 4:2:2 support?

Last time I trialled the Intel HDR route it was still 8-bit RGB only with an HDR EOTF ?

Quote from lrusak

It's very unlikely you can hear a difference between HD audio formats and LPCM

However it's entirely possible that you can hear the difference between an AVR decode that also has the right metadata available to it to assist in additional processing (DialNorm, dynamic range compression information etc.) that is present in the bitstreamed version and an upstream decode to PCM where that metadata is discarded and not available to the AVR.

Dolby and DTS audio streams contain that metadata to allow the AVR to 'know' more about the audio than just the basic audio stream content.

The other big difference is that Atmos and DTS:x aren't carried as basic PCM - so that's another major reason to favour bitstreaming/passthrough over PCM decode upstream.

Quote from mfleigle

All of my HDR content is washed out. Is there a setting I need to get hdr working? I've tried the nightlies from the last few days only.

EDIT: I just noticed its a known problem, but I don't understand why it works for some people and not others.

I think some people may not see the gamut mismatch - where Rec 2020 content (which is pretty much all the HDR10 and HLG out in the wild apart from DIY stuff) designed for much wider gamut primaries is displayed with Rec 709 primaries (giving you far less vibrant colours)

If you aren't comparing with the content displayed properly - you may not see it as an issue. (Or maybe some TVs automatically go into Rec 2020 mode, incorrectly, when they see an HDR EOTF flagged over HDMI, even if there isn't a Rec 2020 flag present)

Quote from lolek

Froggy please read this topic and also this one:

Nightly builds Rpi4 Audio passthrough TrueHD/Master HD not working (huge stutter) anymore

In general, the test builds of libreelec are capable of handling 4k uhd, atmos passthrough but there are still some issues.

Yes. Worth pointing out that the only codec supported at 4K UHD is h.265/HEVC (h.264/AVC is still only supported for 1080p (*)) and that a lot of UHD h.265/HEVC content is also HDR10.

HDR replay is still very much a work-in-progress on the Pi 4B. They have HDR modes being triggered on TVs (i.e. the HDMI signals an HDR10 or HLG EOTF) but they have still got issues flagging Rec 2020 instead of Rec 709 primaries (so images look less colourful), and the output of 10-bit video is still 8-bit RGB (so you will potentially see banding, which 10-bit is designed to minimise)

(*) h.264/AVC decoding is handled by the legacy video decoder module that is largely the same as that on the previous generations of Pi, h.265/HEVC support was added via a separate module. (MPEG2 and VC-1 support is now software only, as the Pi foundation don't offer hardware decode licences for these codecs for the Pi 4B)

Quote from chook55

The encode option wasn't displayed in advanced or expert profile in the passthru section until I did a return to default values. To my surprise it appeared. bug maybe? Anyhow The transcoding works well. Just an observation. the screen blanks momentarily when changing settings.

Thanks again.

Chook

The Enable Transcode option may only appear if you have 2.0 output configured - as otherwise it is assumed that you'd prefer the higher quality PCM 5.1 output option I think. (The 2.0/5.1/7.1 output setting is really your PCM/analogue output config and isn't related to your passthrough/bitstream speaker config).

If you are using Toslink or ARC which is similarly limited to PCM 2.0 and SPDIF/Toslink bandwidth DD/AC3 (and in some cases DTS) then configuring for 2.0 should bring up the option for transcoding to DD/AC3 underneath the Bitstream DD/AC3 option.

OK - have installed the latest nightly LibreELEC-RPi4.arm-9.80-nightly-20210220-f768c9b downloaded this morning.

Running in 1080p mode (to allow >30fps content to be output) my 2160p50/59.94 files largely play - and HDR10 Rec 2020 stuff is played with a PQ ST.2084 EOTF (aka HDR10 HDR) but the output is 8 bit RGB and it looks as if it is being flagged as Rec 709 gamut (so colours are less vibrant as they are using the narrower primaries).

Content I have that flags 1000, 4000 and 10000 nit mastering displays correctly sends this metadata (as confirmed by my HD Fury Vertex)

I'm playing the content from a Samsung Evo+ 64GB uSD card and I'd say I'm getting some dropped frames on p50 and p59.94 content - though whether this is throttling because of high bitrate on the storage or on the HEVC decode and scale down to 1080p I can't say.

I've yet to see any YCbCr 4:2:2 output at any bit depth - I don't know if there is a config.txt or LibreElec setting (or something I can type in at command line level via SSH) to enable YCbCr 4:2:2 output?

HLG content appears to correctly trigger an HLG EOTF (i.e. ARIB B-67 EOTF) - though AIUI BBC iPlayer 1080p SDR and 720p-2160p HDR streams (iPlayer uses HLG for HDR) may now be DRMed preventing playback on non-certified devices.

I can force my TV into Rec 2020 gamut and that makes things look quite a lot better - though I can't say whether Rec 709 or Rec 2020 YCbCr->RGB matrices are being used (the differences are quite small between the two)

I can also only play a couple of files before playback stops working (I get left in the GUI with a play icon top of frame with the name of the file being played, but no video and have to reboot)

Quote from JohnWayne111

Hi HiassofT

my fault, i ask this not about Pi4. My AVR (Denon X4100) has HDMI 2.0 but only HDCP 1.4.

If i go from PI --> AVR --> TV i get no HDR.

If i go from PI --> TV i get HDR.

Is it not possible with HDCP 1.4 to get HDR?

I tried a HDCP Converter, but this doesnt work too.

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If your AVR has HDMI 2.0 support but only supports HDCP 1.4 (and not HDCP 2.2) then that could mean it was one of the first gen UHD AVRs that had HDMI 1.4 inputs and outputs in hardware terms but that got very basic HDMI 2.0 support added (in the same way nVidia added HDMI 2.0 support to their HDMI 1.4 Graphics cards and Sony added HDMI 2.0 to existing HDMI 1.4 UHD TVs via a software upgrade)

The way they did this was to add support for just the 4:2:0 HDMI 2.0 mode for 2160p50 and 2160p60 modes - as HDMI 1.4b already supported 2160p23.976-30 at 8-bit in SDR using 4:4:4/RGB and 12-bit using 4:2:2 (though this mode may not have been supported).

Using the 4:2:0 subsampling introduced with HDMI 2.0 allowed HDMI 2.0 4:2:0 2160p50 and 60 modes to fit into the hardware restrictions of an HDMI 1.4b connection (i.e. you could add HDMI 2.0 basic compatibility using HDMI 1.4b hardware). AIUI this was 8-bit SDR only, and that may also have been true of the HDMI 1.4b 2160p30 and below support also supported. (i.e. you get UHD support at all frame rates in 8-bit, but you don't get HDR support as that would require 10 or 12-bit support - which may not be implemented)

The Pi 4B doesn't support 4:2:0 HDMI output as I understand it (as it would require both vertical and horizontal subsampling of chroma - and the Pi can only really do horizontal (?)

This may also mean your AVR is not HDR compatible ("passthrough" in AVRs isn't helpful in that regard)

The lack of HDCP 2.2 support is a strong suggestion that your AVR is one of those early HDMI 1.4 models that got a partial upgrade to HDMI 2.0 - though I may be wrong.

Quote from HiassofT

noggin thanks a lot for testing, this is in line with my suspicion (video driver using the wrong transformation matrix). Not 100% sure why 10/12bit output isn't automatically enabled, could be that we need to explicitly request it.

Regarding subsequent playback issues: Which testbuild did you use? The one from the first post (from Feb 5) or the one from here RE: RPi4 testbuild with HDR support (Feb 10)? The later build contains some important fixes that may be related.

If you got that issue with the newer build please post a log (ssh in, run "pastekodi" and post the URL) and ideally a link to a sample file so I can try to reproduce that locally.

so long,

Hias

I was using the one from the first post (5th Feb) in this thread. I'll download the new one you linked to and see what happens.

Quote from HiassofT

HLG seems to be properly signaled, my TV displayed "HLG HDR" with one or two of my demo files. Haven't verified the infoframe data in that case but pretty sure EOTF 3 / HLG was set correctly.

1080p and CLL testing is lso highly appreciated. The metadata in the video files seems to be passed on correctly into the infoframe so I think that part should be fine.

I'm quite sure you'll see BT.709 in all cases, the kernel code to fill in the colorspace data into AVI infoframe isn't called from the driver

Could also be that a bit of plumbing in kodi is needed, haven't checked yet if the info is passed on correctly. And as CTA 861 lists three different BT.2020 versions (RGB, YCbCr and YcCbcCrc) there might be some additional work ahead.

so long,

Hias

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Disabling 2160p output modes in the whitelist and playing back a 2160p HDR10 file I get 1080p RGB 8bit output for HDR 10, with an ST 2084 EOTF flagged. I haven't seen >8 bit depth or YCbCr output so far.

Without doing a bit more digging I can't easily see on my HD Fury OSD whether Rec 2020 or Rec 709 gamut is being signalled - but looking at the output it looks like it's in the wrong gamut as expected. (i.e. Rec 709 primaries rather than Rec 2020 are being flagged or assumed by my display). It's also not instantly easy to tell whether Rec 2020 or Rec 709 YCbCr->RGB matrix co-efficients have been used for the YCbCr to RGB conversion (Rec 2020 has different YCbCr<->RGB conversion matrix values to Rec 709, just as Rec 709 HD and Rec 601 SD (*) differ from each other)

(WRT to Rec 2020 - I don't think much content uses YcCbCCrc which is the constant luminance-based option - I think all mainstream content, other than DV single-stream, which isn't going to be relevant here, is 4:2:0 YCbCr - output on most consumer players as 4:2:2 12-bit YCbCr)

Also - only the first 2160p HDR file I play correctly plays. Subsequent files fail to play (I get audio but only see the file list GUI and have to reboot)

(*) Rec 601 even, technically, has different RGB primaries, and thus gamuts, for the 525/480i and 625/576i variants due to the NTSC and PAL legacies before them... (And Japanese NTSC and North American NTSC have different white points...)

Quote from HiassofT

noggin thanks a lot for testing!

The video driver should support 4:4:4 RGB output at 8/10/12 bit, just read through the info in the PR KMS 10 & 12 bpc updates (5.10) by 6by9 · Pull Request #3982 · raspberrypi/linux · GitHub again and noticed that 4kp30 is limited to 8bpp ATM... 1080p should support 10/12 bit output though.

When checking the AVI infoframe this morning I noticed it's missing colorimetry info (C0/1 bits are zero), so there may be a few more bits missing in the driver - I've asked popcornmix about that.

If the driver doesn't handle and signal BT2020 correctly that might explain why there are colour differences to other players.

The dynamic range infoframe however seems to be sent fine, EOTF, maxCLL/maxFALL etc seem to be set accordingly.

so long,

Hias

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I'll see what Gamut (Rec 709 vs Rec 2020) the HD Fury reports.

I'll also see what bit depth I get if I remove 2160p modes from the whitelist.

I've got test signals with various CLL values so can also check those when I get a chance.

Is HLG HDR flagging supported too - or is it just PQ HDR currently?

Just tried the .tar linked in the first post here. I get 2160p23.976 HDR10 HEVC stuff playing back with an HDR PQ EOTF flagged and HD Audio bitstreamed.

However the video output is only 8-bit not 10-bit according to my HD Fury Vertex, so although the TV is in HDR mode and displaying HDR video content with the correct EOTF - there will potentially be banding as the 10-bit source video is being truncated to 8-bits? (If dithering is used this might be partially masked though)

Is there supposed to be 10-bit 4:4:4/RGB or 12-bit 4:2:2 output implemented, to allow 10-bit content to be output in 10 or 12-bit - or is this test build just to get correctly flagged EOTFs?

I notice I'm not offered 2160p50 or 2160p59.94 output options in Kodi and when I play 2160p50/59.94 content rather than output it 1080p50/59.94 - I get no video replay at all. (I understand the Pi can't output 2160p50/59.94/60 with 4:2:0 - so for HDR 10-bit content at p50 and higher 4:2:2 12-bit will be the only option for preserving 10-bit?)

Quote from NJPUSA

Yep, fixed it for me, TV was unwatchable with interlacing enabled - juddering and out of sync mess. Rpi4 + TVHeadend. Switched to a totally different system (Xbian) because it was driving me nuts. Didn't make any sense at all that it could play a 160GB 4k video but not 1080i/480i TV. Tried three different PVR backends/frontend over the last few days!

Worth remembering that h.264 and interlaced content are handled by totally separate parts of the Pi4B SoC to h.265/hevc. The h.264/interlaced stuff is decoded and deinterlaced by the legacy VPU that remains the same as the Pi 3B+ and before, whereas the hevc/h.265 decoder is a separate unit and handled separately. I believe some builds at the moment are not handling stuff particularly effectively using the old decoder?

Quote from powerarmour

I still find it admirable that folks are persisting with these technically dead Intel platforms when there are fully functional ARM alternatives available, waiting for working HDR on x64 is like waiting for this pandemic to end.

I guess the benefit of Intel in speed terms is worthwhile - I switched to AMLogic platforms as my main daily driver and miss the snappiness of my Intel boxes. That said - the Apple TV 4K SoC is a beast - it software decodes stuff that the other ARM platforms just choke on (38Mbs 1080i25 4:2:2 h.264 with deinterlacing is do-able on an ATV 4K in software)

Quote from lolek

Ok,

then I can say that I'm testing this and I've been able to get FullHD but there's a problem with hmm not sure what exactly.

After about 11-12 mins of playback DTS-HD MA Atmos the sounds starts to hickup AVR is blinks but the video is still there.

In the debug.log the only thing that is printed is this line:

ERROR <general>: CAESinkALSA - snd_pcm_writei(-32) Broken pipe - trying to recover

right now I'm trying to play with this hint but can't say much only that after applying the fix, the error is gone. Yet the hiccups are still there and are more aggressive with the time. To fix this it's enough to stop and resume playback.

Fix for HDMI sound dropouts - snd_pcm_writei(-32) Broken pipe

In the beginning the problem could be easily seen just after few mins, but then I've recalled the problem with RPI4 and USB3 transfer rates slowdowns. I've been able to use this hint:

STICKY: If you have a Raspberry Pi 4 and are getting bad speeds transferring data to/from USB3.0 SSDs, read this - Raspberry Pi Forums

which improved things a lot and now the problem occurs as I mentioned in the beginning which is around 11-12 mins.

I may be of course wrong but it kind of looks like it's some kind of buffer issue. The DTS-HD MA requires quite a lot of bandwidth during some extensive action, from what I've found it can be up to 24.5Mbps now if we add there also requirement for video then it if RPi4 has real USB 3 transfer issues, it really look like it could be an issue that's causing the problem.

I'll see if I can get some different chassis for the drive that doesn't need a quirk if I'll test this I'll of course put the info here.

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My understanding is that HDMI 1.4 audio has a max spec of 8 channels of 192kHz / 24 bit uncompressed PCM audio - which gives a max audio output bit rate of :

8 x 192000 x 24 = ~ 36.9Mbs

I guess any buffering for HDMI audio should be considering that as the top audio bitrate that HDMI can carry?

My understanding is that 8 x 192 x 24 is also the spec that is required for lossless compressed HD Audio to be carried over HDMI - which is why the Raspberry Pi 3B+ and earlier can't carry HD Audio - as they could only carry 4 x 192 x 24 bit (or 8 x 96 x 24 bit) which doesn't guarantee enough bitrate for the peaks of HD Audio lossless compressed content (which may not compress hugely on very complex content?)

Dolby True HD and DTS HD MA sound tracks are usually lossless compressed 8 channels at 48k 24 bit (some are 96k and a very small number are 192k) which gives an uncompressed bitrate of around 9Mbs (or 18Mbs if 96kHz is used), however releases like Akira can contain 6 channel 192k 24 bit tracks (and 8 channel is theoretically allowed).

For very complex audio the lossless compression used by DTS HD MA and Dolby True HD may not deliver huge bandwidth savings - and if you add in Atmos and DTS:x data as well on newer tracks this will also increase the bitrate a bit I guess?