SDR content is misrecognized as HDR content playback [SOLVED]

[JeremyPeng]

My playback environment:

Apple TV 4K tvOS 11.2.6
MrMC 3.5.0
frame rate and dynamic range matching all turn on

I have a MKV video file that can be correctly recognized as SDR content playback in other players（Kodi 17.6 in android / infuse pro 5 in tvOS）and color display is correct. But is identified as HDR content in MrMC, and the HDMI output signal is HDR mode. The color display is abnormal, it's look like too grayish.

I try to turn on "Use VideoToolBox for 4K HEVC HDR Content", although this video can be correctly recognized as SDR, the play color is different from the other players, it's also grayish. So, the problem of this video not playing correctly is still not solved.

And when "Use VideoToolBox for 4K HEVC HDR Content" is enabled, all other normal 4K HDR contents will be erroneously recognized as SDR content, and the HDMI output signal will be SDR. So always turn off it, maybe a better choice...

If this will be fixed, MrMC with the plex for kodi plugins, I almost don't need other players in Apple TV

Here is the information for this video, generated by MediaInfo：

Video
ID                                       : 1
Format                                   : HEVC
Format/Info                              : High Efficiency Video Coding
Format profile                           : Main [email protected]@Main
Codec ID                                 : V_MPEGH/ISO/HEVC
Duration                                 : 24 min 12 s
Bit rate                                 : 10.4 Mb/s
Width                                    : 3 840 pixels
Height                                   : 2 160 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 59.940 (60000/1001) FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 10 bits
Bits/(Pixel*Frame)                       : 0.021
Stream size                              : 1.77 GiB (95%)
Writing library                          : x265 2.1M+24-g61fb06d+14:[Windows][GCC 5.3.0][64 bit] Yuuki 10bit
Encoding settings                        : wpp / ctu=32 / min-cu-size=8 / max-tu-size=32 / tu-intra-depth=1 / tu-inter-depth=1 / me=3 / subme=3 / merange=44 / no-rect / no-amp / max-merge=3 / temporal-mvp / no-early-skip / rskip / rdpenalty=1 / no-tskip / no-tskip-fast / no-strong-intra-smoothing / no-lossless / no-cu-lossless / no-constrained-intra / no-fast-intra / no-open-gop / no-temporal-layers / interlace=0 / keyint=600 / min-keyint=1 / scenecut=40 / rc-lookahead=50 / lookahead-slices=4 / bframes=4 / bframe-bias=0 / b-adapt=2 / ref=4 / limit-refs=3 / limit-modes / weightp / weightb / aq-mode=3 / qg-size=32 / aq-strength=0.70 / cbqpoffs=-2 / crqpoffs=-2 / rd=4 / psy-rd=1.80 / rdoq-level=2 / psy-rdoq=2.00 / log2-max-poc-lsb=8 / limit-tu=0 / no-rd-refine / signhide / deblock=-1:-1 / no-sao / no-sao-non-deblock / b-pyramid / cutree / no-intra-refresh / rc=crf / crf=23.7086 / qcomp=0.65 / qpmin=0 / qpmax=69 / qpstep=4 / ipratio=1.40 / pbratio=1.20
Language                                 : Japanese
Default                                  : Yes
Forced                                   : No
Color range                              : Limited
Color primaries                          : BT.2020
Transfer characteristics                 : BT.2020 (10-bit)
Matrix coefficients                      : BT.2020 non-constant

Here is the download link for this video sample：
https://www.dropbox.com/s/4c6numlhs2fb9 ... 1.mkv?dl=0

Jeremy

[cosmoxl]

Yeah, for HDR make sure MrMC is using AVFoundation as decoder.

But, sounds like there's a bug to get worked out. You probably should submit a log of an attempt to play this file.

https://mrmc.tv/forum/viewtopic.php?f=12&t=373

[wesk05]

This is a SDR clip with BT.2020 color space. The clip plays correctly in MrMC. It plays incorrectly in Infuse Pro!

It is true that the clip triggers HDR mode, but HDR10 metadata is set for SDR (Max/Min luminance - 250/0.005 nits, MaxCLL/MaxFALL - 250/100). This is not the ideal setting, but this is what Apple has decided is good for us!

On Infuse Pro, the clips plays as SDR with 8-bit BT.709 color space.

Android case would be different based on what device it is played (one of the Amlogic devices or the nVIDIA Shield).

[davilla]

I'd love to get my hands on a sample of this.

[wesk05]

I'd love to get my hands on a sample of this.

There is a dropbox link in the original post

I analyzed the sample clip and there is no indication that it actually was graded in BT.2020. The gamut is within BT.709 boundaries. It seems that the color primaries for the file was merely changed to BT.2020. This could be the reason why the OP thinks that it plays with correct colors in Infuse Pro and Android.

[davilla]

Sorry, missed that, preoccupied with other matters

[davilla]

I can force it to SDR in AVFoundation Codec and it looks better. BUT I'm at a loss on how to detect this issue. Suggestions ?

It looks right in VideoToolBox because it treats everything as SDR.

I've seen other true HDR content with the same mediainfo output.

Color range : Limited
Color primaries : BT.2020
Transfer characteristics : BT.2020 (10-bit)
Matrix coefficients : BT.2020 non-constant

[wesk05]

I can force it to SDR in AVFoundation Codec and it looks better. BUT I'm at a loss on how to detect this issue. Suggestions ?

It looks right in VideoToolBox because it treats everything as SDR.

I've seen other true HDR content with the same mediainfo output.

Color range : Limited
Color primaries : BT.2020
Transfer characteristics : BT.2020 (10-bit)
Matrix coefficients : BT.2020 non-constant

The transfer characteristics for true HDR10 content cannot be BT.2020 ( # 14). It has to be PQ/ST.2084 ( #16). BT.2020 transfer characteristic is the same as for BT.709 (BT.1886/SDR).

When I disable AVFoundation and select VideoTool Box to decode HEVC HDR, I get a blank screen with no video. This is with the latest 3.5.1 testflight build (180321.1936 @20180321-84871bc).

As for how to detect the issue, visually it is going to be difficult with this short clip. There is some saturation difference between SDR/HDR playback. The clip seem to be just BT.709 with fake BT.2020 SEI parameters entered.

[davilla]

The transfer characteristics for true HDR10 content cannot be BT.2020 ( # 14). It has to be PQ/ST.2084 ( #16). BT.2020 transfer characteristic is the same as for BT.709 (BT.1886/SDR).

When I disable AVFoundation and select VideoTool Box to decode HEVC HDR, I get a blank screen with no video. This is with the latest 3.5.1 testflight build (180321.1936 @20180321-84871bc).

As for how to detect the issue, visually it is going to be difficult with this short clip. There is some saturation difference between SDR/HDR playback. The clip seem to be just BT.709 with fake BT.2020 SEI parameters entered.

Ahh, I see now. was mixing Color primaries with Transfer characteristics for HDR detection.

[wesk05]

Ahh, I see now. was mixing Color primaries with Transfer characteristics for HDR detection.

I had mentioned about this previously. The ideal method for HDR detection would be looking at the transfer characteristics.

http://forum.mrmc.tv/viewtopic.php?f=15 ... 464#p12450

On TVOs, is the color space tied to HDR i.e., BT.2020 & HDR go together?