There are DD+ with Dolby Atmos tracks from streaming services, so why do you think these particular tracks have been converted from TrueHD? Is that what BiTOR is saying somewhere?
ATV 4K supports DD+ 7.1 and supports DD+ with Dolby Atmos, so where are you seeing that ATV doesn’t support the two together, DD+ 7.1 with Dolby Atmos? You’re saying it’s limited to DD+ 5.1 with Dolby Atmos?
Unfortuantely I only have a 5.1.2 setup, so can’t directly test DD+ 7.1 with certainty.
Either way, whether it’s DD+ 5.1 or 7.1 with Dolby Atmos, ATV always converts DD+ with Dolby Atmos to Dolby MAT, which is PCM 5.1/7.1 bed channels with Dolby Atmos object-based surround channels. AVRs that support Dolby MAT should report Dolby Atmos, not PCM. With my Denon AVR, when playing DD+ with Dolby Atmos from the ATV, I haven’t seen if it’s 5.1 or 7.1, but either way, the AVR reports “Dolby Atmos” when receiving the Dolby MAT signal, it doesn’t show “PCM” input.
I just did some quick testing, and I’m going to go back on what I just said.
Every DD+ 7.1 with Dolby Atmos file did indeed show up as Multichannel PCM 7.1 on my Denon AVR, as you indicated, and it didn’t indicate any Atmos or MAT data was being processed, as the height speakers didn’t light up on the input.
Every DD+ 5.1 with Dolby Atmos file showed up as “Dolby Atmos” on the AVR, indicating Dolby MAT was working. In that mode, it didn’t light up any input channels, so it doesn’t let you see how many bed channels are being processed.
So I think the answer to my question — “where are you seeing that ATV doesn’t support the two together, DD+ 7.1 with Dolby Atmos?” — is “lived experience”.
My other question on why you’re thinking TrueHD with Atmos tracks are being converted to DD+ with Atmos tracks still stands, though.
Has anyone tried playing DD+ Atmos mkv files that come from Paramount Plus WEB-DLs? None of them result in any sound for me. The Atmos badge appears on my TV and AVR. But everything is silent. Disabling atmos in tvOS settings results in correct 5.1 audio however.
General
Unique ID : 254693447720944722980360032507805466545 (0xBF9C2C7B916D961C6BA19EF921667FB1)
Complete name : S:\Movies\War of the Worlds 2005 2160p PMTP WEB-DL DDPA 5 1 DV HDR H 265-PiRaTeS.mkv
Format : Matroska
Format version : Version 4
File size : 12.5 GiB
Duration : 1 h 56 min
Overall bit rate : 15.4 Mb/s
Frame rate : 23.976 FPS
Writing application : mkvmerge v91.0 ('Signs') 64-bit
Writing library : libebml v1.4.5 + libmatroska v1.7.1
Video
ID : 1
Format : HEVC
Format/Info : High Efficiency Video Coding
Format profile : Main 10@L5@High
HDR format : Dolby Vision, Version 1.0, Profile 8.1, dvhe.08.06, BL+RPU, no metadata compression, HDR10 compatible / SMPTE ST 2094 App 4, Version HDR10+ Profile B, HDR10+ Profile B compatible
Codec ID : V_MPEGH/ISO/HEVC
Duration : 1 h 56 min
Bit rate : 14.3 Mb/s
Width : 3 840 pixels
Height : 2 160 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 23.976 (24000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0 (Type 2)
Bit depth : 10 bits
Bits/(Pixel*Frame) : 0.072
Stream size : 11.6 GiB (93%)
Language : English
Default : Yes
Forced : No
Color range : Full
Color primaries : BT.2020
Transfer characteristics : PQ
Matrix coefficients : BT.2020 non-constant
Mastering display color primaries : Display P3
Mastering display luminance : min: 0.0050 cd/m2, max: 4000 cd/m2
Audio
ID : 2
Format : E-AC-3 JOC
Format/Info : Enhanced AC-3 with Joint Object Coding
Commercial name : Dolby Digital Plus with Dolby Atmos
Codec ID : A_EAC3
Duration : 1 h 56 min
Bit rate mode : Constant
Bit rate : 768 kb/s
Channel(s) : 6 channels
Channel layout : L R C LFE Ls Rs
Sampling rate : 48.0 kHz
Frame rate : 31.250 FPS (1536 SPF)
Compression mode : Lossy
Stream size : 640 MiB (5%)
Language : English
Service kind : Complete Main
Default : Yes
Forced : No
Complexity index : 16
Number of dynamic objects : 15
Bed channel count : 1 channel
Bed channel configuration : LFE
Text
ID : 3
Format : UTF-8
Codec ID : S_TEXT/UTF8
Codec ID/Info : UTF-8 Plain Text
Language : English
Default : No
Forced : No
Are all the files you have no sound on from the same release group?
I have that movie in Web-dl Atmos and have no issues with it. It is however a different release group.
It’s currently a strict codec requirement/limitation for passthrough. EAC3 is most commonly used by streaming platforms like Netflix. If you had legal BluRay disc rips they would use TRUEHD format, which isn’t passed through correctly by ATV and will be downgraded or transcoded, losing Atmos metadata.
Nvidia Shield is not restricted in this fashion and happily passes-through whatever audio codec is in the source straight to HDMI.
