Passthrough stopped working in tvOS 11.2 b1

[Selest]

I have tried every possible setting but the result is always static noise when passthrough is enabled in MrMC. Multichannel PCM works fine. If I select DD 5.1 (instead of Best Quality Available) for Surround Sound in tvOS settings and disable passthrough in MrMC everything is passed through as Dolby Digital (DD symbol lights up on amplifier) which is strange because, like I said, passthrough is disabled in MrMC.

I am little confused as to why mine i working, or have you not tried my suggestion in the earlier post? 100% working here no static, can switch between DD 5.1 and TrueHD 7.1 in same movie to confirm..... receiver showing 7.1 PCM

Best Quality ATV4K
loud clicks off on ATV4K
DTS capable receiver off
DD capable receiver off <-----

You're not getting passthrough with that setup. You're getting multi channel PCM.

ok that makes sense.. so getting pcm instead of lpcm

[cosmoxl]

I am little confused as to why mine i working, or have you not tried my suggestion in the earlier post? 100% working here no static, can switch between DD 5.1 and TrueHD 7.1 in same movie to confirm..... receiver showing 7.1 PCM

Best Quality ATV4K
loud clicks off on ATV4K
DTS capable receiver off
DD capable receiver off <-----

You're not getting passthrough with that setup. You're getting multi channel PCM.

ok that makes sense.. so getting pcm instead of lpcm

LPCM is a type of PCM. Both are analog signals which you can consider uncompressed. This is because MrMC is decoding and doing digital to analog conversion.

Passthrough or bitstream as it's used in audio/video context such as this is when a compressed, digital, audio stream is sent to a sink (receiver) untouched. The receiver does the decoding, the digital to analog conversion, of the stream. A receiver will generally light up with a DD, or DTS or Dolby TrueHD or DTS-HD Mas, etc. light.

[Selest]

You're not getting passthrough with that setup. You're getting multi channel PCM.

ok that makes sense.. so getting pcm instead of lpcm

LPCM is a type of PCM. Both are analog signals which you can consider uncompressed. This is because MrMC is decoding and doing digital to analog conversion.

Passthrough or bitstream as it's used in audio/video context such as this is when a compressed, digital, audio stream is sent to a sink (receiver) untouched. The receiver does the decoding, the digital to analog conversion, of the stream. A receiver will generally light up with a DD, or DTS or Dolby TrueHD or DTS-HD Mas, etc. light.

I disagree .... Thats not the way it works.... an LPCM stream ,in the sense that everyone refers to it in, is every bit a lossless 1 fo 1 as Truehd and DTS HD, which are in fact LPCM streams. The receiver does not have to light up in the retail codecs (DTS ..ect..) to get lossless audio, example... any flac converted encoded movie 5.1 or 7.1 and a PS4 (which is not dedicated to either dts or dobly) so their bit stream is every bit of true lossless LPCM. So on many receivers this shows up as PCM even though you are getting a true lossless bitsteam... MRMC does the same thing considering the apple tv is not built to decode the higher end codecs...

[cosmoxl]

ok that makes sense.. so getting pcm instead of lpcm

LPCM is a type of PCM. Both are analog signals which you can consider uncompressed. This is because MrMC is decoding and doing digital to analog conversion.

Passthrough or bitstream as it's used in audio/video context such as this is when a compressed, digital, audio stream is sent to a sink (receiver) untouched. The receiver does the decoding, the digital to analog conversion, of the stream. A receiver will generally light up with a DD, or DTS or Dolby TrueHD or DTS-HD Mas, etc. light.

I disagree .... Thats not the way it works.... an LPCM stream ,in the sense that everyone refers to it in, is every bit a lossless 1 fo 1 as Truehd and DTS HD, which are in fact LPCM streams. The receiver does not have to light up in the retail codecs (DTS ..ect..) to get lossless audio, example... any flac converted encoded movie 5.1 or 7.1 and a PS4 (which is not dedicated to either dts or dobly) so their bit stream is every bit of true lossless LPCM. So on many receivers this shows up as PCM even though you are getting a true lossless bitsteam... MRMC does the same thing considering the apple tv is not built to decode the higher end codecs...

I never said PCM, as MrMC decodes and outputs, is lossy.

[Everbrave]

A quick note: PCM (Pulse Code Modulation) is by itself not an analogue Signal, but results from sampling an analogue signal.
https://www.lifewire.com/what-is-pcm-1846928

[cosmoxl]

A quick note: PCM (Pulse Code Modulation) is by itself not an analogue Signal, but results from sampling an analogue signal.
https://www.lifewire.com/what-is-pcm-1846928

Of course, correct. We're dealing with all digital systems when outputting HDMI. But, in trying to compare PCM with streams such as DTS-HD, and how MrMC decodes such and outputs PCM, it's handy to just call it analog.

[higher]

FYI, passthrough (DD and DTS) works again in tvOS 11.2 b3.

[davilla]

FYI, passthrough (DD and DTS) works again in tvOS 11.2 b3.

thx

[higher]

Sorry to resurrect this topic.

I have noticed recently (perhaps after the 3.3.1 update) that TrueHD tracks are sent as DD to my receiver and not as PCM like it used to. Enable passthrough and DD/DTS capable receiver are ticked. TrueHD tracks don't normally have an AC3 core like DTS-HDMA so I wonder how it is possible.

[mrs4t4n]

I also started to have problems with passthrough...
The movie/tvshow starts to play ok, sounds good, but after 1 minute or 2 the signals stops and static/broken noise comes up... If i disable passtrough the sound comes back...

I'm not sure, but i think this behabiour started with 11.2.b5...