eARC implementation and SQ question.

[Davesrose]

Exactly. Tv is the brain, in my opinion too, Gregorio, because it provides the decoding. There is no need for AVR when you downstream downmixed PCM audio. I am simply pointing out, that downmixes executed in the brain (TV) sound better then source stereo track and that through ARC they sound better in my system then via Optical and I also tried to explain why it might be so.

AAC codec is mentioned in signal information of TV, Davesrose. Perplexity says it is quite common in digital broadcasting to use AAC codec for audio.

No, as I said, US TV broadcast is AC3 (not AAC). Broadcast TV in the US adheres to ATSC standards, as outlined in every version (version 3.0 is coming online and addresses UHD resolutions/color space).
https://en.wikipedia.org/wiki/ATSC_standards#Audio

Don't rely on AI: it scrapes data from the web-which can be data that's not correct. I just encountered that when I tried Googling IMAX Enhanced with Nvidia Shield Pro (one of my streaming devices-the most capable for passthrough audio). Google AI said Nvidia Shield is supported for Disney+ DTS IMAX Enhanced. I had to reference a few sources to see that it doesn't work with NVidia because Disney uses an uncommon profile for lossy DTS. Apparently you have one of the few TVs that support it-and most brands aren't rushing to support it because there's only 22 whole movies that have this non-standard lossy DTS:X track. I would be able to rip an IMAX Enhanced UHD and still retain the IMAX metadata within DTS-MA DTS:X, and it would passthrough to my receiver that supports IMAX. But most IMAX Enhanced movies on UHD are IMAX movies (not blockbusters). You may be hearing what I've found when I compare a movie in DD+ Atmos vs TrueHD Atmos-the TrueHD track usually has a higher level (I turn my volume down -5%, and I notice there's a higher LFE level as well). The difference isn't their formats-it's how the tracks were mastered.

One thing I may have exaggerated is the DTS HD MA 7.1 thing. It says English DTS and English Atmos in Pictures Core audio track selection settings. DTS sounded better to my ears.

Again, it's only a few streaming movies that are IMAX Enhanced (a DTS stream) and they also carry a DD+ Atmos track for all the brands that aren't Sony, Hisense, TCL TVs. If you're selecting each of those tracks, they're different mixes. It's not the format! Also, since it's only 17 Marvel Movies on Disney+ that are DTS IMAX Enhanced, you're up a creek if you refuse to listen to all the other streaming and TV content that is AC3/EAC3.

 

[myusernameislove]

There is one thing I do not understand. Does Tv decide to send stereo downmix created from DTS or Dolby surround sourcetrack to Optical or Arc output and not to send PCM 5.1 downmix created from the same sourcetrack because it creates first some kind of handshake that discovers first what decoding capabilities has the device on other end of the cable or because only stereo PCM downmix can be created from surround DTS or Dobby sourcetrack, i.e. decoders never remix to 5.1 PCM?

 

[Davesrose]

There is one thing I do not understand. Does Tv decide to send stereo downmix created from DTS or Dolby surround sourcetrack to Optical or Arc output and not to send PCM 5.1 downmix created from the same sourcetrack because it creates first some kind of handshake that discovers first what decoding capabilities has the device on other end of the cable or because only stereo PCM downmix can be created from surround DTS or Dobby sourcetrack, i.e. decoders never remix to 5.1 PCM?

Well I was addressing your main items of DTS sounding better than Dolby Atmos. It looks like your TV supports the IMAX Enhanced DTS:X (lossy) track that's on the Disney+ app for it. Most systems do not support that profile, and have not supported DTS or IMAX Enhanced streaming. Worst still, even with your TV, it's just a couple dozen titles that have DTS IMAX. Because your TV is able to detect two different audio tracks, and supports IMAX Enhanced, it is processing them separately. I don't doubt that the IMAX Enhanced track is mastered differently and probably has higher levels: and therefore can "sound better". I've found Disney content in general has lower normalization with Dolby Atmos than any other service. The main thing with devices that support IMAX Enhanced audio: it's a separate metadata stream on top of the DTS:X 3D audio stream. Technically, DTS:X is inferior to Atmos as it has 9 dynamic objects vs Atmos's 13-16. But the IMAX stream adds some more EQ settings throughout the movie. So I'm guessing your TV is processing all that before down mixing to 2 channel PCM (and yes, HDMI detects what your other devices support). Since theoretically optical also supports 2 channel PCM, the TV could do the same processing for optical. But because it's using different protocols, there's a possibility it could be different. I'm guessing your TV is still processing to stereo for it....if it was some setting you needed to first enable, you'd quickly realize the audio track sounds odd because you're only hearing the music/ambiance of the stereo channels and not dialogue of the center channel.

I'm also going over your particular configuration. Please keep in mind my main point: most all sources on streaming (save these 22 titles) are AC3 or EAC3. You cannot generalize sound quality by format....it's about how the audio track was mastered. For a bit, Disney was trying to push IMAX Enhanced just on their streaming service-so obviously they would up the sound levels compared to Atmos to make it seem more impressive.

Also for those interested about converting to PCM....platforms like the Apple TV takes AC3/EAC3 and converts it to PCM (whether stereo on up to 7.1...depending on original source). Apple also hasn't done bitstream passthrough. So in order to send Dolby Atmos to my system, it uses MAT 1.0. MAT 1.0 is Dolby's license for extracting the Atmos stream from DD+ and applying to PCM/ALAC. If you have a Plex server that also has titles that are TrueHD Atmos, they'll just be seen as multichannel PCM with Apple TV....because it does not support MAT 2.0 (the standard that extracts from TrueHD). For quite a few years, developers have been asking Apple for MAT 2.0 or have bitstream with Apple TV. Apple has just now allowed bitstream passthrough for their own apps-so we're still waiting for 3rd party support.

 

[myusernameislove]

Wow. That was very detailed response to the point. Many will benefit from that (hopefully). Thank you very much good sir.