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-   -   Someone please explain hdmi arc.. (https://www.avsforum.com/forum/25-hdtv-technical/2935522-someone-please-explain-hdmi-arc.html)

Alex Hall 11-21-2017 09:20 AM

Someone please explain hdmi arc..
 
So I'm running my sony 4k receiver from the arc hdmi output on the receiver to the arc hdmi input on my tv,it sends audio from the tv to my speakers fine. I also have my Xbox one x in hdmi 2 on the tv and for some reason I'm getting the xbox's audio through my receiver and to the speakers. I'm not complaining, I'm just wondering is this how arc is supposed to work? I would have no problem running my Xbox into the receiver, but I tested it and it won't display 4k. Let me know and thanks in advance! My first post on here so go easy lol

sneals2000 11-21-2017 09:50 AM

Quote:

Originally Posted by Alex Hall (Post 55173160)
So I'm running my sony 4k receiver from the arc hdmi output on the receiver to the arc hdmi input on my tv,it sends audio from the tv to my speakers fine. I also have my Xbox one x in hdmi 2 on the tv and for some reason I'm getting the xbox's audio through my receiver and to the speakers. I'm not complaining, I'm just wondering is this how arc is supposed to work? I would have no problem running my Xbox into the receiver, but I tested it and it won't display 4k. Let me know and thanks in advance! My first post on here so go easy lol

ARC sends SPDIF quality (i.e. roughly the same as an optical out or a coax out) audio the 'wrong way' down an HDMI cable. It's really designed to get a TV's tuner audio back down to the amp without having to install a second cable. It carries PCM 2.0, DD and (in some cases) DTS audio. Most high quality HDMI sources like consoles, Blu-ray players etc. will output PCM 5.1/7.1, Dolby True HD (sometimes with Atmos), DTS HD MA/HRA (and DTS:x), and Dolby Digital Plus (I believe there may be some DD+ over ARC - not sure)

Some TVs will also route audio from other inputs - HDMI sources for example - down the ARC connection. However these will be limited to the ARC's capabilities, and if you have a good quality AVR, you will be compromising your audio connectivity if you put ARC 'in the way'.

However if your AVR is a legacy HDMI 1.4b or below device and/or doesn't support HDCP 2.2 AND your source only has one HDMI output yout have to chose between high quality audio and HD video (routed through your AVR), or compromised audio quality and 4K video (routed directly to your TV with ARC audio) (some UHD Blu-ray players have two HDMI outputs for this very reason - one HDMI 1.4 output carries audio only, the other HDMI 2.0 carries both audio and video. My UBP-X800 does this for example)

There are devices that you can get that will sit between devices and strip off the HDMI audio and output it over an HDMI 1.4 connection, and pass through the video over and HDMI 2.0 connection. However they aren't cheap. (HD Fury make one)

There IS a new version of ARC coming - which supports full quality HDMI audio - but it's only going to be supported by - you guessed it - new AVRs and TVs...

Otto Pylot 11-21-2017 11:41 AM

^^^^ good explanation. Simply put, ARC is bi-directional audio that can carry the same formats as optical audio. In other words, discreet 5.1 audio. Some can support ATMOS.

Once HDMI 2.1 is ratified, and the chip mfrs start supplying the chipsets to the device mfrs, ARC will use the never-used ethernet channel on on HDMI cables (eARC) and that should expand the audio capabilities of ARC (eARC). However, all of your HDMI connected devices will have to have the same chipsets on board to achieve this so you're basically looking at all new hardware if you want trouble-free HDMI 2.1.

Currently a lot of folks just use an optical audio cable from the tv to the receiver for 5.1 audio from the tv's SmartApps or OTA tv (if you use an antenna) and a programmable remote such as a Harmony of single remote control of your HTS. ARC is quite often associated with CEC so you either disable both or enable both. Some newer devices allow you separate control over that but all of your connected devices need to be capable of that. A receiver with multiple HDMI inputs makes this a lot easier because the receiver is the hub of your HTS and not the tv so all audio goes thru the receiver with just the video being sent to the tv.

sneals2000 11-21-2017 12:05 PM

Quote:

Originally Posted by Otto Pylot (Post 55174366)
^^^^ good explanation. Simply put, ARC is bi-directional audio that can carry the same formats as optical audio. In other words, discreet 5.1 audio. Some can support ATMOS.

Discreet - but lossy compressed. Atmos is only supported as an extension to lossy Dolby Digital Plus (you won't get Dolby True HD + Atmos over current ARC)

Basically ARC = DVD-quality audio - fine for streaming services and OTA TV audio, but not a great solution for routing Blu-ray or UHD Blu-ray quality audio to a modern AVR. (Also probably not a good fit for 5.1/7.1 audio from games consoles for gaming, as they usually require PCM 5.1/7.1 which isn't supported by ARC)

Otto Pylot 11-21-2017 02:34 PM

Quote:

Originally Posted by sneals2000 (Post 55174620)
Discreet - but lossy compressed. Atmos is only supported as an extension to lossy Dolby Digital Plus (you won't get Dolby True HD + Atmos over current ARC)

Basically ARC = DVD-quality audio - fine for streaming services and OTA TV audio, but not a great solution for routing Blu-ray or UHD Blu-ray quality audio to a modern AVR. (Also probably not a good fit for 5.1/7.1 audio from games consoles for gaming, as they usually require PCM 5.1/7.1 which isn't supported by ARC)

True. ARC has no real advantage over optical. It's just a nice feature cause you can deal with one less cable.

sneals2000 11-21-2017 03:12 PM

Quote:

Originally Posted by Otto Pylot (Post 55175744)
True. ARC has no real advantage over optical. It's just a nice feature cause you can deal with one less cable.

Yep - combined with CEC it's a neat solution though - as your TV then 'knows' the AVR is handling audio, automatically mutes the speakers, and sends volume control commands to the AVR instead when sent from the TV remote. (And the AVR can switch off when the TV does too)

Otto Pylot 11-21-2017 04:10 PM

Quote:

Originally Posted by sneals2000 (Post 55175970)
Yep - combined with CEC it's a neat solution though - as your TV then 'knows' the AVR is handling audio, automatically mutes the speakers, and sends volume control commands to the AVR instead when sent from the TV remote. (And the AVR can switch off when the TV does too)

There's the problem. CEC is poorly implemented across the device mfrs, even within the same model lines, so unless you have individual controls for ARC and CEC, one will more than likely develop issues. It's either or for both for a lot of tv's, avr's, etc. Optical and a Harmony are the fail-proof answers, so far.

Canuck Sonido 11-21-2017 04:20 PM

Quote:

Originally Posted by sneals2000 (Post 55174620)
Discreet - but lossy compressed. Atmos is only supported as an extension to lossy Dolby Digital Plus (you won't get Dolby True HD + Atmos over current ARC)

Basically ARC = DVD-quality audio - fine for streaming services and OTA TV audio, but not a great solution for routing Blu-ray or UHD Blu-ray quality audio to a modern AVR. (Also probably not a good fit for 5.1/7.1 audio from games consoles for gaming, as they usually require PCM 5.1/7.1 which isn't supported by ARC)

Wait a sec, I'm using ARC and you're telling me my new Sony 930E TV that supports Dolby Atmos is not sending Dolby Atmos to my Sony STR-DN 1080 A/V Receiver & 5.1.2 speaker rig that also supports Dolby Atmos?

Otto Pylot 11-21-2017 07:24 PM

Quote:

Originally Posted by Canuck Sonido (Post 55176364)
Wait a sec, I'm using ARC and you're telling me my new Sony 930E TV that supports Dolby Atmos is not sending Dolby Atmos to my Sony STR-DN 1080 A/V Receiver & 5.1.2 speaker rig that also supports Dolby Atmos?

Certainly not HD Audio (Dolby TrueHD, DTS-MA, etc). Just what sneals2000 explained.

Canuck Sonido 11-22-2017 04:23 PM

Quote:

Originally Posted by Otto Pylot (Post 55177346)
Certainly not HD Audio (Dolby TrueHD, DTS-MA, etc). Just what sneals2000 explained.

I don't get it. My brand new 2017 Sony 930E is listed as supporting Dolby Atmos. How can they claim this if there's no ability to get DA to a receiver over HDMI ARC? Should I be using optical to my receiver? Can someone explain this?

Otto Pylot 11-22-2017 06:36 PM

Quote:

Originally Posted by Canuck Sonido (Post 55183056)
I don't get it. My brand new 2017 Sony 930E is listed as supporting Dolby Atmos. How can they claim this if there's no ability to get DA to a receiver over HDMI ARC? Should I be using optical to my receiver? Can someone explain this?

"Supports" Atmos is different from "Atmos totally compliant", which most mfrs don't state. One needs to be aware of the "supports" and "up to" claims.

holl_ands 11-24-2017 02:01 PM

Quote:

Originally Posted by Otto Pylot (Post 55174366)
^^^^ good explanation. Simply put, ARC is bi-directional audio that can carry the same formats as optical audio. In other words, discreet 5.1 audio. Some can support ATMOS.

NIT-PICK CLARIFICATION: ARC technically refers to the ONE-WAY flow of Digital Audio from DTV to AVR [p/o HDMI Data Stream], which replaces the separate OPTICAL cable. Digital Audio from AVR to DTV is embedded into the usual HDMI Video Data Stream.

holl_ands 11-24-2017 02:15 PM

[TrueHD] Dolby ATMOS is an extension to Loss-Less Dolby TrueHD, which is TOO HIGH a data rate to be supported by Optical/ARC, so only supported by HDMI. Readily available on many Blu-Ray Discs:
https://en.wikipedia.org/wiki/Dolby_Atmos
https://en.wikipedia.org/wiki/Dolby_TrueHD

Dolby+ (Dolby Plus, aka Enhanced AC-3) is a COMPRESSED Digital Audio format [incl DD7.1] that CAN be supported by Optical/ARC...although SOURCE and AVR must BOTH implement it....and since the spec was prepared quite some time ago for ATSC implementation, I do NOT see ATMOS mentioned at all in fol. Wiki Article. SOME systems DO use Dolby-Plus to carry ATMOS encoded signals, although it is NOT universally implemented [so ATMOS may only refer to the TrueHD Dolby ATMOS implementation]:
https://en.wikipedia.org/wiki/Dolby_Digital_Plus

Otto Pylot 11-24-2017 02:56 PM

Quote:

Originally Posted by holl_ands (Post 55193386)
NIT-PICK CLARIFICATION: ARC technically refers to the ONE-WAY flow of Digital Audio from DTV to AVR [p/o HDMI Data Stream], which replaces the separate OPTICAL cable. Digital Audio from AVR to DTV is embedded into the usual HDMI Video Data Stream.

A good nit-pick clarification. Thanks.

sneals2000 11-25-2017 02:04 AM

Quote:

Originally Posted by Canuck Sonido (Post 55183056)
I don't get it. My brand new 2017 Sony 930E is listed as supporting Dolby Atmos. How can they claim this if there's no ability to get DA to a receiver over HDMI ARC? Should I be using optical to my receiver? Can someone explain this?

This is the confusing bit about Dolby Atmos... Dolby Atmos can be carried with a Dolby True HD stream. It can also be carried with a Dolby Digital Plus stream. Your ARC connection will only carry - at best - a DD+ with Atmos stream. It can't carry a Dolby True HD with Atmos stream as that is way above the bandwidth limits of ARC. Atmos itself really is more of a branding device for positional audio - rather than a single standard...

However this would only be an issue if you connected a Blu-ray player or similar to your TV, and then used ARC to get the audio to your AVR. That's not a good way of connecting a Blu-ray or similar player. You are far better to connect this to your AVR direct (where True HD + Atmos are then carried the conventional way over HDMI - NOT via ARC)

ARC is really only useful to get internal TV tuner audio and the audio from any streaming sources in a Smart TV to your AMP (i.e. sources that you can't route directly through your AVR). Anything else should really be connected via your AVR.

RoyGBiv 11-25-2017 09:17 AM

Nothing like beating a dead horse, but can I ask more questions about ARC and CEC? My current AV receiver is old and has no HDMI inputs. I have four devices through an HDMI switch going to the HDMI ARC input on my TV (Sony 930D). Audio goes to my receiver via optical cables. All works.

I am planning to buy a new AV receiver in the near future, probably another Yamaha. I plan to run all the devices through the HDMI inputs on the receiver and the output to the ARC HDMI input on the TV. If 5.1 sound is all I will get this way, that is fine with me, but I have some other questions.

Two of my devices are D* DVRs which I have on all the time. I have one Panasonic BD player, and I have Amazon FireTV. If CEC is working correctly, does this mean that when I turn off the TV, the receiver and all these devices will turn off? It's not a big deal if the DVRs are on or off, but I have heard of people having handshake issues and delays when turning the TV on, which I want to avoid. Also, for east of my wife's use, my programmable remotes are set so that when controlling either DVR, the power button controls the TV power but leaves the DVRs on. There would be no button to turn the DVR on. Or would turning any of these devices on or off turn the receiver and TV on or off as well? And, I leave both DVRs on all the time because I frequently switch between them.

Second, obviously the audio from any of these sources will just go through the HDMI cable to the receiver. What is done to make sure ARC is not just sending that back to the receiver. And as a follow up, how does the receiver know when to use the TV's audio on ARC? What is it set to if I want to watch a video on the TV and not from one of these sources so that the audio from the TV is what the receiver plays?

Sorry, if these are Newbie questions, but no one I know is able to answer them.

SMK

Otto Pylot 11-25-2017 09:41 AM

Quote:

Originally Posted by RoyGBiv (Post 55197118)
Nothing like beating a dead horse, but can I ask more questions about ARC and CEC? My current AV receiver is old and has no HDMI inputs. I have four devices through an HDMI switch going to the HDMI ARC input on my TV (Sony 930D). Audio goes to my receiver via optical cables. All works.

I am planning to buy a new AV receiver in the near future, probably another Yamaha. I plan to run all the devices through the HDMI inputs on the receiver and the output to the ARC HDMI input on the TV. If 5.1 sound is all I will get this way, that is fine with me, but I have some other questions.

Two of my devices are D* DVRs which I have on all the time. I have one Panasonic BD player, and I have Amazon FireTV. If CEC is working correctly, does this mean that when I turn off the TV, the receiver and all these devices will turn off? It's not a big deal if the DVRs are on or off, but I have heard of people having handshake issues and delays when turning the TV on, which I want to avoid. Also, for east of my wife's use, my programmable remotes are set so that when controlling either DVR, the power button controls the TV power but leaves the DVRs on. There would be no button to turn the DVR on. Or would turning any of these devices on or off turn the receiver and TV on or off as well? And, I leave both DVRs on all the time because I frequently switch between them.

Second, obviously the audio from any of these sources will just go through the HDMI cable to the receiver. What is done to make sure ARC is not just sending that back to the receiver. And as a follow up, how does the receiver know when to use the TV's audio on ARC? What is it set to if I want to watch a video on the TV and not from one of these sources so that the audio from the TV is what the receiver plays?

Sorry, if these are Newbie questions, but no one I know is able to answer them.

SMK

The simplest solution, and one that a lot of us do, is this: Disable ARC/CEC on all of your HDMI connected devices. Use your receiver as the hub of your HTS so that everything is connected, via HDMI, to the receiver and then a single HDMI cable for video is connected to your tv. Connect an optical (audio) cable from the tv to the receiver. That way, all of your audio goes thru the receiver so you can properly decode any audio format that is presented to it from any source and just send the video to your panel. Any audio (5.1) from the tv's SmartApps (or OTA if that is your television source) will transmit via optical to the receiver. Next, purchase a programmable remote such as a Harmony and use that to control your entire HTS with a single remote control. Once programmed, at best you'd have to press two buttons to use your system. One to turn it on and one to select your source. Channel selection, volume, etc is then controlled just like it would be with the specific devices remotes. Keep in mind that any other external device connected directly to the tv will be using the optical cable to transmit audio to the receiver so you will be limited by what the optical cable can handle. Basically, optical audio and ARC are both 5.1 only. Some systems can even handle Atmos, as explained above, but you will not get HD audio (Dolby TrueHD, DTS-MA, etc) via optical or ARC.

Oh yeah, you can still use the ARC-labeld HDMI inputs even if you disable ARC. In that case, they will function just like a "regular" HDMI input.

holl_ands 11-25-2017 10:08 AM

You should look at the individual MANUALS to make sure....but since I've been looking at my son-in-law's brand new ONKYO TX-NR565 AVR Manual, I can report that it's pretty simple. In AVR's Set-up, ENABLE ARC (i.e. Set to "AUTO", otherwise it will select TV Optical In) and you simply select "TV" on the R/C. TV will output Digital Audio (simultaneously via ARC AND Optical) from whatever APP or Channel you have selected.

BTW: Compressed Dolby Plus (aka Enhanced AC-3, up to DD7.1, including ATMOS) has low enough data rate to be supported via Optical and ARC [although may or may NOT be implemented in any specific component....it is NOT mandatory]. Frequently used in some TV SMART Apps...and Game Stations. And TrueHD ATMOS is an extension of much higher data rate Loss-Less Dolby TrueHD, only supported via HDMI.

RoyGBiv 11-26-2017 06:37 AM

Thanks for the info.

SMK

natchie 01-31-2019 04:28 PM

Does Toshiba FireTV Edition properly send digital audio to Yamaha RX V779? I am having touble, regardless of new HDMI cables connected to ARC HDMI connection jacks. Do I need to focus on the AVR end?

Otto Pylot 01-31-2019 05:32 PM

Quote:

Originally Posted by natchie (Post 57532182)
Does Toshiba FireTV Edition properly send digital audio to Yamaha RX V779? I am having touble, regardless of new HDMI cables connected to ARC HDMI connection jacks. Do I need to focus on the AVR end?


If you are having issues with ARC it could be CEC. Cables are just data pipes. The actual functioning of ARC/CEC is determined by the HDMI chipsets in your source and sink. The problem is non-standardized CEC protocols which can affect how ARC works.


Try disabling ARC/CEC on your devices, if you can, and see it that corrects the problem.


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