Question What is possible with HDMI in home multimedia? HDCP ARC...

[maximdelaet]

Hi everyone,

Despite being a network engineer at Cisco, I am a complete noob within the space of multimedia. I know the basic differences between HDMI and DP and the different versions within HDMI, I also know the basics in 4K Video and Audio. But I lack some basic knowledge to understand how HDMI can be used at this point and what impact HDCP and ARC have on this. Although a lot of info can be found online, the real answers to my questions seem to be hidden away, let's hope I can get them here.

Let's imagine the following scenario's:
1: media player connected to receiver connected to tv
2: receiver connected to media player with dual hdmi connected to tv
3: media player connected to tv connected to receiver
4: home network as media source connected to tv connected to receiver
5: home network as media source connected to receiver connected to tv

Let's discuss the following aspects:
1: Where is the audio and video put together in a container and stripped from eachother?
2: Where is the audio and or video encrypted and decrypted (HDCP --> each hop/beginning and ending/different versions?
3: In what way do ARC and eARC improve this situation?

Basically I would like to know what HDMI can do in these situation and where it lacks certain capabilities (or what it is designed for and what not). I would like someone to explain me this based on what happens with the data flow from source to destination, forgive me for being so network oriented in the way I try to understand this.

 

[jsmithepa]

Standard hookup is: Sources -----(assume HDMI)-----> AVR ------(HDMI again)-------> TV.

This is the "network" view:

HDMI (pretty standard these days) carries video + audio. As it goes through the AVR, AVR copies the audio and send it to speakers and whatever audio processing it needs, then forward everything actually (video+audio) to TV, but on the TV people who use AVR ignore (disable) the TV built-in speakers, otherwise u may get an echo.

Related terms and what they do:

HDMI 1.4 handles 1080 video (so last decade)
HDMI 2.0 handles 4K video.
HDMI in general enables highest quality, uncompressed audio, Optical can only handle compressed audio.
HDCP has to do with Digital Right Management. Anti-pirating.
ARC is just a facility to redirect audio from TV back to Receiver. There are several instances where this is useful, like when you are playing broadcast (antenna) TV, in this case the SOURCE is the TV, how do you get the TV's tuner audio to the AVR's attached speakers? ARC or a secondary Optical hookup. Sometimes for a variety of reasons people can't hookup sources to AVR but they plug them directly into TV, again, how do you get that audio back to the receiver? ARC.
eARC is the next generation ARC allowing more bandwidth still, to accommodate gazillion channels Dolby ATMOS.


So enough about theories. What do you have? what do u want to do?

 

[maximdelaet]

Standard hookup is: Sources -----(assume HDMI)-----> AVR ------(HDMI again)-------> TV.

This is the "network" view:

HDMI (pretty standard these days) carries video + audio. As it goes through the AVR, AVR copies the audio and send it to speakers and whatever audio processing it needs, then forward everything actually (video+audio) to TV, but on the TV people who use AVR ignore (disable) the TV built-in speakers, otherwise u may get an echo.

Related terms and what they do:

HDMI 1.4 handles 1080 video (so last decade)
HDMI 2.0 handles 4K video.
HDMI in general enables highest quality, uncompressed audio, Optical can only handle compressed audio.
HDCP has to do with Digital Right Management. Anti-pirating.
ARC is just a facility to redirect audio from TV back to Receiver. There are several instances where this is useful, like when you are playing broadcast (antenna) TV, in this case the SOURCE is the TV, how do you get the TV's tuner audio to the AVR's attached speakers? ARC or a secondary Optical hookup. Sometimes for a variety of reasons people can't hookup sources to AVR but they plug them directly into TV, again, how do you get that audio back to the receiver? ARC.
eARC is the next generation ARC allowing more bandwidth still, to accommodate gazillion channels Dolby ATMOS.


So enough about theories. What do you have? what do u want to do?

Thank you for your reply!

I know you replied a while back, but I didn't have time to follow up in the meantime.

So, right now I am mostly using my Plex Media Server as a source of video+Audio content and Spotify/Deezer as a source of Audio only content. Both of those are thus sent to the TV where the dedicated applications handle the content. Upstairs I am for now (using some spare equipment) sending the audio to my old AVR over simple AUX to be distributed to my old stereo speakers. Downstairs I run the same scenario using a new Sonos setup which (if I am not mistaken) has a simple receiver built in the Playbar/Playbase able to receive audio over Optical Fiber or Wired/Wireless Ethernet to be distributed over the SonosNet running on Wireless Ethernet to individuel speakers (rears for example).

In these cases, if I am not mistaken, there is no need for a special technology like ARC to return audio from TV over either Optical Fiber or AUX since these don't require the special care that an HDMI Audio signal needs. But this raises 3 more questions for me.

1: If ARC is needed to send audio from the TV to the AVR, does that mean that the AVR itself also uses ARC by default on all its HDMI OUT ports? Or is ARC only needed to send audio out of a port that is configured to receive HDMI audio+video signals?
2: If the second case is true, does that mean that you could use an HDMI IN and HDMI OUT to the same AVR to cover every scenario without any problems? (Imagine an old non ARC compatible TV).
3: When the source is connected to the TV like it is in my case, does the TV copy the audio and send it to the AVR the same way it would be done by the AVR the other way around?

 

[Alabalcho]

1. ARC on AVR is enabled on HDMI OUT only. ARC on TV is usually limited to single HDMI Input.

2, 3. I am not using ARC, but reading questions here it seems that some TVs do not pass back to ARC audio coming from smart apps running on the TV, or audio coming from other (TV) HDMI ports.

 

[maximdelaet]

2, 3. I am not using ARC, but reading questions here it seems that some TVs do not pass back to ARC audio coming from smart apps running on the TV, or audio coming from other (TV) HDMI ports.

Thank you for the reply!

So from this statement it is fair to conclude that some TV's could have problems sending audio to the AVR over HDMI if sourced externally from the Ethernet network or an internal TV application? Also is ARC always mandatory if you want to send audio from different sources from your TV to the AVR (in case it would work)?

 

[Alabalcho]

ARC is "mandatory" if you want to return audio generated by the TV (irrespectable of the source) back to the AVR over the HDMI link between them. You can, of course, use other audio connection for that (optical or analogue).