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What's the big deal in HDMI Pass through

Home Theatre Systems

kannan_r

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Friends,
After reading enough postings, please find my observation on HDMI pass through AVR's Vs Non HDMI Pass through AVR's,
Differences
HDMI pass through AVR's
DVDP thro HDMI cable can be connected to AVR + AVR thro HDMI cables connected to TV +
DVDP thro coaxial cable can be connected to AVR .
Non HDMI pass through AVR's
DVDP thro HDMI cable can be connected to TV directly + DVDP thro coaxial cable can be connected to AVR.
Similarities
HD Audio cannot be played both in HDMI pass through AVR's and non HDMI Pass through AVR's

So what's the big deal in this.
If the combination is TV+AVR+DVDP, I dont think HDMI pass through AVR's can make a difference to reduce the wires between the TV & the AVR's/ players against a non HDMI pass AVR's .
May be yes if the combination is TV+DVDP+PS3/Tata +AVR

So my question is then why HDMI pass through feature is an attractive feature when compared to non HDMI pass through AVR's. Is there any other special advantage available for HDMI Pass through AVR's ( apart from the TV+DVDP+PS3/Tatab+AVR combination) . I am sure there should be something I missed to notice?
 
Last edited:

tellranga

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which means we are forced to pay few additional thousands than non HDMI AVR's on a feature which is not that worth.
hmmmmm...
 

venkatcr

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Both of you are missing the point completely and I have explained this many times in this forum.

HDMI pass through has nothing to do with the connection type. All DVD players can be connected to an AVR through composite, component, S-Video, and/or HDMI depending upon what connections are available in the DVD Player. Most decent AVRs will have all these connection types in addition to other connections.

For video if you use an analogue connector such as composite, component, or S-Video, most AVRs will pass this signal through it's HDMI connection to the TV. This is generally called analog-to-digital conversion. If the incoming signal carries audio also, that will also be transmitted to the TV. There is no other transformation of the incoming signal. This is, sometimes, confusingly I must say, also called up-conversion.

There are two more aspects to video and audio that are important.

Most analogue connectors can only carry a max of 720P signals. Some AVRs accept the 480i, 480P, 720i, or 720P, and do some processing to the output. They send it through an internal processor and scale the video to 1080P or FullHD. They can also scale a 480 signal to 720 or 1080 and a 480/720 signal to 1080i or 1080P. This is called scaling or upscaling.

Some AVRs that do not have an internal video processing unit, pass the video as is through to the HDMI input of the TV. The processing, if any of the video will be done by the DVD Player or the TV.

Now we come to the audio part. None of the analogue signals we spoke about carry multi channel audio. To hear Dolby Digital or DTS, you have to use a digital connection which could be coaxial, optical or HDMI. Irrespective of what you use, digital surround sound cannot be sent to the TV as TVs do not understand surround sound formats. Invariably, if you use a TV, the sound is down-sampled to 2 channel stereo.

Now we come to HD Audio. This carries lossless compression and needs high bandwidth for transmission. HD Audio can be sent to the AVR ONLY through HDMI. No other connection can carry HD Audio. There is, of course, no question of sending HD Audio to the TV as the TV cannot understand what it is.

If an AVR has HD Audio decoding capabilities, you can send the HD Audio through HDMI. Otherwise, you have to choose standard Dolby or DTS coding. All HD Audio DVDs (Blu-Ray discs actually) will necessarily also carry standard surround sound codes. If you have a high end DVD Player and multi channel analogue inputs in you AVR, you can decode HD Audio in the DVD Player itself, and send individual channel data for the AVR to just amplify.

So stop worrying about pass through or non-pass through. Look at what you want in terms of the AVR/DVD Player capabilities. And then look for units that have those capabilities.

Cheers
 
Last edited:

Raghav

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Firstly I assume the audio is being sent to AVR via optical/coaxial route and HDMI is for video only. Your AVR should have all the audio decoding codecs to process the digital audio inputs.

Then, AVR which is only HDMI pass through has no real use (of the HDMI part, Digital audio inputs are needed.) as it does no processing of video signals and passes it onto the TV. However, it has the following minor benefits:

1. You can switch from DVD to PS3 to STB using just AVR. Otherwise you will need to change input on display as well as AVR.

2. Your TV may run out reqd. HDMI inputs.

However, note that it will be difficult to find an AVR without HDMI pass through (this is the basic type of HDMI, higher being Upconverting and Upcscaling) but yet supporting all the latest Audio decoding. Let me know if you find such AVR.

Raghav

Friends,
After reading enough postings, please find my observation on HDMI pass through AVR's Vs Non HDMI Pass through AVR's,
Differences
HDMI pass through AVR's
DVDP thro HDMI cable can be connected to AVR + AVR thro HDMI cables connected to TV +
DVDP thro coaxial cable can be connected to AVR .
Non HDMI pass through AVR's
DVDP thro HDMI cable can be connected to TV directly + DVDP thro coaxial cable can be connected to AVR.
Similarities
HD Audio cannot be played both in HDMI pass through AVR's and non HDMI Pass through AVR's

So what's the big deal in this.
If the combination is TV+AVR+DVDP, I dont think HDMI pass through AVR's can make a difference to reduce the wires between the TV & the AVR's/ players against a non HDMI pass AVR's .
May be yes if the combination is TV+DVDP+PS3/Tata +AVR

So my question is then why HDMI pass through feature is an attractive feature when compared to non HDMI pass through AVR's. Is there any other special advantage available for HDMI Pass through AVR's ( apart from the TV+DVDP+PS3/Tatab+AVR combination) . I am sure there should be something I missed to notice?
 

venkatcr

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Not to contradict you, but my Dell 3008WFP does have a DD/DTS decoder built in (but no speakers) and has a discrete 5.1 analog output to hook up to a speaker system or AVR of your choice. .

You could be right. Some modern TVs with HDMI connection may have an internal Dolby/DTS decoder, but this will be more an exception than a rule. They will invariably down mix this to two channels. The end result is the same.

Cheers.
 

kurups

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Hi Venkat - Just wanted to know some details regarding your below post. Cant HD Audio be sent to the AVR using an Optical Cable. Your post says "ONLY through HDMI"


Now we come to HD Audio. This carries lossless compression and needs high bandwidth for transmission. HD Audio can be sent to the AVR ONLY through HDMI. No other connection can carry HD Audio. There is, of course, no question of sending HD Audio to the TV as the TV cannot understand what it is.
 

Dirac

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Hdmi uses encoding of data from the source with an inbuilt key. The receiver side decodes the data. This ensures that nobody snoops upon the HD audio inbetween.
By the way I think passthrough refers to video only.
 

narenkum

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HD audio (DTS HDMA and Dolby TruHD) requires HDMI. Optical supports DTS and Dolby.

I have connected my Panasonic Bluray player to my Denon X2000 with both HDMI and an digital optical cable, as at times I will connect my Epson projector directly to the Panasonic player.

Now when the Projector is connected to the AVR, will the AVR be able to automatically use the HDMI input for Dolby TruHD and optical input for the normal DTS input or each time I have to manually change the Audio input in the settings?
 

just4kix

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Hdmi uses encoding of data from the source with an inbuilt key. The receiver side decodes the data. This ensures that nobody snoops upon the HD audio inbetween.
By the way I think passthrough refers to video only.
I think that HDMI pass-thru is for video+audio. Otherwise, it wouldn't make sense.
 

baijuxavior

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I have connected my Panasonic Bluray player to my Denon X2000 with both HDMI and an digital optical cable, as at times I will connect my Epson projector directly to the Panasonic player.

Now when the Projector is connected to the AVR, will the AVR be able to automatically use the HDMI input for Dolby TruHD and optical input for the normal DTS input or each time I have to manually change the Audio input in the settings?

When you connect hdmi and optical/coaxial to AVR, hdmi is given preference. You can change this preference in the avr settings. AVR won't automatically select HDMI for DTS-HD and optical for DTS. It uses the port from which it is getting audio. For example, I have connected my htpc hdmi out to avr and the coaxial port to my stb. When both htpc and stb are sending audio signal, HTPC audio is selected.
 

0verkilled

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I think that HDMI pass-thru is for video+audio. Otherwise, it wouldn't make sense.

What I understand from the way its marketed is that Pass-thru is mainly for video. It's always advertised as compatible with 4k videos. If your BDP and TV support 4K and AVR does not then, as Venkat said it will scale the videos to 1080p (or whatever it can), while pass-thru lets video signals pass through it to TV without scaling at 4K.

Not sure about audio. (I'm assuming amplification is done on analog signals only, correct me if Im wrong) Dolby, DTS, HD Audio and other stuff are all digital signals.. ? If so, DAC converts it to analog not matter what kind of Digital signal it is, so what can an AVR do in terms of processing digital audio signals?
 

Dirac

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What I understand from the way its marketed is that Pass-thru is mainly for video. It's always advertised as compatible with 4k videos. If your BDP and TV support 4K and AVR does not then, as Venkat said it will scale the videos to 1080p (or whatever it can), while pass-thru lets video signals pass through it to TV without scaling at 4K.

Not sure about audio. (I'm assuming amplification is done on analog signals only, correct me if Im wrong) Dolby, DTS, HD Audio and other stuff are all digital signals.. ? If so, DAC converts it to analog not matter what kind of Digital signal it is, so what can an AVR do in terms of processing digital audio signals?

The DSPs in the AVR may convert a 2.1 input to other formats and the give it to DAC.
But HD audio is not touched.
 

Rockfella

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The only advantage I see is that one can watch TV or movie (sound coming from TV) while the AVR is off. The question is why would we do that anyway? It saves cables?
 

just4kix

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The only advantage I see is that one can watch TV or movie (sound coming from TV) while the AVR is off. The question is why would we do that anyway? It saves cables?

No. There are a lot of advantages. First, you don't have to switch on AVR and that saves power. Second, it is not just saving cables. Even if you had extra cables how would you connect with limited set of hdmi ports? Third, less cables means less clutter.
 

gauthamnaidu

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The only advantage I see is that one can watch TV or movie (sound coming from TV) while the AVR is off. The question is why would we do that anyway? It saves cables?

Completely agree..
And i find the way to toggle hdmi through or otherwise is very irritating.. I personally wanted to decrease the chances my wife gets to use the avr.. So that the stb signals will pass through and she can listen through the tv speakers since she doesn't prefer boom vrooom.. But the toggle is about ten remote presses and I have to do it every time.. Not easy :-(
 

musicbee

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The only advantage I see is that one can watch TV or movie (sound coming from TV) while the AVR is off. The question is why would we do that anyway? It saves cables?

This is a huge limitation in today's TVs especially the plasmas. My Panny has speakers but the audio is weak and not very loud and hence all of the TV watching is done via the AVR.

Of course you are always limited by the number of devices you can connect via the AVR and there is always the issue of heat and increased power bill but all said and done its no joy watching the latest HD rip on TV speakers (especially the plasmas and the LCDs that are ultra thin and come with the bare minimum in the name of speakers).
 

spirovious

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Hi Venkat - Just wanted to know some details regarding your below post. Cant HD Audio be sent to the AVR using an Optical Cable. Your post says "ONLY through HDMI"
HD audio needs more Bandwidth due to more bits per sec for transfer which optical connection cant give.
 
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