hdmi connections

Forums › Home Theatre (incl HTPC) › hdmi connections

blairm

54 posts

Master Geek

# 20530 29-Mar-2008 14:05

Hi,

Looking at buying a component system and a 37”LCD TV – but utterly baffled by HDMI. After reading countless threads and listening to podcasts, think I have it straight but I would like to double-check...

From what I gather, HDMI passthrough in a receiver means the HMDI cable will carry audio and video; HDMI switching means the HDMI cable takes only video, and a coaxial or optical cable is needed as well for audio.

HDMI upconversion in a receiver takes a signal from a lesser-quality connection and makes it look better- but if the source (eg DVD) has an HDMI output you can just run that cable direct to the TV and have the sound running in a coaxial or optical cable from the TV to receiver, which still allows the surround sound..

Is that right???

Final thing, how important is HDMI/upconversion in a receiver? Seems you pay a hefty premium for it. I'm notlooking for stellar performance, just better than the average HTIB.

Cheers,

Blair

Radiotron

139 posts

Master Geek

# 119608 29-Mar-2008 21:43

While it's a little awkward to answer questions re HDMI without knowing scary details of exact receiver in the system, I suggest to stay away from up-conversion in the receiver, and let the scaler in the display do that job, IMHO, the systems I am familiar with present a much better pic when the scaling is done in the display itself, a $4k display usually does a better job than a receiver or worse an "upscaling" DVD player. Leave the DVD player set to 576p, and get the more $$ scaler in the display to do the work, a better result is usually seen.

stuzzo

534 posts

Ultimate Geek

# 119628 30-Mar-2008 00:57

blairm:
Hi,

Looking at buying a component system and a 37”LCD TV – but utterly baffled by HDMI. After reading countless threads and listening to podcasts, think I have it straight but I would like to double-check...

From what I gather, HDMI passthrough in a receiver means the HMDI cable will carry audio and video; HDMI switching means the HDMI cable takes only video, and a coaxial or optical cable is needed as well for audio.

HDMI upconversion in a receiver takes a signal from a lesser-quality connection and makes it look better- but if the source (eg DVD) has an HDMI output you can just run that cable direct to the TV and have the sound running in a coaxial or optical cable from the TV to receiver, which still allows the surround sound..

Is that right???

Final thing, how important is HDMI/upconversion in a receiver? Seems you pay a hefty premium for it. I'm notlooking for stellar performance, just better than the average HTIB.

Cheers,
Blair

A lot of the descriptions of HDMI features seem to have confusing and conflicting definitions floating around so I'm not surprised you're confused. Join the club.

As far as I can figure it HDMI passthrough refers to when an HDMI signal is "passed through" the receiver to a display device. It seems to be used in describing receivers that can switch HDMI but not decode the audio but is also used in describing a receiver option of sending HDMI directly through to a display device without any upscaling or audio processing at the receiver.

HDMI switching is the ability of the receiver to switch the output between multiple inputs. I have seen it used to describe both receivers that can process audio over HDMI and those that can't.

An HDMI repeater is a device that can input HDMI and output HDMI and in the process do HDCP handshaking . There are HDMI switches that aren't repeaters (as far as I can gather) because they do nothing more than switch the physical circuit so the source and display are effectively unaware of their presence. Receivers that are described as HDMI repeaters can virtually always take HDMI audio streams and process or decode them to play through the receiver. You also need an HDMI repeater to have multiple HDMI outputs.

The important thing is to be sure you know if the receiver can take the HDMI audio part and output it through the speakers however they describe it.

HDMI upconversion (strictly speaking transcoding) is converting a non-HDMI input video signal to an HDMI output signal. This is usually for the convenience of sending all video to the display as HDMI. As you say audio still goes to the receiver via the optical or rca connectors. It doesn't much impact on video quality.

The potential to improve quality is in up-scaling, particularily where de-interlacing is involved. Higher end receivers market their ability to improve video by including high spec video processing chips but as the previous poster states that's probably safely left to the display device in most cases.

blairm

54 posts

Master Geek

# 119665 30-Mar-2008 11:12

Thanks for your help.

HDMI has to be one of the most confusing pieces of technology I've struck before - may be because I'm coming into it pretty cold with no home theatre experience behind me.
At least I know what to look for now

Blair

buzzy

217 posts

Master Geek

# 119839 31-Mar-2008 10:57

If you're in Wellington, I recently bought a TV from Sound Expression on Willis St. The guys there were very helpful when I went to the store and asked about the technologies. They weren't in a rush to sell me things, and it was good to be able to have a conversation with someone where you could easily ask follow-on questions.

I'd recommend finding a good specialist retailer near you, and go have a chat to them. Make it clear you're researching and aren't going to make a purchase straight away; most people will still happily help you out.

Cheers
Buzzy