Understanding HDMI

Posted by: AndrewK7 on 25 May 2008

Hello forum members,

HDMI - the Interface format for the 21st Century, is now the only connection that is fully compatible with Blue-ray, the winner of the high definition video format war. Compatible twith 1080p video format and the HD sound formats from Dolby and DTS. HDMI is backwards compatible with DVI (digital visual interface) on PCs and computer monitors.
HDMI was developed by Philips, Sony, Matsushita and Hitachi which contributes to its success. The brands that use it are Linn, NAD and Naim Audio.
HDMI has an advantage of being able to transmit DSD streams and therefore SACD signals. It can transmit 8 uncompressed channels at 24-bit/192kHz. A lossless compressed version is available from Blue-ray in the form of Dolby True HD and DTS-HD MA. The recommended cable for HDMI is The Chord Company's v1.3 Silver Plus (until Naim builds one, judging by reputation).

There is a lot more information about this in the July issue of Hifi Choice for interested readers, and a good write up on the NAP250.
Posted on: 28 May 2008 by Frank Abela
Andrew,

What are you talking about?

1. So far, Naim do not fit HDMI connections to their equipment.

2. there are many more brands that support HDMI than the ones you mention. Name almost any far Eastern brand including the likes of Toshiba, Panasonic, Pioneer, Marantz, Yamaha, Denon, Onkyo or Sharp and they all have HDMI implementations. So do some European brands.

3. It's spelt Blu-ray.

4. Who recommends Chord's cable? Yes, it's an excellent cable but there are others. Of course in theory once they reach a particular spec, they should all perform the same sinec they're digital cables, but in practice there does seem to be some difference in performance.

5. HDMI is a standard, and the Home Entertainment applications are just the tip of the iceberg. There are many more applications to which HDMI may be used - think home connectivity.

6. The current standard is 1.3a.

7. HDMI is in a mess. Due to a toothless commission (http://www.hdmi.org/) there has not been enough clarity and enforcement of HDMI standards in products which have led to issues arising between devices, such as HDTVs not recognising an HD set-top device and not handshaking leading to loss of lor lowered quality signal. Handshaking between devices has been truly desperate, with blu-ray players not able to tell AV-receivers that they actually are allowed to send TrueHD or DTS/MA streams to them, or projectors not accepting full quality 1080p signal and forcing the upstream device to send reduced quality which then the projector would rescale. This is one rerason why this issue is largely unknown - people often don't realise they're watching or hearing an inferior quality product since even the lower quality is better than they're used to very often. All that said, the HDMI commission is trying to gain some teeth and enforce standards. One hopes they'll be successful since all this uncertainty helps the market not one jot.
Posted on: 28 May 2008 by {OdS}
Actually, HDMI might very well be obsolete soon. Can both standards survive?
Posted on: 29 May 2008 by BigH47
Oh goody another multi standard. They have been so successful in the past.
Posted on: 29 May 2008 by Frank Abela
AFAIK DisplayPort is dead in the water. It's a video-only standard and the world wants less wires...
Posted on: 29 May 2008 by Guido Fawkes
quote:
Originally posted by BigH47:
Oh goody another multi standard. They have been so successful in the past.


Yes it is vitally important to have standards. That is why we need so many of them.

As long as we keep current we're fine - now should I opt for Betamax or VHS?

And why does the local shop no longer stock Elcassets?

Confused Rotf
Posted on: 30 May 2008 by {OdS}
quote:
Originally posted by Frank Abela:
AFAIK DisplayPort is dead in the water. It's a video-only standard and the world wants less wires...


If only it was so simple Winker

quote:
Originally posted on Wikipedia:
Audio signal: Optional, maximum 8-channel uncompressed 192 kHz, 24-bit audio, 6.144 Mbit/s bit rate


With its overall 10.8 Gbit/s bandwidth and strong support from the industry, DisplayPort seems like a real HDMI challenger.
Posted on: 30 May 2008 by Frank Abela
The fact that audio is optional is the killer here. HDMI nearly shot itself in the foot because it didn't enforce standards. DisplayPort is doing the same.