Wednesday, May 24, 2006

Getting hung up on HDMI and eschewing DVI?

Many people have responded and criticized my selection of DVI over HDMI in my previous blogpost here. Many have also questioned the need to connect a PC to the LCD TV in the living room. I was looking for an opportunity to spend a bit of time to post my counter arguments on this.

Thankfully, a certain gentleman Samsas at the MDA HDTV trial forum posted the gist of most of these objections, so I took the effort to write my comments on his reasons for HDMI and against DVI. Here's the post and my reasons:

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samsas wrote:
That's an interesting article. But I don't agree that DVI is the way to go over HDMI. The reasons for this.

1. DVI does not support audio. Period. We're talking TV here, and the HDTV signal will have multi channel sound whenever available in a program. Now if you are going to use a fibre connection to a reciever for audio and DVI for video its highly probable that there will be a sync problem. The sound and video signals won't be simultaneous for the most part, so you will need a reciever that can adjust for this and believe me it's not a simple task.

MT: All receivers will have AC3/Optical out. If you connect via DVI, which does not multiplex digital audio inside itself, you can use the AC3/Optical out to connect to external AC3 receiver or the TV itself since all TVs which support digital audio will have AC3/optical. It is assured that there will not be a sync issue, since this technology has been used ever since DVD was born. We are now using AC3 with DVI for most DVD output even, in computers, and in some China players. NO sync issues as long as encoded stream do not have sync issues.

2. Wer'e talking TV again here. How many of us are going to hook up desk top computers to the living room TV? It's a logistic problem. Even if we did we'd need a tuner for the TV signal going into the PC. It's a bit easier with portable lap tops, but you still need a laptop with a tuner built in. And even if you get one not many laptops give you 5 channel sound output, so you need a card from Creative or whatever.

MT: This is 2006. Intel has released the ViiV, Apple release Mac Mini with frontrow. Many people have content based non-standard codec, and require the flexibility of a CPU to decode. Singapore IPTV service by Mediacorp mobtv.sg is right now PC-only. Many people view football with Asiabookie web page on the same screen, half half. See Donald Trump Apprentice #1? It's an LCD TV connected to the computer leh. Surfing has become a lifestyle, to be performed in the living room, not only the study, bedroom and computer room.

Just surf forums.hardwarezone.com and you see tons of people trying to connect their computer to the living room. The era of a living room PC is here already. LCD TV last you for 10 years. Within this 10 years, you're willing to bet you not gonna connect your PC to the TV?

3. Every upscaling DVD player I've seen in the shops now outputs the upscaled DVD signal via HDMI not DVI.

MT: Upscaled DVD content can traverse whether over HDMI or DVI. There is no issue. HDMI can easily be converted to DVI and vice versa, and yet DVI has the advantage of computer compatibility. This is not a point to get hung up on.

4. Correct me if I'm wrong but the new HD DVD player on the market in US (Toshiba) has only HDMI out.

MT: Toshiba is one of the smallest major brands in the market for DVD, and I don't usually follow them. In any case, HDMI is equal to DVI when it comes to the video protocol profile, therefore, HDMI can easily be converted to DVI using a direct mapping cable. This is also not a point to get hung up on.

5. I don't think HDTV will go beyond 1080i for some years to come, so if you want resolutions beyond 1080i you're back to scalers again. So your PC internal DVD or HD DV player must be able to upscale to the higher PC resolutions above 1080i and 1080p (HDMI ver 1.3). You're going to need a top range desktop to go anywhere near the processing power you need.

MT: My point on preferring DVI to HDMI is not because I want higher resolutions. It's because of PC resolution compatibility, since DVI supports ALL and HDMI by definition only supports 480p, 720p, 1080i and 1080p, pending further developments. Today, a S$1K PC with a nVidia 7600GS card can already drive a WQXGA display very satisfactorily, and that's 2560 x 1600, in 3D even.

So unless the TV came with both DVI and HDMI in, I'd go with the HDMI option. Its the most practical.

MT: As stated in my blogpost at http://miketan.blogspot.com/2006/05/less-discussed-complications-of-hdmi.html most of the dual HDMI+DVI options you can find, only have HDCP on the HDMI port and not the DVI port. The trick is to look for a LCD TV with only DVI and the HDCP will be implemented on the DVI port. if you see Vincent's post here at http://www.mycarforum.com/forum/Help_on_LCD_tvs_P1356966/gforum.cgi?do=post_view_flat;post=1346681;page=1;sb=post_latest_reply;so=ASC;mh=-1;guest=2398 he found a LG 32" which did exactly that.

ALWAYS REMEMBER, the TV and DVD and set top box manufacturers will manufacture an entire range of products with every Input output available, since it's almost free for them. They're not gonna limit the number of outputs and inputs, because more outputs and inputs will make their player more flexible and for reverse compatibility. Don't get hung up on HDMI because it's `newer', because it's not. It's same as DVI for video, and multiplex normal AC3 into is own transmission envelope, nothing we can't do normally even now with AC3 out and DVI combined.

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ALL THIS MAY BE MOOT! I have just been informed by VincentV that HDCP may not be necessary until after 2010 ... I'll read it up and repost.

2 comments:

Anonymous said...

Hi MikeTan,

Your arguments and reasoning are top-notch. If you are referring to my post at mycarforum.com, I would like to add that, the LG LCD tv I found (and bought) is 42" and not 32".

Vincent

Unknown said...

Excellent. Don't just take my word for it. Verify my statements, man! I'm finding my way in this morass of crappy interfaces too!