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AV industry consultant Pete Putman talks about display interfaces, including HDMI 2.0's already-insufficient bandwidth, DisplayPort's greater bandwidth and packet-based transmission (as opposed to HDMI's continuous TMDS transmission), MHL and SuperMHL, HDBaseT, DisplayStream compression, wireless HDMI systems at 5 and 60 GHz, why Wi-Fi isn't ideal for transmitting audio/video data, why he thinks packet-based approaches are better, various types of connectors, answers to chat-room questions, and more.


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Good program Scott!

Got a lot of good information. I have one of the Lenova laptops with the Displayport and red mouse button.

First there was composite, then S-Video, then component video, then HDMI, then ....

Something better comes along!
 

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Great show, Scott! As you stated, Mr. Putman is certainly a font of knowledge on display connectors. I'm going to have to watch this podcast a second time to try and absorb more of it. I learned quite a lot, including how much I don't know! :eek:


- Joe
 

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Something in the arithmetic isn't making complete sense to me:


3840 x 2160 = 8,294,400 pixels per frame


8,294,400 x 60 fps = 497,664,000 pixels per second


497,664,000 x 3 (Red, Green, Blue) = 1,492,992,000 sub-pixels per second


1,492,992,000 x 10-bit = 14,929,920,000 bits per second.


Even if we assume that 1 Gbps = 1 billion bits exactly, that's still only 14.93 Gbps.


So how does that not fit in an 18 Gbps HDMI 2.0 connection?
 

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Great show Scott,

However, I can't agree with much Mr. Putman said. He talked at great length about the limits of HDMI, but did not justify the need for higher bit rates for TVs. Computer displays - sure. But TVs? :

All of our TV sources are compressed medium bandwidth signals. OTA TVs channels are 20 Mbps in which they typically put , 1 HD and 2-3 SD channels (and use inefficient Mpeg2). Blu-rays are ~20 Mbps. Netflix streams are 2-5 Mbps. Netflix 4k seems to be around 15Mbps. UHD Blu-ray may be 50 Mbps.

So why do we need 18 Gbps connections to the TV? Well because we have external devices like cable boxes, Blu-ray players, Audio pass-through receivers, and HTPCs that all want to connect to the TV, and in their infinite wisdom - they decided uncompressed signals would be used between these devices and the TV. So be it.

1) For smartphones and tablets - it makes little sense to have HDMI, or displayport. Why place the processing burden of converting the file/stream to HDMI - run down the battery - and have to connect wires.

The best interface is wi-fi with the player App either in the TV or a blu-ray player - and those interfaces already exist. The notion that wi-fi can't support reliable communication of 5-15 Mbps is just not right. I use 5 GHz wi-fi to simultaneously connect 5 security cameras each at 16 Mbps to my PC with no data loss.

When I streamed netflix - my problem was the network connection, not the local wi-fi.

And UHD for smartphones? This is just silly.

2) 18 Gbps HDMI has enough bps to support 4:2:2 12 bit color, 3840x2160/60p. Yea its not 4:4:4 but there are no 4:4:4 (non-computer application) sources, and likely never will be. You want computer games or workstations - use displayport, but don't burden TVs with it.

3) I hate HDMI (because it complicates audio/video.. Every update of HDMI requires a new display and AVR). But it is successful and it's not going to be replaced by displayport or supermdl just because they have a higher bitrate.
 
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