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Search: Keyword(s): ; Posts Made By: dr1394
Forum: HDTV Technical   04-18-2017, 04:00 AM
Replies: 271
Views: 9,318
Posted By dr1394
ATSC 3.0 has a link layer protocol called ALP...

ATSC 3.0 has a link layer protocol called ALP (ATSC Link-Layer Protocol). It defines several packet types that can be sent.

1) IPv4 packet
2) Compressed IP packet
3) Link layer signaling packet...
Forum: HDTV Technical   04-17-2017, 02:37 PM
Replies: 271
Views: 9,318
Posted By dr1394
ATSC 3.0 will also be a "hardware-based...

ATSC 3.0 will also be a "hardware-based standard", at least at the demodulator level. The economics of using a hard-wired ASIC demodulator will overwhelm using some sort of software defined radio.
...
Forum: HDTV Technical   04-16-2017, 07:28 PM
Replies: 271
Views: 9,318
Posted By dr1394
I'd think a full blown MIMO system could provide...

I'd think a full blown MIMO system could provide 2X capacity (114 Mbps for 4096QAM). But that would require a cross polarized receive antenna with two feed lines to a MIMO capable receiver.

Ron
Forum: Local HDTV Info and Reception   04-06-2017, 03:51 AM
Replies: 15,017
Views: 1,117,532
Posted By dr1394
The timing of the packet loss is definitely a...

The timing of the packet loss is definitely a clue. I'll guess it's some buffer overflow/underflow condition. Most likely caused by the "two clock problem".

KGO has to send their Transport Stream...
Forum: HDTV Programming   03-27-2017, 02:06 PM
Replies: 24
Views: 575
Posted By dr1394
Do any of those chips have a real hardware...

Do any of those chips have a real hardware decoder (that is, dedicated silicon that only does HEVC decoding) in them?

There's probably a whole bunch of requirements for a 4K STB that significantly...
Forum: HDTV Programming   03-27-2017, 12:44 PM
Replies: 24
Views: 575
Posted By dr1394
The Amazon Fire TV only does 8-bit output and 30...

The Amazon Fire TV only does 8-bit output and 30 fps. High wattage Nvidia GPU's and Intel CPU's are a non-starter for STB's. Blue-ray decoder chips are often "captive". That is, they're made in-house...
Forum: HDTV Programming   03-26-2017, 02:26 PM
Replies: 24
Views: 575
Posted By dr1394
Are they? Can you provide a link or information...

Are they? Can you provide a link or information about a chip in volume production?

Ron
Forum: HDTV Technical   03-22-2017, 03:18 PM
Replies: 3,304
Views: 280,214
Posted By dr1394
Is there a way to do that cost effectively? I...

Is there a way to do that cost effectively? I have an LTE node right across the street from me and get 50 Mbps downlink from it when I tether my phone. But I can't live with just 5 GB a month. And...
Forum: HDTV Technical   03-20-2017, 03:44 AM
Replies: 271
Views: 9,318
Posted By dr1394
Looks like the AC-3 patents expire today. ...

Looks like the AC-3 patents expire today.

https://ac3freedomday.org/

Ron
Forum: Local HDTV Info and Reception   03-15-2017, 04:55 PM
Replies: 15,017
Views: 1,117,532
Posted By dr1394
There's a table in part 47, section 73.623...

There's a table in part 47, section 73.623 paragraph (e).

https://www.law.cornell.edu/cfr/text/47/73.623

and part 47, section 74.709

https://www.law.cornell.edu/cfr/text/47/74.709

Ron
Forum: Local HDTV Info and Reception   03-15-2017, 04:25 PM
Replies: 15,017
Views: 1,117,532
Posted By dr1394
Yes, but a single station (let's say KNTV) only...

Yes, but a single station (let's say KNTV) only gets one RF channel. They can transmit ATSC 1.0 or ATSC 3.0. Therefore, there will be no need for any additional RF channels. Are we on the same page...
Forum: Local HDTV Info and Reception   03-15-2017, 04:02 PM
Replies: 15,017
Views: 1,117,532
Posted By dr1394
I'm not sure if I'm reading your post correctly,...

I'm not sure if I'm reading your post correctly, but there will be no "dual transmission period" or "station pairs". A station will be either ATSC 1.0 or ATSC 3.0.

It's one of the impediments to...
Forum: HDTV Technical   03-07-2017, 03:10 PM
Replies: 271
Views: 9,318
Posted By dr1394
A good example of a proprietary codec is the...

A good example of a proprietary codec is the audio codec used for HD radio from iBiquity.

Ron
Forum: HDTV Technical   03-07-2017, 01:53 AM
Replies: 271
Views: 9,318
Posted By dr1394
Well, the whole IP and patent issue is a big bag...

Well, the whole IP and patent issue is a big bag of worms. Here's a few random anecdotes.

If you're an IP holder, it's a pretty sweet deal. I used to work with someone that holds an MPEG-2 patent...
Forum: HDTV Programming   03-02-2017, 03:42 PM
Replies: 330
Views: 10,945
Posted By dr1394
Here's a few frames from a Comcast 1080i H.264...

Here's a few frames from a Comcast 1080i H.264 bit-stream. There's no inverse telecine, so you can clearly see the 3:2 cadence.

http://www.w6rz.net/swavc4079.png
...
Forum: HDTV Programming   03-02-2017, 03:19 PM
Replies: 330
Views: 10,945
Posted By dr1394
H.264 supports 1080i no problemo. For a very...

H.264 supports 1080i no problemo. For a very short time, some of the Comcast H.264 channels were 1080i.

You're probably thinking about H.265, which doesn't have interlaced coding tools. However,...
Forum: HDTV Programming   03-01-2017, 09:32 PM
Replies: 330
Views: 10,945
Posted By dr1394
With inverse telecine, the extra fields...

With inverse telecine, the extra fields introduced by 3:2 pulldown are discarded by the encoder. Then the encoder just codes the progressive frames and signals the discarded repeated fields in the...
Forum: HDTV Programming   03-01-2017, 05:31 PM
Replies: 330
Views: 10,945
Posted By dr1394
Yes, both clips are from the same channel on...

Yes, both clips are from the same channel on Comcast (channel 783 here in Silicon Valley). The MPEG-2 clip was captured back in October of 2015 when the channel was called Palladia. The H.264 clip...
Forum: HDTV Technical   03-01-2017, 03:30 PM
Replies: 271
Views: 9,318
Posted By dr1394
Maybe it should be the other way around. ATSC 3.0...

Maybe it should be the other way around. ATSC 3.0 "lighthouses" instead of ATSC 1.0. The channel width of ATSC 3.0 isn't limited to 6 MHz. It can go up to 36 MHz (and you could transmit 180 Mbps or...
Forum: HDTV Technical   02-28-2017, 12:32 AM
Replies: 271
Views: 9,318
Posted By dr1394
Tone reservation PAPR reduction doesn't distort...

Tone reservation PAPR reduction doesn't distort the recovered data constellation at all. Here's some animations that show what's going on. The first animation is the 256QAM constellation with tone...
Forum: HDTV Technical   02-27-2017, 11:14 PM
Replies: 271
Views: 9,318
Posted By dr1394
The vertical scale for CCDF graphs is the...

The vertical scale for CCDF graphs is the percentage of time a waveform is above a certain PAPR level. So on the DVB-T2 graphs I posted, the PAPR is above 3.6 dB for 10 percent of the time, above 6.6...
Forum: HDTV Technical   02-26-2017, 02:05 PM
Replies: 271
Views: 9,318
Posted By dr1394
Do you have eyesight issues? Perhaps a zoom of...

Do you have eyesight issues? Perhaps a zoom of the area of interest will help.

http://www.w6rz.net/cumulative2z.png

http://www.w6rz.net/cumzoom.png

Ron
Forum: HDTV Technical   02-25-2017, 05:33 PM
Replies: 271
Views: 9,318
Posted By dr1394
I made them myself from actual transmitter...

I made them myself from actual transmitter measurements. I develop digital television DSP code for the open source GNU Radio project. You can see my original DVB-T2 transmitter code here.
...
Forum: HDTV Technical   02-24-2017, 03:36 PM
Replies: 271
Views: 9,318
Posted By dr1394
Unfortunately, PAPR reduction doesn't help very...

Unfortunately, PAPR reduction doesn't help very much. The BBC doesn't use it and I don't see it being used in the proposed German DVB-T2 profiles.
...
Forum: HDTV Technical   02-24-2017, 02:20 AM
Replies: 271
Views: 9,318
Posted By dr1394
36 Mbps is probably too optimistic. If stations...

36 Mbps is probably too optimistic. If stations use a profile that's similar to the BBC DVB-T2 32K profile, that's only 30.1 Mbps.

The required S/N for the BBC DVB-T2 profile is around 18.1 dB. If...
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