AVS › AVS Forum › HDTV › HDTV Technical › Interest in ATSC 8VSB Modulator?
New Posts  All Forums:Forum Nav:

Interest in ATSC 8VSB Modulator?

post #1 of 48
4/17/10 at 11:07am
Thread Starter 
We (Nextcom, LLC) have a design for an ATSC Modulator (8VSB) that was developed into an actual working prototype a couple years ago but was pretty much shelved. I was wondering what kind of interest there is in such a device. Basically it works via a USB connection and modulates any standard MPEG transport stream (HD, SD, or multiplexed) onto a UHF carrier (ch 14/15). It does not do any encoding and thus does not accept component or HDMI input. The stream can be disk-based or captured live via any hardware/software combo that produces transport streams. The main limiting factor is that it is PC-based and not stand-alone.

This would be an inexpensive solution (a fraction of the $1500+ for current commercially available hardware) and could be used to distribute HD via long coaxial runs or part of a MATV system. Could also display media center or other applications on a HDTV without a dedicated HDMI or VGA hookup.

If brought to the market, the only change we anticipate is possibly making it frequency agile. Thoughts, comments?


-R

Anyone interested can register via our website for further information...
Reply
Reply

AVS Top Picks

post #2 of 48
4/17/10 at 1:04pm
bring it on !! I'd love to be able to do my own 8VSB for a/v sources alongside of the OTA channels, even if it is just SD.
Reply
Reply
post #3 of 48
4/17/10 at 1:13pm
I have a Dish Network system and they do not carry my locals so I keep cable for that. The Dish VIP722 receiver can pick up ATSC but not QAM so I can't record my cable channels on the Dish DVR. I keep thinking that it is so close - just convert QAM to ATSC some how. It looks as if your device will not do that however.

If you intend this device to be used to distribute HD video, how will that compete with the Sling devices. These reasonably priced boxes will allow you to distribute HD video over your home wireless network.
Reply
Reply
post #4 of 48
4/17/10 at 1:45pm
I could use it for the broadcast, 8VSB master antenna systems I maintain where the lobby camera signal is still analog. In my applications, I wouldn't require a SAW filtered output, because my channel lineups are light and I could often put it on the VHF lowband by itself.

Is ths device capable of taking a digital output from an affordable surveillance camera and converting it to a form such that a conventional TV tuner would recognize it as a channel, or would I still have to put an MPEG encoder between the camera output and your device's input?

If you do come up with an agile modulator, you would want it to be UHF channel-plan capable, since most digital TVs will not process an 8VSB signal if it is set to its "cable STD" channel plan, nor will they seek out and "capture" an 8VSB signal that is 2MHz off frequency when their tuner is set on "antenna", whereas the AFT circuitry will do that with analog signals.
Reply
Reply
post #5 of 48
4/17/10 at 2:39pm
Quote:
Originally Posted by R5000-HD View Post

Thoughts, comments?

-R

I would buy one or more. Make one that'll do multiple SD video sources and I'll buy multiple!

(I would love to feed some FTA satellite around my house via ATSC...)

- Trip
Reply
Reply
post #6 of 48
4/17/10 at 2:45pm
Quote:
Originally Posted by R5000-HD View Post

Basically it works via a USB connection and modulates any standard MPEG transport stream (HD, SD, or multiplexed) onto a UHF carrier (ch 14/15). It does not do any encoding and thus does not accept component or HDMI input. -R

I don't think that part was heard very well by most here. However what you describe would work very well with TSReader, (Rod would have to write the interface) and I would buy at least one.
It sounds very similiar to this unit:

http://www.dektec.com/Products/USB2/DTU-215/
Reply
Reply
post #7 of 48
4/17/10 at 3:09pm
Hm, I had missed that. Still, I have lots of spare computers. As long as I could figure out how to create a compatible transport stream out of SD video sources, I think I'd be in good shape! =)

- Trip
Reply
Reply
post #8 of 48
4/17/10 at 3:22pm
That's not too hard with a good pc, the right hardware and TSReader. I have
a box I will try that on..
Reply
Reply
post #9 of 48
4/17/10 at 3:53pm
How would one go about doing that? I can do the things I need to with TSReader, but I gather that it's much more powerful than what little parts I use.

- Trip
Reply
Reply
post #10 of 48
4/17/10 at 4:08pm
What most people would find most useful is a device that will let you take an NTSC audio/ video analog inputs , convert to MPEG2 and modulate that out as an UHF ATSC TV signal. THAT would be worth buying....
Reply
Reply
post #11 of 48
4/17/10 at 6:05pm
Certainly there are a few people who would like to have an 8VSB modulator, however, IMHO you dould never make a profit by with the product due to the launch, training and support requirements.
Reply
Reply
post #12 of 48
4/17/10 at 6:38pm
Sad to say Walford is correct, IMHO...even the ever-declining MATV market isn't enough to justify an ATSC modulator. Now QAM is another story..
Reply
Reply
post #13 of 48
4/17/10 at 6:55pm
I wish the CECBs would understand QAM...

- Trip
Reply
Reply
post #14 of 48
4/18/10 at 7:36am
We US Tax payers subsidized the purchase of CECBs in order to allow users watching analog only channels using an antenna to still be able to watch the same channels with a TV's analog tuner after the digital cutover and nothing more.
Reply
Reply
post #15 of 48
4/18/10 at 11:24am
As there exists no inexpensive ATSC modulator, but at least one QAM modulator, I am now unable to watch things I had modulated into my house's coax in analog.

And in the interest of accuracy, US taxpayers paid nothing for the coupon program. Auction revenue paid for that.

- Trip
Reply
Reply
post #16 of 48
4/18/10 at 12:23pm
Quote:
Originally Posted by Trip in VA View Post

...in the interest of accuracy, US taxpayers paid nothing for the coupon program. Auction revenue paid for that...

But we auctioned off the taxpayer's airwaves.
Reply
Reply
post #17 of 48
4/18/10 at 12:45pm
+1
Reply
Reply
post #18 of 48
4/18/10 at 12:50pm
I have connected an HD camcorder with firewire out to TSReader, such as the Sony HVR-Z1. Now if Rod would write an interface to forward a firewire stream to a USB modulator one could do what Mike needs. I have a Canon XL-1 SD camera I need to try that with.
Reply
Reply
post #19 of 48
4/18/10 at 1:35pm
Not that I even need high definition, but here is a camera available new in quantity on eBay for $299. I need the building blocks to get from that output or something like it to 8VSB modulated, channelized RF.

http://cgi.ebay.com/FULL-HD-1080p-12...item2a065bfd57
Reply
Reply
post #20 of 48
4/19/10 at 8:36am
Thread Starter 
The trend in camcorders is away from HDV which is an MPEG-2 format to using AVC/H.264. Firewire connectivity is part of the DV/HDV spec and it supports live streaming, for example using the MSDV driver. However, DV (which is SD) is not the same as MPEG-2. Technically, anything that can be encapsulated into a standard transport stream format can be modulated onto 8VSB. However, your digital receiver is probably not going to know how to handle anything except for MPEG-2 (even though theoretically it can as long as it has a suitable decoder).

The new AVC camcorders are designed to transfer live video via an HDMI or component connection and to offload the video via USB. You could capture the video using an HDMI or component capture board and then encode to MPEG-2 realtime (for HD this is going to take a computer with quite a bit of horsepower).

Our approach would most likely focus on using a standard API like DirectShow for receiving an MPEG transport stream input.

-R
Reply
Reply
post #21 of 48
4/19/10 at 9:12am
Quote:
Originally Posted by bdfox18doe View Post

However what you describe would work very well with TSReader, (Rod would have to write the interface) and I would buy at least one.

Bob,

I assume you mean streaming in realtime from TSReader to the Nextcom ATSC Modulator? If so, do you believe Rod would do an interface?

Files recorded (.TS or .TP) by TSReader should work fine with the Nextcom.

For R5000-HD: Would Nextcom offer a SDK with this device?
Reply
Reply
post #22 of 48
4/19/10 at 9:50am
Quote:
Originally Posted by Wendell R. Breland View Post

do you believe Rod would do an interface??

Only Rod can answer that question.
Reply
Reply
post #23 of 48
4/19/10 at 10:32am
All OTA digital broadcasts are broadcast using 8VSB modulation and the actual content of video is ATSC standard MPEG2. Also the content of almost all/if not all Digital QAM modulated digtial broadcasts is also encoded using ATSC standard MPEG2.
Some of the posters in this thread are confusing the delivery modulation method used with the internal video format of the the content being delivered. They need to realize that when you send a letter by air, ship, or train that does not also determine the lanquage that the letter inside is written in.
Reply
Reply
post #24 of 48
4/19/10 at 8:10pm
Thread Starter 
Quote:
Originally Posted by Wendell R. Breland View Post

Bob,

I assume you mean streaming in realtime from TSReader to the Nextcom ATSC Modulator? If so, do you believe Rod would do an interface?

Files recorded (.TS or .TP) by TSReader should work fine with the Nextcom.

For R5000-HD: Would Nextcom offer a SDK with this device?

Its pretty early to tell what/if anything will be delivered but I imagine if we go ahead with this that some sort of development info would be made available along with a demo app & its source code. The goal would be to make it easy for third-parties to develop applications around it and at this point we're thinking that packaging the functionality into a DS driver maybe the easiest way to accomplish that.
Reply
Reply
post #25 of 48
4/19/10 at 9:09pm
Quote:
Originally Posted by bdfox18doe View Post

Only Rod can answer that question.

Sent Rod an email inquiring about his interest in this project.
Reply
Reply
post #26 of 48
4/19/10 at 9:22pm
Quote:
Originally Posted by R5000-HD View Post

Its pretty early to tell what/if anything will be delivered but I imagine if we go ahead with this that some sort of development info would be made available along with a demo app & its source code. The goal would be to make it easy for third-parties to develop applications around it and at this point we're thinking that packaging the functionality into a DS driver maybe the easiest way to accomplish that.

Thanks for the info. IIRC, TSReader interfaces with devices using BDA drivers to obtain data. I know that he can stream data (.TS) from TSReader to VLC media player or Firewire devices. I have no idea what methods he (Rod Hewitt) uses.
Reply
Reply
post #27 of 48
4/20/10 at 8:00am
Quote:
Originally Posted by walford View Post

All OTA digital broadcasts are broadcast using 8VSB modulation and the actual content of video is ATSC standard MPEG2. Also the content of almost all/if not all Digital QAM modulated digital broadcasts is also encoded using ATSC standard MPEG2.

The standards body for cable (and QAM modulation) is not ATSC, it's SCTE (Society of Cable Telecommunications Engineers). MPEG-2 video constraints are defined in SCTE43.

http://www.scte.org/documents/pdf/st...SCTE432005.pdf

If you analyze actual cable MPEG-2 bitstreams, you'll find that not everyone follows SCTE43 to the letter. Many providers use a full size VBV buffer for HD (9781248 bits) instead of the SCTE43 constrained 7995392 bits. It's because that VBV size constraint goes way back to when 8 Megabits of memory was expensive. These days, where you can't even buy SDRAM smaller than 256Mb, the VBV size constraint is pretty silly.

Ron
Reply
Reply
post #28 of 48
4/20/10 at 9:32am
Has anyone talked with ZeeVee to see if the chipset used in their QAM modulator can support ATSC? Even if they don't offer that capability.
Reply
Reply
post #29 of 48
4/20/10 at 11:00am
All I know about ZeeVee is that they said they won't do it because QAM is open while ATSC transmission is apparently patented or something like this.

- Trip
Reply
Reply
post #30 of 48
4/20/10 at 11:15am
Yes, Zenith holds the patents.. or did..
Reply
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: HDTV Technical

AVS Top Picks

AVS › AVS Forum › HDTV › HDTV Technical › Interest in ATSC 8VSB Modulator?