Any Plans for QAM256 Support?

[byopvr]

And if there's no official plan to support QAM 256, anyone up to the task of a work around

I would think, if the issue is limited QAM decoding in windows ( Dvico products/software ) that there'd be reason for hope for the linux version of SageTV 3.x as the DVB driver tools already have QAM 256 built in/working =)

rampy

[stanger89]

In response to your first question, I believe if you get an "official" answer, it will be either No, or No Comment.

Realistically, the issue with QAM reception is not hardware, and it's not software, it's drivers. Right now, there are no, non-proprietary QAM drivers available. QAM reception is definitely possible in Windows, the MyHD 130 and Fusion 5/3 can do it, the A180 actually can, but has no drivers for it.

Hopefully MCE's update will include (at least) in-the-clear QAM support, and with that Dvico and Aver will release QAM BDA drivers, and then I think we'd see QAM support in Sage rather quickly.

To a post from the other thread:

Originally Posted by byopvr

not to further the digression... but bear with me:

But using a QAM 256 tuner to view unencrypted digital cable (in this case generally this means OTA HD stations rebroadcast on digital cable) isn't illegal and isn't theft of service. They sell HDTV's with integrated ATSC/QAM tuners at Best Buy so it's not like you're in mail order hacker land here, it's common legitimate use.

FWIW (way OT I know ). I would say using a QAM tuner to receive in-the-clear digital stations, is akin to using an NSTC cable ready TV tuner (ie one that goes to 125) to view cable without a box. QAM is just the digital version of analog, cable-ready.

It's the same thing as using firewire to get cable HD but sans digital cable box.

Except you need a cable box with firewire to get HG cable via firewire

I'm under the impression that there's actually some FCC ruling or statute that implies/dictates that the cable companies HAVE to provide local OTA HDTV channels "in the clear". Of course, besides message forum posts indicating that this is "fact" I haven't found substantial proof of this (anyone bueller?) and reading FCC documents is a real snooze fest.

This seems to be a sticky topic, many around the net make the claim and I'm not sure of the details enough to say they're wrong, but I will give my interpretation of what the FCC says on the issue. From what I've read of the FCC docs, it seems as though cable companies must cary local broadcast stations. And they must cary them in their most basic tier such that they don't charge extra for them.

I found no reference to HD channels specifically, thus I think until the analog stations are shut off, there is nothing forcing cable companies to cary HD locals, nor to cary them in the clear. This would explain why a number of cariers are "getting away" without carying HD locals.

[DFA]

I have been giving thought to the QAM256 thing as well. Stanger's analysis I agree with but wonder if perhaps the Avermedia A180 driver might possibly already have the code written in for QAM support and is just not documented. The A180 is built for MCE and is therefore limited to the MCE-included PVR software functionality.

As far as the hardware goes, it seems that getting QAM reception is nothing more than a mode change command to the tuner (8VSB <--> 256QAM). The tuner module spits out an MPEG2-TS stream to the PCI bridge chip as usual for either mode.

I've been meaning to look up the BDA standard which provides for a standard way of controlling A/V devices like tuner capture cards and see if there was enough foresight to include this specific type of mode change. If so, it would seem that mode switching might be fairly easy get at if already written in the driver. Since Avermedia makes mention of 256QAM in their A180 list of capabilities, it makes me think that provisions have been made but not discussed beyond that.

If this type of mode switch is not included in the BDA standard, then something proprietary would need to be coded to the driver which, even if existing, would seem to be very difficult to uncover.

On the Sage side of things, mode switching of the tuner presents certain difficulties since the whole EPG would need to toggle with a mode switch. But even if for now if we could select one mode or the other as a permanent choice, that would be cool with me. In my small town, the available network OTA HD channels are picked up and carried by my CableCo and are free-and-clear anyway, so QAM256 would be the mode of choice for me as a permanent selection.

Any speculation from the code warriers on trying to make a mode change on any of these QAM-capable cards on our own?

DFA

[byopvr]

stanger laid it out pretty well, gj!

DFA, I also think you're on to something... or at least mirrors my experience to date with http://www.pchdtv.com and linux.

basically the difference there between tuning QAM and ATSC was a different frequency table, and a --qam 256 mode

I wouldn't think the hardware would get in the way of a "software" HDTV card, so I'm assuming if there was a way to change the mode from 8VSB somehow a card like the A180 would conceivably work. I know the ATI HDTV wonder "supports" QAM but ATI hasn't released a QAM driver/software to my knowledge so in effect it doesn't =P

I wonder if there's anything a modestly skilled coder could do with the BDA architecture, the open source QAM256 tools, to cobble somethign together for this application.

Also, does anyone know anything definitive about the so called "emereld" MCE 2005 rollup/update stanger was alluding to? There's a beta out supposedly, no idea if it has or will have QAM support.

I'd like to facilitate some sort of community developed approach to this (like the hard work that was done for the firewire/network encoder stuff) and continue the discussion.

rampy

[rotaryracer]

After getting my Fusion 5 Lite spitting out HD on in-the-clear (QAM256) cable channels, I would love nothing more than to see Sage (or some of it's more code-literate groupies) directly support QAM256.

I did try the OTA route with my F5 but my location isn't conducive to good reception, shy of mounting the mother of all antennas on the roof.

I currently run MCE2005 and only switched from Sage (v1.4.10!) for HD. When I learned I couldn't do OTA, I kept MCE but do miss some aspects of Sage - seems to have better intelligence around not recording shows I've already watched. If 'Emerald' (I hear release dates between 9/2 and 10/15) has QAM support, I'm going to be one happy guy. If not, I guess I'll do HD in DVICO's app and keep MCE chugging for SD....unless Sage directly or indirectly supports QAM!

Here's one more vote for QAM support!

Jason

[salsbst]

Originally Posted by DFA

I have been giving thought to the QAM256 thing as well. Stanger's analysis I agree with but wonder if perhaps the Avermedia A180 driver might possibly already have the code written in for QAM support and is just not documented. The A180 is bult for MCE and is therefore limited to the MCE-included PVR software functionality.

As far as the hardware goes, it seems that getting QAM reception is nothing more than a mode change command to the tuner (8VSB <--> 256QAM). The tuner module spits out an MPEG2-TS stream to the PCI bridge chip as usual for either mode.

I've been meaning to look up the BDA standard which provides for a standard way of controling A/V devices like tuner capture cards and see if there was enough foresight to include this specific type of mode change. If so, it would seem that this would be fairly easy to get to if already written in the driver. Since Avermedia makes mention of 256QAM in their A180 list of capabilities, it makes me think that provisions have been made but not discussed beyond that.

If this type of mode switch is not included in the BDA standard, then something proprietary would need to be coded to the driver which, even if existing, would seem to be very difficult to uncover.

On the Sage side of things, mode switching of the tuner presents certain difficulties since the whole EPG changes with mode switch. But even if for now we could select one mode or the other as a permanent choice, that would be cool with me. In my small town, the available network OTA HD channels are picked up and carried by my CableCo and are free-and-clear anyway, so QAM256 would be the mode of choice for me as a permanent selection.

Any speculation from the code warriers on trying to make a mode change on any of these QAM-capable cards on our own?

DFA

I think you're mostly on the right track here, DFA. Note that on this page, though Digital Cable is listed, it is listed as "Not Supported": http://msdn.microsoft.com/library/de...ningspaces.asp

It may be that the Aver driver would allow it by default if it were implemented by Microsoft. I'm sure that the driver could be tweaked to do it anyway even without support from Microsoft.

[rotaryracer]

Originally Posted by salsbst

It may be that the Aver driver would allow it by default if it were implemented by Microsoft. I'm sure that the driver could be tweaked to do it anyway even without support from Microsoft.

With Fusion supporting QAM in their drivers currently, would that be the best starting point? (Not that I'm biased or anything!)

I would hope Avermedia and ATI would rewrite their drivers to include clear QAM support, but at least there's one card that does as a starting point. Hell, if someone got a different card with QAM working in Sage, I'd dump my F5 like a hot potato!

Jason

[blade]

I to would love to see QAM, I cringe at the thought of having to use the cable company's STV and trying to rig up firewire.

I know only so much can be done right now, but I'd be a happy camper if someone could come up with something.

[DFA]

salsbst:

Thanks for the reference. What I meant to eventually search out myself.

I think it just a matter of time before "switching" applet(s) for various cards appear that we can use for our purposes in the interim.

EDIT: The Fusion 5 series most definitely has the code in driver and might indeed be a good test card for developing a mode switching applet.

DFA

[salsbst]

Originally Posted by rotaryracer

With Fusion supporting QAM in their drivers currently, would that be the best starting point? (Not that I'm biased or anything!)

Their driver doesn't expose any QAM features, at least not in a documented fashion. Not sure how their application causes the card to do QAM, but it may talk to the hardware directly.

[DFA]

I think Stanger once mentioned that he thought the Fusion may do mode switching in a proprietary fashion requiring exclusive use of Fusion software and would also keep things hidden.

Is there any way to use the Fusion software to put the card in QAM mode and have it "stick" so that the card is defaulted that way?

DFA

[rotaryracer]

I believe so - there is an icon in their app interface that lets me select analog, digital, ATSC, or S-Video (last doesn't apply since my Lite doesn't have the input). I selected Cable (vs Antenna) on a radio button under channel and then 'Digital' under another pulldown. It defaults to Digital QAM whenever I open the app, typically tuning to the last station I was on.

I'm not sure if that "locks" the card into QAM only or just keeps the app in QAM.

Jason

[salsbst]

The drivers we have access to for the Fusion are BDA drivers. In order to make the card "go", you need to create a tuning request. Since there is no way (that we know of given the current DirectX implementation) to create a QAM tuning request from a client app, we would be forced to create an 8VSB tuning request. So, even if the card had remembered the QAM mode, it would be overwritten by the tuning request from the client.... unless the driver were somehow hard-coded to tune QAM even if the tuning request specifies otherwise.

[byopvr]

Is DVB-C == QAM ?

I've got to think the digital demodulation is done in software.

It's confusing that the DVB driver API in linux supports ATSC (as DVB-T/DVB-S is what I associate with other countries DTV standards)... but i'm finding some interesting info poking around

http://www.linuxtv.org/

http://www.linuxtv.org/wiki/index.ph..._API_Version_4

http://www.linuxtv.org/cgi-bin/viewc....h?view=markup

Yes I realize we're talking about windows, but why reinvent the wheel...

I mean, I look at what comes in on these cards as digital streams that need to be decoded, then demux'd and saved to disk... *shrug* I don't totally understand everything that's involved (obviously) so take this all with a grain of salt...


EDIT-->

on the microsoft side of things

old directX modulation type doc

[stanger89]

Originally Posted by byopvr

Is DVB-C == QAM ?

QAM is just a form of modulation (which uses both amplitude and phase to cary data). DVB-C uses QAM, but it is not necessarily "compatible" with US cable QAM.