DVB-T HD cards? (2 Viewers)

[Roberdin]

Hey, I have a pretty bog standard Haupaugge WinTV 88x DVB-T tuner PCI card installed and I receive signals from the Crystal Palace transmitter in south London. I was updating my TV channels the other day when the BBC 1 HD trial channel added itself to my list of TV channels. Now, it is my understanding that this is being transmitted at very low power and is available to specific households only (I am some distance from the transmitter, near Cockfosters in north London); unsurprisingly I was unable to receive any audio/video when I tried to tune to the channel. But this raises my question - is the failure to tune to the channel simply because it is not being transmitted at high power yet? TV channels can be transmitted at different bitrates - is there anything intrinsically different about a HD channel that will mean that my card will not be able to ever tune in? If so, why has it suddenly appeared in my TV channel list? Therefore, will I one day need to purchase a card capable of receiving high-definition signals?

Thanks guys.

 

[Roberdin]

With some research and experimentation, I'm able to answer my own question. An entire mux is being devoted for BBC HD1's transmission, with about 18 MBit/s for video and around 6 for AC3 audio. The video is being transmitted in H.264 MPEG 4 format so my card is unable to use its on board hardware to decode, but with TSReader Lite and VLC I was able to watch about a minute of HD (TSReader Lite limits me to that much). Unfortunately the signal strength in this area is very low so there were a lot of quality problems; but I'll keep tinkering.

Is there anyway that support for this type of broadcast could make its way into MediaPortal in the near future? I don't think there are any free products around that can do this.

 

[Jake m]

this would be really cool, esp. if you only need readily available hardware.
just voicing my interest to get he ball rolling

 

[Roberdin]

The only thing is that it's not a major concern at the moment because only one transmitter (Crystal Palace, London) is transmitting HD Broadcasts. As I said before, it's on low power so you really need to be within a few miles of the Palace to pick it up. That said, it has allegedly been received as far away as Reading, but perhaps the lucky recipient was using a high-gain aerial and a series of amplifiers. I don't know about the rest of Europe but I've not heard about many foreign DVB-T HD broadcasts. So Crystal Palace and possibly, in the near future, a transmitter on the Scottish border are about the only transmitters in Europe trialling this. Not a massive audience.

Now, once analogue is switched off we may see some of the old bandwidth being devoted to new muxes. However, since each HD channel needs an entire mux, or perhaps half for comparatively low HD quality, it might difficult for broadcasters to persuade the relevant authorities that one HD channel is better than five SD, or wireless internet coverage, or whatever else they're planning to do with the freed-up frequencies. Of course, I'd rather have BBC HD1 than another dozen shopping channels any day. But that's me.

Anyway, back to the point... I'm no expert on this, but I'd have thought that providing the right codecs are installed (ffdshow now integrates a semi-stable H.264 codec), it shouldn't require too much for MediaPortal to receive, record, and show HD - it just needs to use the CPU rather than the card to encode it. Or something.

Whether that (little?) addition to the TV server is worth the demograph they'd be satisfying is not my choice to make, but it would certainly give MediaPortal a lead over a lot of other products - I don't know of any free, easy, integrated solution for watching HD on a PC.

 

[Spragleknas]

Well, when DVB-T is released in Norway (!!!) it will be in MPEG-4 and (most probably ) HD.

I belive it is calle DVB-T2 (not sure)... current "test" sendings are only in DVB-T(1)

 

[Roberdin]

That's because a DVB-T2 specification hasn't been written yet, or even agreed upon except in fundamental principle, to my knowledge. I suspect that DVB-T will last another ten years or so.

 

[tourettes]

All DVB-T cards should be able to receive HD channels as no video decoding are done on the hardware ever. DVB cards are pretty much like network cards, i.e. they just pass the data to the upper levels.

 

[Roberdin]

I was under the impression that they had the capability to transcode the video though. That was where the difference between 'hardware based' and 'software based' cards arose? Or am I completely mistaken?

 

[Jake m]

a harware based card referes to analogue tv, i.e. or the uk an analogue harwdare based card would convert the incoming PAL signal into mpeg2 via a chip on the card. a software based card is designed to be cheaper thus does not have the mpeg2 encoder

 

[Spragleknas]

So every DVB-T (MPEG-2) card is most likely to handle DVB-T2 (MPEG-4)? It is just SW/codec dependent?