How much processing power required for watching BBCHD

[sub]

Why whould there be so much variance in the HD streams between countries? Is there an advantage with BBCHD's MPEG4/AVC video over ATSC HD? An why would it need so much more processing power to decode/display it?

A physical channel frequency on DVB-T and ATSC can carry about the same number of bits per second (DVB-T actually carries a bit more). You can fit a hell of a lot more MPEG4 video in that same number of bits, than what you'd get with the ATSC's MPEG2 video. In theory they can use this to either provide higher quality video than you'd typically get in the US (higher bitrate, or 1080p), or to more provide multi HD channels in the space that the US could only have one.

The early HD adopter countries used MPEG2, including US, Australia, Japan and South Korea. The rest of the world looks like its going with MPEG4/AVC (h.264) for its HD tv services.

I've seen several other countries also mentioned, but the ones that spring to mind include UK, Sweden, Finland, Norway, New Zealand, France, Estonia(?)... and probably all of europe eventually.

An why would it need so much more processing power to decode/display it?

Video cards and decoders are quite well suited to MPEG2, with hardware having evolved to cope with it since the introduction of DVD. Existing hardware acceleration on video cards is really well suited to MPEG2. Very recent videocards are starting to come with MPEG4 acceleration, but these are not mainstream yet, and most decoders cant really take advantage of these features yet. Also decoding an MPEG4 stream in software is much more CPU intensive than decoding an MPEG2 stream.

This same video standard is now used on BluRay and HD-DVD, so luckily hardware acceleration is likely to be improving to cope with this type of video.

[nitrogen_widget]

I have read that the latest intel CPU's will come with some type of special video decoder / encoder instructions to speed up video processing.

[flyswatta]

Thanks Sub. Now that you mention it, I read over at satelliteguys.us that DishNetwork was experimenting with broadcasting HD as MPEG4 to save bandwidth. The main problem was that you need an MPEG4 HD decoder box in order to use it.

[bommaren]

I have read that the latest intel CPU's will come with some type of special video decoder / encoder instructions to speed up video processing.

A little update.
If you want to decode H264/AVC without a really powerfull CPU use
Nvidia 6500 or 6600 GPU based cards if you have a PCIexpress interface for
your graphics card.
ATI 2400 or 2500 are available with AGP also.
These GPU's are the only currently available that do a really good job of
decoding H264/AVC.

When I run the the Nvidia 6500 (make shure you buy a HDCP enabled card)
on my C2D 4300 cpu it indicates 10 to 20 % CPU usage for a 720P50Hz signal from the DVB-T free to air signal in sweden.

Using the Codec from the latest PowerDVD.

- B

[frankmcg]

Picked up an 8500GT (I assume that's what you meant!) myself a couple of weeks back. It does indeed have h264 decoding onboard but I've been struggling to actually use it successfully. My reading is that you need the latest powerdvd ultra to get their h264 codec, as that's the only one with supports purevideo2 acceleration. However I've found I actually get better performance running in software mode!

[Rickos]

Picked up an 8500GT (I assume that's what you meant!) myself a couple of weeks back. It does indeed have h264 decoding onboard but I've been struggling to actually use it successfully. My reading is that you need the latest powerdvd ultra to get their h264 codec, as that's the only one with supports purevideo2 acceleration. However I've found I actually get better performance running in software mode!

Yup that's correct, when you get the right powerdvd version installed and the right nvidia drivers it works very well and you get accellerated HD playback in GBPVR, or any other apps that use directshow (I believe).
Certainly works well for me.