Since there seems to be a huge amount of confusion on the subject I thought I'd start a thread dealing with system requirements for HDTV with MediaPortal. I'm looking for input from people with working HDTV systems.
If you have a working HDTV setup please list your system specs including CPU, RAM, graphics card (include make, model, memory, interface type, etc), country and HDTV source.
Remember, this is a work in progress that will hopefully evolve into a sticky or Wiki on the subject.
Since requests have been made to make this a part of the MediaPortal Wiki, this post will be freqently edited until it looks ready for the move to the Wiki.
To get things started...
last edit: Jan 24, 2007
-----------------------------------------------------------------------------------
MediaPortal and HDTV, an introduction
This page is intended to provide guidlines for using MediaPortal with HD video sources. It offers some suggestions as to what hardware you should use but since there are a limited number of people using HD at the moment you should remember that we make no promise as to the accuracy of the information and it is subject to change.
Failure to meet the minimum system recommendations and the use of the wrong hardware or software may result in bad recordings, video playback that skips or any number of problems.
This information should give you a good idea of where to start in building or upgrading a system for HD but for the most current information please search the MediaPortal forums.
System Requirements
1. Graphics hardware
A lot of people are trying to use a low end graphics card for HDTV and they just don't seem to work with MediaPortal even though they may work with other software. The question is why?
MediaPortal uses Microsofts API for buffering and recording video where many of these other programs use custom software to do the same thing or use other video modes that are less taxing on the system.
I'm not going to get into why MediaPortal can't do the same thing as other software other than to say that it takes time to build an alternative and other video modes don't work as well. VMR9 is what MediaPortal uses and that's what you have to plan for when you build a MediaPortal system.
What's required? The only sure requirement I've seen listed is Microsoft's 10GB/sec memory bandwidth requirement for the video card.
Why 10GB/sec? To be honest I think there is more to it than that but it's what Microsoft published. The 10GB/sec only refers to memory bandwidth on the card itself. A minimum buss bandwidth and hardware support for de-interlacing and scaling video are also important but that is usually included with a card that supports 10GB/sec... hence their choice of that spec.
Why so much? If you compare 1080p to DVD video you'll see that the HDTV mode requires AT LEAST 4 times the data for each frame of video. That's a lot! If you look at the first generation HD-DVD or Blue Ray DVD players you'll find they are a pretty high spec PC without the overhead of windows and some DSPs added on. The amount of data, form of data compression, broadcasting format... it all takes a lot of CPU and memory bandwidth to deal with.
What exactly is required for 10GB/sec?
For the latest generation of cards that could even be a pretty low end model. For older generations of graphics cards, some of the high end models don't even supply that much bandwidth.
The easiest guidline is this:
The card must have a 128 bit or greater memory interface and over a 313MHz memory clock speed (times 2 for DDR = 626MHz data rate) for the DDR memory. If a card supports overclocking you may be able to get away with using a slower card but there are no guaruntees it will work. Some cards list the clock speed and others list the data rate so be carefull when you compare them.
The formula to calculate the memory bandwidth of a graphics card is this:
Multiply the memory clock rate times 2 for DDR memory since 2 memory transfers take place for each clock cycle. This is the data rate.
Multiply the data rate times the memory buss width... probably 128bits or 256. Now divide this by 8000 to convert to GB/sec. If the resulting number is over 10GB/sec you *should* be ok. There may be some cards that have enough memory bandwidth but the GPU is too slow for deinterlacing so search the forums for the best info.
On board video or a graphics card?
Take your pick just make sure your system will meet the demands of running MediaPortal with HDTV. Stick to the latest chipsets of either, a fast enough cpu, enough RAM and you should be ok.
The current onboard video doesn't have all the video playback features of the latest graphics cards and have a limited number of pipelines. This means the CPU will probably have a higher usage than with a recent graphics card. Most importantly... how many boards with integrated graphics actually support a form of HDTV output? On the other hand, onboard video usually has a higher memory bandwidth at a lower price.
The current integrated DirectX 9 solutions from ATi and NVidia work well with DVD resolutions and we have had reports of success with HDTV with both. The newest ATi chipsets even promise flawless HDTV playback as do the latest S3 chipsets. However, even if a chipset does work on one motherboard that doesn't mean it will in another motherboard do to implementation/driver/bios differences and this may also depend on the CPU you use. I'm still waiting for feedback on the intel integrated video chipsets. More info will be posted as it becomes available.
Since onboard video depends on shared memory with the system you will probably want at least 1GB of RAM and it wouldn't hurt to have left over RAM sockets just in case you need to add more. For the best chance of success a socket 939 (old or new) processors would be the better choice since they have a higher memory bandwidth than a socket 754. As for intel... that's still unknown but plan on at least 3GHz or 3000+ speeds for either brand until we know more. Since the onboard graphics have fewer integrated features than their graphics card counterparts (such as some forms of deinterlacing used for HD playback or ATi's Avivo technology) you can expect higher CPU usage so don't skimp on the processor... at least for the current generation chipsets anyway. The latest chipsets from ATi are just hitting the market and I'm sure NVidia isn't far behind. These chipsets may be more capable than the RS480/482 and 6100/6150.
PCI, AGP or PCIe?
Don't even think about standard PCI, it's too slow to support a HD graphics. AGP 8x has a maximum bandwidth of around 2GB/sec. PCI express maxes out around 4GB/sec in the first generation. Even if AGP will work, if there is any delay in the delivery of data to the graphics card you are more likely to see it because you have a lower margin for error because it takes twice as long to catch up. That will make it more prone to skipping than PCIe
NVidia or ATi?
If you use one of the latest generation of these cards or chipsets with a memory bandwidth of 10GB/sec or greater you should be ok. Saying one or the other is better is pointless since one may be more efficient in the current generation and the other may be in the next. Whichever you choose, always use a newer driver than is shipped with the card as they often ship with very early versions of the drivers. Also take into account the requirement for H.264 if you plan to use it. Entry level cards WILL NOT WORK for HD and older cards do not have H.264 support! I'm not saying older cards won't work but it's more likely to require a top end card which will probably be just as expensive as the latest generation cards and may lack some features. If you want to use an older card, search the forums to see if it has been tested. The last reviews I've seen seem to give a slight edge to NVidia for lower CPU use but YMMV.
2. CPU
Faster is better. You will probably need a CPU of 3GHz/3000+ or better if the first generation HD-DVD or Blue Ray cpu choice is any indicator. Microsoft actually recommends a P4 at 3.2GHz but I have heard claims of HD video working on as low as a Sempron 64 2500+ CPU. However, after reading followup posts I have my doubts it works with all HD video formats.
I think it's safe to say that the required speed is just a guess at this point and is going to vary with what graphics card, tuner card(s) and drivers/codecs you use. As the add-on hardware improves CPU requirements may drop a little. Actually, I thought 3GHz was a high guess just to be safe but since an AMD Sempron 64 2500+ can be overclocked to that level why suggest less? I'm sure we'll eventually have people saying they have it running everything on a lower GHz CPU but attempting it is a risk. The other factor that is a huge unknown (with MediaPortal anyway) is the H.264 compression which depends heavily on you're CPU, graphics card or tuner cards. Early reviews related to H.264 indicate a multi-core CPU AND high speed GPU both may be required.
3. RAM
MediaPortal currently runs fine in 512MB of RAM for standard video but with HDTV needing around 4 times the data per frame of video it may need more RAM for buffering to play and record video smoothly. Multiple recordings at one time may also eat a lot of RAM but 1GB of RAM *should* be enough for a dual tuner system with the current version of WindowsXP. If you are planning on more than 2 HDTV tuners you can let us know how it turns out.
It wouldn't hurt to have some open RAM slots just in case your system needs more.
4. Hard drives
The increased bandwidth and file sizes need large, fast hard drives with a fast interface. Sorry, a cheap 80GB drive won't do. A recording of the the last Superbowl in 1080i off air ATSC took over 30GB and stopped before the end of the game. I'd suggest SATA 150 or 300 and if you plan on recording multiple HD channels at a time you may need multiple drives to handle multiple programs at once. The bandwidth required will depend on the source format, compression and your system configuration anyway. I'm not suggesting you can't use a single PATA drive for multiple programs but it is much more likely to cause skipping. Luckily you can always start with one and add another drive later.
5. H.264 compression
H.264 is the latest MPEG4 compression used by HD-DVD and Blue Ray DVD. It's also becoming common for distributing files over file sharing networks. For example, Anandtech's sample video files are even compressed with it now so you can view videos from their reviews.
Why H.264? H.264 can cut file sizes by over 40% from DivX while maintaining the same or better quality. The compression is very hardware intensive and much more complex to compress or decompress than MPEG2 or DivX. That means what can be compressed as MPEG2 or even DivX by a CPU in real time could take 12 hours or even days with a CPU. It can eat every clock cycle of a multi-core 4+GHz CPU and it may still not compress in real time. However, the results are smaller files and video with fewer compression or motion artifacts. Playback of H.264 video requires a much faster CPU than MPEG2. Don't be surprised if it requires 3.5 to 4GHz for reliable playback of HD video.
MediaPortal currently doesn't directly support H.264 compression but it may be possible to convert recordings to H.264 in a post process. Since it just requires a codec for playback the resulting files should work. Don't expect to do anything with H.264 on a low end machine (yet). H.264 even requires a fairly decent CPU just to play it back. Some graphics cards use the GPU to compress or decompress H.264 at much higher speeds than can be achieved with a CPU. However, the resolution and speed varies with which GPU so you should check the guidlines from the GPU manufacturer. HD playback will probably require the highest end series of card. TV tuner cards are just being introduced with built in support for H.264 so support for the format should be available on lower end PCs fairly soon. Still, expect "lower end" to be pretty fast just to handle the bandwidth and processing HDTV requires.
As I stated before, you may need a multi-core CPU and fast GPU to support H.264 and you will need an appropriate codec to play back H.264 content. Currently, CoreAVC seems to be the fastest software codec and I wouldn't attempt H.264 with anything less at this time.
6. Tuner cards
Whether ATSC or other off air, digital cable (cable card), DVB-T or DVB-S you should search the threads in the hardware support forum and read the related faq of supported TV cards. That appears to have the most info on the subject.
Off air HDTV cards are still in the early chipset generations and there are few chipsets to choose from. Some early or cheaper tuners do not handle weak or multipath signals well so ask before you buy. The current ATi HDTV Wonder seemed to work well for HDTV with the latest drivers but the analog tuner didn't have close to the quality of the ATi 550 tuners I've seen... not to mention MediaPortal setup issues. Ask before you buy. This is currently the only way to receive HD via cable that I'm aware of and only content that doesn't require a special receiver for.
With new chipsets like the ATi 650 we should start to see better 'One Card Tunes All' solutions with the same or better quality than the ATi 550 had for analog. Maybe we'll finally see all in one HDTV/TV/FM tuner cards. BTW, ATi's press release did mention tuning DVB-T as well so that's good news. Sorry, DVB-S is not listed. The chipset is supposed to support H.264 but we'll know more about it's performance in July '06 when the cards are released.
DVB-S (satellite) probably has the greatest number of HD channels but availability depends on what country you are in. For example, in the USA I know of no FTA HD DVB-S signals and pay providers currently don't support computer based tuners. Therefore there is no legal way I'm aware of to receive HD via satellite there. For more information on DVB-S availability and providers in your country you should consult the MediaPortal forums or one of the many satellite forums on the internet.
DVB-T (terrestrial) providers provide similar service as satellite but from a ground based transmitter and is more localized. Once again, consult the forums to see if there is a DVB-T provider in your area.
ATi has shown a prototype Cablecard tuner but I am not aware of any that are currently available from a major player like ATi (feel free to tell me I'm wrong). Cablecard 1 also only offers a 1 way connetion so you won't be able to take advantage of interactive features that your cable company provides such as pay-per-view or video on demand. When and if Cablecard 2 becomes available you may be able to use these features.
As of this year's CES, ATi has shown an updated version of their Cablecard tuner. It runs through your USB2.0 connection whether you have an internal or external unit. I believe this was to prevent hackers from trying to steal service. Anyway, there is no advantage to buying an internal unit over external as far as performance goes and certainly no advantage to buying anything but a PCI version since it just uses the slot for power.
NVidia has recently jumped into the TV tuner market so expect an HDTV tuner from them in the future but they appear to be a step behind ATi for the moment. I wouldn't expect an NVidia HDTV tuner until late this year at the soonest.
7. HD-DVD and Blue Ray
At this time I am unaware of any MediaPortal systems with either format currently in operation. However, MediaPortal will probably be able to play either format through an external player if the system has the proper hareware/software.
Given the HDCP digital rights/copyright protection integrated into the technology, special drivers plus a graphics card with HDCP support including onboard ROM and encryption keys appears to be a manditory requirement.
It will also require NVidia's PureVideo HD or ATI's AVIVO so a GForce 7 or X1000 series card with HDCP support is a must. There are no integrated graphics chipsets that list HDCP support at this time.
Plan on it requiring a fast enough CPU/GPU to handle H.264 playback in all HD formats.
8. Audio
HDTV comes complete with digital audio and you have quite a few options when it comes to decoding and playing it. However, it can be broken down into two main categories. Sound cards and onboard audio.
Good sound cards require less CPU use and usually provide better quality than onboard audio. Onboard HD audio takes less CPU and offers better quality than older onboard audio codecs. Take your pick but with onboard HD audio now as cheap as the older codecs why not get the better sound and lower CPU use? Go for the sound card if you wish but as the amount you spend goes up the gain in quality per dollar starts to level off. Only cards that have special software to improve MP3 sound will offer a noticable improvement in sound at some point. However, that is less and less noticable as the bit rate of the MP3 goes up and may introduce other distortions to the audio.
A sound card that can decode AC3, dts or other sound standards will offer a noticable drop in CPU usage which may be important and let you use a slower CPU. But it's a trade off. Buy a $100 or more sound card or spend the money on a faster cpu.
An optical or coaxial output for the digital audio will offer the best quality transmission of the audio to a receiver or TV. Even if your sound system doesn't support it yet it doesn't hurt to get a motherboard or sound card that has the connection just in case you want it in the future.
Summary
With HDTV more and faster is better. Playback may be possible on a low end system but just about everything needs a lot of CPU, RAM, hard drive space or additional hardware support at the moment.
If you are building a compact system your best bet may be integrated video and audio do to heat and space concerns. Just remeber it will require a faster CPU than when a fast graphics card is used.
My initial HDTV attempt was with a 2500+ socket 754 CPU overclocked to 3000+ levels, 1 GB RAM, a passively cooled Sapphire ATi x1300 and HDTV Wonder. MediaPortal didn't work properly for HDTV recording or viewing and I couldn't get the analog portion of the HDTV Wonder to work.
I discovered my CPU overclocking had been disabled, my video card was clocked so low it didn't meet the 10GB/sec requirement and software tuner support had just been dropped from MediaPortal.
Since then I have overclocked my video card to handle 10GB/sec, fixed my CPU overclocking and I am waiting for a new generation of TV cards with a hardware tuner for the analog TV.
The important thing here is that I picked low end components and it gave me problems. I'll get it to work after some tweaking but it has cost me time. A few dollars more and it may have worked on the first try.
Several people on the MediaPortal forums have tried as many as 5 different video cards and various motherboards/cpu combinations before they got HDTV to work properly and some only after reinstalling WindowsXP. What's that carpenters say? Measure twice, cut once. Plan your entire system and ask questions before you buy so you won't have to buy again. A little planning and a few questions will save you time, money and possibly your sanity. It certainly won't hurt when it comes to the WAF.
If you have a working HDTV setup please list your system specs including CPU, RAM, graphics card (include make, model, memory, interface type, etc), country and HDTV source.
Remember, this is a work in progress that will hopefully evolve into a sticky or Wiki on the subject.
Since requests have been made to make this a part of the MediaPortal Wiki, this post will be freqently edited until it looks ready for the move to the Wiki.
To get things started...
last edit: Jan 24, 2007
-----------------------------------------------------------------------------------
MediaPortal and HDTV, an introduction
This page is intended to provide guidlines for using MediaPortal with HD video sources. It offers some suggestions as to what hardware you should use but since there are a limited number of people using HD at the moment you should remember that we make no promise as to the accuracy of the information and it is subject to change.
Failure to meet the minimum system recommendations and the use of the wrong hardware or software may result in bad recordings, video playback that skips or any number of problems.
This information should give you a good idea of where to start in building or upgrading a system for HD but for the most current information please search the MediaPortal forums.
System Requirements
1. Graphics hardware
A lot of people are trying to use a low end graphics card for HDTV and they just don't seem to work with MediaPortal even though they may work with other software. The question is why?
MediaPortal uses Microsofts API for buffering and recording video where many of these other programs use custom software to do the same thing or use other video modes that are less taxing on the system.
I'm not going to get into why MediaPortal can't do the same thing as other software other than to say that it takes time to build an alternative and other video modes don't work as well. VMR9 is what MediaPortal uses and that's what you have to plan for when you build a MediaPortal system.
What's required? The only sure requirement I've seen listed is Microsoft's 10GB/sec memory bandwidth requirement for the video card.
Why 10GB/sec? To be honest I think there is more to it than that but it's what Microsoft published. The 10GB/sec only refers to memory bandwidth on the card itself. A minimum buss bandwidth and hardware support for de-interlacing and scaling video are also important but that is usually included with a card that supports 10GB/sec... hence their choice of that spec.
Why so much? If you compare 1080p to DVD video you'll see that the HDTV mode requires AT LEAST 4 times the data for each frame of video. That's a lot! If you look at the first generation HD-DVD or Blue Ray DVD players you'll find they are a pretty high spec PC without the overhead of windows and some DSPs added on. The amount of data, form of data compression, broadcasting format... it all takes a lot of CPU and memory bandwidth to deal with.
What exactly is required for 10GB/sec?
For the latest generation of cards that could even be a pretty low end model. For older generations of graphics cards, some of the high end models don't even supply that much bandwidth.
The easiest guidline is this:
The card must have a 128 bit or greater memory interface and over a 313MHz memory clock speed (times 2 for DDR = 626MHz data rate) for the DDR memory. If a card supports overclocking you may be able to get away with using a slower card but there are no guaruntees it will work. Some cards list the clock speed and others list the data rate so be carefull when you compare them.
The formula to calculate the memory bandwidth of a graphics card is this:
Multiply the memory clock rate times 2 for DDR memory since 2 memory transfers take place for each clock cycle. This is the data rate.
Multiply the data rate times the memory buss width... probably 128bits or 256. Now divide this by 8000 to convert to GB/sec. If the resulting number is over 10GB/sec you *should* be ok. There may be some cards that have enough memory bandwidth but the GPU is too slow for deinterlacing so search the forums for the best info.
On board video or a graphics card?
Take your pick just make sure your system will meet the demands of running MediaPortal with HDTV. Stick to the latest chipsets of either, a fast enough cpu, enough RAM and you should be ok.
The current onboard video doesn't have all the video playback features of the latest graphics cards and have a limited number of pipelines. This means the CPU will probably have a higher usage than with a recent graphics card. Most importantly... how many boards with integrated graphics actually support a form of HDTV output? On the other hand, onboard video usually has a higher memory bandwidth at a lower price.
The current integrated DirectX 9 solutions from ATi and NVidia work well with DVD resolutions and we have had reports of success with HDTV with both. The newest ATi chipsets even promise flawless HDTV playback as do the latest S3 chipsets. However, even if a chipset does work on one motherboard that doesn't mean it will in another motherboard do to implementation/driver/bios differences and this may also depend on the CPU you use. I'm still waiting for feedback on the intel integrated video chipsets. More info will be posted as it becomes available.
Since onboard video depends on shared memory with the system you will probably want at least 1GB of RAM and it wouldn't hurt to have left over RAM sockets just in case you need to add more. For the best chance of success a socket 939 (old or new) processors would be the better choice since they have a higher memory bandwidth than a socket 754. As for intel... that's still unknown but plan on at least 3GHz or 3000+ speeds for either brand until we know more. Since the onboard graphics have fewer integrated features than their graphics card counterparts (such as some forms of deinterlacing used for HD playback or ATi's Avivo technology) you can expect higher CPU usage so don't skimp on the processor... at least for the current generation chipsets anyway. The latest chipsets from ATi are just hitting the market and I'm sure NVidia isn't far behind. These chipsets may be more capable than the RS480/482 and 6100/6150.
PCI, AGP or PCIe?
Don't even think about standard PCI, it's too slow to support a HD graphics. AGP 8x has a maximum bandwidth of around 2GB/sec. PCI express maxes out around 4GB/sec in the first generation. Even if AGP will work, if there is any delay in the delivery of data to the graphics card you are more likely to see it because you have a lower margin for error because it takes twice as long to catch up. That will make it more prone to skipping than PCIe
NVidia or ATi?
If you use one of the latest generation of these cards or chipsets with a memory bandwidth of 10GB/sec or greater you should be ok. Saying one or the other is better is pointless since one may be more efficient in the current generation and the other may be in the next. Whichever you choose, always use a newer driver than is shipped with the card as they often ship with very early versions of the drivers. Also take into account the requirement for H.264 if you plan to use it. Entry level cards WILL NOT WORK for HD and older cards do not have H.264 support! I'm not saying older cards won't work but it's more likely to require a top end card which will probably be just as expensive as the latest generation cards and may lack some features. If you want to use an older card, search the forums to see if it has been tested. The last reviews I've seen seem to give a slight edge to NVidia for lower CPU use but YMMV.
2. CPU
Faster is better. You will probably need a CPU of 3GHz/3000+ or better if the first generation HD-DVD or Blue Ray cpu choice is any indicator. Microsoft actually recommends a P4 at 3.2GHz but I have heard claims of HD video working on as low as a Sempron 64 2500+ CPU. However, after reading followup posts I have my doubts it works with all HD video formats.
I think it's safe to say that the required speed is just a guess at this point and is going to vary with what graphics card, tuner card(s) and drivers/codecs you use. As the add-on hardware improves CPU requirements may drop a little. Actually, I thought 3GHz was a high guess just to be safe but since an AMD Sempron 64 2500+ can be overclocked to that level why suggest less? I'm sure we'll eventually have people saying they have it running everything on a lower GHz CPU but attempting it is a risk. The other factor that is a huge unknown (with MediaPortal anyway) is the H.264 compression which depends heavily on you're CPU, graphics card or tuner cards. Early reviews related to H.264 indicate a multi-core CPU AND high speed GPU both may be required.
3. RAM
MediaPortal currently runs fine in 512MB of RAM for standard video but with HDTV needing around 4 times the data per frame of video it may need more RAM for buffering to play and record video smoothly. Multiple recordings at one time may also eat a lot of RAM but 1GB of RAM *should* be enough for a dual tuner system with the current version of WindowsXP. If you are planning on more than 2 HDTV tuners you can let us know how it turns out.
It wouldn't hurt to have some open RAM slots just in case your system needs more.4. Hard drives
The increased bandwidth and file sizes need large, fast hard drives with a fast interface. Sorry, a cheap 80GB drive won't do. A recording of the the last Superbowl in 1080i off air ATSC took over 30GB and stopped before the end of the game. I'd suggest SATA 150 or 300 and if you plan on recording multiple HD channels at a time you may need multiple drives to handle multiple programs at once. The bandwidth required will depend on the source format, compression and your system configuration anyway. I'm not suggesting you can't use a single PATA drive for multiple programs but it is much more likely to cause skipping. Luckily you can always start with one and add another drive later.
5. H.264 compression
H.264 is the latest MPEG4 compression used by HD-DVD and Blue Ray DVD. It's also becoming common for distributing files over file sharing networks. For example, Anandtech's sample video files are even compressed with it now so you can view videos from their reviews.
Why H.264? H.264 can cut file sizes by over 40% from DivX while maintaining the same or better quality. The compression is very hardware intensive and much more complex to compress or decompress than MPEG2 or DivX. That means what can be compressed as MPEG2 or even DivX by a CPU in real time could take 12 hours or even days with a CPU. It can eat every clock cycle of a multi-core 4+GHz CPU and it may still not compress in real time. However, the results are smaller files and video with fewer compression or motion artifacts. Playback of H.264 video requires a much faster CPU than MPEG2. Don't be surprised if it requires 3.5 to 4GHz for reliable playback of HD video.
MediaPortal currently doesn't directly support H.264 compression but it may be possible to convert recordings to H.264 in a post process. Since it just requires a codec for playback the resulting files should work. Don't expect to do anything with H.264 on a low end machine (yet). H.264 even requires a fairly decent CPU just to play it back. Some graphics cards use the GPU to compress or decompress H.264 at much higher speeds than can be achieved with a CPU. However, the resolution and speed varies with which GPU so you should check the guidlines from the GPU manufacturer. HD playback will probably require the highest end series of card. TV tuner cards are just being introduced with built in support for H.264 so support for the format should be available on lower end PCs fairly soon. Still, expect "lower end" to be pretty fast just to handle the bandwidth and processing HDTV requires.
As I stated before, you may need a multi-core CPU and fast GPU to support H.264 and you will need an appropriate codec to play back H.264 content. Currently, CoreAVC seems to be the fastest software codec and I wouldn't attempt H.264 with anything less at this time.
6. Tuner cards
Whether ATSC or other off air, digital cable (cable card), DVB-T or DVB-S you should search the threads in the hardware support forum and read the related faq of supported TV cards. That appears to have the most info on the subject.
Off air HDTV cards are still in the early chipset generations and there are few chipsets to choose from. Some early or cheaper tuners do not handle weak or multipath signals well so ask before you buy. The current ATi HDTV Wonder seemed to work well for HDTV with the latest drivers but the analog tuner didn't have close to the quality of the ATi 550 tuners I've seen... not to mention MediaPortal setup issues. Ask before you buy. This is currently the only way to receive HD via cable that I'm aware of and only content that doesn't require a special receiver for.
With new chipsets like the ATi 650 we should start to see better 'One Card Tunes All' solutions with the same or better quality than the ATi 550 had for analog. Maybe we'll finally see all in one HDTV/TV/FM tuner cards. BTW, ATi's press release did mention tuning DVB-T as well so that's good news. Sorry, DVB-S is not listed. The chipset is supposed to support H.264 but we'll know more about it's performance in July '06 when the cards are released.
DVB-S (satellite) probably has the greatest number of HD channels but availability depends on what country you are in. For example, in the USA I know of no FTA HD DVB-S signals and pay providers currently don't support computer based tuners. Therefore there is no legal way I'm aware of to receive HD via satellite there. For more information on DVB-S availability and providers in your country you should consult the MediaPortal forums or one of the many satellite forums on the internet.
DVB-T (terrestrial) providers provide similar service as satellite but from a ground based transmitter and is more localized. Once again, consult the forums to see if there is a DVB-T provider in your area.
ATi has shown a prototype Cablecard tuner but I am not aware of any that are currently available from a major player like ATi (feel free to tell me I'm wrong). Cablecard 1 also only offers a 1 way connetion so you won't be able to take advantage of interactive features that your cable company provides such as pay-per-view or video on demand. When and if Cablecard 2 becomes available you may be able to use these features.
As of this year's CES, ATi has shown an updated version of their Cablecard tuner. It runs through your USB2.0 connection whether you have an internal or external unit. I believe this was to prevent hackers from trying to steal service. Anyway, there is no advantage to buying an internal unit over external as far as performance goes and certainly no advantage to buying anything but a PCI version since it just uses the slot for power.
NVidia has recently jumped into the TV tuner market so expect an HDTV tuner from them in the future but they appear to be a step behind ATi for the moment. I wouldn't expect an NVidia HDTV tuner until late this year at the soonest.
7. HD-DVD and Blue Ray
At this time I am unaware of any MediaPortal systems with either format currently in operation. However, MediaPortal will probably be able to play either format through an external player if the system has the proper hareware/software.
Given the HDCP digital rights/copyright protection integrated into the technology, special drivers plus a graphics card with HDCP support including onboard ROM and encryption keys appears to be a manditory requirement.
It will also require NVidia's PureVideo HD or ATI's AVIVO so a GForce 7 or X1000 series card with HDCP support is a must. There are no integrated graphics chipsets that list HDCP support at this time.
Plan on it requiring a fast enough CPU/GPU to handle H.264 playback in all HD formats.
8. Audio
HDTV comes complete with digital audio and you have quite a few options when it comes to decoding and playing it. However, it can be broken down into two main categories. Sound cards and onboard audio.
Good sound cards require less CPU use and usually provide better quality than onboard audio. Onboard HD audio takes less CPU and offers better quality than older onboard audio codecs. Take your pick but with onboard HD audio now as cheap as the older codecs why not get the better sound and lower CPU use? Go for the sound card if you wish but as the amount you spend goes up the gain in quality per dollar starts to level off. Only cards that have special software to improve MP3 sound will offer a noticable improvement in sound at some point. However, that is less and less noticable as the bit rate of the MP3 goes up and may introduce other distortions to the audio.
A sound card that can decode AC3, dts or other sound standards will offer a noticable drop in CPU usage which may be important and let you use a slower CPU. But it's a trade off. Buy a $100 or more sound card or spend the money on a faster cpu.
An optical or coaxial output for the digital audio will offer the best quality transmission of the audio to a receiver or TV. Even if your sound system doesn't support it yet it doesn't hurt to get a motherboard or sound card that has the connection just in case you want it in the future.
Summary
With HDTV more and faster is better. Playback may be possible on a low end system but just about everything needs a lot of CPU, RAM, hard drive space or additional hardware support at the moment.
If you are building a compact system your best bet may be integrated video and audio do to heat and space concerns. Just remeber it will require a faster CPU than when a fast graphics card is used.
My initial HDTV attempt was with a 2500+ socket 754 CPU overclocked to 3000+ levels, 1 GB RAM, a passively cooled Sapphire ATi x1300 and HDTV Wonder. MediaPortal didn't work properly for HDTV recording or viewing and I couldn't get the analog portion of the HDTV Wonder to work.
I discovered my CPU overclocking had been disabled, my video card was clocked so low it didn't meet the 10GB/sec requirement and software tuner support had just been dropped from MediaPortal.
Since then I have overclocked my video card to handle 10GB/sec, fixed my CPU overclocking and I am waiting for a new generation of TV cards with a hardware tuner for the analog TV.
The important thing here is that I picked low end components and it gave me problems. I'll get it to work after some tweaking but it has cost me time. A few dollars more and it may have worked on the first try.
Several people on the MediaPortal forums have tried as many as 5 different video cards and various motherboards/cpu combinations before they got HDTV to work properly and some only after reinstalling WindowsXP. What's that carpenters say? Measure twice, cut once. Plan your entire system and ask questions before you buy so you won't have to buy again. A little planning and a few questions will save you time, money and possibly your sanity. It certainly won't hurt when it comes to the WAF.
Sweden