The new Freesat based HD Mythbox specification
The BBC have now launched the Freesat service earlier in the year. This service is similar to the existing Freeview service whereby it's free and doesn't cost anything to view - however it is received through a satellite dish and more importantly it carries High Definition programmes. It is also an ideal platform to build HD programming on as it has plenty of capacity unlike Freeview over terrestrial. Irrespective of capacity issues, there has been talk of a new Freeview HD too which could be available later in 2009. But on either platform the HD content uses H.264 encoding, requiring hardware capable of decoding and outputting over a DVI or HDMI connection.
Another recent development is the introduction of Blu-ray content, which is also encoded in either H.264 or VC-1. Given that more and more films will be made available in this format, it would be nice to have the capability to play the format. Although currently Blu-ray decoding and viewing on linux is a bit complication due to the BD+ copy protection, at some point this will no doubt be circumvented so it would be good to have a system capable for the future.
At the same time as Blu-ray gains popularity, so too have HD TV's, with their High Definition functionality just waiting to be utilised. Hence there are many good reasons to consider a specification for an all new Mythbox v2, or MythboxHD.
Below is a list of chosen components that are going to be used for the MythboxHD, along with any respective links.
Motherboard/CPU:
The motherboard and CPU needs to provide enough processing power to decode H.264 and VC-1 streams contained in the Freesat HD tranmissions, Freeview HD transmissions, and potentially Blu-ray content. At the same time, it will need to pass through any AC-3 streams and record. We don't want the new MythboxHD to struggle (which was sometimes the case with MPEG-4 content with the original Mythbox) so a little more power would be welcomed. Additionally, in order to accomodate multiple tuners for Freesat HD and Freeview HD, the board will need to have plenty of PCI slots available. This will mean that rather than compact Mini-ITX form factor, the slightly larger but more commonplace Micro-ATX form factor will be used.
To deal with content decoding, the main chipset choices available are:
- VDPAU (Video Decode and Presentation API for Unix) designed by Nvidia and on Geforce 8+ GPU.
- XvBA (X-Video Bitstream Acceleration) designed by AMD and used on ATI Radeon GPU.
- VA API (Video Acceleration API) put forward by Intel as a common API for linux similar to Window's DxVA. VA API can currently utilise both VDPAU and XvBA. VA API is currently natively supported by Intel's Poulsbo Chipset - however Linux support isn't optimal.
Given that currently VDPAU is most widely supported (MythTV, Xine, MPlayer, XBMC, Boxee) it would make sense to choose a motherboard which has a Geforce 8+ series GPU. This is compounded by the fact that the VA API, once established and implemented, also supports VDPAU.
The Gigabyte GA-E7AUM-DS2H with on-board NVIDIA GeForce 9400 is perfect. The main advantages of this board are that it has plenty of connectivity options (DVI, HDMI, SPDIF TOSLINK), a GPU which meets our requirements, 2 PCI slots and 2 PCI-E slots, and support for HDCP and Blu-ray playback. The on-board chipset is fanless and provides the usual networking and SATA support you would expect, and supports Dual/Quad-core Intel Core 2's. The board's specification can be found here.
After deciding on this specification, it was found that the Geforce 9400 based motherboards have now been discontinued! While these boards used the MCP79 chipset, the newer chipset MCP89 is scheduled for release in Q1 of 2010. The MCP89 is based on the Geforce 200M range, so given the lack of availability and performance improvement of the new chipset, it will be worth the wait.
Of the Intel Core 2 Duo CPU's that will fit into these boards, the Wolfdale Core 2 Duo E7xxx range has the lowest TDP at 65W. This would give us ample power while still keeping the power usage at a minimum. We will use the bundled HSF - with some tweaking of the fan settings this shouldn't be too noticable. Find it to buy on ebuyer here.
TV Card
The TV card will need to receive Freesat transmissions and be capable of handling the HD channels as well as the SD ones.
The Hauppauge WinTv Nova-S2 HD DVB-S2 & DV Tuner, being a DVB-S2 tuner, supports the reception of both High Definition and Standard Definition services. This is an ideal choice for Freesat reception. See the full spec here and the product to purchase from dabs.com here.
Hard Drives
Potential hard drives which are quiet when both idle and seeking, as well as being energy efficient include:
- Samsung F2 EcoGreen range
- WD Caviar Green range
- Seagate Pipeline HD range
After analysing the best that each range had to offer, and based on availability, it was between a Samsung F2 drive and a WD Caviar Green drive. Several reviews show that both drives performed well, but here is a direct comparison between the latest Samsung and WD 1.5TB drives available. Based on this, the WD Caviar Green WD15EADS 1.5TB was chosen which can be found at ebuyer.
Case
The are quite a few cases out there which look pretty, but finding one which matches our requirements is tricky. Most cases don't state whether they have space for an IR receiver. There are quite a few cases with built in IR receivers and VFD displays, solving this issue and providing a means to play music without turning on your TV (plus the iMON based IR/displays are supported by LIRC and LCDproc). Instead of a dedicated IR controller, the original MythBox used the remote control that came with the TV card, which made it quite slow at times. Given this, it makes sense to pick a case containing one of these units, circumventing the need to mod the case in order to accomodate an IR sensor.
In order to fulfill our needs, the case needs to:
- accept a micro-ATX motherboard
- accept two or more standard PCI cards (i.e. not low profile)
- be quiet and cool
- be reasonably priced
- fit on an average sized TV stand (with room for your amp etc.)
- blend in with other AV kit
- contain an iMON IR receiver and display
After looking at what was on offer, the cases which fulfill the above requirements are either:
- expensive case which do everything and more, and usually contain a small LCD touch panel
- slimmer cases which require the use of riser cards (which can sometimes be problematic with tv cards) and also limit future expansion
- larger cases which are extremely deep
It was decided that the compromise to be made will be in size, and the Antec Fusion Remote Black case is the perfect choice. Its built well to help keep the system silent and cool, contains the iMON IR/display, and has four expansion slots. More info can be found here and you can buy it here.
Power Supply
For our power supply, we don't have a huge wattage requirement - 300W should be ample for our needs. Out of the power supplies that we investigated, the Seasonic range seems to be one of the best brands for silence and build quality. Based on this review we decided to go with the Seasonic S12II-380. Availability of Seasonics in the UK seems quite poor, however Scan.co.uk stock a selection and are quite reasonable on price (see here).
DVD drive
Hearing many mixed reviews about DVD drives, we will use one of the cheapest Sony DVD writers and use hdparm to reduce the speed of the drive if noise becomes an issue.
Memory
We don't want to under power the new system, so 4GB of DDr2-800 would be a nice amount for processing HD content. To reduce CAS latency to CL4, we'll choose this Ballistix memory.
Wireless Card
Wireless is not a necessity since we can use the on-board network card, but is included here for completeness. Since there are draft 802.11n based cards now available (and it's highly likely that a firmware upgrade would bring the card to a final 802.11n standard) one of these newer cards would be preferred. The card will obviously need to be supported in linux.
- Linksys Wireless-N Notebook Adapter WPC300N - Having a PC Card interface makes this card compact and tidy, and removes the need for more than one PCI slot. It also currently has partial support by the Madwifi driver, with AP support and 802.11n support yet to be added. This driver is included in the kernel. See the dabs product page here.
- Intel Wireless WiFi Link 5300 PCI Express Mini Card - This card has most of what the Linksys has to offer, including in-kernel driver support via the
iwlagn driver. However, although no AP mode is supported, this card makes things even more tidy with no external wires given a spare PCI-E slot. See here.
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