Is it possible? This is the question that many Linux users are asking themselves about the HDTV (High Definition Television) support on Linux boxes, and the answer is Yes! Several cards are now available for HD capture in Linux: pcHDTV HD-2000, pcHDTV HD-3000, pcHDTV HD-5500, Air2PC, Technisat AirStar HD-5000, AVerTV HD A180, ATI HDTV Wonder and more.
HDTV (High Definition Television) is sent as stream of binary data encoded in the radio spectrum. A digital tuner works much like a modem extracting the original digital data. The digital TV data is sent as MPEG-2, so if you can get the raw data, the compression is already done for you. The HDTV signal comes in three flavors: Broadcast, Cable, and Satellite and because the three standards use different types of modulation, you have to use separate hardware decoders.
With the new HD-5500 TV card from pcHDTV and MythTV software, it's more than possible to watch and record HDTV content on a Linux box. Unfortunately, the card is only useful for those in the United States and Canada, but it might work in other countries like Korea or Australia, with the ATSC channels. The HD-5500 TV card supports ATSC, unencrypted QAM 64, unencrypted QAM 256, and NTSC transmission reception. At this moment there are two different drivers available for HD-5500: the DVB drivers that are bundled starting with version 2.6.11 RC6 of the Linux kernel; and the video4linux drivers, version 1.6 and 2.0.
ATI HDTV Wonder
On the other hand, the ATI HDTV Wonder capture card is partly usable with MythTV, beginning with version 2.6.15 of the Linux kernel. The problem is that this card has no official support for Linux and it can only be used for digital channels. Drivers for this card are available starting with Linux kernel 2.6.15 or higher.
AVerTV HD A180
Another similar card to ATI HDTV Wonder, is the AVerTV HD A180, which is an HDTV tuner for OTA or QAM ATSC signals. This card uses an nxt2004 frontend chipset with a saa7135 bridge interface.
MythTV is the perfect match for all HDTV cards that have support in Linux, in order to watch HD content. It is highly recommended to use the DVB drivers with the MythTV software, which also work with NTSC and ATSC signals, because they are much better supported in MythTV for HD than the video4linux drivers. Also, the DVB drivers require just seconds to get working under most Linux distributions running a 2.6.12 or newer kernel.
HDTV on Linux machines is possible at this moment, but with limitations. Most of the High Definition channels are encrypted and we are still waiting for HD decryption to make its appearance into the Linux world. Right now, if you live in the United States, Canada, Australia or Korea, the best available card for High Definition Television is the new HD-5500 from pcHDTV.