TV-Tuner cards ( NTSC / PAL / SECAM ) - which works best?
freebsd at sopwith.solgatos.com
Tue May 27 15:50:57 UTC 2008
> Hi-def in the UK is available over DVB-S and DVB-S2 (and presumably over
> DVB-C as well, unsure), and is usually very high bitrate MPEG 4 AVC
> MBAFF, which is EXTREMELY hard to decode in real time for a general
> purpose computer. This either means you need a very fast (expensive)
> computer, or you don't have hi-def support. This makes it very
> unappealing - cheap and crap or expensive and not-quite-so-crap.
Do you have a number for this "very high bitrate MPEG 4" ?
> For the US market, it is much easier (I believe), as most of their HD
> content is delivered as MPEG-2, which is much easier to decode.
US OTA is MPEG 2. Max bitrate is approx 19.3 Mbps.
I've read that some cable and sat is converting to MPEG 4.
I don't have bitrate numbers for those.
Some content is only available in HD. If you can't decode HD in
real time you have to record it, transcode it down to SD, then watch
the SD. Not a great solution. Word is that scaling is expensive,
so a display that is at least 1920x1080 would be helpful in reducing
You can get decoder chips, for example:
Broadcom BCM70010 and BCM70012 claim to decode HD.
Mpeg2 up to 125 Mbps, H.264 up to 40 Mbps.
Available as chips, or on PCIe, PCIe mini, and ExpressCard 34 cards.
A BSD device driver would need to be written. And you need
a free slot. (Free slot? What's that?)
ATI has documented some of their graphics chips. The penguins
have them offloading some of the video decode work. Is anyone
working on getting this working with BSD?
The 780G is supposed to be able to decode HD H.264, but I don't know
if they've documented that chip or not.
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