TV-Tuner cards ( NTSC / PAL / SECAM ) - which works best?

[Tom Evans]

On Wed, 2008-05-28 at 09:15 +0100, Dieter wrote:
> > > You can get decoder chips, for example:
> > >=20
> > >   Broadcom BCM70010 and BCM70012 claim to decode HD.
> > >   Mpeg2 up to 125 Mbps, H.264 up to 40 Mbps.
> > >=20
> > >   Available as chips, or on PCIe, PCIe mini, and ExpressCard 34 cards.
> > >=20
> > >   Under $40.
> > >=20
> > >   Product brief:
> > >   http://www.broadcom.com/collateral/pb/70010_70012-PB00.pdf
> > >=20
> > >   A BSD device driver would need to be written.  And you need
> > >   a free slot.  (Free slot?  What's that?)
> > 
> > That sounds freakin awesome. Wonder if they can handle MBAFF encoding.
> 
> I don't know.  We need a data sheet for the chip.
> 
> That is one problem with decoder chips, they may not work with new codecs.
> Some of them are said to not work well with freeze frame, slow/fast motion,
> reverse, etc, anything but normal forward 1x play.
> 
> Another method is a DSP chip.  Less expensive and less power/heat than
> a CPU.  And you can program it to handle new codecs.  The problem is
> finding one that is fast enough.
> 
> > > 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?
> > >=20
> > > 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.
> > 
> > All Nvidia chips from 6600 (ish) up can accelerate H264, and all Ati
> > with 'avivo' (1xxx series) can also do it. The problem is, they can only
> > accelerate within windows. Theres no open API that would allow apps +
> > drivers to accelerate video decoding. There is a started project at
> > freedesktop working on video acceleration apis [3], but it isn't exactly
> > making stellar progress :)
> 
> I was thinking Xv and XvMC.   IIUC the penguins have at least Xv working
> with some ATI chips.

Xv and Xvideo work well with both the beasty and the penguin, at least
for intel, nvidia (closed source). Xv/Xvideo are good for displaying
video (its a good overlay api), not so good for accelerating codecs.
XvMC works on nvidia, intel and via unichrome - I expect the new open
source ati drivers will support it as well, sooner rather than later,
but that does no good for anything other than MPEG-2, and from what I've
read, is virtually no use for H264. 

My best results for H264 come using the 'gl2 (multiple texture)' driver
in mplayer, as opposed to rather than xv or xvmc. XvMC reduces CPU usage
when viewing MPEG-2 content, but I only have access to 480i/p MPEG-2
(standard def DVB-T transmissions and DVDs), so the net effect is
reducing CPU usage from 10% to 5%. If you are fortunate enough though to
get HD content in MPEG-2 format, XvMC is the meal-ticket. According to
the myth wiki[1], even crappy CPUs/platforms can handle 1080i MPEG-2
content with XvMC.

I'm picking up a DVB-S card for my mythtv linux box this weekend, I'll
grab some sample HD content to examine..

Cheers

Tom

[1] http://www.mythtv.org/wiki/index.php/XvMC
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 195 bytes
Desc: This is a digitally signed message part
Url : http://lists.freebsd.org/pipermail/freebsd-multimedia/attachments/20080529/088e3c85/attachment.pgp