[mythtv-users] Broadcom CrystalHD??

Travis Tabbal travis at tabbal.net
Wed Jan 6 15:43:21 UTC 2010


On Wed, Jan 6, 2010 at 6:27 AM, Ben Eisemann <ben at locojeeper.com> wrote:

> So i'm too impatient to let the discussion naturally drift to what I have
> on my mind.
>
> I currently run a Mac Mini Dual Core 1.83ghz with Mac OS 10.6 and MythTV
> 0.22 (from sniderpad) as my frontend.  I most recently noticed a little
> "jerkiness" playing back Bones episodes from Fox HD (clear QAM through
> comcast, so I guess thats 720p... I'm not sure though).
>
> Anywho enough background... I was contemplating eventually trading up to
> NVIDIA based Mac Mini and running linux on it to the VDPAU whatever it is.
>
> But with drivers now available for the broadcom chip on Mac OS... what's
> the missing ingredient to get it working through the mac variant of the
> MythTV frontend?  Is there a whole 'nother level of code that needs to be
> integrated into MythTV source in order to take advantage of the chipset and
> OS drivers?
>
>

You need Myth to support sending the data to the Broadcom card and reading
the decoded frames back, then sending them to the video card. So yes,
another layer of software is required. It's possible support will make the
cut for .23, and I'm sure there will be a patch set available when the code
is ready for whatever version of Myth is current at that time. Though doing
that voids whatever warranty you might have with Myth. :) Much the same as
what happened with VDPAU and .21.

The nice thing about this card, is that the API is supposed to be the same
on all platforms, so once Myth supports it, it should work on Windows,
Linux, and MacOS.

As for the jerkiness, do you know anything else about the video? I can
decode 720p MPEG2 ATSC streams in software with less CPU than that. I'm not
sure, but I thought Comcast was doing passthrough for OTA stations, so it
should be about the same. Perhaps they are compressing it themselves with
h264, that does stress a CPU of that level. To find the problem, you need to
know how much CPU is in use, and what codec, bitrate, etc. for the video
file.
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