[mythtv-users] he shoots. he scores!

Matthias Badaire mbadaire20 at yahoo.fr
Thu Apr 1 09:16:32 EST 2004


I do agree but one small detail though.
You can access the OSD buffer (what you call framebuffer) two ways:
- mmap directly the ram of the card and writing in it => slow
- dma the buffer you want => fast.
You get a confortable 25fps display with divx/dvd.
There IS some artifacts though as said below but it is better than nothing.

One last detail : if you use the normal X driver, it does the mmap stuff.
Use the driver from http://membres.lycos.fr/badzzzz which is using the DMA technique.

We are not there quite yet but getting there.
M


Niklas Brunlid <nbr at ticalc.org> writes:

> On Tue, 30 Mar 2004 17:13:55 -0600 (CST), Coax <coax at cornernet.com> wrote:
>
>> Hello, Ivan.
>>
>> There is 1 good reason to not use the TV-Out on the PVR-350 for all
>> MythTV
>> applications.
>>
>> Its framebuffer (i.e. that which is NOT displayed on /dev/video16) is so
>> painfully slow, it rivals the first Trident PCI video card ever made. :)
>> (It doesn't even seem to support XvMC extensions!)
>>
>> This means it is painfully slow to play anything that is NOT encoded with
>> MPEG-2..
>>
>> I have a PVR-350 in my MythTV box (athlon "2200+", which is the 1.8ghz
>> 266fsb chip...) and if I just so happen to disable hardware decoding -
>> and
>> just out to the framebuffer directly, its like watching TV in
>> slow-motion.
>> (Meanwhile, the box is absolutely flogged.  load skyrockets.)
>
> Why do people keep saying this? I can guarantee that the hardware
> framebuffer on the PVR350 is plenty fast enough to play video in
> fullscreen, full frame rate. On my system (Pundit, P42.4GHz, 512MB
> somethingSpeed memory, MythTV 0.14, Gentoo gentoo-dev-sources 2.6.4-r1,
> Mathias' patched and ready-to-use 0.1.9a ivtv drivers) it simply works,
> and uses ca 20% CPU for mplayer software-scaled output, less for DVD with
> Xine.
>
> As stated many times, once you have the speed, the problem becomes
> tearing, i.e. the players output is not synced with the PVR350:s output.
> Especially noticable on panning scenes or high-action scenes, but
> otherwise fine.
>
> I honestly haven't tried using software decoding for PVR350-recorded
> content (at least not in MythTV) since I haven't had a reason. =)
>
> Also, Mathias mentioned a patch that encodes video output to MPEG2. Could
> be interesting, haven't tried it myself though.


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