For alpha XFree86 users using 'ogle' this 
may be of interest.
-Mel
e-mail response from H}kan Hjort <d95hjort@dtek.chalmers.se>
>Mon Mar 29 2004, mel kravitz wrote:
> Hi,
> I get jerky slow performance on DEC alpha boxes, (XFree86-4.4.0)
> ogle-0.9.2: -scsi dvd drives in both caes, vga mga400 and radeon 9200
cards.
> With either a 600MHZ -21164 CPU or 500MHZ 21264 running
> NetBSD on the 21164 -164LX and Debian on the XP1000-21264CPU.
> Both boxes give after 'ogle -u cli' [ogle_mpeg_vs]: B-frame before
forward
> ref frame @@@@@@@@@@@@@@@@@@display: frame rate: 13.098fps
> what are dropped frame / or dropped audio -symbols?

We've only made some short tests on Alpha, we where not able to get
sufficient transfer rates to the graphics cards even when only running
a small test app (all it did was XvPutImage as fast as it could).
August sent some patched to XFree86 improving, and making the functions
used common, for the YV12 to YUV2 conversion that is needed by most
graphics
cards when using Xvideo data from DVDs.  Only some drivers have good
code
here, others are outright wrong or buggy, others are missing the code
for big endian system and so on.  However these patches where not
accepted.
I don't know if the situation has improved for 4.4.

Theoretical we need to transfer 720x480 x 2bytes x 24Hz (or 30Hz),
i.e. around 16 resp. 20Mbyte/s to the graphic card.   Doing this over
a PCI bus, even without DMA, should be doable but something was not
working as well as it should in our tests.
@ is a audio skipped syncronization check (an interrupt occured between
  writing data and reading the amount of data queued for playback).
- and + and 'mini' resyncs from audio.
! is a dropeed (not decoded not displayed) image
# is a decoded but not displayed image


-- 
Håkan Hjort



-- 
mel kravitz <melk@switchpwr.com>
switching power inc