[libdv-dev] XvImage support, YUV value range

[Stefan L. <lu...@be...>]

Hi,

I just did some tests with XvImages and hardware accelerated YUV to RGB
conversion. One problem was the value range used by the dv decoder.
(Y: [-223,+223]; UV: [~-63,~+63]). So adjusting the offset for 'ylut' by
128 is not enough.

Have a look at the following performance table:

                    |           | NTSC              | PAL              
|
MB, CPU, GRA        | dga       | G[t|d]k | XvImage | G[t|d]k | XvImage
|
--------------------+-----------+---------+---------+---------+---------+
Asus P5A, K6-2/400, |  ~26MB/s  | R 24.13 | R 13.83 | R 25.49 | R 14.84
|
MGA-G200            |             U 18.33 | U  8.81 | U 19.22 | U  9.51
|
--------------------+-----------+---------+---------+---------+---------+
DFIK6BV3+, P133,    |  ~56MB/s  | ------- | --------| --------+ -------
|
MGA-G200            |           |         |         |         |        
|
--------------------+-----------+---------+---------+---------+---------+
Asus P5A, K6-2/400, | ~120MB/s  | R 21.05 | R 10.55 | R 22.40 | R 11.61
|
MGA-G400            |           | U 18.28 | U  8.56 | U 19.39 | U  9.63
|

Numbers mesured on Asus motherboard are with kernel V2,4,0.test5 and X11
V4.0.1
DFI motherboard was checked with kernel 2.0.16 and X11 3.3.?

The NTSC sequence is from pond.dv and PAL sequence is from a private
video.
Both are truncated to 6 seconds (180 farmes for NTSC, 150 frames for
PAL).

R/U values are from 'time playdv FILE' (real/user time values).

I uploaded a patch to sourceforge.
Happy testing. 

-- 

mfg

  Stefan Lucke (lu...@be...)