Hi Bernie,
Thank you :-)
I use Chen's algorithm (takes 16 Mul). It is 8 times faster than MPEG's
float algorithm on my P3 machine.
Best regards,
Davy
Reply by Bernie●October 14, 20052005-10-14
to test use the source code proposed by
http://skal.planet-d.net/coding/dct.html
note :
- there is lot's of different implementation of the DCT.
- some are very fast but less accurate
- if you deal with an mpeg video std implementation only idct is
describe and should respect I3E-1394 precision. DCT is the encoding part
and it's not normalized !!!
- you should find on the web an IEEE-1394 idct tester which test if your
implentation respect the standard requirement.
good luck
Davy wrote:
> Hi all,
>
> I am new to DCT and now testing my FDCT and IDCT program.
> I found some of my high frequency DCT part is higher than low frequency
> DCT part.
> And I don't know whether it is correct.
>
> Where can I find example of 8*8 DCT input and output to test my
> code,thanks!
>
> BTW,
> my code's DCT input:
> 55 60 58 55 60 58 55 60
> 58 55 60 58 55 60 58 55
> 60 58 55 60 58 55 60 58
> 55 60 58 55 60 58 55 60
> 58 55 60 58 55 60 58 55
> 60 58 55 60 58 55 60 58
> 55 60 58 55 60 58 55 60
> 58 55 60 58 55 60 58 55
> my code's DCT output:
> 461 0 -1 0 -1 -1 1 0
> 0 0 0 0 0 -2 0 0
> -1 0 -1 0 -2 -1 2 0
> 0 0 0 0 0 -2 -1 0
> -1 0 -2 0 -3 -3 4 0
> 1 -2 1 -2 3 -11 -3 1
> 1 0 2 1 4 3 -5 0
> 0 0 0 0 0 1 0 0
>
> Any suggestions will be appreciated!
> All the best,
> Davy
>
Reply by Davy●October 10, 20052005-10-10
Hi all,
I use Matlab's dct(dct(x')') and test my code. All OK!
All the best,
Davy
Reply by ●October 10, 20052005-10-10
> > Where can I find example of 8*8 DCT input and output to test my
> > code,thanks!
Simplest way is to use the inbuilt dct&idct functions of MATLAB to
obtain a test vector.
Good Luck.
Parthasarathy
Reply by Martin Brown●October 9, 20052005-10-09
Davy wrote:
> Hi all,
>
> I am new to DCT and now testing my FDCT and IDCT program.
> I found some of my high frequency DCT part is higher than low frequency
> DCT part.
> And I don't know whether it is correct.
>
> Where can I find example of 8*8 DCT input and output to test my
> code,thanks!
>
> BTW,
> my code's DCT input:
> 55 60 58 55 60 58 55 60
> 58 55 60 58 55 60 58 55
> 60 58 55 60 58 55 60 58
> 55 60 58 55 60 58 55 60
> 58 55 60 58 55 60 58 55
> 60 58 55 60 58 55 60 58
> 55 60 58 55 60 58 55 60
> 58 55 60 58 55 60 58 55
> my code's DCT output:
> 461 0 -1 0 -1 -1 1 0
> 0 0 0 0 0 -2 0 0
> -1 0 -1 0 -2 -1 2 0
> 0 0 0 0 0 -2 -1 0
> -1 0 -2 0 -3 -3 4 0
> 1 -2 1 -2 3 -11 -3 1
> 1 0 2 1 4 3 -5 0
> 0 0 0 0 0 1 0 0
>
> Any suggestions will be appreciated!
And what does the inverse of the DCT give from the above?
> All the best,
> Davy
Test it initially with simple patterns that you can work out by hand.
Walking ones will give you a fairly easy test pattern for DCT that
should quickly show if your implementation is OK.
1 0 0 0 0 0 0 0
etc.
Regards,
Martin Brown
Reply by Davy●October 8, 20052005-10-08
Hi all,
I am new to DCT and now testing my FDCT and IDCT program.
I found some of my high frequency DCT part is higher than low frequency
DCT part.
And I don't know whether it is correct.
Where can I find example of 8*8 DCT input and output to test my
code,thanks!
BTW,
my code's DCT input:
55 60 58 55 60 58 55 60
58 55 60 58 55 60 58 55
60 58 55 60 58 55 60 58
55 60 58 55 60 58 55 60
58 55 60 58 55 60 58 55
60 58 55 60 58 55 60 58
55 60 58 55 60 58 55 60
58 55 60 58 55 60 58 55
my code's DCT output:
461 0 -1 0 -1 -1 1 0
0 0 0 0 0 -2 0 0
-1 0 -1 0 -2 -1 2 0
0 0 0 0 0 -2 -1 0
-1 0 -2 0 -3 -3 4 0
1 -2 1 -2 3 -11 -3 1
1 0 2 1 4 3 -5 0
0 0 0 0 0 1 0 0
Any suggestions will be appreciated!
All the best,
Davy