Deblock filter

angelzhang · 7th December 2004, 02:37

hi,everyone
In the JM8.6 software,the deblock filter calculates value of boundary strenth for 16 samples in four 4*4 blocks, which takes large timming cost. and now, i want to cut down timing cost by reducing the calcultion loop. In my opinion, boundary strenth values of four samples in one block are same. then we can just calculate one sample other than four times. am i right?
please give your suggestions!

best regards
angel

hworldjj · 7th December 2004, 05:19

Not sure, I think you can check this idea on JM8.6. But I am afraid there will be a little degradation of subjective quality, especially for low resolution frames.

angelzhang · 7th December 2004, 06:38

thanks for your reply.
Then what do you think a good way to solve the question of much timming cost?

I just run the modified software ,but can't find much change about SNR or picture display performance.

then, i am confused how to know the effect about my modification.

angel

Manao · 7th December 2004, 07:20

angelzhang : your change isn't specs compliant ( since you can get a result different from the JM's one, if I understood you correctly ). Of course, in a quality vs. speed tradeoff, your change may be totally valid, but bear in mind you must respect the specs.

And finally, in the JM, last time i heard of, deblocking was clearly not the slow part of the computation.

hworldjj · 7th December 2004, 09:48

PSNR means nothing for deblock filter. Maybe you should test more sequences, especially low bit rate and low resolution, where artifacts will be observed easily. In addition, bitstreams encoded by your codec will not be complimant to H.264 standard, so decoder will accumulate error.

angelzhang · 7th December 2004, 11:14

acutally, the process of deblock filter in Encoder is idetical to that in Decoder. then the PSNR in the decoder must be same as that in encoder. but i'm confused that how to improve the performance of part of deblock filter. or we can do nothing about the part.

best regards
angel

7th December 2004, 02:37	#1 \| Link
angelzhang Registered User Join Date: Nov 2004 Posts: 22	Deblock filter hi,everyone In the JM8.6 software,the deblock filter calculates value of boundary strenth for 16 samples in four 4*4 blocks, which takes large timming cost. and now, i want to cut down timing cost by reducing the calcultion loop. In my opinion, boundary strenth values of four samples in one block are same. then we can just calculate one sample other than four times. am i right? please give your suggestions! best regards angel

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

7th December 2004, 05:19	#2 \| Link
hworldjj Registered User Join Date: Sep 2004 Posts: 17	Not sure, I think you can check this idea on JM8.6. But I am afraid there will be a little degradation of subjective quality, especially for low resolution frames.

7th December 2004, 06:38	#3 \| Link
angelzhang Registered User Join Date: Nov 2004 Posts: 22	thanks for your reply. Then what do you think a good way to solve the question of much timming cost? I just run the modified software ,but can't find much change about SNR or picture display performance. then, i am confused how to know the effect about my modification. angel

7th December 2004, 07:20	#4 \| Link
Manao Registered User Join Date: Jan 2002 Location: France Posts: 2,856	angelzhang : your change isn't specs compliant ( since you can get a result different from the JM's one, if I understood you correctly ). Of course, in a quality vs. speed tradeoff, your change may be totally valid, but bear in mind you must respect the specs. And finally, in the JM, last time i heard of, deblocking was clearly not the slow part of the computation.

7th December 2004, 09:48	#5 \| Link
hworldjj Registered User Join Date: Sep 2004 Posts: 17	PSNR means nothing for deblock filter. Maybe you should test more sequences, especially low bit rate and low resolution, where artifacts will be observed easily. In addition, bitstreams encoded by your codec will not be complimant to H.264 standard, so decoder will accumulate error.

7th December 2004, 11:14	#6 \| Link
angelzhang Registered User Join Date: Nov 2004 Posts: 22	acutally, the process of deblock filter in Encoder is idetical to that in Decoder. then the PSNR in the decoder must be same as that in encoder. but i'm confused that how to improve the performance of part of deblock filter. or we can do nothing about the part. best regards angel