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View Full Version : bug in dvd2avi's iDCTs?

sapient
14th October 2002, 02:16
Hi,

I am getting a weird picture distortion (blocks resembling those of a corrupted divx file) in the european PAL version of the pilot episode of FRIENDS. The problem appears only in a particular scene when I am using any of the 3 (32bit, 64bit, reference) dvd2avi iDCTs and mpeg2dec.dll. It does not appear with any of the xmpeg iDCTs. Unfortunately I can't use xmpeg since I want to do iVTC and deinterlacing.

Does anyone know anything about this?
sapient
14th October 2002, 02:37
I tried to circumvent mpeg2dec and used vfapi instead. The problem disapears. So the problem seams to be with mpeg2dec.dll
I got the same problem using the build from gordian knot and the one that can be downloaded seperately from doom9. I still can't use telecide with vfapi avi's so my problem persists.
I haven't noticed the same problem in any other dvds, although I haven't actually reviewed all my encoded files.
WarpEnterprises
14th October 2002, 16:28
Why can't you use telecide() with vfapi?
sapient
14th October 2002, 21:20
Because VFapi automatically converts to RGB and telecide requires YUV.
Converting back and forth between RGB and YUV is generally a bad idea. There is quality degradation and a huge processor overload.
So I can't use this process in a regular basis. And until the mpeg2dec bug is fixed, I will always keep wondering if it screwed up again this time.
I could post a screen cap if it will help fixing the bug
Xenoproctologist
15th October 2002, 02:38
Unless you're chaining a dozen yuv->rgb->yuv conversions together in a row, the quality hit isn't even worth thinking about. There is a little bit of a speed hit for each colorspace conversion but, seeing as how I regularly do heavy filtering with encoding times as low as 2-3fps, I have trouble being sympathetic. Until someone releases a fix, suck it up and deal with the extra 5-10 minutes per encode.
WarpEnterprises
15th October 2002, 13:56
There is a new ConvertBackToYUY2, which gives even more precise conversions.

Maybe you can make those piece of mpg available on the net?
trbarry
15th October 2002, 20:33
Sapient -

Have you tried it with mpeg2dec2?

www.trbarry.com/MPEG2DEC2.zip

Also, which version of DVD2AVI are you using. And could you post your AVS script, and a picture of the bad scene?

- Tom
sapient
16th October 2002, 16:05
Sorry, I don't have the vob's anymore.

I had not tried mpeg2dec2. I 'll keep it in mind for the future

sapient