Noisy/Grainy image

Amo-Chan · Post by **Amo-Chan** » Fri Jun 01, 2007 1:06 pm

Yeah..I can upload it to megaupload, no problem. As for Avisynth...I'm not sure why it won't work. It just won't apply of my scripts to my video. It's weird. I think the conclusion we all came to (in a different thread) was that it was most likely just my computer. I'll get back with the upload link.

Amo-Chan · Post by **Amo-Chan** » Fri Jun 01, 2007 1:27 pm

http://www.megaupload.com/?d=IMHJ97HK

Ok, here's the video. This is what it looked like after compression with xvid with vdub.

BlaCk_PeArL_27 · Post by **BlaCk_PeArL_27** » Fri Jun 01, 2007 3:52 pm

Amo-Chan wrote:http://www.megaupload.com/?d=IMHJ97HK

Ok, here's the video. This is what it looked like after compression with xvid with vdub.

guess you have to enter it in the catalog "__" locally if this is done editing

Amo-Chan · Post by **Amo-Chan** » Fri Jun 01, 2007 3:54 pm

Oh, crap. I totally forgot about that...I'm not really done though, since I'm having all these issues. I'll enter it anyway though.

JaddziaDax · Post by **JaddziaDax** » Fri Jun 01, 2007 4:00 pm

this isnt an announcement you dont have to enter it till its done :/

Amo-Chan · Post by **Amo-Chan** » Fri Jun 01, 2007 4:01 pm

Too late...I already entered it. I'm going to anyway. I'll just wait to upload it, I guess. So, since it looks like it's due to the sharpen filter...should I not sharpen at all? 29 is obviously too much right?

JaddziaDax · Post by **JaddziaDax** » Fri Jun 01, 2007 4:05 pm

that deffinately looks like the work of a sharpen filter... thing is sharpen will usually bring out every tiny little grain... my suggestion is to either tone it down alot or just not use it at all...

how does it compare to the original export?

if you want to save space crop off the black bars at the top and bottom... if you have a filter on your video (of any kind, or null transform) you can easily crop it off with just virtualdub...

post-it · Post by **post-it** » Fri Jun 01, 2007 6:34 pm

Amo-Chan wrote:http://www.megaupload.com/?d=IMHJ97HK

This is a codec "low-bit-rate" error; its' trying to Motion-JPEG the images.
This has happened to me many-many times

-- where's Scintilla when you need her!?

the JPG image does not distract from the original problem here.
1) notice the sudden-drop to White before the Black line appears.
2) notice the color rippling on what should have been a clean single color area.

if possible, get with Scintilla on this one

Kitsuner · Post by **Kitsuner** » Fri Jun 01, 2007 8:31 pm

post-it wrote:if possible, get with Scintilla on this one

I certainly wouldn't mind getting with her.

Zero1 · Post by **Zero1** » Sat Jun 02, 2007 7:08 am

This is quite an odd problem. Checking the upload, the quantizers used are fine; it's about what you want to aim for. There are three distinct problems. One is Gibbs effect, and one is blocking. Gibbs effect is caused by oversharpening, or a codec's inability to code fine edges either because there's not enough bitrate, or it's a limitation of the codec.

Unfortunately, XviD somewhat suffers this character flaw, but it shouldn't be that bad at Q2-3; so I would assume perhaps it was too sharp.

The other is haloing, or as post-it identified it, "1) notice the sudden-drop to White before the Black line appears." It's basically where the resize or sharpen algorithm increases contrast to give the effect of sharpness, and in doing so creates white outlines which not only look ugly, but don't compress particularly well.

Third is blocking. I noticed some very blocky areas that used Q2. This should not happen at Q2; all that happens at Q2 if it's a complicated part is that the filesize gets bigger, not the quality drops.

The only thing I can think of is that the original source isn't great, the shapening added to this problem, or that maybe (and now I'm grabbing at straws) Vegas didn't render to Huffyuv and rendered with something else (perhaps you meant to pick Huffyuv and you unknowningly selected another codec in the list like MJPEG?)

This is a strange problem. Try compressing it with XviD using the same settings but without any Vdub filters.