Noise @ 720x480

[mr. phantastik]

I have a strange problem in that I can record (using virtualdub) just fine at 640x480 using pic to encode, but as soon as I do a 720x480 (for dvd eventually), I get noise in the picture (in the form of short horizontal lines). This noise comes regardless of the quality setting, and in both RF and Composite modes. I thought it was hard drive noise interfering with the signal, but apparently not. I've tried using Huffy too, but that gives me noise in every resolution.

System Specs:
AMD T-Bird @ 1.36GHz
768MB SDR RAM
Win 2K SP3
ATI TV Wonder using soucefourge drivers
Via mobo, but with updated 4in1 drivers

Is it a function of the card? I remember reading somewhere this card can't do about 640x480. Any suggestions on how to remove the lines? Is it possible to do DVD burning with a 640x480 source?

[BJ_M]

sure your not seeing interlacing ?

[mr. phantastik]

pretty sure..i'm aware of the lines in the picture, and i realize that a monitor is progressive scan, but these are quick and don't last more than a frame or two. they're also highly noticable. check out these screenies of nigella :]

Piccie 1
Piccie 2

I can't remember what quality i did those at, but i get the same problem at all quality levels at 720x480

edit: i forgot to mention i'm also using an rf amp as well.

edit 2: i played around with the disk i/o settings, and i found out that by increasing the buffer size, i can isolate the noise. It happens every 8 seconds now, with a chunk size of 16mbs and 25 chunks in buffer. Perhaps it IS hard drive noise? Any ideas on isolating the card from rf interference? even though i'm using composite input...

[BJ_M]

you are getting drop outs in the retrace line - not sure of the correct term.

ussually either

cable
connectors
rf amp (since your using one - not always a good thing)
bad contacts
slightly off resolution your capturing at (doing interpolation on the fly)

[mr. phantastik]

so i've tried a bunch of different things (running it through a diff vcr, with and without an rf amp, tried increasing the resolution) but i can't get rid of the noise. Any other ideas?

[saltrats]

This is a common problem with AMD systems using a Via chipset.. I tried everything, but the one thing that did work was a bios update for my motherboard.. try it.. it was the only thing that fixed it for me..

[RoopeT]

Is this happening in VirtualDub even if you turn both overlay and preview off (and capture blindfolded). I used to have preview on and check under capture settings "hide on capture", but then I noticed it's much less CPU consuming just to turn the preview off completely. I think I don't have those interference lines anymore after realizing this.

[mr. phantastik]

Ok. A BIOS update, 4in1 driver update, and a blindfolded capture later, I'm still nowhere. I even redid the cable connectors in my house (which vastly improved image quality). I still have the damned problem, only at 720x480. I've noticed the following:

- It happens when movement happens
- If I change the Disk I/O settings, I can control
how often it happens

The second leads me to believe that its a hard disk problem.

Any other ideas for a fix out there? I'd really appreciate not having to take this card back.

[BJ_M]

did you try increasing buffer size ?

[crahak]

This is a common problem with AMD systems using a Via chipset..

Yea, I got rid of my VIA problems too eventually (after updating bios, 63 newer/older 4in1's and such, PCI latency patches n more fun stuff): I gave the damned thing away. Never had a single computer problem since then...

[mr. phantastik]

you mean the disk i/o buffer? i've had that up to 400mbs..anything higher and it tells me i'm out of mem, which is odd because windows only uses 100, and i have 768.

The higher the buffer, the longer the gaps between fuzz..but at 400 the gap is 8 seconds.

[mr. phantastik]

w00000t i changed the pci slot the card was in, and now it works like a charm. except that its right next to the vid card, and the vid card might eventually overheat..but whatever.

thanks for the help

[shred]

I have a Tyan Trinity 400 (S1854) which has the VIA Apollo Pro 133A chipset.

I was dropping lots of frames (> 25%) at 640x480 and I could only capture at strange rates (33.66, 20.08, but not 29.97)

I applied the pci latency patch from
http://www.georgebreese.com/net/software/
and it fixed my problem.

Now I drop 0 frames at 29.97

[Dodzzz]

but then I noticed it's much less CPU consuming just to turn the preview off completely. I think I don't have those interference lines anymore after realizing this.

ditto, I usually capture from tv broadcast, so when capturing on Virtualdub, I watch it on a TV

[vhelp]

This reminds me of my old Intel 233 MMX days w/ my ATI-tv wonder back
when. Anways, this used to plauge me whenver I went to 480x480
and above for capturing. It turned out that it was a combination
of:
1 * poor bandwidth (mb/chipset/cpu speed/codec)
2 * mostly codec choice ie, YUV12
3 * combo of resources left

During my first initial capturing, if I had set to 480x480, i'd
get small issues, but soon as I started opening up other apps to
do what ever, and then close them all down, and go back to capturing,
I get WORSE issues or they would compound. So, I learned that to
minimize these to the least I could stand, I had to re-boot my pc
and ONLY capture. But, I still got those lines, just not as many.
Another cause (or addition, to) was the amount of processing time
required to compress ie, Huffy not being tuned w/ settings, and/or
MJPEG used a lot of CPU horsepower.
IF you have the hd space, capturing uncompressed would probably reduce
next to zero, those artificats, if not zero'lise them. But, that of
course, depends on a number of things, ie mb/cpu/irq/bios/chipset/
capture card/capture app and settings, and many more. Anyways..

Later on, when I upgraded to an MSI MB w/ T-Brd 900MHz I could
capture 480x480 w/ no problem (or just about) but soon as I went to
640x480 or higher (pending on my resource level) I'd get those same
lines (not those Interlace ones) Again, still using Huffy. I wasn't
satisfied with PIC (MJPEG)

In messing around w/ varoius codecs, I found that it was to my best
interest to use the YUV w/ Huffy and allow it to capture in
distort view (where two lines like Interlaced) and then, later, when
encoding, in vdub, I'd choose (as my first line) Swap Field
and picture would be clear and non-distorted.
But, in short, for my needs then, 352x480 was the best all around
choice for my capture w/ closer to ZERO frame drops, that I lived
with till up yet, again, upgraded my PC's.

Another thing to look into, is the capture card. I have found, BOME,
that the haup wintv go card (RCA only) does a slightly better job as
maintaining video stability at highest resolution.

This has ben my experience, way back when.

The ATI TV Wonder CAN do 640x480 and 720x480, as I've done this many
times, and STILL can/do.
It's all about OS and Driver versions, and a few other things.
I use the VFW drivers, not the WDM ones. With the WDM, you are bound
to only one color space UUYV or something like that. At least in my
experience with WDM (I stil have my ATIRageFuryPro on WDM) it only
allows one setting change, hence the UUYV, but it WILL capture at
720x480 res. As long as I captured WITH Overlay ON, (not preview off)
it would capture fine, but soon as I turn Preview on, it would crash
or give me a belly aike! (1st PC)

Welp, that's about it. Just sharing my similar experience.
-vhelp