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Old November 21st, 2003, 08:46 AM   #1
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People who edit using external monitor via IEEE....

Just wondering if I'm the only one who is seeing periodic "oddities" while reviewing footage during editing out to an external monitor via IEEE.

Sometimes the footage looks jumpy almost like a field dominance problem or bad frame-rate yet the computer monitor states it's playing back at a solid 29.97. It usually is fixed by hitting stop then play again.
Another problem I've been seeing is from time to time, for no reason at all, the screen goes blue for a few seconds...as if it lost connection to the IEEE. It doesn't stay that way I usually get picture within a few seconds again but figured I'd ask to see if it was normal.

Please tell me I'm not the only one encountering these issues with previewing on external monitor.
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Old November 21st, 2003, 09:05 AM   #2
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no issues here mate
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Old November 21st, 2003, 10:40 AM   #3
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Glen,

The “oddities” may be a result of interlaced footage or computer resource limitations. If the jumpiness you are experiencing can be viewed in the middle of a high motion segment, and pausing causes the image to move back and forth, then it is likely just an issue with your footage. If the jumpiness is a result of skipping frames, the frame-rate of 29.97 (or whatever it is) will still show on the Vegas preview window even though your computer (likely your video card) cannot actually produce that frame-rate on your NTSC preview monitor.

We use an ATI 8500 All-in-Wonder video card to feed the computer monitor and a firewire output to a Pinnacle Movie Box. Two different streams of video (with the priority being the computer monitor) require an enormous amount of data transfer. If you are using a powerful PC and “filming” in frame mode/progressive, then your jumpiness issue is probably unavoidable.

I don’t know anything about the momentary blue screen - Sorry.

Brad
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Old November 21st, 2003, 10:47 AM   #4
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Glen,

I just noticed you own a DVX100. Are you having these problems only with 24fps footage? If that is the case, you may have some pull-down issues. I've not been blessed with such problems...yet.

Brad
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Old November 21st, 2003, 10:54 AM   #5
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Yeah the jumpieness seemed to occur during pans. Though not all the time- I can stop the timline scrubber. Move it back and play it over again and it plays fine. Just seems to play like that from time to time.
The stats on this machine are good enough for Vegas (Athlon 2200+, 512megs ddr333, Gforce 4ti 4600) granted I haven't tried it on my other machine (P4 3ghz, 1gig PC3200 XMS ram, SATA HDs, ATi Radeon 9800 Pro).
This is all having to do with 60i footage. It doesn't happen enough for it to seriously affect my editing but often enough for me to raise a question about it.

I have other issues re: 24p footage in another thread.


By the way- does setting the quality (Draft, Good, Best) in the preview window affect the output to the external monitor if you have no rendering in your footage. I know if I changed the footage somehow, whether it be color correction ect....changing the quality have a BIG impact on output quality. However when viewing untouched footage it doesn't seem to affect it...at least from what I can see.
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Old November 21st, 2003, 11:09 AM   #6
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I keep the preview on full and best, and it plays smooth until I make any changes to the original footage. The only exception to note is with widescreen footage captured on the GL2 in 16:9 mode (this footage is always jumpy).
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Old November 21st, 2003, 04:44 PM   #7
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Glen, on the bleu screen problem: make shure the signal ground in the monitor is grounded.This is often not being done by default because for reasons which would take us to far to explain. Also try to use the shortest IEEE cable with damping ferrites near the ends.
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Old November 22nd, 2003, 12:04 AM   #8
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Quote:
By the way- does setting the quality (Draft, Good, Best) in the preview window affect the output to the external monitor if you have no rendering in your footage. I know if I changed the footage somehow, whether it be color correction ect....changing the quality have a BIG impact on output quality. However when viewing untouched footage it doesn't seem to affect it...at least from what I can see.
As far as I know the "best" rendering option sets Vegas to use 32-bit floating point numbers for rendering. This avoids the problem of quantitization error (which may or may not happen when using multiple filters). I think quantitization error will show up as banding. In most cases there isn't a difference to care about. If you can't see it, then for practical reasons there is no difference except for rendering time. Best quality takes much longer to render.

By the way, Final Cut users just got 32-bit rendering with version 4. They're finally catching up! :P On the other hand, it seems to indicate that it wasn't really a useful feature. And most Final Cut users don't use it.

I might go do a test to show you the difference.

EDIT: Did the test. The difference is small. On things that require resizing, best gives lines that look straight (not steppy) while good looks sharper. If this isn't happening then the difference is very subtle.

I also found that there's a lot of banding with the HSB filter. In my test I changes the sat and brightness to 0.25 then used 2 other filters to double the sat and brightness.
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Old November 22nd, 2003, 06:06 AM   #9
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Here's an overall explanation thanks to Dr. Dropout:

Different conversion algorithms are used for the different video rendering quality options, (which you choose from
Render as>[format]>custom>project.) You'll have the option of draft, preview, good, best.

Quality: Best
Scaling: bi-cubic/integration
Field Handling: on
Field Rendering: on (setting dependent)
Framerate Resample/IFR: on (switch dependent)

Quality: Good
Scaling: bi-linear
Field Handling: on
Field Rendering: on (setting dependent)
Framerate Resample/IFR: on (switch dependent)

Quality: Preview
Scaling: bi-linear
Field Handling: off
Field Rendering: off
Framerate Resample/IFR: always off

Quality: Draft
Scaling: point sample
Field Handling: off
Field Rendering: off
Framerate Resample/IFR: always off

------------------------------
Scaling:
------------------------------

These methods come into play when conforming sources that differ from the output size. They are also used when
panned, cropped or resized in track motion.

Bi-Cubic/Integration - Best image resizing algorithm available in Vegas. Quality differences will be most noticeable
when using very large stills or stretching small sources.

Bi-linear - Best compromise between speed and quality. This method will produce good results in most cases.

Point Sampling - Fast but produces poor results.


------------------------------
Field Handling:
------------------------------

This refers to the field conformance stage of Vegas's video engine. This includes Interlaced to Progressive
conversion, Interlaced to interlaced output when scaling, motion or geometric Video FX and Transitions are involved.
Skipping this stage can sometimes result in bad artifacts when high motion interlaced sources are used.


---------------------------------
Field Rendering:
---------------------------------

When the output format is interlaced, Vegas will internally render at the field rate (twice the frame rate) to
achieve smooth motion and FX interpolation.

---------------------------------
Frame Rate Resample / IFR (Interlace Flicker Reduction):
---------------------------------

Frame Rate Resample:

This kicks in when speed changes are made through Velocity Envelopes and/or event stretching. In can also be used
when up-converting low frame rate sources. This only kicks in if the resample switch is turned on _and_ quality is
set to good or best.

Interlace Flicker Reduction:

This kicks in if the event switch is turned on and quality is set to good or best. See Vegas' documentation for a
description of this switch.

Vegas will bypass any or all of these potentially expensive processing stages if the resulting output won't be
affected by the process (e.g. no-recompress pass-through, field render bypass when settings don't change and so on
...). Differences in the output between different quality settings may not always be noticeable, but that largely
depends on various attributes of the source media being used. If you want to see some of these differences first
hand, trying using extremely large or small sources or high-motion interlaced shots with extreme pan/crop operations.

Please note that you should never render your final project using anything other than good or best when interlaced
sources are involved unless the project only contains cuts. If preview quality is used, the resulting video will vary
between acceptable to disastrous depending on your project and its media content.

-----------------------------------------
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Old November 23rd, 2003, 03:26 AM   #10
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Thanks Ed . . and the BIG Doc!

NOW that's what I've needed to know . . Ed, thanks and KUDOS to the Media Medic, Dr Dee ! HAH!

Grazie
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Old November 30th, 2003, 01:10 AM   #11
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Blue Screen

Glen,

I have fought with this issue for months. After tons of investigation I finally solved the problem.

THE PROBLEM:
Blue screen is caused by a drop in the data stream from your PC. This drop can be caused by a few things, slow hard drives, or drives needing defragging, too many processes running etc. BUT in my case it was caused by the motherboard itself. I was running an XP2100+ with a VIA chipset. VIA has a problem in its chipset that controls the PCI bus. It cannot sustain the data for long period of time. It basically interupt the stream for a second, polls the rest of the bus to see if any device needs it, and then resumes the stream. This interupt appears as blue screen on your monitor and can last a second or minutes. It was completely random.

It only showed on the upstream to the camera (either print to tape or viewing on external monitor). I could capture just fine.

VIA has no fix for it, and MSI (the company who made my motherboard) would not admit the problem existed.

I bought a new Gigabyte MB base on NForce2 chipset. I have not seen a blue screen once.

I would bet you have a VIA chipset on your MB. Only way I know to fix it is go with different MB that has the NForce 2 chipset.

Hope this helps.
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Old November 30th, 2003, 06:31 PM   #12
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I have two machines- the one I was was finding this problem on was an older one using an Asus A7V333. Which is Via correct?

So my newer Asus P4C800-E Delux should be fine, it uses the 875-chipset.
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