Reducing Video Size

Paul_Holmes wrote on 9/30/2002, 12:41 PM
Can anyone recommend how best to shrink video size. My problem was with an older VHS tape that I decided to put a border around and make it look miniature-widescreen. I reduced the picture size to get as much of the video in the frame without the edges showing (had bad banding on the left side, also). Anyways, once compiled, everytime there was a pan or quick up and down motion I got horrible banding. Would reduce interlace flicker and resample help, or is there something else I need to do?

Comments

DougDVD wrote on 10/3/2002, 1:23 AM
I have my own problem with the choppy look, but it's when I try to add video on a different timeline. No one knows the answer. Next stop is Vegas Support. I never had this problem with the Ligos encoder in Vegas 2.0. Did you try changing the field order from Lower to Upper when rendering the video? It corrected one of my problems with the video stutter and maybe it will help your situation. Let me know if you find a solution so I can try it out on my problem.
Tyler.Durden wrote on 10/3/2002, 7:40 AM
Hi Paul,

"Would reduce interlace flicker and resample help, or is there something else I need to do?"

These should help quite a bit. You might also try rendering at Best quality.



Here's more info:

I'll quote Dithermaster and Cheeshole quoting Dr. Dropout:

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

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Scaling:
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"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. "


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Field Handling:
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"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. "


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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. "

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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. "

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"Lastly, please note that 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. "

Dithermaster:

"About the only thing I'd add is that if you're using high-resolution stills that are being scaled down to video, use Best and not Good to prevent flicker-causing aliasing.
///d@ "







HTH, MPH
SonyDennis wrote on 10/8/2002, 12:04 AM
I suspect the banding is due to scaling of an interlaced image without first deinterlacing it. Vegas can do all this for you, but it has to know that the source video is interlaced. Check the media properties for the clip and set it to interlaced instead of progressive.
///d@
Paul_Holmes wrote on 10/8/2002, 8:07 AM
It's a project that I will be getting back to that's shelved for the moment. But thanks for the tip. I'll try deinterlacing it first before scaling it and see how that works.