Frame Based vs Field Based Projects

[rawcoconut]

Hi All,

I capture analog video using ADS DVD Express DX2 and its bundled s/w called CapWiz. When I open the file in VideoStudio 9 SE, the file settings are:

MPEG files
24 Bits, 720 x 480, 29.97 fps
Frame-based
(DVD-NTSC), 4:3
Video data rate: Variable (Max. 8000 kbps)
Audio data rate: 224 kbps
MPEG audio layer 2, 48 KHz, Stereo

I have read many posts and tutorials on this forum advising the file settings to be Field Based (either Lower Field First or Upper Field First). So far I have been successful in creating video DVDs with the Frame Based files (only 3 projects), so f it ain broke?, but I like to learn more about this process.

The last project I did was a movie 111mins long and the Frame Based file that I captured was 1.8Gig with the settings listed above. I converted that file to a Field Based file (Lower Field First) and the file ballooned to 5.1Gig (not to mention that it took forever!). Here are the source file settings after conversion:

MPEG files
24 Bits, 720 x 480, 29.97 fps
Lower Field First
(DVD-NTSC), 4:3
Video data rate: Variable (Max. 8000 kbps)
Audio data rate: 224 kbps
MPEG audio layer 2, 48 KHz, Stereo

I used the Frame Based file for burning since it fits in a 4.7Gig DVD, and I had no problems. So, please help me understand why I should use Field Based files instead of Frame Based files. I not being facetious, I am genuinely interested in learning.

Thanks for any advice.

[Ken Berry]

I don't pretend to understand the technicalities involved, but as I understand it, the Frame Based captures you make with your DX2 are in effect synonymous with progressive scan used by digital TVs these days. Thus, if you yourself have a digital TV of some kind, it is more than likely to have progressive scan, and your Frame Based DVD will play back with no problems.

It might not be the same, though, if you play it back on an older analogue TV (which might, after all, happen if you distribute your masterpiece widely among family and friends, at least some of whom may have older TVs and DVD players). Video played back on analogue TVs comes in two fields, Upper Field and Lower. Only when the two are broadcast does a full image appear on your TV screen. A still image/photo is just one Frame and does not need fields. And Progressive Scan as I see it is a sophisticated way of showing proper video as a succession of single frames which a digital TV can read and display properly without Fields.

I stress, though, that I don't know that a totally Frame Based DVD involving video clips (as opposed to slideshows of still photos), may not play well over non-progressive scan TVs. And I would also be more than interested in any answer from someone more knowledgeable than I which might shed further light on this subject.

[jchunter]

Alex,
You would probably like your analog video better if you set the capture properties in CapWiz to Upper Field First. I think the property settings are on the last screen. Caution: most, but not all analog is Upper Field First.

The usual symptom of incorrect field order is that moving objects seem to jitter. If UFF jitters on playback, use Frame Based.

[daniel]

I stress, though, that I don't know that a totally Frame Based DVD involving video clips (as opposed to slideshows of still photos), may not play well over non-progressive scan TVs. And I would also be more than interested in any answer from someone more knowledgeable than I which might shed further light on this subject.

In the (2) companies I worked for, they just display the fields and double its lines, in effect giving you two consecutive picture of 240/288 thick lines.
The good news is that very few people see the difference (even when informed about what they see). You fool the eye much easier than the ear.

People cried from joy when AM radio was replaced by FM.
They threw away their vinyls when CDs came. Bought it all again.
There are lots of home-cinema audio setups, and the advantage is really small over stereo.

BUT, they sold VHS to about everybody and they are few who demand high definition TV. It's been available for ten years and the industry and the public are very slow to switch. And in our homes only now are (standard) DVD recorders becoming mainstream.
The essence of vision is movement, all the rest are details, except for experts.
If the movement is right your eye is happy. Check how many posts here relate to picture quality VS wrong field order...

[rawcoconut]

Thank you all for your replies,

Alex,
You would probably like your analog video better if you set the capture properties in CapWiz to Upper Field First. I think the property settings are on the last screen. Caution: most, but not all analog is Upper Field First.

The usual symptom of incorrect field order is that moving objects seem to jitter. If UFF jitters on playback, use Frame Based.

John, I did not find a way to set the capture properties in CapWiz. I'm using version 3.8.0.3 dated Feb 6, 2006. I did read a help document in CapWiz on Video Formats that said:

"MPEG-2 file for DVD
The most commonly used video compression standard today is MPEG-2, which is used on DVDs, satellite television, digital cable TV and HDTV. MPEG-2 yields highly compressed files of extremely high quality. There are a couple things you should consider about this format.

First of all, MPEG-2 files for DVD are captured at full broadcast resolution. NTSC MPEG-2 (DVD) is 720x480 pixels, while PAL MPEG-2 (DVD) is 720x576 pixels. This fairly large resolution implies that the MPEG-2 file size is bigger than MPEG-1. A two hour movie will use up about 4 GB of hard drive space.

With that in mind, MPEG-2 is an excellent choice for any type of movie. Your new video capture hardware allows you to capture directly from your camcorder or other video source directly to the MPEG-2 format. You can then use the included Video Studio application to perform frame-accurate editing, and author a DVD movie that can be played directly on a home DVD player or the DVD-ROM on your PC.

Instant DVD + MP3 allows you to set specific bit rates for capture from 2 mb/sec. up to 15 mb/sec. Keep in mind that most Hollywood DVD are produced at 4.5 mb/sec. this allows up to 133 minutes of audio and video on a DVD disk. With the ability to capture MPEG-2 and create DVD movies at 4 or 5 mb/sec. with variable bit rate you can produce video with the same high quality achieved on Hollywood DVD movies.

The DVD Xpress DX2 uses a very sophisticated motion detection algorithm that examines each frame of video as it is being processed and automatically adjusts the video bit rate to achieve the best quality video. This is called variable bit rate encoding an generally results in the best quality video with the lowest overall file size. Since the goal for most of us is to get the best quality video and the maximum amount of video on a disc, variable bit rate encoding is a great advantage."

What puzzles me most is that, using the "Video in DVD Format (MPEG-2)" selection in CapWiz, I captured a 111min video that was only 1.8Gig (which implies that I can fit about 4 1/2 hours into a DVD) and this help article says: "A two hour movie will use up about 4 GB of hard drive space." I've captured 2 videos about the same length using this same settings and they are both about the same size.

I thank you all for your wisdom. I'd like to learn more so I can improve the quality of my movies.

[jchunter]

I tried to open my ancient version of Capwiz (v3.1.03), which I haven't used for many moons and it crashed immediately, so I can't give you any guidance on how to set up the capture properties in your newer version. But in my version there was a menu item in the last Capture screen and then I had to drill down a bit, but could set up just about any capture property.

Your help file should give you some help for your version.

What puzzles me most is that, using the "Video in DVD Format (MPEG-2)" selection in CapWiz, I captured a 111min video that was only 1.8Gig (which implies that I can fit about 4 1/2 hours into a DVD)

Something is definitely wrong, here, because at an 8Mbps video bitrate, one hour of video will fill a DVD with about 4GB of video.

This suggests that the capture properties are screwed up and that there must be a way to set them properly in your version of CapWiz!

BTW, I used to also capture analog with Video Studio 9 and could set up capture properties but the installation was dicey - I had to install ADSCirrusUSB2RC.dll and ADSCirrusUSB2RC.dll in Program Files\Ulead Systems\ Video Studio 9.0 folder. (BTW, these interfered with the Video Studio 10+ installation and I had to disable them)