Field order

dprozzo · Post by **dprozzo** » Fri Mar 03, 2006 3:59 pm

I am checking out VideoStudio 9 trial.

I'm using Plextor GoCap to capture analog tape, and am trying to use the Recommended Procedures in the sticky, which indicate I should select "Upper Field First." GoCap doesn't include this setting. After I perform the capture, VideoStudio indicates that it is "Frame based."

What does this mean, and how does this change the subsquent steps?

GoCap also has two additional settings: "Sequence," which if checked gives 3 choices, IBP (default), IP only, I only. And "GOP Size," which if checked has a default value of 15.

What are these settings? What is the best setting for them....the default for both of them is to be checked.

Thanks for posting the Recommended Procedures; my opinion of VideoStudio is higher after following them.

Thanks

Trevor Andrew · Post by **Trevor Andrew** » Fri Mar 03, 2006 4:25 pm

Hi

Frame Based is used for PC playback.

Field based is associated with TV playback.

Field ‘a’ or ‘lower field’ is usually from a digital source.

Field ‘b’ or ‘upper field’ is usually from an analogue source.

Trevor

ps welcome

dprozzo · Post by **dprozzo** » Fri Mar 03, 2006 5:32 pm

So, how then do I obtain an mpeg as "upper field," because ultimately I want a DVD to want on my TV? Or will it make much difference?

It appears that I can change from frame-based to upper field when I go into Project Settings, but this produces a subsequent Rendering that takes forever.

What to do?

Trevor Andrew · Post by **Trevor Andrew** » Sat Mar 04, 2006 4:39 pm

Hi
I am not familiar with the Go Cap software. Others on the forum may be able to help.

But if you cannot select a field order, upper or lower then the software may be restricted in capturing Frame Based.
This would normally be used for pc monitor viewing over the internet.
I have surfed the web and cannot find any reference to field order and GoCap.

Extensive editing in Mpeg format is not recommended.
Saying that:-
Once you have edited your project, you have to Create a Video File, this will be dvd compatible and used to burn a disc. This process should be carried out for every project you do.

Its at this point that you have to select your settings and in your case the field order.
Normally you would choose the same as the captured order.
i.e. Analogue capture is Upper—Digital Capture is Lower

The properties of this file has to have a field order, as your original file is Frame Based then choose Lower Field First aka Field ‘A’

The quality of your dvd is controlled by the Bit Rate.
A rate of 4000 is VHS quality
A rate of 8000 is Top quality Dvd

As your source is Vhs then I would use 4000 for capture through to burn.
This will allow you to fit 2 hours onto a single dvd.

Use the ‘Custom’ option from Share Create Video File.
I am in Pal country but would use these settings for Ntsc.

MPEG files
24 Bits, 720 x 480, 29.97 fps
Lower Field First
(DVD-NTSC), 4:3
Video data rate: 4000 kbps Constant.
Audio data rate: 256 kbps
Dolby Digital Audio, 48 KHz, 2/0(L,R)

Rendering will take a long time, (forever as you say) depending on what you are converting, and the spec of your pc. (fill this in on your forum profile)
Expect 2.5 times the run time.

All the Best

Trevor

dprozzo · Post by **dprozzo** » Sun Mar 05, 2006 4:39 am

Thanks Trevor.

I find this very confusing, but I think I've got it.

sjj1805 · Post by **sjj1805** » Sun Mar 05, 2006 5:14 am

To answer your other query regarding the GOP structure.
This comprises of I Frames P Frames and B frames. there are usualy 15 frames in a GOP but you can have less or more.

It is a part of the MPEG compression process where the I frames form a complete picture, the P and B frames merely note the changes to that picture.

If you have filmed a "fast action" video such as racing cars then you may wish to alter the GOP from the standard 15 frames to something smaller.

Terry Stetler the Moderator of the MSP forum has written an article here:
http://phpbb.ulead.com.tw/EN/viewtopic.php?t=10880

Regards
Steve J

dprozzo · Post by **dprozzo** » Sun Mar 05, 2006 5:46 am

Well, I thought I had it.

I appears that all my captures are VBR, no option to change it in GoCap. Should I carry this all the way to the DVD, or change to constant.

(I see that you suggest constant bit rate above, but I didn't know you realized that the original capture is VBR.)

sjj1805 · Post by **sjj1805** » Sun Mar 05, 2006 6:08 am

Trevor has answered correctly except for the fact that Variable Bit Rate is the recommended setting.

The information is in the "Recommended Procedure" here:
http://phpbb.ulead.com.tw/EN/viewtopic.php?t=27

Regards
Steve J

Trevor Andrew · Post by **Trevor Andrew** » Mon Mar 06, 2006 8:39 am

dprozzo wrote:Well, I thought I had it.

I appears that all my captures are VBR, no option to change it in GoCap. Should I carry this all the way to the DVD, or change to constant.

(I see that you suggest constant bit rate above, but I didn't know you realized that the original capture is VBR.)

Hi dprozzo

I was unaware of the further limitations of your capture device, Go Cap.

Whatever properties you use to capture your Mpeg, use these properties wherever possible through-out the whole video process including the burner stage.

In your case use Variable Bit Rate.
The Frame Based option should be rendered to a Field Order (Upper or Lower) during the Create Video File stage. Unfortunately the choice may be a case of trial and error, but I would use Lower Field.

Variable Bit Rate

This uses an amount of data depending on the action within the video.
A lot of movement / action gets more Kbps (max limit).
Less movement receives fewer Kbps.(lower limit) The resulting file being very good quality with the advantage of reduced file size compared to using Constant bit rate.

A bit-rate setting of 8000 max variable will produce an upper and lower limit of 8000, and is exactly the same as selecting Constant. The variable effect is more noticeable as the rate is reduced.

I am not convinced that the Variable rate has any advantage to the quality of my video and at the moment use the Constant rate.
Its just a personal choice.

Hope these comments do not confuse the matter further

All the Best

Trevor

dprozzo · Post by **dprozzo** » Mon Mar 13, 2006 7:29 pm

Thank-you.

Another question: Other things being the same, and capturing from analog VHS, will I be able to see any improvement in clarity, less blurring with movement, etc by increasing the bitrate from say 6000 to 8000?

sjj1805 · Post by **sjj1805** » Mon Mar 13, 2006 8:24 pm

Please view this post you will find the answer in here.
http://phpbb.ulead.com.tw/EN/viewtopic.php?t=11379

Regards
Steve J

dprozzo · Post by **dprozzo** » Mon Mar 13, 2006 9:09 pm

quote:
Quality levels depend upon how much you want to squeeze onto the DVD.
Standard play = Bit rate 6400, Peak 8000 Variable – approx 1 hour
Long Play = Bit rate 4800, Peak 6200 Variable – approx 1.5 hours
Extra Long Play = Bit rate 3000, Peak 4400 Variable – approx 2 hours

I was aware of this, but what I was wondering: Since analog VHS video isn't very high quality, especially if it is a recording of a TV show, do the highest bitrates translate into a discernably better video on the final DVD?

In the "recommended procedure," a bitrate of 4000 is suggested, but it seemed that there the emphasis was on putting as much on the DVD as possible.

Put another way, is there a bitrate threshhold, above which doesn't really give you anything better to view?

sjj1805 · Post by **sjj1805** » Tue Mar 14, 2006 12:05 am

From reading a number of posts in this forum over a period of time, the concensus of opinion amongst the veteran users is that for video originating from VHS then nothing is to be gained by going above 4000.

Regards
Steve J