My VCD's WORK!!! But I have a question?

[MrCairo]

First I'd like to thank ALL who have posted here and those that keep this site alive and kickin'!!! Without you I would of "never" figured out as much as I have! So "Thank you"
Ok...I have ripped and burned and watched several VCD's now and everything is working pretty good I think. I use DVD Dycrypter to rip and
DVD2AVI to convert and TMPGEnc to encode.
But I have a question about some of the guides found here. The part I'm curious about is where they talk about the "Expert setting for Source", on some of the guides the video type is "non-interlace" on others it's "interlace" and I'm not sure about the Field Order either, some say Top Field First and other's say Bottom.
Could anyone tell me what these settings mean and/or if I need to really worry about them? Does it have something to do with if your file is one file with both video and audio combined? I always have two files, an .avi and a .wav
So anyway I was just curious and wondering if a change in these settings would help or hurt how the VCD turns out.
Hope this isn't "that" stupid of a question...like I said "I am learning!"

Thanks,

MrCairo

8)

[adam]

Interlacing is a process where each frame is split into two fields. One field contains all the odd rows of pixels and the other contains the even ones. Picture it like two combs. When played in sequence all you see is the single frame but its actually two separate pictures.

If your source is progressive (non-interlaced) its simply one frame after another, no fields are present. Its important to let your encoder know what your source is so it knows what to do with it. This is what the "Expert setting for Source" box is. You can determine whether your source is interlaced or progressive in dvd2avi.

The field order is the sequence of these fields, either top (odd) first or bottom (even) first. Again, its important to tell the encoder what your source is. The best way to determine your field order is to load your file in TMPGenc and go to the advanced tab and double click on the deinterlace filter. Set the filter to Even-Odd Field (field) and scroll through your movie. If it looks ok your field order is fine. If it plays a few frames then jumps backward every sec then your field order is incorrect.

Now having said all that, since your making vcds it probably doesn't matter what you use for these settings, though its always a good idea to get them right anyway. Vcds do not support interlaced output so if your source is interlaced the encoder will simply throw away one of the fields, regardless of whether you tell it that its interlaced or progressive and regardless of what your field order is.

If you ever start making svcds or dvds then you should definitely pay more attention to these settings and ensure that they are set correctly.

[Akai Rounin]

Primer on Interlacing...

adam: Thanks a lot for a well stated response. I must admit, this is something that I did not fully understand as it applies to digital media. I had been under the impression that interlacing was strictly the function of the display device used to watch video. I had no idea at all that a video source could be encoded as interlaced or progressive. I assumed that all sources were progressive by default and that the display device simply did its best to adapt as needed.

I do have a few questions though... Why are video sources interlaced on DVD to begin with? I mean, NTSC television sets are interlaced by standard, with 30 frames per second, 60 fields per second, refreshing each display line at 60 Hz. I don't see how interlacing the video data on disc would improve quality...

If anything it would seem to be a way to degrade it instead, as all the data for a single frame would be divided in two. Is this done as a security measure to prevent the playing of these DVDs in different (PAL) territories? Aren't PAL television sets all progressive scan? Is it done to conserve disc space? Is there any technical advatange to be gained from having the DVD source interlaced, or is this just a means to hide Macrovision within the display signal?

Unta Glebin Gloutin Globin,

Akai Rounin, The Cyber Sage

[MrCairo]

Thanks a lot adam! That was very informative and helpfull. Sorry it took so long to post a reply....I just got home and it was a very long Friday at work. I hope to soon get a dvd burner and I'll tackle the learning curve for that, and your explination I'm sure will help me with that!
And I'm glad my question helped you too Akai Rounin! I guess it's true what they say..."if you have a question, you can bet there is someone else with the same one not far away"

Have a Great night and weekend everybody!

Best Regards,

MrCairo

8)

[banjazzer]

Aren't PAL television sets all progressive scan?

Almost all PAL DVDs are progressive. The very few interlaced ones seem to be from TV material,and I've only come across 2 interlaced movies.