Hi...sorry for this stupid question.

I'm confuse about de-interlace and interlace. When making VCD, is it always to de-interlace the captured video? Is the de-interlacing process done through editing, such as an deinterlace field option in Adobe Premiere, or through the export setting for final video file?

Such MPEG1 encoder like Panasonic and TMpeg has an advance setting to de-interlace an input source. Should I turn it on or leave it alone to get a good VCD result?

Why SVCD or DVD produce a 'comb like effect' when seeing on PC monitor? Are MPEG2 files always interlaced?

-- Beni K. (b_kartono@hotmail.com), October 17, 2000

Answers

VCD calls for non-interlaced files. Even if you do not specify "interlaced" you will get a progressive file if you compress to VDC specs. However, you can get a cleaner compression by specifying "deinterlace".

Most MPEG players (Windows Media, Direct Show, etc) cannot handle interlaced files and give a "comb" effect at higher vertical resolutions. DVD/SVCD players like Power DVD do handle interlaced fields and produce good images on a PC monitor, assuming you have the processing power (500 Mhz or so) to make them run smoothly.

If your display device can deal with it, interlaced MPEGS do a better job with high-motion scenes.

-- Paul Hamilton (p_hamilton@pipeline.com), October 18, 2000.

paul,

so, it sounds like you can encode to mpeg1, interlaced, if the source is interlaced by setting your encoder for mpeg1, non-VCD standard, compression, right?

should this always be the setting if you are burning mpegs to VCDs for t.v. viewing exclusively?

-hitechjunkie

-- hitechjunkie (jconde@tidalwave.net), October 18, 2000.

When the VCD template of any encoder is chosen the result will always be one field (240/288 lines), which, when played back later by the VCD player will always be displayed twice to produce a frame. One full frame is made up of 480/576 lines, composed of two fields of 240/288 each, "interlaced" (meshed, one line after the other). When this matter is looked at this way it becomes clear that at the end of the day interlacing has little relevance to matters VCD, except, maybe, when: you captured full interlaced 480/576 to begin with, and prior to encoding you have to either tell the encoder which field of the two there are specifically it is you want it to encode for the 240/288 output we are all after; or tell it "non-interlaced" which will make it, by default, take the first field it sees and take it from there. If you captured 240/288 to start with then this interlacing thing has no relevance to VCD templates because there is just one field present which means it's pointless to choose between field A or B (because ONLY A or B is available) or to tell the encoder "non-interlaced". Deliberately taking just a field that makes up our 240/288 spec instead of one whole frame contributes to VCD MPEG-1 having the low CBR it has. Sly, no? MPEG-2, though, for DVD and SVCD purposes, uses the whole frame and IS therefore duly interlaced, which is what you'll have to tell the encoder. One other thing that could be a problem here in MPEG-2 is specifying the field order during capturing and/or encoding so that it plays back properly.

-- MT (turk690@yahoo.com), October 20, 2000.