ntsc source and resizing

[azurenights]

The problem I am having with the svcd I created is that the picture looks bigger and a little stretched on the svcd than on the DVD video. The letterboxing is the same on both the dvd and svcd. I could tell there was a difference because the subtitles looked bigger on the svcd than on the dvd. Does anyone know what my problem is?? I used decomb 3.4 to ivtc and then used pulldown to convert the movie back to 29.97 fps. Here is my avs file

LoadPlugin("c:\vid\mpeg2dec.dll")
LoadPlugin("c:\vobsub\vobsub.dll")
LoadPlugin("c:\decomb\decomb.dll")
mpeg2source("c:\Killer\killer.d2v")
Vobsub("c:\killer\subs\vts_01_0")
BilinearResize(480,480)
Telecide()
Decimate(cycle=5)
audio=wavsource("c:\killer\ding.wav")
resampleaudio(44100)

Have I resized it wrong?? In CCE I encoded enabling progressive frames. I hope you guys can understand what my problem is here. If you didn't the problem is that the picture on the svcd looks a little magnified and I can tell by the increase in the size of the subtitles. The aspect ratio of the movie is 4:3 and it is interlaced.

thanks guys

[Wilbert]

Assuming your movie is 720x480 you have to:

1) resize to 480x416 (see below)

2) add black borders (480-416)/2 = 32 vertically to get the resolution 480x480, in aviscript the last will be:

BilinearResize(480,416)
addborders(0,32,0,32)

As for (1). The resolution 720x480 is the same as 480x320 (scaled).
Suppose you resized to 480xV and added black borders to obtain the resolution 480x480. When viewing full screen (thus 480x360) the vertical size of your image, V, will be squeezed by a factor of 360/480 = 3/4 and this must be equal to 320 when played correctly. Thus 3/4 * V = 320 and it follows that V = 427. Since it must be a multiple of 32 the vertical size will be 13*32 = 416.

[azurenights]

thanks for the piece of advice

do you have to resize like this for all ntsc sources?? won't that mean things like anime will have letterboxing???

the movie I am encoding has letterboxing already. if i were to add borders on the top and bottom will that mean the letterboxes will get bigger???

do you have any faqs or guides to show me about ntsc resizing?? thanks

[hoops10]

If you are encoding an NTSC dvd, then you have to resize this way:
BilinearResize(480,360)
AddBorders(0,60,0,60)

SVCD needs to be 480,480 for ntsc. The numbers in the addborders command equate out to 120 which when added to the 360, gives you 480. Hope this makes sense.

[azurenights]

hoops10 i think you only resize in that fashion when you encode a ntsc movie that has an aspect ration of 16:9

the movie i am encoding is only 4:3 so I don't think it will resize correctly. Thanks for your input anyways

[Kedirekin]

You're right. Resize to 480x360 (with borders to get back to 480x480) is only appropriate if you want to letterbox and anamorphic NTSC DVD. For full screen NTSC DVDs, your resizing to 480x480 is correct.

Are you playing the DVD and the SVCD on the same player? The only reason I can think of for why they might be different size is different players with different mpeg decoder/overlay firmware. Even then, 480 scan lines is 480 scan lines, so there shouldn't even be any difference between players (at least vertically).

Wait a sec - one additional thought. A DVD does a 720x480 overlay on a 720x480 video stream. An SVCD does a 720x480 overlay on a 480x480 stream. I wonder if that makes a difference. Can you compare the relative size of just the video (maybe by choosing a 'landmark' that is just on the edge of the screen). Perhaps it is only the size of the subtitle overlay that is changing.

[Kedirekin]

Wait another sec. I see you're doing permanent subs. I wonder if that's the cause of the difference.

The two would only be the same if the coordinate system for DVD overlay is exactly the same as the coordinate system of the video stream, and I don't know that it is. I don't know that it's not either (and I don't see any reason why it would be), but I don't know that it is.

Not much help, I suppose, but at least it's something to think about.

[azurenights]

damn so you have no idea at all eh??? I am playing the DVD and svcd on the same player but I not only compared the subtitles but the pictures as well. Have you ever had this problem before?????

Do you think it could be the ivtc that affected it or using progressive frames in cce when encoding??? thanks

[Kedirekin]

No I guess I really don't know what's causing it. IVTC shouldn't affect the size at all. Neither should encoding it progressive.

It almost has to be something in your stand-alone player. Something in the firmware that produces different results converting the 480x480 SVCD resolution into the analog TV signal than when converting the 720x480 DVD resolution.

I've never noticed any difference on my player, and I actually use two different stand-alones. Is the difference large? Is the difference only in the horizontal direction? That'd be a little easier to understand (going back to the 480 scan lines thing).

I fear that if this is really bothering you, you may have to solve it empirically; use trial and error to determine what resize settings give you an SVCD that plays back the same as your DVD on your player. Of course, I don't know what affect that will have if you ever switch to a different player down the road.

[azurenights]

I definately think their is overscanning cause I played the svcd on my computer and it played exactly like the dvd.

I think it must have something to do with the firmware!!! damnit!!!!!
Is it possible to get it changed you think?? my player is a pioneer dv 344 which is the australian version of the pioneer dv 343.
How do you convert ntsc to pal when encoding????

do you think I may not encounter problems if the ntsc signal is 4.43 instead of 3.58???

thanks again for posts they have been really helpful

[Kedirekin]

Overscan is an effect that originates in the TV, not in the player. Your DVD 'should' exibit the same overscan when played in your stand-alone.

[Aside: Incidentally, I heard that you can have your TV adjusted (by a professional) to virtually eliminat overscan. I personally don't think it's worth the effort.]

[Another aside: Incidentally, I've also heard the new 16:9 TVs don't suffer from overscan.]

The only thing I can think is the player is actually producing a different analog TV signal - with a larger or smaller horizontal scan sawtooth resulting in a wider or narrower picture (which pushes more or less into the overscan area of your TV).

I don't know if you can update the firmware on the Pioneer dv 344. I also don't know if it'll help. you might try asking in the hardware forum. You might also ask at vcdhelp.com. I believe they're more into the player side of things.

I've never tried to convert between NTSC and PAL. I believe DVD2SVCD has this feature built in. I basically boils down to changing the resolution and the framerate, and adjusting the audio to match.

I'm not sure what you mean by 4.43 vs 3.58.

[azurenights]

the 4.43 and 3.58 refer to the different ntsc signals. My TV supports two different ntsc signals one which is 4.43 and the other is 3.58

anyways I figured out my problem and I feel like the biggest idiot. A think maybe a week ago I changed my video settings on my dvd player to 4:3 pan and scan. I figured this out cause I tried playing a pal svcd and it was having the same problem. DUH!!! I am so @!#$@#$ stoopid

Kedirekin thanks so much for your help and advice. I appreciate it heaps. You always seem to reply to my problems and I thank you for that!!! later