roxy99

User Group: Members
Join date: 26-Mar-2007
Last activity: 30-Mar-2007
Posts: 6

Post History

Post: #279913
Topic: Panorama() - an AviSynth function for converting 4:3 into 16:9
Link: https://originaltrilogy.com/post/id/279913/action/topic#279913
Time: 30-Mar-2007 11:55 AM

Ahh I Understand now. Is there a picture quality penalty to using the extra resize factor? I suppose you can also execute a ConvertYUY also.

Compared to executing a ConvertYUV() and then using exact resolution versus the 4 factor adjustment, which approach is better for
(a) Picture quality
(b) encoding speed

I realize colorspace conversions are lossy but aren't resizes also lossy?
Please excuse the questions just trying to learn.

Post: #279910
Topic: Panorama() - an AviSynth function for converting 4:3 into 16:9
Link: https://originaltrilogy.com/post/id/279910/action/topic#279910
Time: 30-Mar-2007 11:08 AM

I hava another question Moth3r.

Why does the function expand the horizontal resolution by a factor of 4? What I mean is that if you look at the result of the stack horizontal then you end up with an avi with a resolution of 2880xht (ht= 480 or 576) just prior to the resize to 720xht.

Could'nt we have just calculated rezize horzontal values for each wedge ( a,b....g ) such that the total already is 720xht?

Post: #279617
Topic: Panorama() - an AviSynth function for converting 4:3 into 16:9
Link: https://originaltrilogy.com/post/id/279617/action/topic#279617
Time: 28-Mar-2007 10:50 AM

Thank you. Actually I don't mind cropping because the same principle applies whether using an xvid or standard mpeg2. That is, I want a compromize between moderate cropping and moderate distortion. If I crop a little off the top and bottom, then maybe I don't need to use a strengh of 3 and hence there is less disortion needed to achieve the same screen coverage.

You have a point about the blackbars being a waste. By expanding the vertical resolution with 640x384, I end up with minor pillar boxes anyway because it will place a 1.66 video on a 1.78 AR screen. So this way I don't waste bitrate whereas by adding blackbars I Xvid ends up allocating cpu cycles for nothing. The only drawback to this is that the center portion of the screen will be distorted vertically a little.

Post: #279519
Topic: Panorama() - an AviSynth function for converting 4:3 into 16:9
Link: https://originaltrilogy.com/post/id/279519/action/topic#279519
Time: 27-Mar-2007 5:29 PM

I get it. Mpeg2 for DVD by definition MUST be 720 x 480.
So it has to do with anamorphic ar on DVD then? If you burn to DVD the panorama converted avi then the resultant mpeg2 will play back in 16:9 resolution suitable for widescreen tv.

In that case given I am producing an Xvid mpeg2 is not applicable and I should add another resize at the end as follows:

lanczos4resize(688,508)
crop(0,14,0,-14)
addborders(16,0,16,0)
panorama(3)
lanczos4resize(720,400) [ or lanczos4resize(640,352) ]

Is that correct?

Post: #279484
Topic: Panorama() - an AviSynth function for converting 4:3 into 16:9
Link: https://originaltrilogy.com/post/id/279484/action/topic#279484
Time: 27-Mar-2007 12:24 PM

I have a question. When I call your function with a 720x480 (ntsc) source, using DGIndext to frameserve an mpeg, it still produces a 720x480 output.

Ie:

I created an avs script using a d2v file of a DGIndex frameserved mpg source with these commands:

lanczos4resize(688,508)
crop(0,14,0,-14)
addborders(16,0,16,0)
panorama(3)

In virtualdub I the loaded that script to produce an xvid file. I expect that the output avi resolution would have been 720x405 to yield 16:9 AR, however the avi was still 720x480. I am wondering does it automatically get stretched to the proper 16:9 AR whem played back on widescreen? Because on my 4:3 computer monitor the image appears stretched vertically.
Whats interesting is when I play the avs script in WMP, the AR appears to be 16:9 on my 4:3 computer monitor (letterboxed). The outputed final xvid avi product however plays back on my 4:3 monitor as being stretched vertically to fill the screens with no letterbox. What am I doing wrong?

Thanks

Post: #279330
Topic: Panorama() - an AviSynth function for converting 4:3 into 16:9
Link: https://originaltrilogy.com/post/id/279330/action/topic#279330
Time: 26-Mar-2007 4:59 PM

Moth3r,

I just wanted to first of all thank you for this ingenious function. Its is brilliant the way you managed to use existing avisynth commands to produce a very useful function.

I'd like to take advantage of your work in a non-commercial avisynth batch file that I have produced here http://forums.sagetv.com/forums/showthread.php?t=21932

Do I have your permission to modify my batch batch file posted at SageTV using your code? How would you like me to credit your work so that others will see your contribution?

Thank