Resizing question

[bigggt]

Hello guys

I use DVD mode for my dvd backups and also use D2Sroba

I am a little confused on resizing with dvd2svcd

I would like to fit 2 roughly 2 hour 16:9 movies on 1 dvd and have been doing this for a while now using this

[AVISYNTH_DVD2DVD_NoResize]
0=Undot()
1=Deen()
2=DCTFilter(1,1,1,1,1,1,0.5,0)
3=Letterbox(16,16,16,16)

I did some searching and found this by jsoto

[AVISYNTH_BicubicResize_DVD_16_9_noresize_704x576_KISS]
0=Undot()
1=Deen()
2=BicubicResize(704,576,^b_value,^c_value)
^b_value=0.00
^c_value=0.60

so I would like to know if this script will be ok to resize to 704x480 and if there can be any improvments

[AVISYNTH_BicubicResize_DVD_16_9_noresize_704x480_KISS]
0=Undot()
1=Deen()
2=DCTFilter(1,1,1,1,1,1,0.5,0)
3=BicubicResize(704,480,^b_value,^c_value)
^b_value=0.00
^c_value=0.60

thanx

[Nick]

Well, your initial script looks best to me. You are cropping out TV overscan and using KISS filtration along with DCTFilter at the end which should significantly improve compressibility.

I am not sure what you aim to achieve by resizing to 704 horizontal pixels. If the source DVD is 704x***, the resize line will be completely ignored anyway, as if source x,y parameters match resize x,y parameters, Avisynth skips the resize command altogether. If the source is 720x*** then resizing to 704 will cost you quality.

The only other thing I can think of that is worth a try is CVD framesize (352x480). A 16:9 CVD encode is NOT DVD-VIDEO COMPLIANT but most players will play it. Note that DCTFiltering should come at the very end of the script for best results. Also, since 2x352=704, Resizing from704 to 352 works better than from 720 as you are dealing with direct multiples. I find Bilinear resizing good for this.

From a 704 framesize DVD a decent script would be

[AVISYNTH_BilinearResize_DVD_16_9_HALFSIZE_704x480_KISS]
0=Undot()
1=Deen()
2=BilinearResize(352,480)
3=Letterbox(8,16,8,16)
4=DCTFilter(1,1,1,1,1,1,0.5,0)

Or from 720 source

[AVISYNTH_BilinearResize_DVD_16_9_HALFSIZE_720x480_KISS]
0=Undot()
1=Deen()
2=BilinearResize(352,448,8,16,712,464)
3=Addborders(0,16,0,16)
4=DCTFilter(1,1,1,1,1,1,0.5,0)


This latter script will intoduce a miniscule AR error but I sincerely doubt it would be noticeable and a worthy tradeoff for added compressibilty.

EDIT - The advantage of CVD framesize, by the way, is a trade-off between resoultion and bitrate. Although resizing will inevitably lose detail, there is only half the physical data to compress for each frame so the low available bitrate can be put to better use, decreasing MPEG artifacts and blocking. Try it. For 4 hours of video on 1 DVDR I think you might find the results pleasing.

EDIT AGAIN - Error in second script. Corrected.

[bigggt]

Thanx Nick