Is SVCD worth it for a VHS stream ?

[iparout]

Hi there. I am capturing from my VHS and want to encode the captured video to VCD or SVCD.

I am in a great dillema here cause I have read that SVCD is not worth it for a low-quality signal like VHS. and that VCD is the best deal for getting your VHS movies on CD.

Can you guys give me your ideas on this ? What do you believe and which option (VCD or SVCD) do you use for encoding video captured off your VHS ?

I appreciate it.

[J.O.N]

If your VHS footage is interlaced (i.e. from video not film) then SVCD is required to maintain the 'video look'.

J.O.N.

[iparout]

Hmmm... What do you mean video not film ? Most of it was recorded off TV... In which category does this belong ?

[Peter B]

I use SVCD where ever possible.

Yes VHS is only about the same resolution as MPEG1 used in VCD, however, SVCD can be varaiable bit rate and therefore allocate more data to the busy/action sequences and less to the parts that don't need it. This can reduce blocky "noise" in the final product as VCD is constant bit rate only.

Note also that broadcast is hiqher resolution than VHS (apporx 240 lines res for VHS, 350-400 lines for broadcast reception), therefore if you have a s-vhs source, eg High quality TV, S-VHS VCR, internal TV card etc with s video out and s-video into your capture device you will get better than VHS quality.

Note most 1 hour TV programmes are about 40 minutes with the adds removed and easily fit with MPEG2 quality on to a SVCD.

The only reason to use VCD format is if you want more than 50 minutes on a CD, though depending on your DVD player there are "illegal" formats that can record more at higher quality if your DVD can read them, have a look at www.vcdhelp.com for these formats and more on SVCD/VCDs or www.doom9.org also has a lot of information on SVCD/VCD formats.

[J.O.N]

Depends if what you actually recorded was itself recorded on video or film!

Er, this is quite difficult to explain but visually its totally obvious. Video looks a certain way because the picture is recorded 50 times a second (using PAL times here) on each field. Film is recorded 25 frames a second and looks a different way. If you put video originated footage onto a VCD it will give it a 'film look' because the format does not support two different fields in each frame. In film this would just reduce the vertical resolution, in video this will lost half the motion captured.

J.O.N.

[iparout]

Nice suggestions here guys... Thanks a lot.

[Flying dutchman]

Another problem is, VHS contains quite a lot of tape noise. If you want to encode this to Mpeg-1 or 2 and get any reasonable quality, you must filter-out this noise else the mpeg encoder wastes a lot of bandwidth in encoding noise.

I use "VirtualDub", and get quite good results using the following filter setup:

- 1) Use the "Levels" filter to make sure the output luminance is between 16 and 235. "Black" corresponds to 16 and "white" to 235. For PAL DVD players, rather use the range 0-235.

- 2) "smart deinterlace", but only if the source material originates from film. This way you can obtain the original progressive frames.

-3) Use the "DNR" filter at strength 8-12 to remove noise. This magnificent filter removes noise without blurring.

-4) For VCD, use the simple 2:1 resize filter. This has the pleasant side-effect that it improves S/N ratio tremendously by averaging 4 pixels into one. It also does a smooth, eye-pleasing de-interlacing if the source material is interlaced. For SVCD, rather do a BILINEAR resize to 480x576 (PAL) or 480x480 (Ntsc). Avoid bicubic scaling because it amplifies VHS tape noise, and noise is a killer for Mpeg.

[Peter B]

Hi

Flying Dutchman, I use most of your techniques (1,2 & 4) but I do not have a DNR filter in Virtual Dub, is this an available plug in?

[Flying dutchman]

Hi Peter,

DNR is an available plugin by Steven Don. I really
can't do without that one!


There's a good overview of available filters on:

http://sauron.mordor.net/dgraft/mine.html