Need help with calculating bitrate with odd aspect ratio

[Neishaverse]

I'm putting some TV shows on DVD, and the quality isn't the biggest issue for me.
I was gonna put 6 Episodes (23 min each, so full DVD=139min) per DVD.
I was going to capture at either 352x480 or 352x240
I used the DVDRHelp.com calculator, but because I'm not using 720x480 I'm not getting the best bitrates for my project.

I downloaded fitCD, but it's alittle more confusing then I can figure out.

Can someone tell me the best way to figure out what my best bitartes for my project would be.

Barney

[andkiich]

I know this doesn't seem right, but if your encoding at MPEG-2, resolution doesn't effect bitrate. Whether it's 720X480 or 352X480, the bitrate calc doesn't change.

Just remember, though that a lower bitrate will be more acceptable with a lower resolution, so some experimenting on your part will be needed to find out what is acceptable to you.

As far as bitrate calculators go, I wrote my own, but I based it's functionality on the online Java calculator found right here on this site under the TOOLS section. I think it works just fine, so check it out.

[Neishaverse]

So if I capture at 720x480 with a bit rate of 3.95MBps I'm going to have the same file size if I capture at 352x480 with the same bit rate? I would imagine the file would be smaller because the image size was smaller.

The only reason I'm using a lower capture size, is because I feel the quality will be too blocky for 138 minutes encoded 720x480 at only 3.95MBps.

My goal was to drop down resolution and maybe boost up the bit rate to compensate.

My masters are 10 year old VHS tapes, so the quality isn't their in the first place, but I don't want to make it look too bad.


Barney

[geek rock]

So if I capture at 720x480 with a bit rate of 3.95MBps I'm going to have the same file size if I capture at 352x480 with the same bit rate?

you're right. resolution is irrelavant to the final file size.

[Vejita-sama]

MPEG size is the result of bitrate and source runtime only.

If I encode at 8000kbit/s for 60min I'll get a 3.6GB file, period. The resolution, size of my source video, etc. has no affect on the final MPEG size.

However, resolution does affect the quaility of the encoded MPEG. As a general rule the higher the birate and resolution the better the quaility. That means if you lower the bitrate the quaility also goes down.

However, if you also lower the resolution at the same time the quaility doesn't decrease as much. That's why most people perfer to capture at 352x480 for VHS/TV sources (the quaility isn't that great to begin with). You can use lower bitrates (and thus get more runtime per disc) while maintain good quaility.

[Neishaverse]

Ok, next (Just noticed problem) I can't capture at 352x480 directly to MPEG-2 in real time, only 352x240.
(Using CyberLink PowerVCR II Deluxe)

I'm gonna just stay with real time MPEG-2 Captures at 352x240.
Because it's only VHS as my master, is dropping from 352x480 to 352x240 a big difference in quality?

Thanks for all this help guys!
Barney

[geek rock]

Ok, next (Just noticed problem) I can't capture at 352x480 directly to MPEG-2 in real time, only 352x240.
(Using CyberLink PowerVCR II Deluxe)

I'm gonna just stay with real time MPEG-2 Captures at 352x240.
Because it's only VHS as my master, is dropping from 352x480 to 352x240 a big difference in quality?

well, yes, you'll get half the lines of resolution as you would with 480.

the only way to check the quality is to view it on your DVD player..

can you not capture to uncompressed AVI and then encode to 352 x 480?

-Mark

[Vejita-sama]

Capturing at ???x240 instead of ???x480 means you are only capturing 1/2 the lines (ie. one field). That makes a huge difference in quaility, well maybe not huge but noticable

I'm not sure why your software will not allow you to capture at 352x480 to MPEG2, several other programs (eg. neoDVD) all this. In the end, quaility is a person choice. I normally capture my VHS tapes to 352x480 MPEG2, because as you said the quaility is only so-so to start with.

I capture my LDs to 720x480 w/ huffy, then encode them to 352x480 because my source quaility is better (although my capture card could be better). Either way good luck...