DVD resolution

[Cole]

While encoding a DVD recently, I noticed that the resolution on a DVD encode is reduced to 352x288 if the bit rate falls lower than about 4,000 K/bits per second using TEMPGEnc.

The resulting movie had a very clear picture and faultless screen caps were taken from it.

A similiar movie (same source just shorter) was done at a slightly higher bit rate (aprox 4,500 K/bits per second), was at the bigger resolution 720X576, but the resulting picture, still being good, was not as sharp as the first clip.

I realise that the smaller picture has its bit rate more thickly spread, but is there any benefit in making all DVDs at the lower screen res?

Prob. a silly question, but I am just curious as to what people think.

Thanks

[Baldrick]

PLEASE post converting/encoding in our converting forums. moving you.

[jimmalenko]

I would assume you were using the wizard, and it autodetected what it thought was the best resolution for that bitrate.

Given a perfect (DVD quality 720 * 480/576) source, I use the following:

(where ave is the calculated video bitrate)

If ave is < 1000kbps, I'd use 352 * 240/288 2-Pass VBR (min 100 ave ave max 2000)
If ave is > 1000kbps & < 2000kbps, I'd use 352 * 240/288 ave CBR
If ave is > 2000kbps & < 5000, I'd use 352 * 480/576 2-Pass VBR (min 1000 ave ave max 5000)
If ave is > 5000kbps & < 7500, I'd use 720 * 480/576 2-Pass VBR (min 1000 ave ave max 9000)
If ave is > 7500kbps, I'd use 720 * 480/576 ave CBR

[Cole]

Thanks for the resoponse jimmalenko; very useful.

[jimmalenko]

Thanks for the resoponse jimmalenko; very useful.

No problem, Cole.

I must stress that these numbers are optimised for excellent (ie DVD) quality input. They work in reverse as well - ie. if you were converting a 352 X 288 AVI to DVD, there wouldn't be any point using a bitrate in excess of 2000kbps.

[Cole]

All of my AVIs are captured using a Canopus ADVC-50. I assume that these are of the normal resolution.

The input for the DVD was an off air recording from a Digibox. The screen caps for this file after encoded to the smaller screen res are the sharpest that I have ever created, which is what prompted the original question.



thanks again.

[jimmalenko]

I've got the ADVC-100, and capture TV with it also. Your capture program should output in 720 X 576 DV AVI, so you'll have no problems using these figures. All you need to do is throw the total time into a Bitrate Calculator, then read off my chart using the calculated bitrate, ave.

FWIW, If you want to experiment a bit, you might want to look at FulciLives' excellent guide, which covers the editing and filtering stages. It makes editing really easy, and applies the Convolution3D noise removal filter also. Basically, once you have transferred your video, use that guide and then encode using your AVS script as your source in TMPGEnc. It really does a great job of handling typically-noisy TV/VHS captures.