Converting from different formats - maintaining quality question

[rede]

I would like to convert some media I have (in various formats) to either Divx or maybe using Nero recode.

As these other clips are of various bit rates, when I convert them, what settings should I use to ensure that I maintain video quality. (File size it not too important to me at this time.)

Is it just a case of ensuring that the new video bit rate is the same as the old one?

Any help would be much appreciated.

T.I.A.

Red

[mats.hogberg]

No. Source bitrate has no connection with what bitrate to encode to.
Every reencode will introduce a quality drop. The higher bitrate you encode to, the closer to the source quality you'll get.

/Mats

[rede]

Hi Mats,

So I guess when re-encoding it will always be a trade off between file size and quality.
I'll have to do a bit more reading.

Anyway, thanks for the help.

Cheers
Red

[mats.hogberg]

when re-encoding it will always be a trade off between file size and quality

I couldn't have put it better myself!

/Mats

[jagabo]

Since you don't need a specific file size use a constant quality encoding mode. Pick the quality you want and the encoder will use however many bits is required for each frame to get that quality. Divx calls this "quality based" encoding where you set a "fixed quantizer". Xvid calls it "single pass" with a "target quantizer". Some MPEG encoders have constant quality modes too -- TMPGEnc Plus for example.

The higher the quantizer the worse the quality and the smaller the file. Try using quantizer values of 2 or 3 as a starting point. At 2 the output will be nearly identical to the input. At 3 there will be a little macroblocking if you examine enlarged still frames but you won't notice them at normal playback speeds.