Where to find tutorials on advanced rendering

Havspappan wrote on 6/27/2010, 5:03 AM
Hi Do you know of any text digging a bit deeper in the issue of render video. I can do the the simple things and using a template bit I cant argue for my choice and I don't know if a can improve the result by using advanced settings. Does any one know of suitable information for me?
Regards
Bengt

Comments

farss wrote on 6/27/2010, 6:53 AM
Wirth advanced codecs such as mpeg-2 changing anything other than bitrates and choosing between CBR, VBR and 2 Pass encoding is getting into very mirky waters. Fast forward to more recently developed codecs such as H.264 and I'd suggest getting a PhD first :)

If you want a wealth of information on how encoders work Wikipaedia is your friend. The maths involved in the inner workings is way over my head.
I can offer you one tidbit of information. The results from any lossy encoder are primarily determined by the quality of what goes into it. I was quite surprised to discover how much this even applies to lossy audio codecs such as mp3.

Bob.
musicvid10 wrote on 6/27/2010, 7:04 AM
The results from any lossy encoder are primarily determined by the quality of what goes into it.

I wish more people understood that.
ritsmer wrote on 6/27/2010, 8:21 AM
Bengt - and one thing is theory and another thing is real life...

i.e. I had to show something via a PC and on a 50 inch plasma which natively did 1366x768 - and what naturally should be the best format.

No matter what I tried, however, the result was somewhat blurred - and only when I showed the video in 1360 (not 1366) x 768 the result became perfect...

Also the player on the PC (windows media player, VLC etc) has much influence on the final (seen) quality - combined with how you connect to the TV (RGB, DVI, HDMI)... sorry, it's not easy.

What I'm trying to say is that if you have a ceartain hardware setup then only some trial and error can lead you to the best result at the end.
Havspappan wrote on 6/27/2010, 11:53 AM
So trial and error is what you advice, as life in general :-) But there are things that would be nice to have explained. The two mpeg4 codecs in vegas pro 9 for instance. How to think when choosing between them.
Havspappan wrote on 6/27/2010, 11:58 AM
Thanks Bob
I think I have to lower my expectations on what is possible to actually change regardless of the options in the software. But wikipedia could be a start.
farss wrote on 6/28/2010, 1:10 AM
One thing not mentioned is you can easily use Vegas to compare the quality of a render and you don't need a degree to do it.

Put your original video on one track and the rendered video on a track above. Simplest way is to change top tracks composite mode to Difference Squared. Only issue is that small differences in levels give small values and they'll be hard ro see as they'll be close to black. You can use the waveform monitor of course. Ideally it should be a dead straight line with no bumps.

The method I prefer is to set the upper track to exactly 50 opacity and the composite mode to subtract. This should give you frames of even mid gray if both images are identical.

Neither of these techniques are valid if you've scaled the images as part of the encoding and you do need to look at the pixels 1:1 at Best.

Bob.