wath is better small or large size ?

[bbouchaib2002]

suppose we have an mpeg2 video 720x576 120 min.
the goal is to compress it to divx or xvid and put it to a single CD-ROM 700 Mo so that we can read it in a divx player (KISS DP450 for example).
A so large 120 min video in a single CD required a very low bitrate, and the result may be bad.
My quetions are :
1- If we resize the video to 352x288 the result is better ?
2- wath is the largest size we can use to have the best result ?

Thanks.

[SeeMoreDigital]

Well bbouchaib2002,

You've stumbled onto a very volitile issue here!

I personally don't crop and resize my encodes, as I have an Xcard and 16:9 TV. And like to keep the same pixel size as the DVD source.

But for people who have a 4:3 TV it may be a different story!

If you do have a 16:9 TV make sure that when you create your encodes and play them back, that you're not having to stretch them vertically. As this defeats the object of encoding them using 720x576 pixels (or crop variants)!

I've got loads of 700MB DivX encodes on CD-R and on my PC. Some of the 130-140min encodes even have audio at 64kbps. But all of my encodes below 120min have audio at 96kbps.

It's all about experimentation and having fun. So don't be too upset if you recieve bad comments!

Cheers

[Soulhunter]

1. Lower res. = less blocks (GOOD) but lower res. also = LOWER RES. (BAD) !!! :D :D :D

2. Best quality ans largest size = Use QB@Qunatizer1 !!! :D :D :D

Just jokeing ;)

You should search in other threads...

You could read this (http://forum.doom9.org/showthread.php?s=&threadid=58109&perpage=20&pagenumber=1) or that (http://forum.doom9.org/showthread.php?s=&threadid=59065) and maybe this (http://forum.doom9.org/showthread.php?s=&threadid=58632) and also that (http://forum.doom9.org/showthread.php?s=&threadid=24584) and maybe this (http://forum.doom9.org/showthread.php?s=&threadid=52162) or this (http://forum.doom9.org/showthread.php?s=&threadid=57899)...
And much more can be found HERE !!! (http://forum.doom9.org/search.php?s=)

Find out what quality is enough for you...
For me, I make mostly 3CD or 1/2 DVD encodes !!!
Try out different bitrates, or try to use different filters, till you find the result YOU are happy with !!!

Bye

[jggimi]

One important link you should also see is #12 (http://forum.doom9.org/forum-rules.htm).

One measure used frequently in DivX quality measurement is bits/pixels*frames. This single value takes into account resolution, bitrate, and length. However, this b/p*f formula in and of itself cannot be used to measure visual quality.

A compressibility test compares the b/p*f at the maximum bitrate obtainable at the current resolution, with the b/p*f at the currently selected bitrate. The percentage returned gives you an objective measure of quality at that particular resolution.

Unfortunately, quality is subjective, and a "good" percentage returned from a test does not necessarily mean you will be happy with the encoding results.

[SeeMoreDigital]

Originally posted by jggimi
... One measure used frequently in DivX quality measurement is bits/pixels*frames. This single value takes into account resolution, bitrate, and length. However, this b/p*f formula in and of itself cannot be used to measure visual quality.

A compressibility test compares the b/p*f at the maximum bitrate obtainable at the current resolution, with the b/p*f at the currently selected bitrate. The percentage returned gives you an objective measure of quality at that particular resolution...

Yes, there are indeed many factors to take into consideration when encoding. And the quantity of active 'image' pixels (not black matte pixels) encoded per movie is crucial and is often overlooked when encoding in anamorphic (720x576 pixels).

For example, a 90min (5400sec) movie with an aspect ratio of 1.85:1 contains around 398,800 active 'image' pixels per frame. Which means the total pixels encoded could be as many as 53,848,800,000.

By contrast, a 90min (5400sec) movie with an aspect ratio of 2.35:1 contains around 313,920 active 'image' pixels per frame. Which means the total pixels encoded is a paltry 42,379,200,000.

Which makes quite a difference. Around 27% infact!