SVCD CBR quality question.....

[Dat]

Hi, after doing some tests on CBR encoding at SVCD resolution i wondered if there is a point in which a quality difference is not noticeable.

For example:

i have encoded a high motion scene at 480x576 (PAL progressive anamorphic widescreen source) at 2498Kbps with very good quality results, then i decided to see what the difference in quality was at 2000Kbps the quality difference was very little if not none (to my eyes).

This made me think if there was a point in which quality did not improve to the eye after a certain bitrate.

Maybe i cannot see a difference because of my TV or the high motion scene is not the highest motion scene or something.....

Anyway, does anyone know if there is a point in which quality differs none after it.

Hope that made sense...

Any ideas anyone? :D

[kdiddy]

Beauty is in the eye of the beholder, what you have asked will be different for every person.

[Dat]

well, i will run some more tests, but i am pretty sure there must be some point in which quality is only slightly different with a lower filesize.

Thanks for the reply :)

[waldok]

Well, from my humble experience, there would not be any such thing.
I tried several different CBR values with different sources (analog camcorder, DVD, DV source); I tried several different bitrate values for each type of sourec and really, results don't prove anything.

As the good old Kdiddy said in amore poetic way :D, quality is far too subjective and depends on the quality of your source, the quality of you TV set, your viewing conditions and so on.
Some sequences I tried gave great results at 1900kbs while no fast motion was involved, but then, if some fast action occurred, damn, this was really too blocky for my taste.
This is the point of CBR vs VBR. CBR is some kind of "dumb bits allocation", no matter what your movie is, no matter what the picture contains, it always uses the exact same amount of bits to encode the samples (at least it should). In my opinion, it will be better to use VBR and let the encoder allow more bits for scenes that really need it and fewer bits for "quiet" scenes (unless you like your movies split over a dozen of CDs :D

My 2 cents, I like VBR.

Waldok

:cool:

[marie]

So does the file size tend to get larger if you use VBR multi pass?

Sorry I am new to this thing

[Kedirekin]

For VBR with average bitrate = X versus CBR with (constant) bitrate = X, the file size will be virtually identical.

However, the VBR encode will probably look better because, to a large extent, quality is determined by maximum bitrate (within reasonable limits, of course).