Generational loss in the digital age - a thing of the past?

[next]

Are the codecs improving? I've had the experience.

Quality can actaully improve depending on the codec. A far cry from a few years ago. Set top boxes may have the answer. Opinions?

[Gees]

My opinion:

Quality can actaully improve depending on the codec

That's impossible. :c) You could never improve on an original file's quality simply by using a different codec. You could "fake" a perceived improvement with the use of filters, but it's all subjective.

If one process smooths or sharpens an image, you may prefer that, while another person does not.

Just one opinion. You'll probably get others.

[The village idiot]

Well ther are still problems when editing and adding 3D effects. Every time you uncompress to make an effect, and then recompress you are going to lose something. That is unless you are using completely uncompressed video. Even the "lossless" codecs can be shown to provide loss after enough cycles of decompress and recompress. Not sure if this what what you were looking for.

[ztank]

Yes, codecs are improving. If you encode the same video to the same file size, the recent MPEG-4 based codecs are superior to older codecs.

However, you cannot "improve" quality. Pretty much all video codecs these days are lossy, so you always lose a bit of quality each time you encode. You may not notice it, and as Gees said some filters give the impression of higher quality, but you have actually lost some quality.

"Quality" here refers to the amount of information in the image or video, not what may actually look more appealing to a particular person.

Here is a good article on MPEG artifacts:
http://www.doc.ic.ac.uk/~nd/surprise_96/journal/vol4/sab/report.html

I always look for artifacts like that when I encode something at a lower bitrate. That's how you know when you have lost too much quality.

[Gees]

Excellent article ztank. Thanks for that. :c)

[FOO]

OK, I zip and unzip a file 10,000 times ,
do I lose anything ?

right

now why do the lossless codecs lose anything ?

[BJ_M]

OK, I zip and unzip a file 10,000 times ,
do I lose anything ?

right

now why do the lossless codecs lose anything ?

some can -- because of color space conversions or down conversions from 64 bit color to 8 bit as most of you use... 4:4:4:4 to 4:2:2 and so forth ...

good resource here on codecs and testing the good ones .. http://codecs.onerivermedia.com/