Improve the quality of an MPEG

[Skysaber]

I can take an .avi and convert it to .svcd format fine; however, the quality seems to get worse by doing so. I use TMPG Encoder to encode an .avi to .mpeg format, then I use Nero to convert to .svcd but the quality always hits the shitter with I do that. I was wondering if there's anyway to improve the quality of an .mpeg so it's closer to DVD quality? I know it can be done because I've seen some .svcd movies that are absolutely perfect. Any help would be greatly appreciated.

[Anonymous65]

SVCD is not really the same as DVD. A SVCD has less resolution, and about a quarter of the bit rate. What defines the quality of video is the pixel resolution of the video and the bit rate of the video stream. Full DVD quality video has 720x480 pixels with a bit rate up to 9Mb/sec, while SVCD has a resolution of 480x480 with a max bit rate of 2.5Mb/sec. So, if you want to get ebtter quality video from your AVI's, then encode them to 720x480 with a bit rate of at least 5Mb/sec. Of cource, you will need DVD burner to put the video on a disk...

[Dave B]

I will presume that your AVI file is a DivX downloaded from the internet..?

DivX isn't a good source for re-encoding to VCD or SVCD. It contains a lot of artifacts (some visible, some not) that make it very difficult for encoders such as TMPGEnc to allocate bitrate efficiently.

The decent SVCDs you have seen have undoubtedly been made from a good quality source such as a DVD Rip.

You may be able to get small quality improvements by using video filters or increasing the bitrate of the SVCD. But it will never look better than the original.

[Skysaber]

Yeah, I got this movie from a friend who got it from a movie channel on IRC. I now understand that I can't IMPROVE the quality, but why does the quality go down when I convert it from .avi to .mpeg? I don't understand that. Thanks.

[Solnzevo]

Its not a conversion, even if we talk about converting it - its always a dencoding and encoding if u make an mpg from an avi. The algorithm used is different - that means the content changes, not the way it is stored/organized in the file.
Also its wrong to say you cant improve quality - certain things might be filtered or surpressed, also colours might be modified. Several programms may use scratch, notch, brur sharpen etc. filters on a mpg/Avi. But if the resolution is low you can not winn any quality by blowing it up - only hide extreme artifacts e.g. by blurring (but that means a loss on sharpeness) - so you will get the bad or the evil. - Decide!

[dcapp1]

If DVD is 740x480 and xvcd resolutions can go that high also then what is the bitrate for an xsvcd? Can an xsvcd be comparable to a DVD?

[Skysaber]

Again, I don't understand why quality decreases when converting .avi to .mpeg.

[Solnzevo]

if u decode you loose quality, each time you decode. so first time it was decodet maybe to dvd, than to avi and now you do to mpg1 or meg2.
Each time compressin algorithm change or took a bit away from the information.