Understanding Resolutions Better

[crash447]

I have been around video editing and most aspects for a few years, but I still want a better undersanding of resolution, so I thought I would ask a few questions.

Here are some examples.

1) Let's say I have an MPEG-2 file at 720x480, what happens if I change it to 544x480.

2) What happens if I have a 544x480 MPEG-2 file and change it to 720x480.

3) What if I have a 544x480 MPEG-2 file and change it to 640x480 MPEG-4.

4) What happens if I have a 544x480 MPEG-2 file and I change it to 544x480 MPEG-4.

I thought maybe these examples would help me understand a little better. From my understanding you never want to go up.

Thanks.

[Cobra]

Whenever you change resolution, there is no change in the aspect. You probably knew that one already, but best to make sure.

OK:

1 - Takes less bitrate to encode it, degraded picture quality
2 - No change in quality (perhaps a few resizing artifacts), more bitrate needed
3 - Again, possible resizing artifacts and much less bitrate required - MPEG-4 is very efficient, you may notice some smoothing or different types of artifacts associated with MPEG-4
4 - Just smoothing/different artifacts from MPEG-4 and less bitrate required.

I hope these are all correct, if not I'm sure someone more knowledgable can set it straight.

Cobra

[crash447]

So between 3 and 4 my best option would be 4 right and would there be any other setup that would be better, for the change of a 544x480 MPEG-2 changed to MPEG-4

Thanks again.

[Capmaster]

So between 3 and 4 my best option would be 4 right and would there be any other setup that would be better, for the change of a 544x480 MPEG-2 changed to MPEG-4

Thanks again.

"Better" is subjective. It all depends on what you're going to use it for, and what it's going to be played on. MPEG-4 has advantages if you're going to watch it on your PC. MPEG-2 has advantages if you're going to mail it to cousin Cindy in Duluth, and you want her to be able to play it on her set-top DVD player

[crash447]

I was asking specifically which would be better between options 3 and 4. I know the advantages of MPEG-2 and MPEG-4. Questions 3 and 4 were specific to converting MPEG-2 to MPEG-4.

[Capmaster]

I was asking specifically which would be better between options 3 and 4. I know the advantages of MPEG-2 and MPEG-4. Questions 3 and 4 were specific to converting MPEG-2 to MPEG-4.

Again, "better" is subjective. Everyone's eye is more sensitive to some things and less to others.

For example, I'm much more tolerant of macro blocks than my wife because she sees them better and they annoy the hell out of her. What you consider OK someone else may not. Since both options 3 and 4 offer the possibility for different artifacts, it's going to be your subjective judgment what is OK and what isn't. Bottom line - try both and decide then

[teegee420]

Remember that if you are planning to author your mpegs to DVD there are only a few resolutions that you can use. Read more about the DVD spec here. Some players can read raw mpegs with odd resolutions but most can not.