REQ: Encoding resolution and bitrate advice

[rdrnws]

I have an avi file that is 480x480 (ntsc svcd format) and decoded at an average 960 kbps as reported by avicodec. I have the following basic encoding questions for all the experts out there:

1. Is there a way to determine if the file was decoded using variable bit rate? I am assuming avicodec is reporting a mean value here.

2. Is there any reason why I should encode at a bitrate higher than 960 kbps, if the file was actually decoded at a constant 960 kbps?

3. Is there any reason why I should encode at a bitrate higher than 960 kbps, if the file was actually decoded at a variable rate averaging 960 kbps?

4. Is it possible to lose quality if I encode at the highest bitrate allowable by media size limitations?

5. If I encode at 720x480 (ntsc dvd format) instead of svcd, will I lose quality?

Thanks in advance,

Nikolas

[[P]ako]

The video is most likely to be VBR.

As for you other questions, one should encode at a higher bitrate if the codec of choice is less "efficient." Whenever you re-encode you lose quality, the idea is to do it so it's not noticeable.

[Awatef]

If you're about improving quality, forget it.
Re-encode only if you need to transform into another format, like if you need to have DVD-Video playable on any standalone DVD player.

[manono]

I have an avi file that is 480x480 (ntsc svcd format)

It might be AVI (althought I doubt it) or it might be an SVCD (MPEG-2). It can't be both. Open it in GSpot to find out what it really is.

1. Open it in Bitrate Viewer (if MPEG-2). If the Bitrate graph wobbles around a lot, it's VBR. As mentioned, it's probably VBR. Only idiots might be inclined to make CBR SVCDs.

2. It depends on what you plan on doing with it. If, for example, you want to reencode to a 320x240 AVI, then no.

3. Possibly, if it's MPEG-2 now and you want to reencode to a 640x480 AVI.

4. As stated, any reencoding entails a loss of quality (unless reencoding into some huge lossless codec).

5. Yes.