About bitrate

[UMO]

Hello!
I've got some questions about bitrate.

I'm comparing two videos, both are compressed by virtualdub.
The first one is *.ts > *.avi, the bitrate is 4500kbps; the second one is *.vob>*.avi, the bitrate is 7500kbps.
However, the quality of the first one is much better than the second one.
Also, is that means with the same bitrate, videos from blu-ray have better quality than dvd?
How about the file size?

Thanks

[jman98]

It's impossible to give you the simple answer you are looking for.

What is the resolution of the 2 videos? The resolution of the 1st video might be a lot lower than the 2nd. Lower resolution can cover up a lot of bit rate issues. One source file might be cleaner than the other. And AVI can hold almost anything. They might not have even been encoded with the same video codec or the 2nd one could have been encoded with some poor quality options, etc.

I can tell you that the larger the bit rate, the bigger the file size.

[UMO]

The first one is 1280X720 and the second one is 702X404.
Both are XviD 1.2.1 <is thos the video codec that you are talking about?
So the larger the bit rate doesn't mean the better quality if the source is different?

Situation 1
If I got a source file, the same video (same resolution,format) but one is 8000kbps and the other one is 5000kbps,
and compressed with the same setting (codec, bitrate), so the one from the 8000kbps has better quality?

Situation 2
With the same source *.ts, if I convent it into avi with 6000kbps *.avi and then compress to 4000kbps *.avi,
is the quality will be worse than the other one that I compress from *.ts to 4000kbps *.avi directly?
Also , which one got the bigger file size as all other setting are the same?

Thanks

[guns1inger]

mediainfo tree view both files and post the results

[jagabo]

Situation 1
If I got a source file, the same video (same resolution,format) but one is 8000kbps and the other one is 5000kbps, and compressed with the same setting (codec, bitrate), so the one from the 8000kbps has better quality?

Yes. But if the paritcular video only needed 5000 kbps you might not see much difference.

Situation 2
With the same source *.ts, if I convent it into avi with 6000kbps *.avi and then compress to 4000kbps *.avi, is the quality will be worse than the other one that I compress from *.ts to 4000kbps *.avi directly?

Yes, avoid multiple consecutive compressions.

Also , which one got the bigger file size as all other setting are the same?

Same bitrate = same file size.