How to encode with a desired bitrate?

[empty007]

Hi,
is it possible to encode a file with a desired bitrate (e.g. 1100 kbps) and not for a special filesize.
Filesize doesn't matter here, because of a HDD-Divx Player, but I'd like to have files with a constant quality.
TIA

[Brother John]

Bitrate and filesize are essentially the same thing measured in a different unit. When you specify a size you implicitly specify a bitrate as well. If you aim for constant quality without a fixed file size, use 1-pass constant quality mode: "target quality" in AGK, quite tricky to do in GK.

[empty007]

So it looks not so easy to do.
I do a dirty trick in the moment. I calculate the following:

Movie duration in minutes multiply with the "magic factor" 9,1 = filesize. That will give me a xvid file with a bitrate around 1100 kbps. But I thought that there will be an easier way.

Viele Grüße nach D :-)

[weaver4]

If you are not trying to get a specific filesize then you may want to try a quality factor instead; this sets a quantizer value. Generally the codec does a better job of selecting the proper rate than you ever could.

One problem with setting a standard bit rate is that some movies need 700kbps to look great and others need 1500kbps and there appears not to be an algorthim to determine this. For example a few months ago I tried to compress a video that filmed mostly in the jungle; wow did it take a large bit rate to get a good picture. I guess it was the moving leaves, or the texture on the leaves, but it was one big file.

Another problem is that 640x272 movies don't need the same bps as 640x480, so do you have different rates depending on aspect ration?

So try a quality value of 75 (for xvid) and then move up or down to see what you like best for quality vs filesize.