Nandub: Resolutions and Bitrates?

[VideoJedi]

Hi! Any idea why in Nandub if I use anything smaller than 512X384 resolution, the video file size will always come out smaller than expected, even though I tell it to be 700MB (I'm using the version of Nandub with the bitrate calculator built in)? I almost always use 512X384 from satellite TV rips, but recently decided to start cropping the black bars off widescreen presentations. After encoding I was surprised the file was much smaller than it should have been. Perhaps since I am doing the cropping in Nandub with the null-transform filter, it is throwing the calculator off? The AV streams are being fed into Nandub with AVISynth. I tried cropping in AVISynth in the AVS file, but got errors when trying to crop the top and bottom of the picture (for some reason.. I can onyl crop the sides effectively). Any ideas how I might get an accurate bitrate that incorporates the resolution? I haven't found a bitrate calulator that takes into fact the encoder might be using a different resolution that the 'standard'. Any help appreciated!

[Acaila]

The bitrate has nothing to do with the video resolution, only the size of the final output file. If the codec is any good decreasing the resolution should not decrease filesize, neither should increasing the resolution result in an increase in filesize.

What I suspect happened is that your video is maxed out. i.e the codec gave it the best quality it had and could no longer make the file any bigger. Decreasing the resolution often has this effect, which means you can just increase the resolution if you want a slightly bigger file (because a low resolution video maxes out at a lower filesize than a high resolution video).

[VideoJedi]

Thanks! I've done a bit of reading since I posted and came to recognize this "max out" thing. I guess I shouldn't worry as much about having a smaller file in the end.. I can use higher quality audio if I really want to take up an entire CD. I also figured out why I was having trouble cropping the top and bottom of my encodes.. stupid over-looked detail in adding the pixels to get the resolution I wanted. I don't think I really need to add borders unless I want to ensure I keep the OAR. I do see the difference between the original black bars and the new ones I have added in. I bet if I encode the same file with the original black bars left in and no cropping, I will approach the 700MB filesize I told Nandub to work towards. This particular encode I am working on is 512x288 after the cropping. I'm just amazed an hour and a half video came out to be 523MB before adding in the 96kbps MP3 audio track. You'd think Nandub would find a way to utilize the maximum bitrate allocated to achieve the file size desired. I feel like bitrate has been wasted. Weird.