Reencode to small resolution

[Markstar]

Hi,
I consider myself a fairly experienced when it comes to encoding files (been doing it for ~7 years) but stumbled onto an unexpected problem when trying to reencode files to mp4:

What I want:
Downsize a source file (XviD/DivX, high resolution (eg 576*420)) to an MPEG4 compatible stream with a really low resolution (eg 160*116).

I was succesful with an MPEG2 file (480*576, 206MB) that I got down to just 12MB using DivX 5.2.1 (using DGIndex, GordianKnot, BeLight and YAMB).

However, with a XviD/DivX source all I get is heavily oversized files (loading them directly in GKnot, for examply a 180MB (512*384) XviD file turns out to be 250MB - even more than my source file!!! :( I tried combinations of XviD and DivX, also I first used GKnot, VirtualDub and then even went back to Nandub and DivX3.11 (on the last two I used the GKnot avs file and manually entered an average bitrate ranging from 25 to 250)). Every single time my result is ~250MB. :scared:

Another problem: While I got oversized files with a XviD source, reencoding a DivX file (to DivX or XviD) didn't work at all: I could load it in GKnot but when encoding I get the error message (GKnot and VirtualDubMod): "Avisynth open failure: ACM failed to suggest a compatible PCM format".

Does this mean I have to reencode my DivX/XviD files to MPEG2 before going back to a smaller DivX/XviD file? Or is there a simpler solution?

Thanks in advance!

[CWR03]

Start by uninstalling XviD and reinstalling it or installing the latest version. Many sizing problems can be corrected by just doing that.

After you've done that, on the GordianKnot Options tab, click the XviD default codec settings "First Pass" button and select (unrestricted) for Profile @ Level. Repeat for "Second Pass" and try again. You can test a sample by using the selection tools with DGIndex and select only one minute, for example, of video and estimate the desired target size from that selection.

[Markstar]

Thanks for answering! :)

It did not work, I reinstalled XviD 1.0.3, changed the settings and set a target size of 37MB for the video (233kBit/sec). The result was a 288MB video file. :(

I'm really out of ideas here.

[communist]

Are you recompressing or compressing the audio at all?

[Markstar]

Are you recompressing or compressing the audio at all?That depends (even though it doesn't really concern my problem since I seperate the original files first). For the MPEG-2 file that I converted I encoded the audio to AAC. In the files I use now I did both MP3 and AAC.

[communist]

Ah OK. I though that it got decompressed to wav and muxed as such - but that doesnt seem to be the problem.

[CWR03]

Just an assumption here based on the selected resolution and the use of AAC audio, but it seems as if you're encoding video to play on a phone. If what I've read is correct, you'll need to disable everything (uncheck Trellis, set VHQ mode to 0, etc). This may also help with your file size.

[Markstar]

Yes indeed, I want to play the videos on my phone.
But regardless of that, I simply don't understand how the output can be larger than the original with 3 different codecs and a much smaller resolution (especially since it works flawlessly with MPEG-2).