DivX 4 in Gordian Knot

Go to the preview window and Select Save & Encode from the file menu.

Now you have quite a lot of options:

Gordian Knot will select a resizing filter for you depending on the bitrate. If you don't like its selection modify it. I always select Neutral Bicubic here.

Then we have some more filtering options.

If DVD2AVI showed your source as interlaced PAL and the preview was interlaced you enable Fast Deinterlacing here.

If DVD2AVI showed your source as NTSC FILM below 95% you enable Inverse Telecine here and you must also change the framerate that you set in step 4.

In all other cases set Field Operations to None.

If you're dealing with a noisy source you can also select a noise filter of your liking. I personally never use that filter since I find it degrades the image quality (makes the image less crisp).

The next option concerns subtitls and can be jumped if you have no subtitles.

Then the subtitles. Here you are at a crossroads: If you want permanent subtitles press the Select VobSub Files button and select the ifo file from the 3 files that VobSub has created for you. If you prefer to have subtitles that you can switch on and off during playback and in multiple languages you're better off using DirectVobSub (part of the VobSub package) during playback instead of "burning" them into the AVI. The after Borders option is for VCD/SVCD creation only and does not concern us.

And last but not least the compressability check.

It's possible to run a short first pass to find out the optimal compressability of a movie (and make an even better resolution choice). Turn the Compressability check on and set it to 5%, then press the Now button, wait for a few minutes until GKnot comes up again.

Now check the lower line of values shown in the screenshot below:

Values between 40% and 100% mean good quality, below 40% the quality will be inferior so you should compensate by reducing the resolution (you'll see how the value adjusts.. if the field background is white it's ok, if it's yellow it's critical but can still look good and if it's red it will look bad, period). The ideal range is 45% - 55%, above that value you could select a higher resolution by moving the slider in the resolution tab of GKnot. Once the value is in the acceptable range, save the avs again but this time turn off the Compressability Check off.

A word of advice: This compressability check for DivX4 hasn't been as thoroughly tested as the one for DivX3 so the ideal values might not always be in the suggested range. Personally I usually go lower than the lower bound for good quality and the quality is still ok for me. However, 35% should definitely be something like a lower bound not to be crossed. Also, select trim:

This way the end credits will be encoded in constant quality mode at a really low bitrate and then appended to the main movie.

Note that if you have to perform IVTC you can use the following instructions to get a better and faster IVTC.

Now the encoder tab comes up:

First you'll get a stats screen with the current options. Keep in mind that since GKnot does the audio encoding for you the final bitrate won't be correct and the audio size won't be either.

Then the encoding options. The default values are good. Re-calculate bitrate if needed should be checked in any case, as should append credits. Also check delete intermediate files so that only the final AVI remains in the end. Finally you can change the end credits compression levels if you want to.

Then go to the audio1 tab:

Press the select button and select the AC3 that DVD2AVI has demuxed. If you want to keep the AC3 check Just Mux. Otherwise select MP3, custom Parameters and enter the strings shown in the red rectangle. Replace the number after --alt-preset with your desired average bitrate. For 1 CD that's usually 128kbit/s, for 2 CDs 160kbit/s or higher depending on your priority on video or audio quality (higher audio bitrate = lower video bitrate -> higher audio quality but lower video quality). Re-calculate video bitrate should be checked in any case, and delete wav will save some space so it should be checked, too. Azid is run in 2 pass mode to find the maximum overflow free gain so you won't have to normalize the audio.

Actually you won't have the BeSweet and Downsample option and the dropdown lists, just make sure that you manually put the parameters into the appropriate field and you'll be all set.

Now go back to the DivX4 encoder tab without pressing the Add Audi-Job to Encoding Queue as this would only encode the audio. If you have a 2nd audio track do the same operation again before returning to the DivX4 encoder tab.

Pressing the Add Job to Encoding Queue button will add the job you just set up to the queue. You'll then be asked whether to start encoding or not. This allows you to add multiple jobs to the queue and then encode them all without any further manual interaction. It's of course also possible to add jobs while the encoding is already ongoing by simply starting to follow this guide from the top again (of course you must not close GKnot and do everything in the already running instance of GKnot).

From now on you won't have to do any manual interaction until your AVI is finished. You can even safely work on your PC while it's encoding, just make sure you don't kill any windows that suddenly will pop up. That's GKnot launching different programs on its own.


This document was last updated on 07/10/02