ProjectDivX Version - The Oracle

The Oracle is in internal algorithm which can decide which conversion is better than the other. You don´t have to look at the whole movie. Instead activate the Oracle and look, what the Oracle recommendates. If you are not satisfied with the result, change an value, called the Oracle Value and try again.

And you can configure a value which compares the frame with Low-Motion with the frame with Fast-Motion. If the difference of both quality values is less than the Comparison Value (in percent), then both frames are identical and the Oracle now checks the size in KBytes and takes the smaller one. So you get smaller DivX AVIs.

Now the Oracle is much better than before. See and believe it.

What i have to do to use the Oracle?

Well, you need at least the original AVI file from which the DivX Low and Fast-Motion AVIs are generated.

What does the Oracle do?

The Oracle takes every frame from the original movie and compares it with the compressed frames from the Low and Fast-Motion DivX AVIs. Then it calculates the quality of the compressed frames from key frame to key frame and decides, which part is better than the other; depending of the calculated quality.

When you start the Oracle, it only once creates a file which contains the quality values. From this values the Oracle decides which part is taken. If the Oracle Value is not correct, change the value and next time, the quality values are taken from this file. Remember: the quality file has only to be calculated ONE TIME.

What does the the "Oracle Value" mean?

The Oracle Value is a value which is direct used by the Oracle. The more positive the value is, the more scenes with Low-Motion-Encoding you get. The more negative the value is, the more scenes with Fast-Motion-Encoding you get.

Look at this example: you set 5 to the oracle value. Now the quality of the Fast-Motion-Part has to be 5% bigger than the Low-Motion-Part. In this case, the oracle decides for the Fast-Motion-Part. If the quality of the Fast-Motion-Part is less than the Low-Motion-Part, than the Low-Motion-Part is taken.

What does the "Comparison Value" mean?

Well, look at this example: you have got a frame encoded with Low and Fast-Motion. The Low-Motion frame takes 32 KBytes and the Fast-Motion frame takes 25 KBytes. The qualities of both frames are identical (depending of the Comparison Value; the bigger the Comparison Value gets, the more and more the Oracle decides, that both frames are identical). What frame would you take? The Oracle decides for the smallest one. In order to save as many place as it can save.

So if you set the Comparison Value to 10000, the Oracle Value don´t take any advantage. Instead you get the smallest file (in KBytes) but not the file with the best quality. You need to experiment with the different values to get the best results.

What does Maximum File Size Limit mean?

Look at this example: The Final AVI File Size is 720 MByte, but you want to write it on a CD with 700 MByte. Then you can specify the Maximum File Size Limit. The Oracle tries to reduce the size down to the Maximum File Size Limit, so that the AVI fits on the CD. The Oracle first searches the parts where Low and Fast-Motion are very equal and takes that parts, which are smaller (in Bytes).

Remember: The smaller the file get, the worse get the Final AVI.

Short example how to start the Oracle

• 1. You have an Original-AVI with some Codec (Intel Indeo, Motion-JPEG, ...)
• 2. Create DivX AVI with Low-Motion
• 3. Create DivX AVI with Fast-Motion
• 4. Start ProjectDivX
• 5. Load both AVIs (Low and Fast-Motion)
• 6. Press "Auto Create Encoding List"
• 7. Select Original-AVI
• 8. Change the Oracle Value and the Comparison Value
• 9. Press Start
• 10. Wait and look at the results; compare them in the preview. If you are not satisfied, you can change the results manually or go to step 6. and change the oracle value. Next time, the calculates don´t take some time. Instead the Oracle takes a special file and after a few seconds, you get the new results.
• 11. Press "Start Creating" and you get your final DivX AVI with Low and Fast-Motion

How the Oracle can decide which part is the best?

Well, look at this example:

Currently the Oracle takes the original frame and looks, which parts are better. Do you see the difference of both frame (watch at the green gras).

Tips

The best way is to play around with the Oracle Value. If you do so, you get a feeling which values are better than other values.

The Oracle can help the user in creating the Encoding List, but it is not the human eye. So after the creation of the list, look at the results, if they are ok or not (try chaning the Oracle Value).