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Old 28th December 2002, 10:14   #13  |  Link
?¿öM¿?
Delphi Guru
 
Join Date: Nov 2002
Location: Narnia
Posts: 62
Hmm, I am getting really interested in this topic again and am going to do some comprehensive research.

I always use 1/2 frame count for my RCa on 2pass encoding. It gives me the best distribution of bits. I think that i'll write a prog for comparing the motion values versus bits from the divx log file and analyse.log from 2 encodes of the same movie of different RCa and let the computer do my thinking for me.

To explain:
I take 2 DivX movies, and their respective log files.
I will take the motion values from the 2 DivX log files that were created in first pass and if they are not the same(haven't checked that) I will average them out to another file(motion.txt).
Next I will compare the number of bits that is shown in analyse.log on a frame by frame basis with the corrisponding motion value for that frame. I will do this for both encodes. It will require a bit of research to decided what to say is optimal bits for motion value versus given (average)bitrate, but I will come up with something.
Then the prog outputs into a textfile the difference(+ or -) between the optimal bits and the actual bits.
The two resulting textfiles are then compared and the results are outputed into a final textfile that tells which encode was better at each frame and which is the best over all.

The parametres:
Same average bitrate given to the codec.
BiDirectional encoding disabled. Reason being, the 2 encodes will probably have I,P and B frames everywhere. I don't want to check different frame types against eachother.
If from one encode, a frame is an I-frame and from the other it is a P-frame, the frame will be dismissed.
No GMC or q-pel.
Quantizer set on 2-12.
2passes.
The actual program will take bitrate given to the codec and directories where the DivX encodes and logfiles are located. I say 2 encodes the whole way through, but I will design it so many more can be included and all compared against eachother.
As the encodes will have the same given resizing methods and no filtering and the DivX log file records are from an all intra frame 1pass, it is safe to assume things like the detail from the input(my.avs) to the codec is the same, so I shouldn't need to compensate for the texture value.

I made all this up as I went along, so I haven't thought this through yet and I will begin to do so. Can't begin it yet(when back from holidays). I would like some feedback as to possible adjustments and the feasibility of such a program. If anyone thinks this is a really silly thing to do, please tell me and why you think so, don't let me go ahead and waste my time.
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