Quote:
Originally Posted by kwag
Quote:
Originally Posted by incredible
I said the "default" calculation of my sampler AVS routine gives me a 5% of the whole movie output which should match 5% of 785(-Audiosize)MB IF CQ is set right!
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No. The 5% you encoded will not be the same size as another 5% of some other part of the movie. If you got a final size close to your wanted, you were lucky
-kwag
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Ok ... lets see it in the case if we do a 2pass before .. as I also did.
The 2% "reference"-output as it's based on the sampling routine in my script gives me an output of 2% of the whole amount of frames of the movie and .... the 2pass result will give me a size which would fit the needed final size (in this case 2% of 785) cause its based on avrg.Bitrate calculation.
So i.e. I calculate using Calcumatic ... to fit 2%movie on 2%media I need an average of i.e. 700kbit. and thats the point .... the 2% reference encoding is not made using CQ which really would give me on each slice diff. sizes as you mentioned.
And thats also what Krassi and I talked about yesterday in the Chat.
2% will be a sliced-amount of minutes which as to fit to a determined size (in this case as it makes the sense: 2% of 785) and thats what 2pass should calculate correct if Tmpegs internal calculation does this correct!?.
No matter if the reference-samplestream includes high motion or less moving dark scenes --- the result will base upon average bitrate and thats why it ca. matches. Maybe within the sample encoding the allocation of the bitrates will differ a lot in comparosion to another sliced sample but the output will be ca. the same
2pass
And as Krassi also said ... to do this calculation the 2pass of tmpgenc is not needed cause it also refers to a formula where the average bitrate is the main component of the calculation to fit the result to the wanted size.
And that's also a point ... can we believe tmpgEnc's internal calculation to fit an amount of frames refering to average bitrate to a needed final size?
And to be shure Krassi used a mathematical formula.
I think IF there would be a size-difference in encoded 2%-reference streams this will not belong to different slice-contents but to tmpgEnc internal 2pass avrg. bitrate calculation. And so I did yesterday again a new test:
- No 2pass before done to get the refered reference-size but used Krassis formula also based on an avrg.bitrate value determined using Calcumatic.
- Movie "The english Patient", ca.150mins 480x576mpeg1 using a gop length of 84! (1-41-1) to test. Therefore the variable Gop in the script was determinet to 84! but I choosed a GOPlength multiplicator of 1 cause 84 frames each slice are enough.
-Again sliced-sampler size calculation set to 2% in the script.
- ca. 9 ping-pongs where needed. In this case pong-offset was set to 40 sec! Cause of less slices (larger gop lenght!) where auto-calculated by the script to get still 2% of the movie.
- Final encoding and therfore muxed output was a 787 MB! mpeg stream, 795 where wanted.
I can't proof that this is really Luck
BUT Im Going to to more encodings to see the average acuracy of this way .... just to be safe.
But Kwag .... I think the thread finally NOW does not base only on "2pass or not" , it changed ALSO to verify a "offset ping-pong" calculation method (which by the way is not new) ... so if there still will be a precise calculation needed refering to generate a acuarate first-reference sample ... then this will be another workout. There i agree with you definitely, thats right.
I don't say THIS IS the right method to determine the first-reference sample stream! (although my tests do match)
BUT even if we got a precise method to determine the right referenze stream size ... we still have to do prediction turns to match the right reference size ... and IMHO this will be done best by using offset-intervalls in CQ matic which is faster than larger samples and even more precise cause the offset-method offers more DIFFERENT scene contents in the slices within the whole prediction.
And exactly that's it what I wanted to say in the other thread where you replied.
But as I said ... Im not at the end ... Ill do more and more tests and maybe if this will end by seeing that there will be needed a right first reference sample calcu-method we continue by figure that out.
Belongig to acurate predictions
I will not give up