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Topic: estimated filesize 2x higher than it should be @x264

Hi,

when I use x264 in CRF mode, the calculated estimated filesize is 2x higher than it should be.
As far as I remember this is an old bug, which appeared in previous versions, too (and now it seems to be back).

greetz,

mogobime

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Re: estimated filesize 2x higher than it should be @x264

Note that:
a. that estimated file size is just the file size of the raw video stream
b. depending on the source it might fluctuate a lot

So let's see what is happening.

x264 outputs:

  • the current frame rate

  • the current average bitrate

  • the position of the last encoded frame

using the frame count that Hybrid assumes the output should be it calculates the probable output file size based on those values.
(not taking any container overhead or other streams into account)

In case that estimation is off a lot it is probably because:

  • Hybrid assumes the wrong number of output frames
    (sounds like some bobbing is done and Hybrid doesn't account for it during the output frame count estimation,...)

  • x264 reports wrong values

  • the x264 output format changed (this can happen if modded x264 builds are used or the official output format changes)

since I haven't touched that code for quite some time my guess is that Hybrid assumes the wrong number of output frames.

Just encoded 4 movie sized clips and the estimated file size shows the proper values, so my guess is that some setting you choose let's Hybrid assume a wrong output frame count.

=> not enough details for me to do more than trying to blindly reproduce the issue which I did and here the estimated output size behaves as estimated.


Cu Selur

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Re: estimated filesize 2x higher than it should be @x264

Don't know if this will help, but I forgot to mention that I also used AviSynth filters (try fft3dfilter/fft3dgpu).
-Happens on two different systems and the frame rate showed on the main tab is correct  and CFR. No deinterlacing/bobbing is used.
-One system uses DGDecNV and the other one doesn't. Happens with different mkv + mp4 sources.
-Container+Stream+Output frame rate and input frame count+output frame count @filtering->AviSynth->Current Frame Rate / Count shows correct values
Can't make a debug atm, if this doesn't help, maybe I'll do later.

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Re: estimated filesize 2x higher than it should be @x264

Both fft3dfilter and fft3dgpu don't change the output frame count.
-> no clue

5 (edited by mogobime 2017-04-22 14:50:04)

Re: estimated filesize 2x higher than it should be @x264

Mysterious, just recognized that one of the systems shows the wrong output frame count (2x) because "bob" is ticked at deinterlacing.
But Deinterlacing isn't used (progressive source and deinterlacing is set to "auto". If I untick it output frame count is correct.

I think this might be the problem ?!?

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Re: estimated filesize 2x higher than it should be @x264

Might be,... read the sticky,..

7 (edited by mogobime 2017-04-22 14:50:14)

Re: estimated filesize 2x higher than it should be @x264

Sticky? I know that bobbing doubles the frame rate, but it isn't used because of progressive source and deinterlacing set to "auto". Also the output frame rate is correct (not bobbed).

Sorry for no debug, but I don't want to break encoding and need to leave now, will look back this evening.

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Re: estimated filesize 2x higher than it should be @x264

OK, I don't know, if it's still useful or if you could reproduce the problem, but I made a debug L4 havig the "bob" option ticked and unticked, still using a progressive source and deinterlacing set to "auto".
Estimated size is definitely wrong, when having it ticked and correct when it's unticked.

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Re: estimated filesize 2x higher than it should be @x264

Problem is that the repoted frame count and the timecode count seemes to differ a lot.

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Re: estimated filesize 2x higher than it should be @x264

will look into it after some sleep (was the whole day on the road and visiting a friend)

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Re: estimated filesize 2x higher than it should be @x264

Does this only happen with that source for you or also with other sources?

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Re: estimated filesize 2x higher than it should be @x264

Happened with different sources, but not anymore with the 2017.04.24 dev version.

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Re: estimated filesize 2x higher than it should be @x264

okay.