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Rendering Extremely Slow If Auto-Color On


Lynn Lynn
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In VW, I see that my wife's most recent home movie has a severe white balance problem, due to not removing lens cap before turning on the camcorder, and shooting under incandescent lighting. I just this morning noticed that VW has an "auto-color" function, which I presume is to correct the white balance. I had never tried this function before. I see that it seems to do what is intended in terms of color changes that I see on the screen, when just the first frame displayed in VW, when I toggle it on. I note that when I do not apply this correction, and output as MPG DVD Playback, each clip is rendered quickly, at several times the "real-time" rate. When I select "auto-color", I note that the rendering is at about 21 frames per second, meaning much slower than real-time, based upon a sample of clips I timed. It is as if the color correction is being applied to each frame, on the fly, during rendering. That would explain the slow speed.

 

I sometimes use the autocolor function of Adobe Photoshop to correct white balance, so I understand the concept.

 

If I want to correct the color balance, am I stuck with very slow rendering?

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Well, since it would pretty much have to be applied to each frame as it is rendered, yes, you're "stuck" with slow rendering when applying the color balance option.

Actually, that was the presumption that I arrived at. And if my rough estimate of the speed is anyway near close, 21 frames per second is not terrible.

 

My wife confirms that she made sure that the lens cover was in effect before she turned on the camcorder, because for some reason she thought that was the correct sequence.

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Actually, that was the presumption that I arrived at. And if my rough estimate of the speed is anyway near close, 21 frames per second is not terrible.

 

My wife confirms that she made sure that the lens cover was in effect before she turned on the camcorder, because for some reason she thought that was the correct sequence.

I just spotted a gigantic error that I made in typing. I should have written "21 frames per minute" (and that is on a very fast computer.)Factors in rendering speed are several, such as the "video file quality," disk I/O speed, CPU power, etc. I am just learning to be more patient, and doing other things around the house and coming back every 15 minutes or so, depending on the size of the individual clip.

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I just spotted a gigantic error that I made in typing. I should have written "21 frames per minute" (and that is on a very fast computer.)Factors in rendering speed are several, such as the "video file quality," disk I/O speed, CPU power, etc. I am just learning to be more patient, and doing other things around the house and coming back every 15 minutes or so, depending on the size of the individual clip.

 

Is there a short clip( a minute or so) you could upload to some free website (like Up4Down) from where we could download and also do a test on the render speed? 21 frames per minute seems incredibly slow but then I have never had to do that kind of "correction". How good is the result?

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21 frames per minute?! Ouch! That IS slow. I have to assume then that you're working with 1080 HD video? I would think that "standard def" would render significantly faster, more like the 21 frames per second.

The camcorder that my wife uses is NOT HD. (Mine is, but I have not had white balance issues with video, as I use AWB and the lens cover retracts as the power comes on.) There are replies below which tell more.

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Is there a short clip( a minute or so) you could upload to some free website (like Up4Down) from where we could download and also do a test on the render speed? 21 frames per minute seems incredibly slow but then I have never had to do that kind of "correction". How good is the result?

I think that I shall upload, perhaps tomorrow, the shortest clip of the 15 my wife shot, maybe tomorrow. With respect to the quality of the result, what little "experimentation" I have done so far leaves me open minded as to whether it introduces some artifacts. Hard to say, because if one is shooting under indoor lighting, there is bound to be some artifacts if the camcorder introduces extra gain. This experimentation is hindered by the Standard Definition quality to start with. I may try it with an HD camcorder, recording at 17 or 24 MB/second.

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I have just done a trial rendering, with autocolor, of part of a standard definition clip. 1019 frames took 678 seconds, which is 1.5 frames per second. Since I originally posted my question about slow rendering if autocolor is on, Roxio support replied to my ticket, with the suggestion to go to tools/options and switch to Software rendering. So I did, and rendered the entire 2 mins 2 sec 14 frame clip, and it took only 82 seconds. If my calculations are correct, this is 44.59 frames per second.

 

 

When I configured my new Dell on the Internet, I thought that I chose a good video card.

MS Windows 7 64-bit SP1

Intel Core i7 920 @ 2.67GHz 49 °C

Bloomfield 45nm Technology

9.0GB Triple-Channel DDR3 @ 531MHz 7-7-7-20

DELL Inc. 0X501H (CPU 1)

Dell 2209WA(Digital) on NVIDIA GeForce GTS 240

Sound Blaster X-Fi Xtreme Audio

 

So, it seems that the answer to my original question lies in selecting the Software rendering option, at least when autocolor is involved. I do note that when I select the tools/options "render using" software radio button, then do "graphics test," VW resets the radio button back to Hardware. That seems strange to me.

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