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  #1  
07-09-2003, 01:25 PM
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Wonder if anyone could shed some wisdom on my attempt in capturing from a Hi-8 video sourse to a KVCD encode. What I did was capture about 42 mins using the PICvideo MJPEG codec (18 setting), resoultion was 352x480 @29.97fps, resulting in about a 4GB file. Didn't have any problem (dropped fames) and looks fine when viewed.

I planned on using the optimal script for AVIsynth 2.5x, applying (after the avisource statement)

Telecide()
Decimate()
Convolution3D(preset="movieLQ")

A short segment seems to encode OK (I used a CQ of 70) however it seems to produce a relatively large filesize

What m1v file size can I expect in encoding this 42 mins of video. I used TOK and with a free size of 420Mbytes (I was assuming 10Mbytes/min of video at this resolution) the calculated CQ ends up being about 36. This sounds pretty low (didn't look that good either).

My question would be how can I get the great compression rates and quality like when I have converted DVD to KVCD (>100 mins at 480x480)
Is there a step I am missing (or don't understand) in converting the capture to KVCD? Should I be converting the MJPEG capture to a MPEG2 file first?

Any help for a lost KVCD user is appreciated - sure the answer will make me look
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  #2  
07-09-2003, 02:19 PM
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Hi ChuckM,

If your target is MPEG-1, you need to deinterlace your source. When you added telecine and decimate, TPMEG will probable detect your source as 23.976fps, and that's wrong. You can't encode at 23.976 and you can't inverse telecine, because your capture is 29.97fps interlaced. So for MPEG-1 KVCDs, you need to deinterlace with either Bob() or FieldDeinterlace() (I belive I spelled it right!)

-kwag
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  #3  
07-09-2003, 03:21 PM
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Thanks Kwag,

The little is going on
.............. .

So since I have a pure interlaced source @29.97fps I must use a de-interlacer and encode the MPEG-1 file @29.97fps. Will the quality suffer noticeably using the deinterlacer - one better than the other? Any suggestions for filters after the de-interlacer [Convolution3D(preset="movieLQ") a good choice]?
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07-09-2003, 03:29 PM
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A quick and dirty suggestion

Add Bob() after your source line, and try the current adaptive script. Make sure you change the frame rate to 29.97fps, because it will change when you load the script
Try a small clip and see how it looks

-kwag
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07-09-2003, 05:47 PM
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Tried it and it looks fine encoding at a CQ=70

Still have the file size problem with a CQ=70 a 1 min clip is 17.4M. Using TOK to try to predict the CQ value to achieve 500,000,000 free space I get the following (actually cancelled before it found)

================================================== ===========
ToK Log: C:\Video\Work\home_video.AVS
================================================== ===========

Resolution (fps):352x480 (29.970 fps)
Total Frames: 151470
Total Time : 01:24:14
-------------------------------------------------------------

Audio Size: 80,864,000
Required Video Size: 519,136,000

Factor: 59.940
Desired Sample Size: 8,660,928

-------------------------------------------------------------
New Faster Prediction
-------------------------------------------------------------

Full Sample
Next CQ: 62.500. Sample Size: 22,375,373
Small Sample
Next CQ: 62.500. Sample Size: 2,163,052
Predicting...
Next CQ: 24.192. Sample Size: 12,315,252
Next CQ: 14.953. Sample Size: 9,967,239
Next CQ: 10.551
Cancelling.... Sample Size: 9,337,599
Next CQ: 7.817
Tries : 5


Final CQ: 7.817
Total Time For Predicition: 00:08:44

Total Time (all operations): 00:08:44

Cancelled

===================

What could be wrong?
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07-10-2003, 05:19 AM
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Hi ChuckM,

Don't know if these suggestions are of any use but try resizing it to 352x240 in the avs script. This way you won't need to deinterlace as it should do it naturally. The result will be slightly softer but should allow for hgher cq. It may also be worth cleaning the source a little more, perhaps use the dust filters (with the LoadPluginEx filter).

Finally, try and crop the top and bottom slightly as there is usually some noise on this part of the capture. You can use Letterbox(0,0,8,8 ) at the end of the script to do this. I've had some joy in the past doing it this way.

Hope this helps.

Fiz.
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07-10-2003, 10:21 AM
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Thanks Fiz,

I will definately try the dust filters and a lower resolution encode (352x240)

Maybe my problem is just the bad capture (non-steady hand? - any filters for that ) quality from my camcorder.

If I load the .avs (optimal) script in VirtualDubMod and observe the 'nf' frame-to-frame difference value I see it going from the 5s to the 20s, much higher when I do a DVD->KVCD encode (1-2 during the majority of the scenes)

Kwag- what 'nf' values are 'normal'? Are my high values the reason I'm not getting the compression I was hoping for?
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