Quantcast KVCD: MPEG-1 KVCD at 480x480 or 480x576? - Page 2 - digitalFAQ.com Forums [Archives]
  #21  
02-28-2003, 11:26 PM
heller heller is offline
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Peter,

Sorry to hear that your player may be at fault. I actually have loved my Apex 1500 for the most part because it takes any disc I throw at it, and accepts standard VCD and SVCD without any problem at all. Non-standard KVCD is another matter as we both know well...

How do you find the quality of mpeg-2 vs. mpeg-1 at 480x480? I switched to mpeg-1 relatively recently because I was unsatisfied with mpeg-2 at the low bitrates needed to fit 1.5-2 hours on one disc (way too many DCT blocks in monochromatic areas). On top of that, with kwag's matrix mpeg-1 just looks beautiful at the higher resolutions (if you're willing to span multiple discs for one movie).

Next I'm going to check 544x480 and 704x480 with 29.97 to make sure it works okay, but it seems like it should with a 23.976 source.

Let me know if there's anything else you'd like me to check on my Apex for you.
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  #22  
03-01-2003, 01:41 AM
Peter1234 Peter1234 is offline
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Heller,
704x480 and 544x480 both work for me at 29.97 fps. KVCD is better than mpeg2 and encodes faster, but I am getting very good quality with 480x480 mpeg2 for 1 hour SVCDs and good quality for 2 hour SVCDs. With mpeg2 I can watch 480x480 videos full screen using Windows Media Player but not with 480x480 mpeg1. With mpeg2 I am making spec SVCDs that should play in most DVD players while 480x480 mpeg1 does not play in many players. I am constrained to 480x480 by my bar problem so it seems reasonable to make SVCDs, but you aren't. KVCD mpeg1 will give you more video per CD.
Peter
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  #23  
03-01-2003, 02:09 AM
Peter1234 Peter1234 is offline
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dazed&confused,

I do not understand your audio problem. I am encoding from AVI files and so I use system (video + audio) for stream type and there are no audio problems converting between frame rates. I have also generated separate audio and video files and then muxed them using TMPGEnc MPEG tools and there were no problems with that either when converting between frame rates. One second of video should match one second of audio no matter what the frame rate is.

Thanks for your inputs. I am trying modifications of your script and getting great results. I still need to install AviSynth 2.5 so I can try the DctFilter. The DctFilter filter documentation says it only works with 2.5 alpha version, but the only download I can find is 2.5 beta. Which version of AviSynth are you using?


Peter
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  #24  
03-01-2003, 07:43 PM
dazedconfused dazedconfused is offline
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Peter1234,

I don't have any audio problems, I've only heard about it. Right now, I'm only interested in backing up my dvd collection (mostly hollywood movies) to kvcd using the full manual method as in Black Prince's dvd2kvcd guide, so probably all the source material I'm dealing with will be shot on Film @23.97fps. The audio problem I was referring to is something that occurs when people use the line AssumeFPS in their .avs scripts to increase the framerate from 23.97 up to 25fps (they might do this if their dvd player supports kvcd @25fps, but not @23.97fps). Then they have to change the rate of the audio so it keeps up with the increased video framerate, and in doing so, the pitch of the audio increases a bit (hence, the "mickey mouse" effect). At least, this is my understanding of it from reading other peoples' posts on the subject...I could be mistaken. I've read it's then possible to eliminate this high-pitch problem with some other audio editing programs like Cool-Edit or SoundForge or something, but this all seems like way too much hassle to me for the roughly ~20% compression increase I'd get using 25fps instead of 29.97fps(that is, IF my dvd player could even handle 25fps kvcds...I have no 25fps dvd source material to test with, and doubt I ever will...I also have no real interest in divx/xvid/etc material). So this method doesn't sound like something I'll be trying anytime soon.

I'm glad you're getting some extra compression with the mergeluma/chroma lines in your script and enjoying the results. I believe it was jellygoose who brought this to everyone's attention, so he's truly the one to thank(and as always, kwag and the other higher-ups who do all the great testing)...all I did was point it out to heller in case he wasn't aware of it yet since he had mentioned he was struggling for extra compression. As I said in my previous posts, quality is pretty subjective, so you'll definetly need to experiment with what's best for you. I only have a midsize, regular 4:3 TV (and not the greatest set of eyes in the world either), so I don't notice a difference when using the mergeluma/chroma lines at my chosen strength settings, but some people would I'm sure (especially if they have an hdtv I guess). Same way some people wouldn't notice a difference between using FaeryDust or SpaceDust, but personally I do, especially with the lower CQ levels that I'm forced to use sometimes for ~120-135minute movies. To each his own.

Regarding your DCTFilter question, no, you don't need to install Avisynth2.5 to use it. Sansgrip made it compatible with 2.07. Here's the link: http://www.jungleweb.net/~sansgrip/DctFilter_YUY2.zip . (the documentation that comes with it still only says that it's for 2.57, but that's not correct. Actually, DCTFilter won't save you much space (I'm thinking probably less than 10MB in the end), but it adds practically no time to the encoding process so it really can't hurt if you need every extra drop of space you can get. I usually take overburning into account when I do my kvcd's so that I can get an extra 15-20MB of space (I really hafta use every trick I can to gain space since I have to encode @29.97fps! ), and there's been a couple times when I went over the max by just a couple MB, so it would've helped in those circumstances.

Regards,
-d&c
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  #25  
03-01-2003, 07:59 PM
heller heller is offline
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Dazed&confused,

Thanks for the wealth of information!
I'm playing around with mergechroma and mergeluma right now--the first settings I tried caused too much bluriness on my big screen TV, so I'm going to have to try and tweak it a little bit. I'll also have to check out using DCT.

Happy encoding!
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  #26  
03-02-2003, 12:50 AM
Peter1234 Peter1234 is offline
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Dazed&confused,

Yes, thanks from me also. With your help I was able to download and try the DctFilter. However, I feel that it blurs the image noticeably with your settings. I think the following script is the best I have been able to do so far at 480x480.

AVISource("C:\WINDOWS\Desktop\test.avi")
ConvertToYUY2
LegalClip()
GripCrop( width=480, height=480, overscan=0 )
Gripsize(resizer="lanczosresize")
mergechroma(blur(1.1))
mergeluma(blur(0.2))
FaeryDust()
Convolution3D(preset="movieLQ")
# DctFilter(1,1,1,1,1,.5,.5,0)
GripBorders()
LegalClip()
ConvertToRGB24

Peter
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  #27  
03-02-2003, 08:58 PM
dazedconfused dazedconfused is offline
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Quote:
Originally Posted by Peter1234
However, I feel that it blurs the image noticeably with your settings.
Yeah, you'll hafta keep testing 'til you find your "acceptable" settings and perfect script. I certainly know mine is not 100% ideal for everyone, but it's what I need to do on longer movies to fit them on 1 disc @29.97fps...unfortunately, it's necessary for me to be a bit less stringent with my tolerance levels than some other people . The trick is finding that sweet-spot that gives you the most compression at a still-tolerable (or almost unnoticeable) quality loss. Luckily, due to my tv's medium-small size and the fact that it's just a regular 4:3 one and not hdtv, the quality loss is barely noticeable to me at those settings.

So you did notice a difference between using DCTFilter(1,1,1,1,1,.5,.5,0) and not using it? 'Cause I didn't...although it could be due to my tv or dvd player (or eyes!) I guess. Was that the only change you made in your script when you did the comparison? You could try (1,1,1,1,1,1,.5,0) and see if that's acceptable to you. That is the strength that kwag and some others are currently using on it. You'll get even more miniscule space-savings that way, but even if you only save 3MB, it could be the difference sometime between your being able to use 128kbps or 160kbps audio....you never know.

Thanks guys...let me know how you get along.
-d&c
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  #28  
03-02-2003, 11:20 PM
Peter1234 Peter1234 is offline
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dazed&confused,
I only commented it out, that way if I need just a little more compression I can put it back in easily. Most of my videos are less than an hour so I really don't need it right now. If you want to put a lot of video on one CD use the script I posted with a 352x240 frame size at 23.976 fps. It will give you almost normal VCD quality at 3 hours per CD if you use 96 kbps audio. That really amazed me. But I am not happy with normal VCD quality, which is why I am trying all this.
Peter
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  #29  
03-03-2003, 09:37 AM
heller heller is offline
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Since it came up in this thread before, I figured I'd let you know about my results with converting 23.976 source material to 25fps KVCD.

If you use assumefps(25) the audio becomes out of sync and you'll have to jump through hoops to resample it to the proper length.

However, I found that if you use convertfps(25) the result is smooth playback that sync's with the audio just fine (I let TMPGEnc mux for me with a wav file as the audio source--it may not work as well if you mux with BBMPeg after encoding with TMPGEnc, I didn't try it that way). However, when I used the appropriate PAL resolution of 544x576 the image was "squished" vertically so everything looked a little flat. I used gripcrop, gripsize and gripborders, but it was still squashed compared to 544x480 at 29.97.

Any ideas on why this happens?

Also, I found that 544x480 at 29.97 vs. 544x576 at 25fps(converted) was only very slightly bigger file size (like 3-4%), so doing this doesn't save much space anyway. I'm just curious as to why the aspect ratio problem is occurring.
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  #30  
03-03-2003, 10:00 AM
ARnet_tenRA ARnet_tenRA is offline
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Heller,

When you use AssumeFPS the number of frames in your movie remains the same but it plays at a different number of frames per second. In a 23.976fps to 25fps conversion this means your film will play slightly faster and the audio must be converted.

When you use ConvertFPS the speed of your film remains the same but some frames are blended to create the correct framerate. This results in a slight loss of quality. A good benefit is that the film plays at the correct speed and the audio does not have to be converted.

The best option is to not change the framerate if you can help it, because either method changes how the movie was meant to be viewed. If you need to change the framerate then it is up to you to decide if the speed changing or the picture quality loss is the better of two evils.

Regards, Tenra
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  #31  
03-03-2003, 12:29 PM
Peter1234 Peter1234 is offline
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Heller,
Why don't you just set the frame rate to 25 in TMPGEnc and let it change the speed? It seems to do a pretty good job of changing from 23.976 to 25 fps for me. It probably doubles one of the frames each second.
Peter
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  #32  
03-03-2003, 12:47 PM
heller heller is offline
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Peter,

The thread that will never die!

I tried that on an animated 23.976 source and it looked fine, but when I tried it on a different live-action source there was visible stuttering every few seconds. I confirmed this on another live-action source as well. I don't understand why I didn't see it with the animated source. The stuttering was gone if I used convertfps however.

In the end, though, it hardly saves any space to convert to 25fps at 544x576 vs. 29.97 at 544.480, and visually I don't see much of a difference between the two, so I'm not going to fool around with this converting anymore. I think I'll just use 29.97 for everything.

Thanks for the continued assistance!
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