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  1. Originally Posted by HartsVideo
    Where do fps come into play?
    It doesn't. Not unless, maybe, it's the wrong framerate. The best way to judge the relative quality of different XviD encodes is with your eyes. Although a deinterlaced 29.97fps video might need a higher bitrate for the same quality when compared to a 23.976fps film.

    I already told you you can get some quality information, including the average quant, from DRF Analyzer.
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  2. Lower frame rates do require lower bitrates. But you get jerky video in return. Think of a JPEG picture. If you stare at it for an hour you have a 1 frame per hour video encoded at a very low bitrate. Not much action there though.
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  3. I checked out DRF Analyzer but if the video bit rate or frames/s don't tell me what I want to know, I'll know by the quality by the large Mb/Gb that I convert the files. As for other people's convertions, I've given up hope that even using AutoGK would give them a decent picture. I think a lot of people convert to small .avi files to save room but the square pixels that can be seen ruins the movie. Somebody actually converted a 2-hour movie into a 588Mb .avi file. It was horrendous! I like to give each hour of a movie 1Gb. It gives really good clarity, no grainy affect, no fuzzy affect, and the best dimensions (Winsows terminology).

    Thanks for all of your help and explanations, and patience.

    Hart
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  4. Originally Posted by HartsVideo
    I checked out DRF Analyzer but if the video bit rate or frames/s don't tell me what I want to know, I'll know by the quality by the large Mb/Gb that I convert the files. As for other people's convertions, I've given up hope that even using AutoGK would give them a decent picture. I think a lot of people convert to small .avi files to save room but the square pixels that can be seen ruins the movie. Somebody actually converted a 2-hour movie into a 588Mb .avi file. It was horrendous! I like to give each hour of a movie 1Gb. It gives really good clarity, no grainy affect, no fuzzy affect, and the best dimensions (Winsows terminology).
    You have yet to post an AutoGK log so we can see the settings used and advise how they might be tweaked to produce better quality results.
    I think a lot of people convert to small .avi files to save room but the square pixels that can be seen ruins the movie.
    If you're getting macroblocking then you're doing something wrong in AutoGK, probably hamstringing it by setting a defined width and/or a predefined size. Unless the blockiness is in the source. You could do one-pass target percentage encodes at the default 75% and probably all blocking will be gone. You could even set the width to 640 or whatever you like. Again, a log might be very helpful.
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  5. I don't understand people's obsession with file size. They'll specify 700 MB then do a nine pass VBR encode to maximize the quality they can get for that size -- but it will often still be crap. What a waste of time.

    If quality is your main goal use constant quality encoding. That tells the encoder use whatever bitrate is necessary to deliver that quality at each and every frame. With Xvid and a Target Quantizer of 3 (a good compromise of quality vs. file size, use a lower quantizer if you want higher quality and larger files, a higher quantizer if you want lower quality and smaller files) the final average bitrate usually turns out between 1000 and 2000 kbps. You don't know beforehand the exact size the video will turn out but you know the quality will be what you specified every single time.
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  6. I think that what I've written in my last couple of posts hasn't been thoroughly read or understood. I mentioned that I'm not having a problem with my conversions. I had asked whether the frames/s or the video bit rate would give the best information to determine the quality of a video. Manono advised me to run DRF Analyzer and explained that the bit rate number will be slower for slower action and faster for faster action in a movie. I understand that. I've decided that the best way to tell if my conversions are the best that they can be would be to either use the Target percentage at 100% or use the option to size the .avi file at 1G per hour.

    You have yet to post an AutoGK log so we can see the settings used and advise how they might be tweaked to produce better quality results.
    I'm not having a problem with AutoGK. There are extremely few settings to choose. I use XviD at a Target percentage of 100% or I give 1G per hour of a movie.


    If you're getting macroblocking then you're doing something wrong in AutoGK, probably hamstringing it by setting a defined width and/or a predefined size. Unless the blockiness is in the source. You could do one-pass target percentage encodes at the default 75% and probably all blocking will be gone. You could even set the width to 640 or whatever you like. Again, a log might be very helpful.
    My conversions are very good. I use either the option to give me 1G per hour or Target percentage of 100% to give me the best quality. I convert them to 1Gb per hour. A 2 hour movie will be a 2G .avi file. I had mentioned that another person converted a 2 hour movie to 588Mb in order to save space. It resulted in an extremely poor .avi file.


    If quality is your main goal use constant quality encoding. That tells the encoder use whatever bitrate is necessary to deliver that quality at each and every frame. With Xvid and a Target Quantizer of 3
    AutoGK doesn't have a number for a desired bitrate. It offers only percentages. I use either the option to give me 1G per hour or Target percentage of 100% to give me the best quality. I'm not having problems with my conversions.
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  7. Originally Posted by HartsVideo
    I had asked whether the frames/s or the video bit rate would give the best information to determine the quality of a video.
    Movies are shot on film at 24 fps. For release on NTSC DVD or broadcast on NTSC television they are slowed down to 23.976 fps and telecined to 59.94 fields per second. For PAL DVD or TV they are sped up to 25 fps. Generally, if the frame rate is not 23.976 fps or 25 fps the video has probably been mangled. Otherwise, you can't really use fps as any indication of quality.

    Bitrate, as has been discussed, is only the vaguest indication of quality.

    Originally Posted by HartsVideo
    Originally Posted by jagabo
    If quality is your main goal use constant quality encoding. That tells the encoder use whatever bitrate is necessary to deliver that quality at each and every frame. With Xvid and a Target Quantizer of 3
    AutoGK doesn't have a number for a desired bitrate. It offers only percentages. I use either the option to give me 1G per hour or Target percentage of 100% to give me the best quality. I'm not having problems with my conversions.
    Sorry, that last comment from me wasn't aimed at you but rather those who insist on 175MB, 350 MB, 700 MB or 1400 MB files. Several years ago that made some sense because people were storing video on CDs. But with DVDs being cheaper per MB now it no longer does.

    AutoGK has a setting for file size. That's essentially the same thing as bitrate since:
    Code:
    file size = bitrate * running time
    So by specifying size you are indirectly specifying bitrate.

    1 GB/hr (roughly 2000 kbps) will usually give decent results from a DVD source. It won't be enough for some movies though. And will be overkill for others.
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  8. Movies are shot on film at 24 fps. For release on NTSC DVD or broadcast on NTSC television they are slowed down to 23.976 fps and telecined to 59.94 fields per second. For PAL DVD or TV they are sped up to 25 fps. Generally, if the frame rate is not 23.976 fps or 25 fps the video has probably been mangled. Otherwise, you can't really use fps as any indication of quality.
    I've been noticing this when I used GSpot.

    Bitrate, as has been discussed, is only the vaguest indication of quality.
    I understand this also.

    AutoGK has a setting for file size. That's essentially the same thing as bitrate since:
    Code:
    file size = bitrate * running time

    So by specifying size you are indirectly specifying bitrate.
    I noticed this also.

    1 GB/hr (roughly 2000 kbps) will usually give decent results from a DVD source. It won't be enough for some movies though. And will be overkill for others.
    There are times when I try to convert a movie by setting the size to 1G/hr, it won't convert to a full Gb/hr. A 3 hr movie might give me a 2300Mb .avi file even though I set it for 3Gb. The video quality of the .avi file very good though.

    This thread has a lot of good information about conversion and I learned some good stuff. You're right, jagabo, that it will be helpful to other people too.
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  9. Originally Posted by HartsVideo
    There are times when I try to convert a movie by setting the size to 1G/hr, it won't convert to a full Gb/hr. A 3 hr movie might give me a 2300Mb .avi file even though I set it for 3Gb. The video quality of the .avi file very good though.
    That's called "saturating the codec". AutoGK has given it the best possible quality and couldn't use all the bits you had allotted. Again, the log explains what's going on. The compression test returns a value close to or (usually) over 100%. The log will tell you the result will be undersized.
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  10. AutoGK gives the message that says that it will be undersized before it does the first pass, but I know that I'm going to get the best possible conversion that I can.

    When I look at the .avi files that I've made and look at the .avi files that other people make with programs that have much more complicated settings, I think that mine are as good as theirs, and I also get bigger Dimensions (Windows word).
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