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Is there a way to have Dr. DivX run continously and scan a directory for files to conver to DivX?


I would love to just have it convert all my DV Archive shows and then delete the original MPG.
 

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Discussion Starter · #3 ·
not in this version


but that is in the works


probably not in the next version, but in the one after that.


I'm designing that feature now


thekid...
 

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thekid, can you give a rough comparison of file sizes. For example, if I have a 2-hour medium quality RTV mpeg2 movie that consumes about 4G disk space how much of a shrink could I expect by converting to DivX? Also, would the quality be comparable to the mpeg2? I would assume the main motivation to convert to DivX is for more compact storage, but are there other compelling reasons?

Thanks.
 

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Discussion Starter · #6 ·
i can give you examples of what I do


for high quality captures encoded files usually run something like this


High Quality 1 hour ReplayTV mpg = 2.5GB


Same file encoded in DivX = ~300-325MB


High Quality 1/2 hour ReplayTV mpg = 1.3GB


Same file encoded in DivX = ~150-170MB



Those are for Home Theater certification files for playback on DivX certified DVD device or Xbox or PC, or whatever


you can also encode for pocketpc or handheld devices as well and of course filesizes will be smaller


thekid...
 

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I downloaded the trial version to give it a try and everytime I try to open a source video file the program crashes. I have tried it on two different machines with several different source MPG files with the same results. What gives?
 

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The only error i get is the generic (read useless) windows error:


Dr Divx has generated errors and will be closed by Windows.

You will need to restart the program.
 

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Quote:
Originally posted by thekid
not in this version


but that is in the works


probably not in the next version, but in the one after that.


I'm designing that feature now


thekid...
Ahhh.. Good to hear. FWIW, I would think even something like some "basic" command line options would give users that functionality (use this profile on *.mpg). I'm not sure if that would be more or less complicated than what you're doing. Just a thought..


Great program, BTW. I just started playing with it last night, but suspect I'll be buying it pretty soon. Now I just need SD memory to drop in price a bit.. :)


Daniel
 

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Quote:
Originally posted by thekid
i can give you examples of what I do


for high quality captures encoded files usually run something like this


High Quality 1 hour ReplayTV mpg = 2.5GB


Same file encoded in DivX = ~300-325MB


High Quality 1/2 hour ReplayTV mpg = 1.3GB


Same file encoded in DivX = ~150-170MB



Those are for Home Theater certification files for playback on DivX certified DVD device or Xbox or PC, or whatever


you can also encode for pocketpc or handheld devices as well and of course filesizes will be smaller


thekid...
Wow, that's pretty impressive, about 12% of the mpeg2 size. Surely there must be some quality compromise right?
 

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Discussion Starter · #12 ·
actually its better than the source


it actually makes your comedies funnier and makes action movies have more action!


:D


Like MPEG2 there is a trade off between filesize and quality.


the compression is much better than MPEG2 and looks phenomenal playing back on a DivX Certified DVD player


at those numbers i have no problems watching those files on a very large TV. And of course you can trade between filesize and quality by raising or lowering hte bitrates at which you encode or at what speed you encode etc.




It all depends on your tastes. You can encode at lower bit rates and backup a few shows on CD or record at higher bitrates and backup a whole bunch of shows to DVD-R. Whatever you want really


thekid...
 

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Now if I could only stream those Divx files back to my Replay, I'd be happy!

(until I can get a new DVD player that will play Divx encoded files)
 

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How exactly does one use the ReplayTV profile you have posted? I downloaded it to my Profiles directory where I installed Dr. Divx, but it does not show up in the drop down when I select "Show More Options" -- in fact the 'Choose a DivX profile' option is greyed out. Is this disabled in the trial?
 

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OK, I tried this out on a 30 minute medium quality show and using the custom ReplayTV profile and here are the results:


RTV MQ mpeg2 used as source with these specs:

720x480

29.97 fps

4000Kbps VBR

MPEG1-II 48.0KHz 16-bit stereo audio with 224Kbps bit rate

30 min duration

Total size: 959.97Mbytes


I chose custom replayTV profile mentioned in first post of the thread.

Pass 1 encoding took 22 minutes (2.8GHz P4 laptop)

Pass 2 encoding took another 22 minutes

Resulting avi had following specs:

DivX Pro 5.1.1 Codec

640x480

29.97 Frames/Sec

MP3 44.1KHz stereo audio with 128Kbps average bit rate

Total size: 256.12MBytes

30 min duration


I was quite impressed at final total size which is only 26% of the original, though dissapointed it was not 12% as in the example given above.


Encoding time of around 45 minutes for a 30 minute clip is hardly surprising given the size reduction taking place, so that's not an issue for me.


Playback of the resulting avi in a couple of software players (including the Divx player) revealed that quality diminished quite noteably compared to the original source. There's a semi-transparent channel logo on bottom right of the clip that was very noticeably showing ghosting and other artifacts around it in the avi. Also, motion scenes were not as crisp as in the original.


Overall impression is I'm still quite impressed at the compression factor compared to mpeg2, but obviously it comes at the expense of some quality loss. I will say that the picture quality of the source mpeg2 was not that great to begin with, so perhaps starting from a good quality source the signal degradation may not be even noticeable. I'll try re-encoding a DVD source next to test that out.
 

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OK, I tried out using replayTV custom profile on a clip from a DVD source:


10 min source clip from DVD (clip made with Womble):

720x480

29.97 fps

9000Kbps VBR

Dolby AC-3 2-channel 48.0KHz 16-bit/sample audio with 192Kbps bit rate

10 min duration

Total size: 463.91Mbytes



Resulting avi had following specs:

DivX Pro 5.1.1 Codec

640x464

29.97 Frames/Sec

MP3 44.1KHz stereo audio with 128Kbps average bit rate

Total size: 88.08MBytes

10 min duration


So final size of avi was 19% - so looks like for high quality mpeg2 you get excellent size reduction.


pass1 encoding = 9 mins

pass2 encoding = 9 mins

=> 18 min encoding for 10 minute clip - again pretty reasonable IMO


Quality: Again quality degradation was very noticeable. I specifically chose a clip that included credits and again I saw a lot of artifacting and ghosting around the credits. Again, motion scenes were not as crisp.


Perhaps this replayTV profile is not the best to choose and this program certainly merits a lot more tinkering with to see if resulting quality can be improved, and at what expense. With this current profile I would restrict viewing of the resulting AVI to a PDA or non full-size display on a PC.


Of course this is all IMO and YMMV.
 

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Discussion Starter · #18 ·
using the replayTV profile on a DVD source may not be the best option


usually for DVD sources i aim for a specific filesize, i.e. backup on CD or whatever


there are other encoding profiles on that guide page if you want to try some others



also a point of clarification


the origional filesizes i specified are after i cut out the commercials so those numbers might seem a bit low


just wanted to clear that up


thekid...
 

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OK, this time I took the DVD source mpeg again and the goal was to generate a higher quality avi by selecting home-theatre certified & high quality as the output target. After several tries I didn't get any improvement, so finally I decided to simply shoot for 150M output size (from around 88M I was getting with other tries). This did result in a better avi. Still not as good as original and some ghosting around credits still noticeable, but quite an improvement. I found that around 50% size of the original mpeg2 the avi was comparable in quality.


As a comparison I ran DVDshrink on the source mpeg2 with 50% compression ratio (to halve the original DVD size) and saved the resulting VOBs to hard drive. The resulting playback was no worse than the avi generated above for motion scenes, and the credits had no ghosting. My guess is going for much more of a shrink with DVDshrink would really impact quality, but at 50% it is very comparible with converting to DivX using 50% target size.


My conclusion is that encoding to DivX is extremely useful for dramatically shrinking the size of an mpeg while preserving enough quality to be played nicely on a PDA or non-full screen PC display, but I don't think it cuts it if the goal is to dramatically shrink the file size while preserving all/most of the quality.


Kudos to Dr. DivX however, for handling DivX encoding extremely well without any glitches. Very intuitive and easy to use and no problems encoding the mpegs I threw at it.
 
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