Xvid/DIVX 2 DVD problem

[King-Of-DK]

Can anyone tell me howcome my converted videos play very jerky and irregular? I have a 120" screen with a projector,and i can watch SVCD quality video on it, and it looks great,what i thought i could do was convert the DIVX/Xvid avi´s to dvd compliant mpg files and have 2 movies in better quality than SVCD on 1 DVD-R.

Problem is SVCD is as i remember about 2500 in bitrate and i convert the AVI´s to 2 pass vbr min 2000,avg. 3000, max. 4000 so acording to my calculations the bitrate should be greater than SVCD,and therefor better quality. Only this does not seem to be the case,i have very jerky playback,and rather blocky picture (SVCD looks very good on my screen) so why is that when i have a bitrate that is avg. 3000, 500 better than SVCD.

I am experimenting a little with the settings,like going for CBR or CQ of about 3000 (higher and it won´t fit 2 movies on 1 DVD-R),and i have now converted some avi´s with a bitrate of 2-pass min.4000,avg.5000 max.6000 but these files size is just too big for me to fit 2 movies on 1 DVD-R..

Does anybody have any thoughts as to what i am doing wrong (opicture quality wise)??

[Hardcoreruss]

When you are converting are you using the same frame rate.

e.g original 23.97 to 25 fps

[bugster]

SVCD, 480 * 480
DVD 720 * 480.

Lots more pixels means you need lots more bits. I dont have time to do the maths right now, but going from 2500 Avg SVCD to 3000 Avg for DVD does not seem enough of an increas to get the same quality. You need to ensure you are encoding with the same number of 'bits per pixel' to ensure the same quality w.r.t block noise. Higher resolutio should give more detail to the picture but if you don't increase the bitrate in line with the resolution block noise is the result.

[King-Of-DK]

OK Bugster,how do i increase the bits per pixel? I am converting avi 2 DVD mpg2.

I am converting 23.976 to 29.97 NTSC i have just read about the 2:3 pulldown option,should i use that? Should i instead of converting the 23.976 to Pure NTSC convert it to 25 PAL??

[Gazorgan]

Your talking Apples and Oranges. The bitrate of the DivX/XviD isn't realted to an SVCD or DVD bitrate. The codecs are different, so the bitrates aren't related. Wha tis important is that the AVI has a high enough bitrate to not be blocky in and of itself.

If the original is 23.97, then leave it that way, there is no reason to convert to 29.97. Same for 29.97, leave it don't try and IVTC it to 23.97. Avoid 25 fps PAL unless you are a PAL person.

For DVD, you should have a bitrate above 5000. For SVCD, the standard is 2250. 2 movies/DVDR will yield low quality, sorry, but that's the way it is. You can't fit 4 hours on a DVDR, from a DivX source, with some blockiness.

[King-Of-DK]

If i leave the framerate then Ulead MF2.0 won´t accept the file,and convert it to compliant NTSC. and the conversion done by this program is really shitty..

all my sources have a bitrate of about 900 DIVX/Xvid and i did a test with a 2-pass vbr of min.4000 avg. 5000 max. 6000 i get the same blockiness as the lower bitrates.

[bugster]

Try encoding at CVD resolution which is 325 * 480 for NTSC. You can get away with a lower bitrate at the expense of some picture detail. Do a test encode at 4000 average. If this is still blocky then I suggest your siurce material is the probable cause.

[King-Of-DK]

I do not want it in CVD i want it on DVD.. How can it be that SVCD with a bitrate of 2250 is better than a DVD with a bitrate of 5000??

[bugster]

I do not want it in CVD i want it on DVD.. How can it be that SVCD with a bitrate of 2250 is better than a DVD with a bitrate of 5000??

CVD is a valid resolution for DVD. Most authoring programs should accept it as such.

As for quality, the DVD should be better, I don't understand why it is not.

[Laddydaddy]

Region 1 DVDs are encoded at 23.97fps with a 3:2 pulldown so they play back at 29.97fps. You can encode at 29.97fps without the 3:2 pulldown, or
encode at 23.97fps with the 3:2 pulldown. I don't know what you use to author and burn DVDs but Ulead DVD Movie Factory does not accept DVD files unless they are encoded at 29.97fps. What program are you using to encode?

[King-Of-DK]

I use TMPGenc,but i did not know about the 3:2 pulldown till today when i read about it.. Maybe that is why i get jerky,blocky picture,as i try to convert NTSC 23.976 fps to 29.97 fps without the 3:2 pulldown. And i use Ulead MF2 for the authoring,that is why i have to encode the 23.976 to pure ntsc as MF2 will not accept 23.976 as a valid framerate. I will try to convert my 23.976 files with the 3:2 pulldown option instead of interlace.

[King-Of-DK]

I have now tried the 3:2 pulldown option,but TMPGenc wont let me encode,as it says it can only use the 3:2 pulldown option if the framrate is 23.976 or 24,and i use Gspot codec indentifyer to make sure the avi has a framerate of 23.976. Why wont TMPGenc accept the 3:2 pulldown when playback option??

[King-Of-DK]

OK,it works with the 3:2 pulldown option if i don´t load a DVD template. This means i have to set all the settings my self,and i havew no idea what GOP is and all the other settings..

[King-Of-DK]

OK,i have now converted a 23.976 AVI file with the following settings.

720x480 MPG-2
23.976 (3:2 Pulldown for playback enabled)
CQ 65 (Constant Quality of 65 and a min. bitrate of 2000 and a max. of 8000)
48000hz 384kbps sound

and with these settings i have a file that is great quality,small size (1,5GB) and generally looks good,now how the hell can that be? When i use 2-pass vbr with an avg. 3000 i get a filesize of about 2GB for the same movie and the quality stinks,please explaine that?

[bugster]

Now I can see your problem is with framerate you can try this:

In TmpGenc load the DVD (NTSC) template. Click load again and load unlock.mcf from the extras folder.

Click settings and set framerate to 23.97fps and encode mode to 3:2 pulldown on playback. This should now match what you did manually.

CQ Vs 2-pass VBR in TmpGenc.

CQ produces pretty good encodes in a decent time with the downside of unpredictable file sizes. If encoding only short(ish) videos this is not a problem. 2-pass VBR can also produce good quality encodes, it takes longer but you can predict the final file size fairly closley. If you want to fit as much on a disk as possible then this is the way to go (IMHO).

Once you have all your settings to your satisfaction you can save a custom template just by clicking the save button in TmpGenc.

[King-Of-DK]

I have been using the 2-pass vbr option,but i am not satisfied with the result. I have now done a test with a CQ setting,and it looks great,and the filesize is only 1.5GB for a 1½hrs movie. Why is it harder to predict the filessize with CQ option? why is the filesize lower than my vbr 3000 option i.e. lower quality option?

Secondly why wont Ulead MF2 process my file when i have used the 3:2 pulldown option? It keeps saying

Some chapter entry frame numbers exceed the total frames

Seems like something happend during conversion,Ulead DVD workshop says my clip is only 1:15 hrs long,and that is not right.when i play it in WMP it says the file is 1:34hrs long,what the hell is going on??

[bugster]

Why is it harder to predict the filessize with CQ option?

CQ is Constant Quality. You specify a min and MAX bitrate, but no average. TmPgenc determies how much bitrate to allocat to each frame to maintain the quality at the value you set, within the min and max specified. If your movie has a mix of High and low motion scenes, you can not easily predict how much bitrate TmpGnec will allocate to each frame, hence you cannot estimate the final filesize. With 2-pass VBR you also specify an average bitrate. This is the average over the whole movie and can therfore be used to determin the final filesize. I must say however that an avergae of 3000 is pretty low for DVD. If you are happy with the size and quality of CQ encodes then by all means stick with it, just don'r be surprised when one day you encode a movie and it ends up bigger than expected.

Secondly why wont Ulead MF2 process my file when i have used the 3:2 pulldown option?

Well, it ought to, but no software is perfect and it obviously has a problem with this kind of file. Plenty of other DVD authoring apps will accept these such as Sonic Dvdit PE, Dazzle DVD complete and Spruce Up to name just a few.

Seems like something happend during conversion,Ulead DVD workshop says my clip is only 1:15 hrs long,and that is not right.when i play it in WMP it says the file is 1:34hrs long,what the hell is going on??

It looks like Ulead products have problems with 3:2 pulldown video, try another authoring app.

[King-Of-DK]

Thanx Bugster.. I don´t know why,but now MF2 has no problem working with the 3:2 pulldown file.. I have Spruc Up also but can´t figure out how it works. Every time i try and load a mpg it takes forever,and when it is almost done,it gives me some error..

Can you explain why the filesize of 2-pass 3000 vbr is about 2.1GB and when i use the CQ 65 option it is better quality and only 1.5GB??

[bugster]

Can you explain why the filesize of 2-pass 3000 vbr is about 2.1GB and when i use the CQ 65 option it is better quality and only 1.5GB??

Not really, except to say that quality is very subjective.

It is possible that the 2-pass algorithm distributes its data differently than CQ and maybe does not allocate enough data to the high motion scenes when using a lowish avg of 3000. What did you set your MAX bitartes to whne using CQ and 2-pass VBR. If these were not the same then it is an unfair comparison. (IMHO).

A while back there was a very long thread regarding the merits of TmpGenc CQ mode Vs 2-pass VBR. It got quite heated at times and some people took an almost religous stance on there mode of choice. Basically I suggest you use whichere you find suits your circumstances best. Personally I prefer 2-pass VBR. I find the qulaity at least as good as as CQ, it does take longer but gives predictable file sizes. I like this fact as I prefer to use the highest (Average) bitrate I can to fill a disc, giving me the best chance of getting a high quality encode. But as I said, choose what you feel is right for you.

[King-Of-DK]

Thanx again Bugster,i will ofcourse use what i get the best result from. When using CQ the max bitrate is 8000 and when i use the 2-pass it is only 4000,that is why i would think the filesize of the 2-pass version should be smaller than the CQ file,and it is not..

I am going to encode some more files to get an idea as what to use,but so far CQ looks very good,in half the time..

[bugster]

Thanx again Bugster,i will ofcourse use what i get the best result from. When using CQ the max bitrate is 8000 and when i use the 2-pass it is only 4000,that is why i would think the filesize of the 2-pass version should be smaller than the CQ file,and it is not..

That explains why the 2-pass video doesn't look so good in high motion scenes. Just to be sure CQ is what you really want/need, try a 2-pass VBR encoe with Min 2000, Avg 4000 and max 8000, feel free to adjust the avg to get the file size you want, but be sure to leave the max at 8000. It should be much better than having a max of 4000 as before.

[King-Of-DK]

OK,i will do that,but how can i predict the filesize using a span of 2000-8000 in vbr?? even if i use 4000 as avg.

And still it dosn´t explaine why my 3000avg. vbr file is bigger filesize than the CQ65 file

[bugster]

OK,i will do that,but how can i predict the filesize using a span of 2000-8000 in vbr?? even if i use 4000 as avg.

And still it dosn´t explaine why my 3000avg. vbr file is bigger filesize than the CQ65 file

Use a bitrate calculator and use the AVERAGE bitrate, thats what matters. As to why the CQ 65 file is smaller, it must use a lower average, which is why I suggsted you may want to play with this value. However, with CQ mode, you have no control over the average bitrate, only max and min, which is why you can't predict final filesize very easily.

A thought. Get bitrate viewer from the tools section (its a commercial app but the freeware version has enough functionallity for us). Load your CQ encode into it and look at the avergae bitrate (and the max too, for interest) Then encode 2-pass vbr with the same average but remember to set max to 8000. See what happens, it should be the same filesize and quality as the CQ encode.