Getting optimal quality when converting Divx to DVD.

[Wondermoose]

Hey.

Ive looked around like a mad man and havent found the right thing yet.

Well, here is my situation.
I have alot of TV-series and would like to burn them to a dvd-r with menus and stuff. I want to play them in my DVD-player (it doesnt support divx) I want to fit in as much as I can on a DVD without lowering the quality of the series.

Some are VCD format and my solution for them is Low-res DVD from tmpgenc. That will fit about 4-5 hours on on a DVD 4,7
But the other ones are Divx/xvid format.

My little dilemma is that the divx has a higher frame size than low res DVD (352*288). So I have to use the higher one I guess... But how can one compare the bitrate on a divx and a VCD/SVCD/DVD. Divx is much lower and I dont see how one can compare them or can I?? As I said before I dont wanna have reduced quality when I convert them.

[jimmalenko]

You can use 352 * 288, 352 * 576, 704 * 576 or 720 * 576 on PAL DVDs.

Unfortunately there is no hard-and-fast formula for calculating divx --> MPEG bitrates. All you can do is do a couple of test encodes at different bitrates and compare them to the original for yourself. The bitrate and frame size you use depends on the runtime you wish to fit on any given DVD too.

If you have VCD clips, you shouldn't have to re-encode them. All you need to do is resample the audio to 48KHz, which most DVD Authoring software will do for you automatically (TMPGEnc DVD Author definitely does it).

[monzie]

For your AVi's (divx/xvids) you need to know their resolution...if above say 512 horizontal then go for full DVD (720) res....use FITCD for instant resolution conversion.

[Wondermoose]

Well I havent gotten around converting my dvix, I have tested Fitcd (thx monzie )some and researched more.

But one thing I can say, TMPGenc DVD author was an excellent program And I didnt have to convert my VCD... But one thing that puzzles me... Is there any sense in using DVD low resolution? When you can use VCD on your DVD-r?? Or is there the problem of compitability when using VCD on DVD??

[bugster]

And I didnt have to convert my VCD... But one thing that puzzles me... Is there any sense in using DVD low resolution? When you can use VCD on your DVD-r?? Or is there the problem of compitability when using VCD on DVD??

DVD low resolution IS the same as used for VCD. Just the audio is different at 48Khz for DVD and 44.1khz for VCD. Also DVD allows low res (352 * 288 PAL) to be up to about 1850kbit/s wherase VCD is only 1150, so low res DVD can look better than VCD if the higher bitrate is used and needed (lots of motion).

Also, with NTSC, DVD does not support NTSCfilm framerate of 23.97fps and as VCD is mpeg-1 you cannot use 3:2 pulldown to play it at the proper NTSC framerate of 29.97fps. So if you have a VCD at 23.97fps and want to put it on DVD the only option I know of is to re-encode.

[jimmalenko]

Another reason for using the low-res DVD template as opposed to the VCD template is that the VCD template, by default, allows open GOPs, which TMPGEnc DVD Author will complain about. If you know what to change with the VCD template then all well and good, but if you don't, it's probably wise to stick to the low-res DVD template.

[Wondermoose]

Well I figured out how to change the template concenring GOPs. So Now I can use the normal VCD on DVD without problem...
And I saw that I only got too long GOP sometimes in the first place. But Now I have no problem

And as for converting DivX to VCD or DVD I simply test wether I see any change in quality. And use whatever help I can get from different programs.

A thank to everyone for helping me, all posts have been very usefull

[TBoneit]

Well I havent gotten around converting my dvix, I have tested Fitcd (thx monzie )some and researched more.

But one thing I can say, TMPGenc DVD author was an excellent program And I didnt have to convert my VCD... But one thing that puzzles me... Is there any sense in using DVD low resolution? When you can use VCD on your DVD-r?? Or is there the problem of compitability when using VCD on DVD??

Unless your VCDs had a non-standard audio of 48Khz already DVD Author will transparently to you re-encode the audio. It just takes longer that way. It will use mp2 audio or re-encode to AC3 if you have the AC3 plug-in and choose that option.

Some Divx have AC3 that can be demuxed with VirtualdubMod and and used in DVD Author as is. Some AC3 from Divx it doesn't like and that'll need to be reworked. Note i'm using Divx and Xvid interchangeably above.

For conversion to MPEG2 it depends what your goal is, Quality or Amount on a DVD. for quantity use the VCD on DVD (IE VCD Video 352 by 240 (288) @ 1150 kb with 48Khz Audio) for quality look at the resolution of the source. I use 352 by 480 (I'm in NTSC land) you'd use 352 by 576 at 5000 bitrate CQ=100 Unless it's 720 (704) by 480 (576) then I keep that size up the bitrate as needed to fit on the DVD using the bitrate calculator from here. I may also tweak the brightness or sharpness in TMPGenc Plus.
I usually opt for quality as disks are cheap! Unless the source is lowres such as 320 by 240


Good Luck

[jimmalenko]

I use 352 by 480 (I'm in NTSC land) you'd use 352 by 576 at 5000 bitrate CQ=100 Unless it's 720 (704) by 480 (576) then I keep that size up the bitrate as needed to fit on the DVD using the bitrate calculator from here.

Isn't CQ=100 effectively doing CBR ?

[TBoneit]

I use 352 by 480 (I'm in NTSC land) you'd use 352 by 576 at 5000 bitrate CQ=100 Unless it's 720 (704) by 480 (576) then I keep that size up the bitrate as needed to fit on the DVD using the bitrate calculator from here.

Isn't CQ=100 effectively doing CBR ?

From the help file: When one is more concerned about picture quality than file size, one should use this mode. Using the CQ mode, one can set all of the aspects of quality to use in the encoding. This mode will guarantee a high quality movie; however, movies with many scene with rapid motion can become rather large

In other words as I have understood it, This will give good quality, not a constant bitrate. However the downside is unprdictable file size. Plus I wasn't totally clear above, I use the CQ settings on 352 by 480 but use 2 pass VBR using the bitrate calculator when doing 720 b y 480 res.

Hope this helps
Cheers

[jimmalenko]

I use 352 by 480 (I'm in NTSC land) you'd use 352 by 576 at 5000 bitrate CQ=100 Unless it's 720 (704) by 480 (576) then I keep that size up the bitrate as needed to fit on the DVD using the bitrate calculator from here.

Isn't CQ=100 effectively doing CBR ?

From the help file: When one is more concerned about picture quality than file size, one should use this mode. Using the CQ mode, one can set all of the aspects of quality to use in the encoding. This mode will guarantee a high quality movie; however, movies with many scene with rapid motion can become rather large

In other words as I have understood it, This will give good quality, not a constant bitrate. However the downside is unprdictable file size. Plus I wasn't totally clear above, I use the CQ settings on 352 by 480 but use 2 pass VBR using the bitrate calculator when doing 720 b y 480 res.

As I understand it, CQ=100 is basically telling it to do the whole movie at whatever you have your max bitrate set at, which is essentially the same as telling it do CBR at that same bitrate.

[bugster]

I use 352 by 480 (I'm in NTSC land) you'd use 352 by 576 at 5000 bitrate CQ=100 Unless it's 720 (704) by 480 (576) then I keep that size up the bitrate as needed to fit on the DVD using the bitrate calculator from here.

Isn't CQ=100 effectively doing CBR ?

From the help file: When one is more concerned about picture quality than file size, one should use this mode. Using the CQ mode, one can set all of the aspects of quality to use in the encoding. This mode will guarantee a high quality movie; however, movies with many scene with rapid motion can become rather large

In other words as I have understood it, This will give good quality, not a constant bitrate. However the downside is unprdictable file size. Plus I wasn't totally clear above, I use the CQ settings on 352 by 480 but use 2 pass VBR using the bitrate calculator when doing 720 b y 480 res.

As I understand it, CQ=100 is basically telling it to do the whole movie at whatever you have your max bitrate set at, which is essentially the same as telling it do CBR at that same bitrate.

I am not sure how TmpGenc measure 'quality' in CQ mode, but CQ=100 does not give a CBR type result. It will allocate more bitrate to an action scene than a talking head low motion type scene. A Higher CQ will allocate more bitrate to the action scene than a lower CQ in order to maintain 'quality', so you end up with a larger file.

[jimmalenko]

I am not sure how TmpGenc measure 'quality' in CQ mode, but CQ=100 does not give a CBR type result. It will allocate more bitrate to an action scene than a talking head low motion type scene. A Higher CQ will allocate more bitrate to the action scene than a lower CQ in order to maintain 'quality', so you end up with a larger file.

I don't know exactly how the CQ works (if you couldn't already tell ), so I'll bite my tongue before I make an even bigger NOOB out of myself

With the possibly large fluctuations in file sizes as a result of using CQ mode, is it then a bit of a risk to be using it when your target format is DVD ?

[bugster]

I don't know exactly how the CQ works (if you couldn't already tell ), so I'll bite my tongue before I make an even bigger NOOB out of myself

With the possibly large fluctuations in file sizes as a result of using CQ mode, is it then a bit of a risk to be using it when your target format is DVD ?

Yes it is a risk, but the quality it produces is often as good as if not better than 2-pass VBR at the higher CQ levels with much shorter encode times (close to 1/2. It is slower than CBR but not by that much), so to some it is worth it. If the mpeg comes out just a little too big for a DVDr you can always author to HD and then shrink to fit.

[jimmalenko]

Yes it is a risk, but the quality it produces is often as good as if not better than 2-pass VBR at the higher CQ levels with much shorter encode times (close to 1/2. It is slower than CBR but not by that much), so to some it is worth it. If the mpeg comes out just a little too big for a DVDr you can always author to HD and then shrink to fit.

Thanks. I get it now

I now know why I haven't used it. I'd much rather encode to fit first time, but that's just my preference I guess.

[TBoneit]

I suggested it since the person asking the original question had TV series in Divx, if done as 1/2 D1 with a high CQ setting he should get more than one on a DVD. Using the Videohelp Bitrate calculator for 2 hours 21 minutes, 3 1 hour shows minus commercials or Six 1/2 hour shows (approx.) gives a bitrate of 4096 which should be enough bits at 1/2 D1 for decent quality.

or in other words I use a CQ setting for shorter things such as compilations or Episodic shows etc.

Cheers

[Wondermoose]

Well Ive started using CQ, Thats really great. Ive figured out ways to Get both quite good quality and not so large files using this and Half D1

I care for both good quality but also large quantity, Im a poor student so I cant afford to buy that many DVD. This was a really good way of getting abit of both.

But one thing still puzzles me. Maybe Ive read something wrong but when setting for instance CQ= 100 and bitrate 1000 - 4000 How could the average become over 4000 ?? According to G-spot.

THX

[bugster]

I am not sure G-spot reports the average correctly, in fact I didn't think it handled Mpegs at all (maybe a newer version than the old thing I have). Anyway, to be sure. open your mpeg in the free version of bitrate viewer and see what that says.

I suppose it is possible for the average to be slightly higher than expected as most encoders can't/don't stick the the specified bitrates exactly.