Mpeg experts help with Mpeg-1 vs. Mpeg-2 resolution, currently, different, actually

andy

I am no expert on the different versions of Mpeg and have some questions.  

Basically it always seems that whenever higher bitrates are wanted Mpeg-2 is used and whenever lower bitrates are wanted Mpeg-1 is used.

Is Mpeg-1 actually better at lower bitrates, say under 1500Kbit?

If you can is there any reason not to use Mpeg-2 with lower bitrates and VCD resolution.  Again under 1500Kbit?

I am asking because currently I am having some minor issues with DVD2SVCD and VCD's, but if I make a XVCD with Mpeg-2 instead of Mpeg-1 the issue goes away and my players don't have a problem with it.

Thanks,
Mark

Hmmm.. there's a number of issues here.

for example:

MPEG1 is arguably better than MPEG2 for lower bitrates.

Although TMGPEnc is capable of encoding MPEG1 using Variable Bit Rate, this is not officially supported by the DVD spec, or, indeed, the MPEG Standards as a whole (at least as far as I'm aware it isn't. this is almost definitely the reason your player is rejecting your disks!

Officially, the MPEG2 standard adds a number of features over the older MPEG1, including Variable quantization and VBR. What you really need to bear in mind is the fact that MPEG1 may well be superior to MPEG2 with low bitrates if you are using CBR in both instances, but you may still get a superior result from MPEG2 if you use it in VBR mode, for obvious reasons. If it were me, I'd generally use MPEG2 VBR rather than equivalent filesize MPEG1 CBR.Arky  ;o)

Actually my player is not rejecting anything.  It's an issue outside of my main question.  The problem brought up some questions in my head about mpeg-1 vs mpeg-2.  
My problem has to do with the way DVD2SVCD detects the frame rate of AVI's when using TMPG or doing Mpeg-1, which of these two is the reason I do not know.  

Whenever I do Mpeg-1 I always use CBR anyway.  I never use CQ or VBR.  It just doesn't feel right to me for the reasons you said.

Lets say you have to make a file with 1500Kbit and CBR.  In this case should I use Mpeg-1 or Mpeg-2?

At what bitrate point would you say Mpeg-2 starts to show it's superior nature?

Mark

I think that MPEG1 is more appropiate or tuned for lower resolutions and MPEG2 for higher resolutions. Don't know about bitrate or other things.

Originally posted by markrb

Lets say you have to make a file with 1500Kbit and CBR.  In this case should I use Mpeg-1 or Mpeg-2?

At what bitrate point would you say Mpeg-2 starts to show it's superior nature?

Mark

Well, all of us who have been at this lark for a while have had the experience of running test encodes, and it is no secret that MPEG encoding is every bit as much a quot;black artquot; as it is a mathematical process, although this fact is widely-ignored. Therefore, anyone who has spent months or years encoding MPEG will have formed their own preferences over time. As I'm sure you would agree, it is often difficult to explain (in a tangible sense) why a decision is made, based on this experience - one simply relies on a learned intuition!

Therefore, others may well feel different intuition from myself, but my subjective opinion would generally be to use MPEG1 up to the limits of the DVD spec (which, I approximately recall, is circa 1800kbps), and use MPEG2 thereafter (even though you are not specifically referring to DVD authoring). However, there may yet be valid arguments for reverting to MPEG2 beneath the 1800kpbs bitrate threshold, where, for example, your source footage varies a lot in complexity from scene to scene. In this case, MPEG2 VBR might be a far more practical solution than MPEG1 CBR, hence my previous statement about my general preference for MPEG2 VBR. To be honest, I don't think we'd even be having this discussion if space were not an issue, so I am assuming that all your work is written to 800-900mb CDRs rather than DVD-R?

I would also agree with Mulder that MPEG1 is not really optimised for large framesizes in the same way that MPEG2 is, this optimisation being directly related to the times each of the standards were born, and the prevailing hardware during the respective time periods.

So tell me - what framesize are you encoding? Arky  ;o)

In my situation now I am trying to make the best encode possible out of a Divx file.  The Divx is about 350mb's so I figure that if I try to go above 352 x 240 I am just forcing the video beyond what is originaly there anyway.  Best to keep it small and use as much info on that area as possible.
My encodes are 352 x 240.  I can use either Mpeg-1 or 2 and my player doesn't care.  
I also figure that at best I am lucky to have what is about the same as 1500kbit of mpeg video in the Divx there as well.  I am thinking any higher bitrate and I am just wasting space here.  This is all just theory since I know more about mpeg then I do about Divx and I am still learning on mpeg.

I just did a test encode of mpeg-2 vbr for the first time.  I haven't had a chance to really compare it yet.

Because of the issue with framerates that I have yet to solve I have been unable to truly test Mpeg-1 yet.  
Edit: It seems that I was wrong about the frame rate issue.  DVD2SVCD works fine.  Now I have to find out why the occasional jerky motion when doing a CBR Mpeg-1 video.  The same video doing mpeg-2 had no issues.  I am curious if it was my use of the Msharp Filter on mpeg-1.  I don't know I need to test more.

Thanks,
Mark

You weren't inadvertantly invoking interlaced encoding via the wizard or template were you?

BTW, you said that you are encoding FROM Div-X. Without wishing to be a killjoy, I have to be totally honest with you and say that I believe you are wasting your efforts. This is because, as you know, MPEG relies on a clean source file - that's precisely why MPEG encoding is so efficient - it works (very simplistically-speaking) by estimating frames on the basis of regularly-interspersed reference frames (hence I, P, and B frames). If you are feeding it a noisy source (which Div-X DEFINITELY is - it's chock full of artifacts due to overcompression - that's the nature of the beast, sadly), then TMPGEnc will be unable to create a clean job from a noisy source - it can't successfully calculate P and B frames because the artifacts and general noise of the source file mean that there is very little consistency between frames - i.e. there is little or no redundant data across adjacent frames, so none can be discarded by TMPGEnc, which means it will run out of bitrate to spread around - DISASTER for output quality!

I appreciate that, for reasons best left unsaid, you may have a large collection of films which just happen to be in Div-X format, and which you wish to play on a a standalone player. Since you do not, presumably, own a quot;Kissquot; player, you need to re-encode to MPEG1 or MPEG2 for your standalone to play the films. Nevertheless, the hard truth is that I don't think you will ever be satisfied with your re-encodes of Div-X footage. Sorry to rain on the parade

Re-encodes of DVD footage only work well (although not perfectly, despite what people may tell you otherwise) because DVD's are a very cleanly-encoded MPEG 'source', when ripped to your HDD. Div-X encodes are simply not in the same league, sadly.Arky  ;o)

Yes what I have is a collection of TV shows.  I am not super critical and any ability to play them would be fine.  I have converted about 25 so far and although less then perfect I can still watch them.
I was just wondering given the source and the low bitrate what would be better?  There is no need to be perfect and I don't expect DVD rip quality.
I have no other source for these shows and would like to take these lemons and make a passable lemonade.

I have been playing with filters and so far the best I have come up with seems to be Mpeg-2 VBR with and AVG of 1500 using both Sharpen2 and a heavy CCE Anti-noise filter setting of 22 with VCD resolution.
It is blocky in the background and not exactly first run, but it is watchable.  I was playing some with Unfilter today, but results haven't been great, but I only tried one strength setting.

I plan to play a little with TS along with more Sharpen2 which is a nice speed boost over sharpen for sure.  I know adding Sharpen2 adds to an already noisey Divx, but if I don't it's way too soft.

In the end I am looking for the best I can get with a less then perfect source.  Eventually these will be released on DVD and I will buy them, but until then I need to know what I have missed.

So I think I will stick to what I think you suggested and just go with a VBR Mpeg-2.  I was trying to stick to Mpeg-1 until I thought about why I cared what standards I am messing with.  These are for me to watch and then probably erase.

Mark

Originally posted by Arky

I appreciate that, for reasons best left unsaid, you may have a large collection of films which just happen to be in Div-X format, and which you wish to play on a a standalone player. Since you do not, presumably, own a quot;Kissquot; player, you need to re-encode to MPEG1 or MPEG2 for your standalone to play the films.
Arky  ;o)

A Kiss player only plays Divx 4 and 5. So you can forget about Divx 3. I guess most of your movies are divx 3 and you'll have to re-encode them all to divx 4 or 5 to play them on your Kiss player.

I've heard the X-box can now play ALL DivX movies. You'll have to do some simple hardware modification though.

i have done a few test recently to compare mpeg-1 and mpeg-2 with very  low bitrate ( lt;500kBit) and the mpeg-1 was never better than the mpeg-2, maybe the same but never better.
i used tmpegenc with vbr encoding and vcd resolution (352x288) for both.