Scan type - "Alternate" .... What setting in CCE?

[guv]

Ive been looking at a ripped film that I wish to back up and downsize for the kids room.

Basically Ive been using CCE, and have enjoyed good success by following the robshot guide. However what I am seeing is something Ive not encountered before.

Basically when you examine the m2v file, I notice that the scan type states it is alternate. ie parts are interlaced, parts are not.

So when inserting the setting for "progressive" or not, part is going to be incorrect and the interface problem will be seen.

Anyone seen this before and know a work round (or correct setting for CCE)?

HAve a feeling the only way to tackle this would be to rip chapter by chapter, and then reassemble the same way.

Any views appreciated.

Cheers

Guv

[banjazzer]

If your source material is DivX then it will be progressive, as DivX does not support interlacing. If there are signs of interlacing, it means the DivX has been created incorrectly from an interlaced source, and you will be unable to remove any interlacing artifacts.

[guv]

The source isnt from Divx. The source is DVD.

[banjazzer]

I see. The ripped film reference threw me.

Why not try a sample encode and see how it turns out if you encode as if interlaced?

Alternatively, you could run it through Gordian Knot and see how the de-interlace options work out, or go via a TMPG project file before encoding with CCE. TMPG has a vast array of de-interlacing options.

BTW, are you the Guv from usenet?

[guv]

Because it is a ripped DVD and needs to be downsized (I want to put 2 films on one disc for the kids bedroom - and save my originals.), it is framserved to CCE after running DVD2avi and VFapi.

When using dvd2avi, it starts up and is shown as interlaced, a bit later its not showing interlaced which I guess is why it comes up in bitrate viewer as "Alternate". ie its neither all one or the other.

I know I can encode a sample - but the interlace problem generally doesnt appear until you use a set top and tv that the problem is evident.

I have a feeling this is going to be one that will remain as a one disc option, and have seen this on a couple of titles Ive just looked at. (Monsters Inc and Shrek) I am certainly not going to arse about with each chapter and reassemple after downsizing. Far to much hassle - the kids will have to miss out on that!

And yes to the last question, though there must be more than one! But dont tell Nige.


Les

[banjazzer]

I would just treat it as interlaced, and either leave it as interlaced when encoding in CCE, or try one of the de-interlacing suggestions. In any case, my experience is that kids are less demanding than we are about the quality.

And yes to the last question, though there must be more than one!

We have met before. 8)

[guv]

Hmmm. I dunno if that would work! I would imagine if I did that, the first 5 minutes (which is interlaced) would be fine, but the bits that are not, would be shagged.

I agree that kids are less likely to be bothered about it than we would, but to be honest there is a lot of time used on it (not to mention Im a tight git and dont want to waste a disc!) I will try it though if no one knows.

Cant see this hasnt been tackled by someone - hence the question!

As to the "we have met" you now make me nervous! Hope it wasnt cross words email me from UMD.... Dunno why, but have a hinkling that you like diving?

Les

[banjazzer]

Hmmm. I dunno if that would work! I would imagine if I did that, the first 5 minutes (which is interlaced) would be fine, but the bits that are not, would be shagged.

I'm not so sure. Remember, there is a difference when watching the result on a TV to your PC. Can you not use a re-writable in your DVD player?

[BJ_M]

Ive been looking at a ripped film that I wish to back up and downsize for the kids room.

Basically Ive been using CCE, and have enjoyed good success by following the robshot guide. However what I am seeing is something Ive not encountered before.

Basically when you examine the m2v file, I notice that the scan type states it is alternate. ie parts are interlaced, parts are not.

So when inserting the setting for "progressive" or not, part is going to be incorrect and the interface problem will be seen.

Anyone seen this before and know a work round (or correct setting for CCE)?

HAve a feeling the only way to tackle this would be to rip chapter by chapter, and then reassemble the same way.

Any views appreciated.

Cheers

Guv

"alternate" and its opposite "zig-zag" are not directly releated to if the film is interlaced or progressive.

The zig-zag scanning pattern for run-length coding of the quantized DCT coefficients was established in the original MPEG standard. The same pattern is used for luminance and for chrominance. A modified (alternate) pattern more suitable for coding of some interlaced picture blocks was added in the MPEG-2 standard. A bit in the picture layer header, if set, selects the alternate scan.

The patterns are represented below, in which the upper left corner is the DC term.

zig-zag scan order:

0 1 5 6 14 15 27 28

2 4 7 13 16 26 29 42

3 8 12 17 25 30 41 43

9 11 18 24 31 40 44 53

10 19 23 32 39 45 52 54

20 22 33 38 46 51 55 60

21 34 37 47 50 56 59 61

35 36 48 49 57 58 62 63



alternate scan order:

0 4 6 20 22 36 38 52

1 5 7 21 23 37 39 53

2 8 19 24 34 40 50 54

3 9 18 25 35 41 51 55

10 17 26 30 42 46 56 60

11 16 27 31 43 47 57 61

12 15 28 32 44 48 58 62

13 14 29 33 45 49 59 63

there are specific matrix tables for each type and they shouldn't be mixed (but i see they often are)


so remember to use zig zag for progressive source and alternate for interlaced source in MOST cases ..... some hardware encoders do use alternate method for any source.

The Main Concept encoder is one of the few that allow you to set the method for luminance and chrominance seperately.

there is no switch for this in TNPGenc and it encodes everything as alternate . (i think - someone can correct me if i'm wrong)

[banjazzer]

The zig-zag scanning pattern for run-length coding of the quantized DCT coefficients was established in the original MPEG standard.

I couldn't have put it better myself.

[guv]

Banjazzer. Dunno - but good point! HAve just bought a new pioneer player and not tested that. My old machine wouldnt! Still have to do my multi pass conversion first though!

BJ_M

OK, not 100% sure on what you are saying for the mo.

When I looked in bitrate viewer, it was shown as zig zag and alternate.

So in CCE, what settings would you suggest I should use for these options:

Progressive frames (I have it unchecked)
Zig Zag scanning order (I have it checked.


Cheers


Les

[banjazzer]

If you want to experiment with a sample, load up into TMPG with the SVCD template and use the source range setting. Then save a project file (.tpr) and convert to pseudo-avi with VFAPI Converter. Also, whilst you are experimenting, to save time use CCE's CBR encoding.

[BJ_M]

if the source is progressive - use zigzag as first choice and alternate as second

if the source is interlaced use alternate ONLY ...

if its mixed - use alternate

i should write a guide on what matrix tables to use for each but there are already GREAT matrix tables already avaible for DVD bit rates on down.

alternate scan does not mean that the film is nessessarly mixed progressive and interlaced as i think you thought in your first post .. but these terms and DCT and quantization tables are not well understood or used properly...

a really good practise with these and other settings is to go back a program that really was around way before current mpeg encoders and can do anything really ... and is perfect for seeing what every setting can do .. it is real slow though - but it one of the first programs i used on pc's switching over from IRIX (SGI) (all origanal dvd's were made on sgi workstations pretty well - scenarist was origanialy written for sgi)

That program is called "pixel tools mpeg repair" - i dont mean to use it for major work , but you can see and change all settings avaiable in mpeg encodes

[baker]

Sorry but I had not time to read the whole post.

Basically just go with an interlaced encode. Scenes that are interlaced will come out great and non-interlaced scenes will be interlaced by CCE anyway. This is definetly the way to go...

Baker

[Sully]

So is it fair to assume it's btter to just use alternate in CCE instead of using an external de-interlcer (ie: GeedyHMA)?

I never actually thought of the alternate setting, but on VERY high motion video it can be kind of jumpy when using the greedy .dll (from the frames being removed).

[guv]

Thanks for the replies:

Within CCE there isnt a setting for alternate, but it seems that by not checking the progressive frames box, it achieves this.

The film in question, I took the plunge with and burnt.

As mentioned the source said it was alternate. The settings I used in CCE were :

Add sequence code - tick
upper field first - tick
progressive frames - nothing
linear quantizer scale - tick
zig zag - tick
dvd compliant - tick

Ive just authored 2 films to 1 DVDR and they both look every bit as good as the original.

Might take a while to complete this task, but the results are suprising excellent.

Hope this helps anyone else who is stuck!

Just wish there was a guide somewhere that actually explained in English exactly what all these settings do, and which to use for the various combinations out there. I'm sure there is one somewhere - just never found it!

Cheers

Les

[banjazzer]

Just wish there was a guide somewhere that actually explained in English exactly what all these settings do, and which to use for the various combinations out there. I'm sure there is one somewhere - just never found it!

There is the manual in .pdf format in the CCE install directory. It is in English - sort of!

[guv]

Its the "sort of" bit that I dont understand!

Besides, it doesnt really talk much about ripping and the formats distributors use.

Cheers

Les

[banjazzer]

It may well be worth your while looking in the CCE forum at www.doom9.org The CCE FAQ there has some useful links. 8)

[guv]

Will do....thanks John.