Question about Interlaced / Progressive.

[ZiGGY909]

hi, i have just one question i never really understood...

If the source is progressive should my output be progressive?
Same goes for interlaced... if source interlaced, output should be interlaced or not?

Im also encoding to mpeg2 using cce (4pass). Thanks, Zig

[daamon]

Hi ZiGGY909,

There's a simple rule - if it's ever gonna be watched on TV, irrespective of the source, it should always be interlaced.

If it's only ever gonna be watched on a PC monitor then it can be progressive (again, irrespective of the source).

Players like WinDVD or PowerDVD can take interlaced material and play it on a progressive PC monitor without the jaggy lines you'd normally see in interlaced material on a progressive display.

Hope that helps...

[celtic_druid]

If the source is progressive the output should be progress.
If the source is interlaced then the output should be interlaced unless you have de-interlaced in which case the source would be progressive anyway.

[ZiGGY909]

thanks for that, but i have 2 different oppinions here... Which one is right?
thanks

[ZiGGY909]

Also... yes my output is watched on a TV.

[sanjayk]

ZiGGY909,

Both opinions are right as they are stating the same thing. Since you are going to watch on TV, your output should be interlaced.

[edDV]

For a standard TV output try to maintain interlace through the process for best motion fluidity. Ignor what it looks like on the computer.

Your original question's answer depends on the CCE encoder setups.

[ZiGGY909]

daamon said: Always use interlaced for TV.
celtic_druid said: The source should be the same as output.

That to me isn't the same or am i missing something?
So now i know that i should encode my progressive/interlaced source to a interlaced output.

Another thing you can help me with please is... The field order... Should i maintain the same field order as the source or doesnt it matter?

Is there a program out there that tells you if its interlaced or progrssive and the field order?

Many thanks for replying all, appreciate it

[junkmalle]

Standard definition TV can only display an interlaced signal -- 59.94 fields per second (NTSC). Anything that feeds it must provide that signal. You never see an entire frame on your TV.

DVDs can produce that signal in two ways:

A disc can combine pairs of fields together into 29.97 interlaced frames per second. The DVD player then sends one field at a time to the computer

Or a disc can contain 23.976 progressive frames per second and the DVD player performs a 3:2 pulldown into 59.94 fields per second as it plays the video.

If your source is truely interlaced (a live sporting event, news, most camcorders, etc) it's not possible to convert it into a progressive source without mangling the picture. It's best to leave it fully interlaced and encode it that way in your DVD MPEG file.

If your source is 23.976 progressive frames per second it's best to encode to MPEG that way, but marked for 3:2 pulldown on playback.

If you source is telecined film (a movie that was recorded off TV for example) it is interlaced but it's possible to inverse telecine back to the original 23.9786 progressive frames per second. This can be difficult to do though.

Oh, it's also possible to have 29.97 progressive frames per second. Some camcorders record this way. In this case the MPEG is encoded as 29.97 frames per second. The DVD player splits each frame into two fields and sends one at a time to the TV.

[edit]

Sorry, for PAL:

Standard definition TV can only display an interlaced signal -- 50 fields per second (NTSC). Anything that feeds it must provide that signal. You never see an entire frame on your TV.

DVDs can produce that signal in two ways:

A disc can combine pairs of fields together into 25 interlaced frames per second. The DVD player then sends one field at a time to the computer.

Or a disc can contain 25 progressive frames per second and the DVD player sends one field at a time to the computer.

The difference between the two is when the two fields were taken. In a progressive frame both fields come from the same instant in time, the same picture. In an interlaced frame the two fields are from two different points in time, two different pictures.

If your source is interlaced (a live sporting event, news, most camcorders, etc) it's not possible to convert it into a progressive source without mangling the picture. It's best to leave it interlaced and encode it that way in your DVD MPEG file.

If your source is 25 progressive frames per second it's best to encode to MPEG that way.

[celtic_druid]

They are in the UK though which would most likely mean a PAL source. Most retail PAL DVD's are progressive. Simply the progressive 24fps film source sped up to 25fps.

[edDV]

edit

[ZiGGY909]

Ok thanks, i see now, cool
is there a program out that can tell you if its interlaced or progressive?

PS: ... im using CCE 2.70SP for encoding an i dont see a option to interlace in there (i see deinterlacing). Does CCE output a interlaced mpeg2?

Thanks for help

[lordsmurf]

This may help:
http://www.digitalfaq.com/dvdguides/capture/understandsource.htm#interlace

[junkmalle]

is there a program out that can tell you if its interlaced or progressive?

No, use your eyes. Use a program like VirtualDubMod to step through the video frame by frame. If you see interlace comb lines it's interlaced.

[lordsmurf]

GSPOT can tell you. Use v2.55 or later.

http://www.digitalfaq.com/dvdguides/convert/intro.htm#analyzesource

It can even tell field dominance.

It will show PROG or I/L
and the if interlaced either TFF or BFF

[dphirschler]

GSPOT can tell you. Use v2.55 or later.

Where are you finding v 2.55? The latest I can find is 2.52 beta 01.


Darryl

[gadgetguy]

GSPOT can tell you. Use v2.55 or later.

Unless your source is DV Type1...

[monzie]

Dont know if this well help but personally I cant tell any difference on VIEWING on a PAL CRT TV a progressive DVD (wether an original progresive DVD movie or a DVD encoded from a progressive source like a avi/xvid/divx) or viewing an original interlaced PAL DVD.

...most (but not all) PAL DVD's seem to be progresive anyway...maybe my 3 CRT TV's are fantastic (or maybe they're just crap)...but watching my same DVD's on other peoples TV's (like my parents or friends) give exactly the same results...ie. you cant say that one is better than the other, which is odd as you would THINK that you SHOULD see a better picture with interlaced DVD's on CRT TV's (but dont)...maybe its our DVD players most are 'progressive' but what does that actually mean when viewing on a CRT, anyone know? (I dont mean to hijack)

What you DO NOT want to do is butcher your source...so keep prog sources prog (eg divx/xvid avi's) and interlaced sources interlaced (eg DV)...unless you WANT to create a prog video from an interlaced source (eg interlaced DVD to xvid).

So, in short, as CELTIC says match the ENCODING to the source.

As for CCE, interlaced is the default encoding option PROGRESSIVE is checked for well, progressive sources (i also find ZIG ZAG scanning works great with PROG).

Also what are you encoding? Do you REALLY need 4 pass?

[junkmalle]

The picture you see on a standard definition PAL TV is always interlaced. SD televisions only display one field at a time -- EVER.

With PAL the only difference between an interlaced source and a progressive source is whether the two fields are from the same picture or not.

With film sources each pair of fields come from the same picture (film frame). You see 50 fields per second but the fields are from 25 different pictures (frames).

With a live video source you see 50 different half pictures per second. The TV camera grabs one field and sends it to the TV, 1/50 second later it grabs the next field and sends it to the TV, etc.

So the difference between the two is only temporal -- interlaced has slightly smoother motion because you see 50 different (half) images a second rather than 25.

[ZiGGY909]

Thanks for all the help !

Also what are you encoding? Do you REALLY need 4 pass?

I'm just encoding some old films i have in xvid format that are NTSC 29FPS, im then converting them to DVD 25FPS PAL. 4 Pass is good as it only takes 8-10hrs, which is quite fast !

Cheers for replying all, thanks!![/quote]

[monzie]

If they are xvid source then I would suggest that you try encoding with a 1 pass VBR (aka OPV mode) with a Q value of 15 to 20 (try encoding a few minutes and then stop encoding, look at the quality of the mpv file and adjust the Q lower to increase bitrate and higher to reduce IF REQUIRED.. does 4 pass look any better?)...and dont bother with converting NTSC to PAL....just about all PAL DVD' players will happily play NTSC DVD's...ditto PAL TV's....that should save you up to 8 or 9 hours of needless multi-passing....worth a try eh?

[ZiGGY909]

ok thanks, il try that 1 pass VBR way but i have to have PAL as my hardware only plays PAL, i've tried before with NTSC and it comes out black and white. I use my ps2 for watching films. Though i have got a DVD player that plays everything, but thats downstairs.

Thanks for help!

[ZiGGY909]

What happens when G-Spot doesn't show if its interlaced or progressive?
(see pic)

For some reason i dont think Gspot shows this info with a AVI file....
Works great with MPEG files... Can anyone or is it just me not see this info with a AVI?

[junkmalle]

MPEG files have interlace/progressive flagged within the file. AVI files do not. But even with MPEG files the flag may not be correct. The only way to know for sure is to look for yourself. Interlaced material will have files that look like this when there is motion:



Don't use a media player application to look for this. Many of them will deinterlace while playing because interlaced video looks so bad on a computer monitor. Use a program like VirtualDubMod which does not deinterlace.

[ZiGGY909]

ok thanks junkmalle, now i know how to identify a file from interlaced/progressive... But how do i find the field order?

I've been using TMPGENC Xpress 3.0 for this... i open the file and it gives me the field order... Is there any other way?

Thanks

[celtic_druid]

avi may not but MPEG-4 does. MPEG-4 modifier will tell you if it is interlaced.

[ZiGGY909]

thanks celtic, thats the program im looking for!
Will try out in the next few days.
Thanks for help everyone, appreciate it alot

[junkmalle]

MPEG4Modifier will only tell you if the person who created the file selected the interlace option. The actual video content may be interlaced or not.

Fortunately, you rarely see interlaced MPEG 4 files so it's not much of an issue.

[celtic_druid]

If they didn't encode it as interlaced then it is progressive, just means that the 2 fields were encoded as one frame. So basically rubish, no longer interlaced.

[junkmalle]

If they didn't encode it as interlaced then it is progressive, just means that the 2 fields were encoded as one frame. So basically rubish, no longer interlaced.

Here are crops from two AVI files. One was encoded as Xvid with the interlace option set. One was encoded without the interlace option set.



Can you tell which is which? Can you tell me what the differences are? If the files were converted to MPEG and burned to a DVD do you think the source interlace and field order settings would matter?