I asked Canopus which field is first in PAL. I received the following reply.
PAL DV is lower field first. Just like NTSC DV.
Lower Field First is the correct setting.
DV is lower field dominant.
-Jerry
Canopus Tech Support
When using Avid Xpress DV in PAL, the manual tells me PAL is Upper Field First.
Who is right ? And why ?
This is interesting, DV is always lower field first, I've checked it using after effects and its very easy to tell when its wrong. Interesting, my Matrox RT2000 manual also says PAL is upper field first.
However, things aren't (as always) that simple. If all you are dealing with is interlaced video shot on a camera then it's not a problem. However, if you ever end up with footage shot progressively (either film or off a HD camera) then things become very weird depending on the codec.
With lower field first footage, each DV frame should be made up of fields from two separate film frames interlaced together. My Panasonic DV2000 deck does this and everything shows interlacing artefacts on the TV. However, my Sony DHR1000 doesn't each DV Frame from it represents one film frame. This would suggest Upper field first footage, but it renders out as lower field to get the correct motion... What is going on?
It turns out the Sony codec captures in Upper field first format, and then moves everything down one line to make it lower field first. The advantage being that it can compress images as progressive rather than interlaced which should maximise the bitrate usage. The downside being that it makes it very hard to handle the footage in computers and maintain the quality. It's great, I can tell programs like Commotion and AfterEffects that its progressive and maintain the pic quality, but the problem comes if I move the image vertically by an odd number of lines, because the field ordering then comes out of sync. And what was playing out as the odd-field now plays out as the even field which would cause them to be drawn in the wrong place on screen (though probably not noticed on a CRT TV -- would cause havoc for a scaler feeding an LCD, DLP or plasma based display). But if you use a Lower field first to render, you end up with it becoming interlaced and a mess again.
Things can get even nastier as I've seen footage thats been dubbed off digibeta (via S) that by the time its been played into the computer has the fields in completely the wrong order (and its happend on more than one occasion). Why didn't they make DV a field based system like Digibeta?
Its worth bearing in mind that all cuts on DV happen between the odd and the even field though. And its also a very good idea not to ever copy DV footage via analogue links EVER as it could move the fields down again...
There should be a good article on fields, frame and orderings in CV at some point to explain it all and how to use it to our advantage.
See you earlier,
Steven
You're mixing a lot of different things up here Steven.
Analogue devices play and store video as separate fields so they automatically come in the right order. The only issue is where you make a cut which is called the Field Dominance, and has for some time been standardised by the EBU.
Digital devices mostly store fields stacked in pairs that will make up the interlaced frames. For various reasons, digital formats have each been developed with different order for which field is stacked higher. This is particularly a problem in 525 where there are 486 active lines in NTSC but only 480 in some digital formats like DV. If you do the obvious and crop 3 lines off top and bottom, then you are changing the field order.
The bottom line is that if the decoded digital video has the fields in each frame reversed (giving a stuttery motion) then there is a mistake in the stacking order. If the two fields from a progressive scan don't appear in the same frame, then there is a mistake earlier with the field dominance.
Changing the stacking order is relatively painless, involving a single pixel vertical movement of the whole frame. Changing the field dominance is rather more difficult, but possible using say After Effects.
Changing either order is not possible with a simple analogue dub.
Based on experience:
DV is always lower field first (both PAL and NTSC).
Most PAL analogue capture devices I've used on PC's are upper field first, but this hopefully isn't the case with things like the DV500/RT2500 when used to capture analogue to DV (which should be lower field first...)
For users of Ulead software:
lower field first = field order A
upper field first = field order B
Hope this helps.
Tony
Just to expand on Tony's post; the stacking order is only relevant to the digital files. ANY device capturing to DV thus needs to put the lower field first. Most other digital formats are related to a particular piece of hardware (like Avid, Media100, etc) and each manufacturer will choose their preferred rather arbitrary solution. My own Digital Voodoo is upper field first. The only thing that really matters is that you know which it is and select appropriately when it counts.
Thank you all for your replies. I recently bought Avid Xpress DV 3 and find that I am having to output 32bit animations both in Upper Field First for Avid and Lower Field First for Raptor Edit/Premiere. This is a pain but I find that Avid is good at some things and Premiere is better at others. I can't believe for example that Avid can not produce an MPEG1 or 2 file with both video and audio combined. It produces seperate files for video and audio. What good is that to anyone ?
Anyway it would appear that I will have to go one way or the other Premiere or Avid to avoid doubling up on everything.
Basically the separate files for MPEG2 video and audio are required for DVD authoring which is what many folks need MPEG2 for.
If you need to generate a 'multiplexed' (or 'muxed') MPEG-2 Program stream from separate video and audio 'elementary' MPEG streams, try TMPGEnc (it's in the 'MPEG tools' section) or bbMPEG. There are other possibilities if you want to spend more money...
It's a fairly quick operation since no re-encoding is involved.
Tony
I am presuming that you ask this question not simply out of interest but because you wish to share DV files created in different software.
If this is the case, and the problem you have - which you mentioned in an earlier posting that went unanswered - has nothing whatsover to do with fields.
Different DV files cannot always be shared and what is needed is a tool to convert one type to that which another program can use.
Usually all that is required is a change of "wrapper" - so if you can find a program that does the conversion, then the process is very fast, since it does not involve transcoding the video, merely making some minor adjustements to way in which the file is "seen" by programs.
Check out the free converter program that Canopus offers.
I am not sure, though, whether this will do the trick. If not, Canopus is just introducing a new program that, seemingly can convert almost any video file to any other type.
Trouble is, it's VERY expensive - considerably more even that Discreet's Cleaner software.
Also check out http://www.baobab.net/softcs.htm for a US$50 converter program - but, again, I'm not sure whether this will do the trick.
If this is not clear from a careful read of Baobab's site, then you might want to email the company to ask.
Bob C
You say this has nothing to do with fields but .avi files I have captured via DV Raptor using lower field first do not play back correctly when imported into Xpress DV unless I first put them into Premiere and re-export them as Microsoft DV (PAL) with the upper field first. The files, in their original lower frame first state, import readily into Premiere, Raptor Edit, Media Studio Pro and Vegas Video but not Avid Xpress DV.