PAL HV20 25p Questions

[warrj]

Hi,

Sorry, to post yet another question on PAL 25p. I've read many threads on 25p and the Mac and because I don't understand much of the video-specific terminology I end up not understanding the answers.

I recently bought a PAL HV20 in order to capture moments from the life of my new daughter. I'm pretty much up to speed on still digital photography (Canon 40D, RAW, Lightroom etc) however I don't wish to delve too deeply into the technical side of digital video - I just want to get the best footage I can with the minimum amount of effort on my part.

My editing system will be a PowerMac dual 2.7Ghz G5. At the moment I only have iMovieHD and 06. Output will (initially) be to Apple TV and h.264 video files (which I'll send to relatives in the US for viewing on computer) and then later (perhaps) to Blu-Ray.

So, I have a few questions:

Is it possible for me to shoot in 25p and then edit the footage in iMovie 06?
If so, how?

If not then could I do so in FCE?
If so, how?

Lastly, if I start shooting in 25p are there any considerations I need to make when editing a mixture of 50i (which is what I've been shooting) and 25p.

Any help or advice (very very) gratefully received,

Jules.

[warrj]

Anyone?

[svar]

im not shure, but I think you must at least use FCE.
It is not wery hard (the way I have understanded how to do it), I can make I guide then I come home from work.

It is however, esyer on a PAL cam than a NTSC cam.

[warrj]

Hi Svar,

That would be much appreciated. I don't mind buying FCE if necessary

Regards,

Jules.

[mattias]

25p works fine in imovie. it will render all effects as interlaced, which can look strange, but it will work. when you mix you have the same problem, it can look weird, but there are no technical concerns really. (until you venture further, upgrading your software, and so on, but that's another story) :-)

/matt

[svar]

warrj: sorry for the wait, but here is a guide the way I understand is right, for fce of fcp:

1: import youre 25p footage as normal, as far as I know import it as HDV 1080i50

2: right click on the clip and select item properties-->format:


3: Right click on "field dominance" and select "none":


4: make a new sequence (or edit a old) Right click on it and select "settings"

5: Set the "field dominance" to "none":



As far as I understand that that is it for hv20/30 PAL version.
I dont know btw, if the compressor settings (picture in step5) shal be 1080i50 or 720p25, maybe someone else know the ansver.
Not ssure too if step5 look exaply the same in fce.

Why import as hdv 1080i? As far as I understand it is because the 25p footage from hv20/30 is covered in a 1080i stream.

[mattias]

compression settings should definitely be 1080i50 if it's a 1080i50 sequence. if it's a 720p25 sequence it should be 720p25. :-)

/matt

[warrj]

Hi,

Thanks everyone for taking the time to reply so helpfully (especially svar). I'll give some thought to a purchase of FCE.

matt - is it OK to mix interlaced and progressive footage in the same sequence and if so do the interlaced and progressive components of the sequence need their own compression settings?

I have to say that digital video processing seems to be an order of magnitude more complicated than still digital photo processing. I'm guessing that as things mature people (such as me) with neither the time or inclination to understand the underlying technology will be better served by software which really 'just works'

Regards,

Jules.

[mattias]

why would they need different codec settings when they are both 1080i50? :-) setting the field order to none just tells fcp how to interpret the clip. it's still interlaced, just with the two fields captured at the same time thus no jaggies, and will stay that way as long as you're editing hdv since there is no 1080p in hdv.

if you put interlaced clips in a progressive sequence they are automatically deinterlaced. if you put progressive clips in an interlaced sequence nothing happens. how you mix depends on how you want to output.

/matt

[deniser]

I have found the tutorials on Apples site extremely helpful with FCE

[funwithstuff]

if you put interlaced clips in a progressive sequence they are automatically deinterlaced. if you put progressive clips in an interlaced sequence nothing happens. how you mix depends on how you want to output.

/matt

The automatic deinterlacing halves resolution -- you need to set field dominance to none if you're using HV20's progressive-stored-as-interlaced footage and put those clips in a progressive sequence for true progressive results. Not sure if you'll be able to do that with FCE, but it's easy enough in FCP.

More info for 25fps progressive HV20 footage (old, potentially needing an update!) on my site here:

http://funwithstuff.com/therules/200...-solution.html

-- Iain Anderson
-- Final Cut Pro Certified Trainer

[mattias]

The automatic deinterlacing halves resolution

i already addressed the issues with progressive clips above. if the clips are *interlaced* and you want progressive output the automatic deinterlace is a good thing. of course there are smarter methods around, like my own, see website, but the built in does a decent job.

/matt

[funwithstuff]

i already addressed the issues with progressive clips above. if the clips are *interlaced* and you want progressive output the automatic deinterlace is a good thing. of course there are smarter methods around, like my own, see website, but the built in does a decent job.

/matt

I find the built-in feature just pixel-doubles, whether you wanted that or not -- disaster if you have HV20 25PF footage that you want to work with in a true progressive sequence. For true interlaced footage, you may get better results applying filters like Flicker Filter (or one of your filters). But I don't disagree with your post above, and kudos for your great work with the TMTS filters!

[mattias]

I find the built-in feature just pixel-doubles, whether you wanted that or not -- disaster if you have HV20 25PF footage

but you don't. what part of "interlaced" is it you don't quite get? :-) but yes, you need to manually mark all progressive clips as such for them to be treated correctly, that's not what i'm talking about.

/matt

[funwithstuff]

but you don't. what part of "interlaced" is it you don't quite get? :-) but yes, you need to manually mark all progressive clips as such for them to be treated correctly, that's not what i'm talking about.

/matt

This stuff confuses the hell out of a lot of people, so I'm going to put down a quick summary of the issues -- Mattias, feel free to comment. Obviously this has gone way beyond helping the original poster...

1. With interlaced HDV footage (field dominance: upper), edit it as interlaced -- it won't look good in a progressive sequence. You *can* use progressive HV20 footage into an interlaced sequence.

2. With progressive HV20 footage, field dominance must be set to "None" if used in a progressive sequence. Given that it works in an interlaced sequence, why would you? Well, if you want to convert to DV (field dominance: lower), change speed, or use transitions (like Push) that move video around, you'll get better output from a progressive sequence. (This is not an option with iMovie or FCE, only FCP.)

This advice only applies to the HV20 camera and others that store progressive footage as interlaced (25PF, AKA PsF). The HV20's big brother, the Canon XH-A1, stores footage as true progressive frames (25F), and you'd import that using the 1080p25 Easy Setup in FCP.


OK. All that out of the way, to answer the original question: go ahead and edit the progressive footage and the interlaced footage together with iMovie, FCE or whatever. Avoid push and similar transitions. Avoid speed changes if possible. Keep the camera running for your daughter's first steps. Good luck!

[mattias]

a good summary, but i'd like to add that it works quite well to edit interlaced footage in progressive sequences. it will automatically be deinterlaced and that's generally what you want if you're editing in progressive. the solution if you want a better quality deinterlace than the automatically applied one, is to set the interlaced footage to "none" as mentioned above and then apply a third party filter, like magic bullet or my own tmts filters. but i'd like to stress that simply dropping the footage there will usually look perfectly fine. the vertical res will get slightly lower, around a 30% decrease, but "won't look good" is not true in my opinion.

/matt

[DamoRais]

This stuff confuses the hell out of a lot of people

It's certainly confusing me!

I certainly don't want to lose resolution as with mattias' workflow.

Funwithstuff - I've tried the workflow you describe on your web site but every time I attempt to lay a clip on the timeline Final Cut Pro tells me that the sequence doesn't match the clip settings and asks whether I'd like to change the sequence settings to match.

I've followed your instructions...

These clips are shot in 25p and I've changed field dominance to 'none' in FCP.

I'm attempting to lay them in a new ProRes 422 1440x1080 25p sequence as described on your site and I keep getting the warning message each time.

Is this correct?? - Should I be getting the warning? - Do I just ignore it.

Many thanks.

[Tuj]

Funwithstuff, you are being very diplomatic. Mattias, you are confusing issues here. Trust me you are. That I am a long-time developer of image-processing algorithms does not on its own mean that I know what I'm talking about, but in this case I can assure you that I certainly do.

The method you describe for de-interlacing footage does not apply to progressively recorded footage on the HV20. It will work - but the result will be discarded information, and a loss in quality. Applying the more advanced filters to which you refer, to try and improve the result, will not change this fundamental fact and is not the appropriate solution in this (very special) case.

The HV20 stores full-resolution progressive images in two half-resolution fields (owing to a limitation of the HDV transport standard). What Funwithsutff is describing is the simple process of re-merging those half-resolution fields into full-resolution progressive frames.

The de-interlacing methods you describe are not for doing this; they are for taking genuinely separate fields from interlaced footage and *turning them into* progressive footage. They do this usually by doubling pixels from a single field, or cleverly merging information from both fields. The latter "advanced" approaches do this in the knowledge that the fields come from an interlaced source and therefore represent slightly different moments in time, and hence the results are never perfect (some kind of motion artifacts are always present).

The information in HV20 fields does not come from separate moments in time; it is all from the same frame - half in one field, half in the other. Applying this process to progressive HV20 footage will throw away or distort valuable information, and is to defeat the purpose of the camera's true progressive capture mode.

The solution of choosing "no field precedence" and therefore telling the video software simply to display the two fields simultaneously is therefore exactly correct - if you have it, and if it works. Alas, I'm using Avid Media Composer, and this is not an option available to me. Any ideas how to get 25p HV20 footage into a 25p timeline *correctly* would be very gratefully received.

24f/25f footage, incidentally, as found on some Canon cameras, is essentially interlaced footage which has has a de-interlacing algorithm pre-applied in-camera (as far as can be reasonably assessed without a written statement from Canon). If it is re-stored in an intermediate interlaced format however, then the same process of re-merging the two fields once one gets it into one's video software applies as applies to the HV20. Likewise, one would have to be equally (or arguably even more) insane to apply a de-interlacing algorithm to it.

The *only footage* (to my knowledge and understanding) which it makes sense to explicitly "de-interlace", is footage which explicitly or implicitly claims to be interlaced (50i/60i etc). The *only times* (to my knowledge and understanding) that one wants to de-interlace this footage is if one genuinely wants progressive output because of the look, or because it is to be displayed on a device which cannot deal with interlaced footage or the high frame-rates usually involved.