A1 30f is actually interlaced? at DVinfo.net

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Canon XH Series HDV Camcorders
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Old October 27th, 2007, 05:57 PM   #1
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A1 30f is actually interlaced?

I normally do 60i, but recently did 30f a few times. But when I came to encode into DVD compatible mpeg2, I realized that A1 30f was actually interlaced, rather than real progressive. How I found it? When I encoded I thought I should use "no field", and "progressive" settings in the encoder, but it came out streaky. So took me quite a while before I tried the normal interlaced setting: lower field first, then it came out great.
so I realized why they call it 24f/30f instead of 24p/30p, because 24f/30f is still interlaced with 2 fields, the only difference is that 24/30f has 2 exactly the same fields, odd field and even field are the same frame. Obviously the exposure to the CCD happens only once, but that makes me wonder, why they didn't make it true progressive:no field....any reason behind this?
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Old October 27th, 2007, 07:00 PM   #2
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You must have captured it wrong. I shoot 24f, capture in FCP's 1080P24 HDV setting, edit in a 23.98 timeline, export, no interlace settings, and it will stay progressive all the way through. If you don't have your capture settings properly set, you can capture with pulldown and interlaced.
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Old November 1st, 2007, 09:14 AM   #3
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Quote:
Originally Posted by Juni Zhao View Post
I normally do 60i, but recently did 30f a few times. But when I came to encode into DVD compatible mpeg2, I realized that A1 30f was actually interlaced, rather than real progressive. How I found it? When I encoded I thought I should use "no field", and "progressive" settings in the encoder, but it came out streaky. So took me quite a while before I tried the normal interlaced setting: lower field first, then it came out great.
so I realized why they call it 24f/30f instead of 24p/30p, because 24f/30f is still interlaced with 2 fields, the only difference is that 24/30f has 2 exactly the same fields, odd field and even field are the same frame. Obviously the exposure to the CCD happens only once, but that makes me wonder, why they didn't make it true progressive:no field....any reason behind this?
Check this out and let us know if this is how you are capturing your 30f footage in Final Cut.

http://dvinfo.net/conf/showthread.php?t=84763

Capturing and editing 30f in Final Cut Pro is strange since it is done using the 1080i60 compressor and sequence, but for some reason the footage remains progressive.

Hugh
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Old November 1st, 2007, 09:24 PM   #4
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You are mistaken.
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Old November 2nd, 2007, 03:09 AM   #5
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Originally Posted by Juni Zhao View Post
I realized why they call it 24f/30f instead of 24p/30p, because 24f/30f is still interlaced with 2 fields, the only difference is that 24/30f has 2 exactly the same fields, odd field and even field are the same frame. ?
If both fields are the same then the image is progressive.
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Old November 2nd, 2007, 06:40 AM   #6
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All TV video is recorded interlaced, with 2 fields, even if they are shot at the same moment, a.k.a. progressive. This is just the recording standard, has nothing to do with how the material was exposed. Actually there are programs which can use DV tape as a data recorder. Then you could say your Word documents are interlaced, if that made any difference.
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Old November 2nd, 2007, 10:31 AM   #7
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Originally Posted by Petri Kaipiainen View Post
All TV video is recorded interlaced, with 2 fields, even if they are shot at the same moment, a.k.a. progressive. This is just the recording standard, has nothing to do with how the material was exposed. Actually there are programs which can use DV tape as a data recorder. Then you could say your Word documents are interlaced, if that made any difference.
Hi Petri. I'm not really sure what you are trying to say here. If the whole frame is shot at the same moment then it is progressive by definition.

Some cameras might record this using pulldown to span the progressive frames across the fields of an interlaced format, but by no means does this apply to all cameras. For example, the XH-A1 stores and outputs 25P, not 25P over 50i, which is why in the early days of the A1, not all NLEs could handle its progressive output properly.

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Old November 2nd, 2007, 12:33 PM   #8
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Originally Posted by Petri Kaipiainen View Post
All TV video is recorded interlaced, with 2 fields, even if they are shot at the same moment, a.k.a. progressive.
Recorded interlaced doesn't mean anything. If the 2 fields are the same then the image is progressive.
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Old November 2nd, 2007, 04:00 PM   #9
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The datasteam format is identical on 25p and 50i, there are two fields for each frame. The recording system does not know or care it the fields are exposed at the same moment or 1/50 seconds apart, they still follow one after another. 25p is not recorded as 25 separate complete pictures per second on tape, but as 2 fields. Of course the 25p is progressive, just the recording (data) format is identical with 50i.

We are talking about the simple and elegant PAL here, I do not want to know anything about pulldowns...
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Old November 2nd, 2007, 06:20 PM   #10
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25p is not recorded as 25 separate complete pictures per second on tape, but as 2 fields.
Except on the xh a1. And we are on the xh a1 forum.

I must confirm this now, the A1 does record the 25f as a progressive mpeg2-stream right? Atleast the 24f mode on the ntsc model does so.
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Old November 2nd, 2007, 07:23 PM   #11
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Originally Posted by Mikko Lopponen View Post
Except on the xh a1. And we are on the xh a1 forum.

I must confirm this now, the A1 does record the 25f as a progressive mpeg2-stream right? Atleast the 24f mode on the ntsc model does so.
Hi Mikko. Without going into how the A1 creates the progressive frame in the first place, yes it does record the video as progressive 25P.

In general Petri is sort of correct, but it aint necessarily so and the A1 is an example of that.

Richard
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