P2 1080 30i down-convert is UGLY
by John-Michael Trojan
on
Sep 14, 2009 at 4:36:35 pm
HI -
I just recieved some p2 footage from a director who shot both 720p and 1080 30i. My delivery is a standard NTSC d-beta and I'm trying to down-covert the two by setting up a standard NTSC timeline and rendering before output.
The 720p footage looks fine but the 1080 29.97 footage is completely falling apart. After downconvert there are what looks like extremely large interlacing artifacts.
I should also note the 1080 footage looks incredibly ratty, but I'm guessing that is the codec - although I've seen acceptable looking 1080 footage from the p2 format previously.
Any suggestions would be great. If you need more specific info let me know. Unfortunately I don't know what camera was used during production. By looking at the clip is seems to have standard 2:3 pull-down, but I don't think it was shot 23.98 with pull-down added.
Re: P2 1080 30i down-convert is UGLY by Shane Ross on Sep 14, 2009 at 5:17:01 pm
Software downconverts of footage aren't always good. Going from 720 to 480 might be fine, but 1080 to 480...that is a BIG distance. Having capture cards that do this via hardware is always best. AJA, MATROX, Decklink all do this.
Re: P2 1080 30i down-convert is UGLY by John-Michael Trojan on Sep 14, 2009 at 5:19:20 pm
thanks - thought that and will do a test shortly using my Aja Kona 3 card. Still, this is unusually bad. I could send you a still to look at if that helps.
Re: P2 1080 30i down-convert is UGLY by Shane Ross on Sep 14, 2009 at 5:29:46 pm
NO need to send the still...I know what it looks like. I did that myself early on, when trying to output 1080i DVCPRO HD to DV. UGH! It faired much better via my Kona LH.
Re: P2 1080 30i down-convert is UGLY by John-Michael Trojan on Sep 14, 2009 at 5:33:09 pm
I also just noticed there is some pretty bad rolling shutter artifacting going on - has anyone seen this on the 30 p setting before? I have a man's face distorting rather severely.
Re: P2 1080 30i down-convert is UGLY by walter biscardi on Sep 14, 2009 at 5:40:21 pm
[John-Michael Trojan]"My delivery is a standard NTSC d-beta and I'm trying to down-covert the two by setting up a standard NTSC timeline and rendering before output. "
As Shane says, use a capture card to do this, we use the AJA Kona 3's here. If the footage truly is 720/30 then that is never going to interlace well since it's missing half the information for each frame, but the Kona 3 does a really good job with it nonetheless.
And when you drop your material into an SD timeline, you're reversing the fields, FCP does not handle this well.
Walter Biscardi, Jr.
Editor, Colorist, Director, Writer, Consultant, Author.
Credits include multiple Emmy, Telly, Aurora and Peabody Awards.
Owner, Biscardi Creative Media featuring HD Post Biscardi Creative Media
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Apple Final Cut Pro, Apple Motion, Apple Color, AJA Kona, Business & Marketing, Maxx Digital.
Re: P2 1080 30i down-convert is UGLY by John-Michael Trojan on Sep 14, 2009 at 6:07:20 pm
OK - I think I've got this straight.
Since it is really recording 59.94 at all times what I have is two matching fields creating a 1080 30p file that runs native at 29.97. (When brought into FCP it says its 1080p30 codec with a frame rate of 29.97).
Then - since it is 30p adding pull-down doesn't work since it is already at 30 - so some other odd math is being applied and most likely losing frames somewhere along the line.
What has provided limited success is using a separate piece of software to convert the file to 23.98pN then adding pull-down. The footage ends up rather smeary, but doesn't display the same ugly large interlaced looking artifacts.
Re: P2 1080 30i down-convert is UGLY by Shane Ross on Sep 14, 2009 at 6:24:20 pm
[John-Michael Trojan]"Since it is really recording 59.94 at all times what I have is two matching fields creating a 1080 30p file that runs native at 29.97. (When brought into FCP it says its 1080p30 codec with a frame rate of 29.97). "
1080 is 29.97. 720p is 59.94. What confuses a lot of people is the fact that 1080i is often referred to as 1080i59.94. That is NOT frames per second. Because of the "i" that means FIELDS per second...to 30 frames per second. Whoever thought to call it 1080i59.94 has a screw loose. 1080i29.97 is what it should be called.
[John-Michael Trojan]"Then - since it is 30p adding pull-down doesn't work since it is already at 30 - so some other odd math is being applied and most likely losing frames somewhere along the line. "
Why are you adding pulldown? Where?
[John-Michael Trojan]"using a separate piece of software to convert the file to 23.98pN then adding pull-down. "
Wait...what? What are you trying to do? Take 1080i 29.97, convert it to 23.98, then back to 29.97? What on earth for?
Re: P2 1080 30i down-convert is UGLY by John-Michael Trojan on Sep 14, 2009 at 6:52:37 pm
yes - it is getting rather ridiculous.
I was mistaken in my original post. The footage is not 29.97i, it is 30p running at 29.97.
I really just want to get it into a 720x486 29.97 NTSC sequence - or at least master out that way using the aja kona 3 to add pull-down.
Since I can put the 30p footage into a interlaced timeline nicely I thought I would use a high-end coverter to get the footage to 23.98 (which looks pretty great) then add the pull down back in during the down-convert (still looks ugly).
I think I may just ask the client to check with post before he shoots P2 again for the correct settings...
Re: P2 1080 30i down-convert is UGLY by walter biscardi on Sep 14, 2009 at 7:02:40 pm
[John-Michael Trojan]"I really just want to get it into a 720x486 29.97 NTSC sequence - or at least master out that way using the aja kona 3 to add pull-down. "
Then leave it in the HD timeline and let the Kona do the downconvert to SD. Do Not put your footage into an SD timeline or re-set FCP to SD. Leave FCP in HD and use the Kona to downconvert that signal to SD properly.
Walter Biscardi, Jr.
Editor, Colorist, Director, Writer, Consultant, Author.
Credits include multiple Emmy, Telly, Aurora and Peabody Awards.
Owner, Biscardi Creative Media featuring HD Post Biscardi Creative Media
Creative Cow Forum Host:
Apple Final Cut Pro, Apple Motion, Apple Color, AJA Kona, Business & Marketing, Maxx Digital.
Re: P2 1080 30i down-convert is UGLY by John-Michael Trojan on Sep 14, 2009 at 8:17:41 pm
FYI - made it slightly better by switching the field dominance to upper from none. I think this is as good as it gets but still less than satisfactory in my book.
Actually he kind of has a point wanting to call it 540/60i, but it runs counter to industry traditions going back more than half a century. It's more of a case against interlace.
Re: P2 1080 30i down-convert is UGLY by walter biscardi on Sep 16, 2009 at 11:48:12 am
[Scott Thomas]"I'm not saying he's right, but you are saying that one of the founders of Pixar "has a screw loose"??? :) "
Absolutely, positively. I can't stand that 1080i / 29.97 is labelled as 1080i/60. It makes absolutely NO SENSE.
720p/60 is 60 frames per second.
1080i / 60 is 60 fields per second which actually equals 30 frames per second which actually equals 29.97.
AJA has this right with all of their Easy Setups which list it as 1080i / 29.97 because is the ACTUAL frame rate.
So to call it 1080i / 60 means you have a screw loose somewhere to equate 60 fields with 60 frames.
Walter Biscardi, Jr.
Editor, Colorist, Director, Writer, Consultant, Author.
Credits include multiple Emmy, Telly, Aurora and Peabody Awards.
Owner, Biscardi Creative Media featuring HD Post Biscardi Creative Media
Creative Cow Forum Host:
Apple Final Cut Pro, Apple Motion, Apple Color, AJA Kona, Business & Marketing, Maxx Digital.
