G
Guest
Guest
I am shooting a music video 2moro. I am going to edit w/ VV4 and output to DVD using DVDA 1. Should I film 24pN or 24pa? PLEASE HELP!!!!!!!!!
Thanks
Hodges
Thanks
Hodges
Re: Music Video Shoot 24pa??
It doesn't matter.
It doesn't matter.
Barry_Green
Moderator
Re: Music Video Shoot 24pa??
Doesn't really matter. You can use either. If you're making a 24P DVD, you might get slightly higher quality by using 24PA.
Doesn't really matter. You can use either. If you're making a 24P DVD, you might get slightly higher quality by using 24PA.
Barry_Green
Moderator
Re: Music Video Shoot 24pa??
Okay, now that I think about it, I'm going to take that statement back. If you're making a 24P DVD, the quality should be indistinguishable whether you sourced it from 24PN or 24PA. As long as you're outputting MPEG-2, it will make no difference which mode you recorded in (assuming all other settings are equal, such as THIN/THICK, etc).
The only place where there could be a quality difference would be if you were editing in a 24P timeline and outputting a DV-format 24P .AVI file, inserting 2:3:3:2 pulldown. In that one and only circumstance will the recording format (24PN/24PA) make a quality difference, and for that one case, 24PA would be the better choice. (it is possible, but I think unlikely, that 24PN would source better for a DV-format 24P .avi file with 2:3 pulldown inserted, but I don't think the editing programs likely bother with taking advantage of that).
So, to sum up (once and for all?): if editing in a 60i timeline, shoot 24P Normal. If editing in a 24P timeline, there is almost no circumstance that will cause a difference, you're fine with either, but a little more fine if you use 24PA.
Okay, now that I think about it, I'm going to take that statement back. If you're making a 24P DVD, the quality should be indistinguishable whether you sourced it from 24PN or 24PA. As long as you're outputting MPEG-2, it will make no difference which mode you recorded in (assuming all other settings are equal, such as THIN/THICK, etc).
The only place where there could be a quality difference would be if you were editing in a 24P timeline and outputting a DV-format 24P .AVI file, inserting 2:3:3:2 pulldown. In that one and only circumstance will the recording format (24PN/24PA) make a quality difference, and for that one case, 24PA would be the better choice. (it is possible, but I think unlikely, that 24PN would source better for a DV-format 24P .avi file with 2:3 pulldown inserted, but I don't think the editing programs likely bother with taking advantage of that).
So, to sum up (once and for all?): if editing in a 60i timeline, shoot 24P Normal. If editing in a 24P timeline, there is almost no circumstance that will cause a difference, you're fine with either, but a little more fine if you use 24PA.
Re: Music Video Shoot 24pa??
I have a slightly different take on this. I'd recommend always shooting 24p Advanced if you've got an editing system that can remove a 2:3:3:2 pulldown (like Vegas). The reason has to do with the way fields are compressed in the DV format. Because the DVX ultimately records to an NTSC (or PAL) standard, you're always going to have two fields compressed into a frame. In the case of 24p, instead of two fields, you have two frames compressed together.
When you shoot 24pA you'll always be able to extract each 24p frame from a compressed frame that includes two identical 24p frames. When you remove the 2:3 pulldown from 24pN footage you end up having to extract some frames from a compressed frame that includes two different 24p frames. Because the compression is lossy, you'll lose some quality when the 24 p frame is extracted.
If you're going to a 24p DVD, you might as well start with the highest quality source material you can get--which is 24pA footage with the 2:3:3:2 pulldown removed. With Vegas you always have the option of inserting a standard 2:3 pulldown (the telecine standard) for broadcast or tape distribution.
We're not talking about a huge quality difference here, but because DV is such a highly compressed format, it's helpful the have the highest quality posssible before color correcting, editing, and rendering.
I have a slightly different take on this. I'd recommend always shooting 24p Advanced if you've got an editing system that can remove a 2:3:3:2 pulldown (like Vegas). The reason has to do with the way fields are compressed in the DV format. Because the DVX ultimately records to an NTSC (or PAL) standard, you're always going to have two fields compressed into a frame. In the case of 24p, instead of two fields, you have two frames compressed together.
When you shoot 24pA you'll always be able to extract each 24p frame from a compressed frame that includes two identical 24p frames. When you remove the 2:3 pulldown from 24pN footage you end up having to extract some frames from a compressed frame that includes two different 24p frames. Because the compression is lossy, you'll lose some quality when the 24 p frame is extracted.
If you're going to a 24p DVD, you might as well start with the highest quality source material you can get--which is 24pA footage with the 2:3:3:2 pulldown removed. With Vegas you always have the option of inserting a standard 2:3 pulldown (the telecine standard) for broadcast or tape distribution.
We're not talking about a huge quality difference here, but because DV is such a highly compressed format, it's helpful the have the highest quality posssible before color correcting, editing, and rendering.
Barry_Green
Moderator
Re: Music Video Shoot 24pa??
We're basically in agreement -- if you can edit in 2:3:3:2, you'd be slightly better off to just go ahead and shoot in 24PA, regardless of the destination.
However, I don't understand what you mean in this statement:
Even so, since fields are compressed separately, it shouldn't make any difference whether those fields are pulled from one compressed frame, or across two. At least, that's the way I understand it. If it turns out that DV compression is frame-based instead of field-based, then yes, there's a definite potential for higher quality from 24PA vs. 24PN.
At least, that's the way I understand it. Please, anyone who can correct this, fire away!
We're basically in agreement -- if you can edit in 2:3:3:2, you'd be slightly better off to just go ahead and shoot in 24PA, regardless of the destination.
However, I don't understand what you mean in this statement:
In either 24P or 24PA, you're going to have progressive frames that get divided into fields, and as far as I understand DV, each field is compressed separately (i.e., I don't believe that DV can compress a full frame, it compresses fields). 24PA will always keep the progressive frame's fields together in the same frame, whereas 24PN will occasionally make a "frame" of one field from one 24P frame and one field from the other 24P frame. But if the fields are compressed individually, it shouldn't make any difference, should it?
This statement is confusing. I think what you're trying to say is "each 24P frame can be extracted from a compressed frame that includes fields that were from that same frame". I don't know what you mean by "two identical 24P frames".
Yes, but no. You do have to extract some fields from compressed frames that were encoded separately (a field from frame 32, and a field from frame 33, for example) but the uncompression process isn't lossy (or at least it shouldn't be). The compression is lossy, but the uncompression should result in a bit-for-bit reconstruction of the compressed data. The loss takes place at the time of compression, that's when data is thrown away. The uncompress should theoretically be lossless.
Even so, since fields are compressed separately, it shouldn't make any difference whether those fields are pulled from one compressed frame, or across two. At least, that's the way I understand it. If it turns out that DV compression is frame-based instead of field-based, then yes, there's a definite potential for higher quality from 24PA vs. 24PN.
At least, that's the way I understand it. Please, anyone who can correct this, fire away!
Barry_Green
Moderator
Re: Music Video Shoot 24pa??
AH HA! Let me repent, the great Barry_S has indeed pointed out something that could be significant.
DV compression is field-based, but it is ALSO frame-based. There are two methods used: 2-4-8 DCT for field-mode, and 8-8 DCT for frame-based. The codec chooses which method to employ, based on the amount of motion within fields. So 24PA footage is almost certain to employ the frame-based compression, whereas 24PN footage is more likely to employ the field-based version.
Which is better?
Don't know, scientifically. But I've always thought that static shots looked sharper than motion shots, so maybe the frame-based compression is better. Seems like it would have to be... so, officially, I agree with Barry_S: 24PA has even more of an advantage than I thought initially. If your system can remove 2:3:3:2 pulldown, and you intend to edit 24P, shoot 24PA. If your system can't remove 2:3:3:2 pulldown, or you intend to edit on a 60i timeline, use 24PN.
(for anyone who wants to know way too much about DV compression, I found this to be fascinating and overwhelming reading: http://www.sony.ca/dvcam/pdfs/dvcam format overview.pdf. As a programmer, I found the discussion of shuffling data blocks around the picture before compression to be fascinating and brilliant. Them DV guys shure knew their stuff!)
AH HA! Let me repent, the great Barry_S has indeed pointed out something that could be significant.
DV compression is field-based, but it is ALSO frame-based. There are two methods used: 2-4-8 DCT for field-mode, and 8-8 DCT for frame-based. The codec chooses which method to employ, based on the amount of motion within fields. So 24PA footage is almost certain to employ the frame-based compression, whereas 24PN footage is more likely to employ the field-based version.
Which is better?
Don't know, scientifically. But I've always thought that static shots looked sharper than motion shots, so maybe the frame-based compression is better. Seems like it would have to be... so, officially, I agree with Barry_S: 24PA has even more of an advantage than I thought initially. If your system can remove 2:3:3:2 pulldown, and you intend to edit 24P, shoot 24PA. If your system can't remove 2:3:3:2 pulldown, or you intend to edit on a 60i timeline, use 24PN.
(for anyone who wants to know way too much about DV compression, I found this to be fascinating and overwhelming reading: http://www.sony.ca/dvcam/pdfs/dvcam format overview.pdf. As a programmer, I found the discussion of shuffling data blocks around the picture before compression to be fascinating and brilliant. Them DV guys shure knew their stuff!)
G
Guest
Guest
Re: Music Video Shoot 24pa??
Thanks for the help!
One more Q-- Is it possible to burn a 24p DVD on DVDA 1? Does it make a big difference if it is burned at 24p. As long as I edit on a 24p timeline and render MPEG2 then burn is the quality alright?
Thanks again-
Hodges
Thanks for the help!
One more Q-- Is it possible to burn a 24p DVD on DVDA 1? Does it make a big difference if it is burned at 24p. As long as I edit on a 24p timeline and render MPEG2 then burn is the quality alright?
Thanks again-
Hodges
Re: Music Video Shoot 24pa??
Sorry for my less than clear explanation and thanks Barry for elaborating. With 24p normal footage, not only do you potentially employ the less efficient 2-4-8 DCT compression, but you also need to go through an extra decompression-recompression step when extracting 25% of your 24p frames from 60i frames.
Sorry for my less than clear explanation and thanks Barry for elaborating. With 24p normal footage, not only do you potentially employ the less efficient 2-4-8 DCT compression, but you also need to go through an extra decompression-recompression step when extracting 25% of your 24p frames from 60i frames.
Re: Music Video Shoot 24pa??
HOWEVER, does it really make nine exclamation points' worth of difference?
I guess my point there is, don't get too worked up about it. You'll be fine either way. 8)
HOWEVER, does it really make nine exclamation points' worth of difference?
I guess my point there is, don't get too worked up about it. You'll be fine either way. 8)
Barry_Green
Moderator
Re: Music Video Shoot 24pa??
[quote author=Barry_S link=board=Vegas;num=1087238992;start=0#8 date=06/14/04 at 15:08:51]but you also need to go through an extra decompression-recompression step when extracting 25% of your 24p frames from 60i frames. [/quote]
But if you're going to DVD, you aren't doing an extra cycle at all -- it needs to be uncompressed, and then converted to MPEG-2. It doesn't get recompressed in DV format, unless you're going back out to a DV file... so there shouldn't be an extra uncompress/recompress cycle happening. That would only happen if making a DV output, or pre-rendering sections...
In any case, if you're going to edit 2:3:3:2, you're going to be better off shooting 24P Advanced in all cases, is what I think we're saying...
[quote author=Barry_S link=board=Vegas;num=1087238992;start=0#8 date=06/14/04 at 15:08:51]but you also need to go through an extra decompression-recompression step when extracting 25% of your 24p frames from 60i frames. [/quote]
But if you're going to DVD, you aren't doing an extra cycle at all -- it needs to be uncompressed, and then converted to MPEG-2. It doesn't get recompressed in DV format, unless you're going back out to a DV file... so there shouldn't be an extra uncompress/recompress cycle happening. That would only happen if making a DV output, or pre-rendering sections...
In any case, if you're going to edit 2:3:3:2, you're going to be better off shooting 24P Advanced in all cases, is what I think we're saying...