8GB 20 minutes of 720p 24fps?
- Thread starter braw
- Start date
Luis Caffesse
Admin
As far as I know it is still an assumption.
Although I would say that it is a safe assumption to make.
It makes absolutely no sense to record duplicate frames to P2 cards, and seeing as P2 size is a major obstacle for Panasonic to overcome, I would shocked if they didn't have the foresight to do away with the junk frames.
Although I would say that it is a safe assumption to make.
It makes absolutely no sense to record duplicate frames to P2 cards, and seeing as P2 size is a major obstacle for Panasonic to overcome, I would shocked if they didn't have the foresight to do away with the junk frames.
Barry_Green
Moderator
I went on record over at the Cow, guaranteeing that there will be no duplicate frames recorded on P2 when shooting 720p. Now, the guarantee is that I'll fork over $100 to the first person (and only the first person) who proves otherwise. But as an ex-programmer and as a current video guy, I feel very confident in saying: ain't no way they'll waste P2 card space storing redundant, unnecessary "padding" frames! No way. Won't happen.
I do not know this for a fact, but I believe the Panasonic engineers are kind of smart and I feel very confident in saying that there's no way they'll do something as dumb as waste 2/3 of the space on a P2 card by recording duplicate frames! I do predict the duplicate frames will be streamed out the firewire port (assuming that it allows streaming out the firewire port), because I think they will keep the 100-megabit stream intact. But I can't fathom them recording duplicate frames on the P2 card in 720p mode. Maybe in 1080i, but definitely not in 720p.
I do not know this for a fact, but I believe the Panasonic engineers are kind of smart and I feel very confident in saying that there's no way they'll do something as dumb as waste 2/3 of the space on a P2 card by recording duplicate frames! I do predict the duplicate frames will be streamed out the firewire port (assuming that it allows streaming out the firewire port), because I think they will keep the 100-megabit stream intact. But I can't fathom them recording duplicate frames on the P2 card in 720p mode. Maybe in 1080i, but definitely not in 720p.
Gary_McClurg
Well-known member
Barry, how bout duplicate frames in 1080p?
braw
Well-known member
I thought it would be smart and easy to only store useable frames on the card, and have pulldown directions in the header so it could duplicate on the fly the doubled frames as yuo import it.
Not sure if that can be done with this medium, but it seems easy and keeps the stuff compatible with what's already out there while optimizing storage space.
Not sure if that can be done with this medium, but it seems easy and keeps the stuff compatible with what's already out there while optimizing storage space.
Barry_Green
Moderator
Well, that's the wild card. I mean, the very fact that they're doing 1080p means they're inventing something new, because DVCPRO-HD doesn't have any provision for 1080p at all (unlike with 720p, where the support for variable frame rates was built in at the beginning).Gary_McClurg said:
So, I'm certain they'll use a pulldown scheme to implement 24p within a 60i stream. If it uses 2:3 pulldown, you *cannot* drop duplicate frames, because there *are* no duplicate frames.
If instead it uses 2:3:3:2 pulldown, then yes, there's one frame that could be dropped, but technically it is *not* a duplicate frame; it's a frame that's made up of one field from the preceding frame and one from the following frame. So in 2:3:3:2 there are technically no duplicate frames at all, so will it drop it? I don't know. There is an *unnecessary* frame, yes, but not a duplicate, so the technology is a little more complex.
But if I was programming it, I'd find a way to just not record that frame. However, for compatibility with the 100mbps data stream, there may be reasons why they can't do it. I don't know what, but there may be some. However, it's not that big of a deal; in 720/24p you get 150% more recording time by dropping duplicate frames (2.5 times as much). In 1080/24p, dropping the "c" frame, you'd get 25% more recording time. It'd be nice to have that 25%, but it's not nearly as significant as the difference for 720/24p.
thisiswells
Retired
Thing is, we don't yet even know if the camera will have a variable-scan system
besides 24p, 30p, and 60p. The question is what happens between 30p and 60p?
An easy way to get Barry's money is to find out how 24p will be implemented in the
SPX800 camera. It is doing 24p in a P2 card and while there isn't a provision for 24p
without a 30p stream in PRO50, thus requiring a pulldown in post... neither is there a
provision for 720p24 without doing a pulldown from 720p60, thus the only way of doing
24p in *any* Panasonic product is to do a pulldown process in post from the original
footage. Of course, new tech changes things, and the SPX800 is the new tech.
So, find out how 24p will be implemented there and you've got your answer.
: )
besides 24p, 30p, and 60p. The question is what happens between 30p and 60p?
An easy way to get Barry's money is to find out how 24p will be implemented in the
SPX800 camera. It is doing 24p in a P2 card and while there isn't a provision for 24p
without a 30p stream in PRO50, thus requiring a pulldown in post... neither is there a
provision for 720p24 without doing a pulldown from 720p60, thus the only way of doing
24p in *any* Panasonic product is to do a pulldown process in post from the original
footage. Of course, new tech changes things, and the SPX800 is the new tech.
So, find out how 24p will be implemented there and you've got your answer.
: )
thisiswells
Retired
My prediction is there will be two recording formats in P2/720p:
50Mbits format up to 30p stream
100Mbits format for up to 60p stream
That way, the editing software only has to include a single new version of DVCPRO-HD Codec.
And I shall call it, drum roll please. . . . . DVCPRO-HD50.
Under this definition, the DVCPRO-HD50 format will *have to pad* 24p into 30p.
I will gladly accept your offer. Barry, you're on. In a friendly way, of course.
: )
50Mbits format up to 30p stream
100Mbits format for up to 60p stream
That way, the editing software only has to include a single new version of DVCPRO-HD Codec.
And I shall call it, drum roll please. . . . . DVCPRO-HD50.
Under this definition, the DVCPRO-HD50 format will *have to pad* 24p into 30p.
I will gladly accept your offer. Barry, you're on. In a friendly way, of course.
: )
thisiswells
Retired
Brian’s Predictions on the suspected DVCPRO-HD50 video recording system
720p30 achieves alternate framerates using pulldown
Four uncompressed monophonic audio tracks, down from eight in DVCPRO-HD
= 50Mbits/Second High-Def recording system
NOTE: DVCPRO-HD50 IS NOT REAL. IT IS NOT BASED IN FACT. IT IS A GUESS.
PLEASE, DO NOT DISCUSS THIS *GUESS* IN ANY WAY OUTSIDE OF THIS EXACT THREAD.
720p30 achieves alternate framerates using pulldown
Four uncompressed monophonic audio tracks, down from eight in DVCPRO-HD
= 50Mbits/Second High-Def recording system
NOTE: DVCPRO-HD50 IS NOT REAL. IT IS NOT BASED IN FACT. IT IS A GUESS.
PLEASE, DO NOT DISCUSS THIS *GUESS* IN ANY WAY OUTSIDE OF THIS EXACT THREAD.
satellitebunny
Member
I'm kind of skeptical about the camera recording only 24 frames in 720p. If it would do so, it would be easy for the camera to pad on the fly to get the full 60p 100Mbit/s stream out of the firewire. But, once you plug the P2 card on to your laptop, then your NLE should be aware of this non-standard DVCPRO-HD 24p non-padded stream. And that would require some more updates to the NLEs.
I'm not saying it couldn't happen, but I'm just guessing that it might be awkward to break the 100 Mbit/s standard. But, the thing thisiswells is suggesting about the new 50 Mbit/s DVCPRO-HD codec variant, that might be just the way to implement it, but I wouldn't bet on it.
I hope you all are right, and my guess is wrong.
The 24p 1080p is propably going to be 80 Mbit/s with pulldown on a 60i stream and the 1080/30p and the "PAL" 1080/25p is propably full 100Mbit/s without any kind of unnecessary data. So, again it would make the 25p "PAL" framerate a little better than it's "NTSC" counter part. But only by a hair. (Unless you don't want to slow down the 25p to 24p. I really see no reason to be using the PAL version in an NTSC-land this time though.)
I'm not saying it couldn't happen, but I'm just guessing that it might be awkward to break the 100 Mbit/s standard. But, the thing thisiswells is suggesting about the new 50 Mbit/s DVCPRO-HD codec variant, that might be just the way to implement it, but I wouldn't bet on it.
I hope you all are right, and my guess is wrong.
The 24p 1080p is propably going to be 80 Mbit/s with pulldown on a 60i stream and the 1080/30p and the "PAL" 1080/25p is propably full 100Mbit/s without any kind of unnecessary data. So, again it would make the 25p "PAL" framerate a little better than it's "NTSC" counter part. But only by a hair. (Unless you don't want to slow down the 25p to 24p. I really see no reason to be using the PAL version in an NTSC-land this time though.)
Barry_Green
Moderator
Ah, but -- and someone correct me if I'm wrong, but I don't think I am -- Panasonic/Apple released a DVD with some sample DVCPRO-HD footage on it, when FCP-HD was introduced. And, on that disc, there were 720/24p files, and they were encoded as 40-megabit with no pulldown frames!
Which means the editors already know how to handle it.
No chance for a new limited-audio 50-megabit format. Nope. It's gonna be full DVCPRO-HD, with the only difference being whether inactive/"pad" frames are recorded, which I'm saying they won't be...
Which means the editors already know how to handle it.
No chance for a new limited-audio 50-megabit format. Nope. It's gonna be full DVCPRO-HD, with the only difference being whether inactive/"pad" frames are recorded, which I'm saying they won't be...
thisiswells
Retired
After sitting on this, I am even more convinced.
Let's examine completely variable frame rates on a camera. You can do anything between
time lapse and 60Fps. So, you record everything one-to-one on a frame-by-frame basis. If
the camera is set to 24Fps, it only records 24Fps. Well, this could easily be at least 56 variations
of the same Codec, assuming the limit is 4Fps to 60Fps. That's not a big deal. So, you only
record discrete frames... But, think about how you would play them back? Currently there is
specialised hardware (Panasonic FRC27) or software (FRC in FCP4HD) that will perform this.
If the camera is totally variable frame rate, then you would have to instruct it on how to
do playback. Here is why. Filmmakers would want to record at 60Fps and playback at 24Fps.
Video shooters for TV would want to playback at 60Fps. This becomes really complicated if
you wanted to shoot 40Fps. But, wanted to playback at 24Fps. Or, record at 27Fps and
playbackat 27Fps instead of 30Fps or 24Fps. Point is: Where do you draw the line between
reasonable and too much? I can't imagine ever having to record 27Fps and have the choice between
different playback rates, but really for any of this to work it would have to be there
as an option, at least. I don't think it's reasonable to build a camera and software to encode individual,
discrete frames and set a variable playback framerate on the fly.
I just don't see it happening.
So, let's look at other another option.
The reasons to record at 60p are (1) "that reality look" (2) slow motion
The discussion of not recording pad-frames for 24p or 30p in a 60p stream is relevant.
Why waste 2.5 times the bandwidth when it simply isn't necessary? It isn't. You won't.
That's why I think there is going to be a separate, reduced bandwidth 30p version.
It sets a necessary restriction on the recording and playback systems for better integration.
Really, if you *could* do any frame rate, this would be very complicated to edit without a
standard. You would have to tell your system how to play it back. Presuming the camera
would record framerate in metabata, the editor would still need to be instructed for playback speed.
Could you batch tell it that "all these one's are 24p, so make em' 24p" or "all these
ones are 27p" ? I don't think that is reasonable. It's too much. It's too congested. Too many choices.
It's too confusing to explain. For these reasons, I think there will be a 2nd version of the DVCPRO-HD codec
at 50Mbits... It creates a standard playback speed.
The way I see it, most will want to record at 24p or 30p most of the time -and- for that, they
will provide us with a second 50Mbit version of DVCPRO-HD that only records up to 30p.
Anytime we would want to go into 60p, then that would be a full bandwidth 100Mbit.
So, yeah -- it's a small compromise to accept a 6-frame padding to do 24p within 30p,
but it isn't ridiculous like doing 24p in 60p, either. It is reasonable and it is a standard.
thoughts?
Let's examine completely variable frame rates on a camera. You can do anything between
time lapse and 60Fps. So, you record everything one-to-one on a frame-by-frame basis. If
the camera is set to 24Fps, it only records 24Fps. Well, this could easily be at least 56 variations
of the same Codec, assuming the limit is 4Fps to 60Fps. That's not a big deal. So, you only
record discrete frames... But, think about how you would play them back? Currently there is
specialised hardware (Panasonic FRC27) or software (FRC in FCP4HD) that will perform this.
If the camera is totally variable frame rate, then you would have to instruct it on how to
do playback. Here is why. Filmmakers would want to record at 60Fps and playback at 24Fps.
Video shooters for TV would want to playback at 60Fps. This becomes really complicated if
you wanted to shoot 40Fps. But, wanted to playback at 24Fps. Or, record at 27Fps and
playbackat 27Fps instead of 30Fps or 24Fps. Point is: Where do you draw the line between
reasonable and too much? I can't imagine ever having to record 27Fps and have the choice between
different playback rates, but really for any of this to work it would have to be there
as an option, at least. I don't think it's reasonable to build a camera and software to encode individual,
discrete frames and set a variable playback framerate on the fly.
I just don't see it happening.
So, let's look at other another option.
The reasons to record at 60p are (1) "that reality look" (2) slow motion
The discussion of not recording pad-frames for 24p or 30p in a 60p stream is relevant.
Why waste 2.5 times the bandwidth when it simply isn't necessary? It isn't. You won't.
That's why I think there is going to be a separate, reduced bandwidth 30p version.
It sets a necessary restriction on the recording and playback systems for better integration.
Really, if you *could* do any frame rate, this would be very complicated to edit without a
standard. You would have to tell your system how to play it back. Presuming the camera
would record framerate in metabata, the editor would still need to be instructed for playback speed.
Could you batch tell it that "all these one's are 24p, so make em' 24p" or "all these
ones are 27p" ? I don't think that is reasonable. It's too much. It's too congested. Too many choices.
It's too confusing to explain. For these reasons, I think there will be a 2nd version of the DVCPRO-HD codec
at 50Mbits... It creates a standard playback speed.
The way I see it, most will want to record at 24p or 30p most of the time -and- for that, they
will provide us with a second 50Mbit version of DVCPRO-HD that only records up to 30p.
Anytime we would want to go into 60p, then that would be a full bandwidth 100Mbit.
So, yeah -- it's a small compromise to accept a 6-frame padding to do 24p within 30p,
but it isn't ridiculous like doing 24p in 60p, either. It is reasonable and it is a standard.
thoughts?
thisiswells
Retired
I wish to add that if I am dead wrong, I would like to see a really good implementation
of doing variable frame rate playback in camera at necessary playback speeds and a
reasonable post-production workflow. Actually, I really hope that I am wrong.
FWIW, I bet there will not be any framerates besides 24, 30, and 60.
This is of course, fine as my desire/need for 32,40,48 is fairly seldom. 60p is cool enough.
And, 60p is probably there for the reality and sports, anyways.
brian wells
of doing variable frame rate playback in camera at necessary playback speeds and a
reasonable post-production workflow. Actually, I really hope that I am wrong.
FWIW, I bet there will not be any framerates besides 24, 30, and 60.
This is of course, fine as my desire/need for 32,40,48 is fairly seldom. 60p is cool enough.
And, 60p is probably there for the reality and sports, anyways.
brian wells
thisiswells
Retired
Barry_Green said:
I hope so. If that is the case then 24p would have four stereo tracks embedded, then.
Please, correct/edit this post if it is incorrect. Stereo tracks on DV and HD100 are to
be recorded in a 6mbps dedicated audio portion on tape. This is uncompressed 16/48.
Well, wouldn't that indicate 6mbpsx4 Stereo tracks=24mbps? I think so. This is the
"missing variable" in the logical deduction of where we came up with a 24p/40mbps
recording. If it is still going to be the full 8-mono or 4-stereo tracks, then that only
leaves 14mbps for video if only 40mbps is recorded. That is never going to happen.
It may be more accurate to say that 4Fps could be 30mbps and that 24Fps could be
more like "under 60mbps" (too tired to work this one out) but it isn't anywhere
close to 40mbits as we had previously thought... Or, reduce the audio tracks in the
recorded format, and save space. LMK what you all think. I'm going to sleep now.
brian wells
Barry_Green
Moderator
I can't see any logic to what you're saying. Reason being -- this camera isn't a tape-based camera, it's more likely to be a "camputer", as they call the SPX800. Think about Windows Media Player -- you can encode a file in .wmv format to play back at 12fps, or 24fps, or 30fps, or whatever you want. The computer just plays it back at whatever rate the file tells it to. I'm sure the HVX will be just as "aware". And, again, re-examine what I said earlier about the demo DVD for FCP-HD: I'm certain there are 40mbps 720/24p clips on that disk, which means the computer already knows what to do with it.
As for playing back at different frame rates, you can do that today with editing software. I could import a 30P .AVI into Vegas, and tell it to play back at 80% speed, and it'll lay down frame-accurate slow-mo video into my 24p timeline. I'm sure you could do the same thing (with the proper percentages applied) to your 27p footage (90% speed, presumably) or with whatever frame rate you wanted.
The only restriction on playback rates is for analog or HDMI output... there the system will have to conform to some sort of ATSC standard in order for the playback to be viewable on an ATSC-compatible display. And the solution is simple; it just pads the playback rate. If the file is encoded with a header that says "24p playback", then the camera will know to do 3:2 pull-up on playback.
This really seems like a very simple thing to implement, and IMHO doesn't necessitate any sort of need for inventing some new 50mbps variant. The files are computer files. The camera is a computer (or a "camputer"). It's not bound by tape and tape's restrictions. It can play back files, at whatever the appropriate frame rate is, just like quicktime or windows media files.
As for playing back at different frame rates, you can do that today with editing software. I could import a 30P .AVI into Vegas, and tell it to play back at 80% speed, and it'll lay down frame-accurate slow-mo video into my 24p timeline. I'm sure you could do the same thing (with the proper percentages applied) to your 27p footage (90% speed, presumably) or with whatever frame rate you wanted.
The only restriction on playback rates is for analog or HDMI output... there the system will have to conform to some sort of ATSC standard in order for the playback to be viewable on an ATSC-compatible display. And the solution is simple; it just pads the playback rate. If the file is encoded with a header that says "24p playback", then the camera will know to do 3:2 pull-up on playback.
This really seems like a very simple thing to implement, and IMHO doesn't necessitate any sort of need for inventing some new 50mbps variant. The files are computer files. The camera is a computer (or a "camputer"). It's not bound by tape and tape's restrictions. It can play back files, at whatever the appropriate frame rate is, just like quicktime or windows media files.
Barry_Green
Moderator
The audio portion of DVCPRO-HD is 8 tracks of 16-bit 48khz sampling. All told, all together, they occupy about 6 megabits of the 100-megabit data stream. That's not 6 megabits per stereo pair, it's 1.5 megabits per stereo pair. So 4 pairs, i.e. 8 uncompressed tracks, = 6 megabits, not 24.thisiswells said:
thisiswells
Retired
Well, then that's really good news. Cool.