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DVCPROHD capture
Captured some 1080i59.94 HDCAM footage in FCP5 via DecklinkHD. Specified DVCPROHD codec for capture and sequence. Resulting clips’ format settings INSIDE FCP showed up as 1280X1080. That’s not ATSC standard and looks geometrically distorted (slightly); also requires render to play out. I expected fully native 1920X1080 square pixel raster. ??? In the finder, QT files are info’d as 1920X1080, and play out OK from QT on the Cinema Display. Is there some error in the codecs for HD as tabled in FCP5? When I attempted to export a clip to After Effects, AE saw it as 1280X720/24p. This is weird, eh? Any similar experiences/ideas out there? Thanks.
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11 Replies
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[Michael Krupnick] “Any similar experiences/ideas out there?”
Michael
your settings need to be reset in your seq settings the files you are capturing should not need to be rendered in the timeline
FCP is indeed doing what you told it to do,
YES – 1080 DVCPROHD compressed content is indeed 1280×1440 –think of it as an anamorphic squeeze
Gary Adcock
Studio37
HD and Film Consultation
Chicago, IL USA -
Gary (and JBB):
Thanks. I fiddled around with the settings and finally got something that worked. But my head aches. My assumption was that 4:2:2 samples were counted the same as pixels by Sony and Panasonic…but apparently they’re not identical. Nomenclature is the confusion for me, apparently. And the fact that these numbers do not (readily) appear in publications of SMPTE or ATSC doesn’t add clarity, either. I naiively just figured that all pixels were equal. When does 1920=1280? When marketing and engineers conspire -hee hee-.
Cheers,
m -
[Michael Krupnick] “My assumption was that 4:2:2 samples were counted the same as pixels by Sony and Panasonic.”
That would be great if both formats were 4:2:2-oonly the Varicam captures at 4:2:2
HDCam is 3:1:1 and the HDV camera captures 4:2:0[Michael Krupnick] ” And the fact that these numbers do not (readily) appear in publications of SMPTE or ATSC doesn’t add clarity, either. I naiively just figured that all pixels were equal. When does 1920=1280? When marketing and engineers conspire”
Yes but we are talking about a a huge amount of Data that needs to be laid sown to a very very small track on tape. Think of this “squeezing” of the image in the same way as the old anamorphic lenses for film.
You shot on film and the accessory lens squished the widescreen format to something similar to what you see in the compressed versions of these files. When the footage is projected the lens on the projector would be rotated 90 degrees to “spread” or “expand ” the image back for widescreen playback.Gary Adcock
Studio37
HD and Film Consultation
Chicago, IL USA -
Hi Andy. I stand corrected on HDCAM sampling, but actually, DVCProHD IS spec’d at 4:2:2 sampling. While I understand what you’re trying to say by example, I think it is somewhat misleading to equate anamorphic optical processing with data compression. People might think there is some geometric distortion, and we both know that’s not really what we’re talking about. And HDV wasn’t even on the table as a subject…bringing that up is only adding to the ambiguity of the situation. There is already alot of confusion in HD, much of which has happened because of improper analogies or sometimes even misinformation about the basics. Almost all popular tape formats are compressed to accomodate the huge amount of data in HD. Baseband 1080i/59.94 HD is 1.5 GB/second, enough to make the signal cable warm on a live switcher trunk. I just wish all the manufacturers would agree on a common benchmark terminology to define their specs instead of juicing up the figures for their marketing. Engineering and production benefit when everyone is on the same page. I’ve had some experience with trying to deal with that aspect of HD “salesmanship” vs objectivity, and the headaches it caused were migraines, for sure. The crux of my problem in this thread came from a relatively simple math dilemma: two codeccs both claiming to 1080 lines high and 16X9 aspect had different horizontal dimensions (1920 and 1280). That is not possible even in elementary-school math. The reason that occurred is because Sony and Panasonic differ on what they call a pixel. I was hoping after all these years of television there was agreement on that basic fact by now. That’s the important point for me. Again, thanks, Andy.
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Jeez, Gary; I’m sorry I called you Andy. That’s waht I get for talking on a cell while driving and posting -hee hee-
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[Michael Krupnick] “I stand corrected on HDCAM sampling, but actually, DVCProHD IS spec’d at 4:2:2 sampling.”
The Varicam uses DvcproHD, but footage from HDCam converted to DVCPROHD cannot miraculously make the color space better than what the camera captures. I was talking camera format vs compression format.
[Michael Krupnick] “Almost all popular tape formats are compressed to accomodate the huge amount of data in HD. Baseband 1080i/59.94 HD is 1.5 GB/second,”
All HDTV broadcast video signals are 1.5 GBs not just 1080.
[Michael Krupnick] ” The crux of my problem in this thread came from a relatively simple math dilemma: two codeccs both claiming to 1080 lines high and 16X9 aspect had different horizontal dimensions (1920 and 1280). That is not possible even in elementary-school math. “
Thats because your assumption is in error, the 720p version of the HD Broadcast spec is 1280×720. It is NOT a 1080 signal format.
[Michael Krupnick] “The reason that occurred is because Sony and Panasonic differ on what they call a pixel”
No they do not – What we are discussing are 2 different fame sizes for the captured signal
Sony Captures — 1080i (psf)— 1920×1080 (1440×1080 on the tape)
Panasonic Captures –720p — 1280×720 (960×720 on tape)The math for this aspect ratio change is the same.
Gary Adcock
Studio37
HD and Film Consultation
Chicago, IL USA -
You said:
All HDTV broadcast video signals are 1.5 GBs not just 1080.Not correct, Gary. Only the baseband signals carried through wires are that high. NOBODY broadcasts a signal like that. While at CBS network operating their first HD post bay, I learned alot about about bandwidth limits and compression. When you speak of BROADCAST, you are talking about MPEG2 streams of only 19MB. That’s a lot more compression than anything going to tape (except HDV) , as it must be to squeeze onto transmitters.
If you examine the codec tables for HD in FCP, you will see two different widths for 1080: 1920 and 1280. Forget 720, forget HDV; and think about your fourth-grade geometry class. THAT’S what I am talking about. DVCProHD (100) 1080 qualifies and bringing in other formats only confuses the issue. I guess very few people have actually looked into the 1080 variants and just make general assumptions as to what HD is limited to. I have been discussing only one raster – you keep detouring to another. I think you’re missing my point.
Some interesting reading on that subject is available at https://www.atd.net/HDTV_faq.html and even includes some mention of your beloved 720 line raster. The article is from DoD, NASA, DARPA, and NIST, who, unlike manufacturers, have no interest in selling a format but doing an understanding evaluation of the true nature of these beasts. It’s indeed very interesting how communications pros like us can get so confused talking about this stuff, ain’t it? In a time when the technology is popularizing ever more complex tools, the facts still seem to conspire to limited comprehension.
Cheers,
m. -
[Michael Krupnick] “ou said:
All HDTV broadcast video signals are 1.5 GBs not just 1080. Not correct, Gary. Only the baseband signals carried through wires are that high.”
I have not mentioned transmission at all, I will stand corrected and say baseband.
We have been talking about the HD editing process and native frame sizes, so I assumed that was what we are confining the conversation to.720p it is the format I work in. Too bad you choose to discount a HD acquisition market that is as large as the one in 1080.
if you already knew all of this info already and just wanted to argue why didn’t say so.[Michael Krupnick] “I have been discussing only one raster – you keep detouring to another. I think you’re missing my point.”
Sorry but there is not just one “raster” in HD, not everyone works in 1080,not every broadcaster transmits in 1080, and less the 25 HDTV sets sold in North America can even display 1080 content and it is nearsighted to think or assume that 1080 is the only format for HD. I will not limited my informational explainations on this very complex subject to a view that is not mine.
Direct capture to the DVCPROHD 1080 codec (HDX400 camera) is actually limited outside of the EU. I am not missing the point, I am looking at it from a larger perspective
Gary Adcock
Studio37
HD and Film Consultation
Chicago, IL USA -
Hey Gary, chill, will ya? When you say “broadcast”, that IS about transmission, in this country. You work in 720p. So do I. I like it, too. But that wasn’t the subject of my query. I was asking about 1080i. A simple question it was, too: 1280 vs 1920 at 1080 INTERLACE. I’m not advocating one over the other or asking about marketing, just math. But you seem to be wanting to go everywhere else but there. I’m not making an argument – YOU are. I’m not talking down any format; I was just trying to get an answer or opinion on a simple specific question, which you obviously are unwilling to focus on. The idea was to stimulate a discussion on the discrepancy in pixel count on a line in what should be identical rasters, get it? But since this subject is political rather than technical for you, never mind. I’m sorry this upsets you so much. Thread CLOSED.
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Michael
many people on this list never send out footage for transmission, and you were asking the question first put as if you thought something was in error, which it was not. Fill out your profile, so those of us that try and offer guidance have some idea about your level of experience.
Your first question (BELOW) did not limit the discussion to just HDCam and while you asked a Question about 1080i content it is necessary to understand that without knowing where you were coming from all bases need to be covered. You mention HDcam, yet you captured at a frame rate that many associate with HDV content – that is often brought into FCP via 3rd party cards in the manner you describe.
I brought up the additional formats and compression to try and explain the how and why. You commented that you work in 720p also, so this type of compression squeeze should not have been too far out of your knowledge base if you have ever captured content via FW from 1200a deck.
[Michael Krupnick] “Captured some 1080i59.94 HDCAM footage in FCP5 via DecklinkHD. Specified DVCPROHD codec for capture and sequence. Resulting clips’ format settings INSIDE FCP showed up as 1280X1080. That’s not ATSC standard and looks geometrically distorted (slightly); also requires render to play out. I expected fully native 1920X1080 square pixel raster. ???”
the DVCPROHD codec was created by panasonic so that it would be possible to read the native 1’s and 0’s directly from the tape stock, there is not anything like this for the Sony HDcam format in FCP. The aspect ratio you are looking at is a result of how HD content is compressed at the CCD / tape level Panasonic does this differently than Sony does.
All of the “Digital” HD formats do some sort of horizontal compression, it is how that huge 1.5GBs of information is squeezed onto something as small as the recording head on tape. IF you are not capturing or converting your footage to one of the “Tape — Native” formats — no you would not see this, for no other reason that the compression / decompression cycle is handled by your deck when the content is played out. Just as DV25 footage looks better when handled via SDI rather than over FW.You are correct it is not an ATSC standard frame size, but don’t those standards only relate to the baseband video pipe and not the content as it is recorded on tape. As far as I know, ATSC does not have standards for tape compression and that was all you were looking at, how a panasonic camera would capture content as one’s and zero’s on the physical tape media.
If every company did everything the same there would not be a need for places like that Cow.
If you want (or need) a full size frame to work with, choose a different compression, or based on the knowledge you have expressed here, you really should be considering an uncompressed workflow solution.
Gary Adcock
Studio37
HD and Film Consultation
Chicago, IL USA
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