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Dual format recording in AJ HDX900
Anyone know if the AJ HDX 900 record both DVCPRO HD 1080i (SMPTE 247 M) and Varicam 720 60p?
Full marks if it does this!Would one need to change tapes when changing format?
Mike Brennan
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5 Replies
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[Michael Brennan] “Anyone know if the AJ HDX 900 record both DVCPRO HD 1080i (SMPTE 247 M) and Varicam 720 60p? Full marks if it does this!”
Yes Mike it does do both! in both 720 and 1080 it will do 23.98p, 24p, 24pA (1080 only) 25p, 29.97i, along with 50i and 60i
I would not recommend putting both types of content on the same tape ( which it can do-but I am not going to try)
gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows
Chicago, IL -
Mike,
According to the newly posted HDX-900 brochure on the Panasonic website the CCD picture elements are 1370 (H) x 744 V, effective 1280 (H) x 720 (V). Based on this it looks like the 1080i is being internal uprezzed and is not native. A great test would be to compare a 1080i recording in camera versus recording at 720P and uprezzing via a Kona or vtr.
In anycase what else could we expect from a low cost camera compared to other cameras that can output the native resolution?
In addition the recording is not the varicam variable frame rate and is recorded in the HD-LP mode (AKA DVCPRO HD EX). The tapes themselves are the smaller medium size tapes not the larger size used in the Varicam hence forth you could not play back a HDX-900 tape in a varicam not only due to thet tape size factor but also because of the HD-LP/dvcpro HD EX recording. Lastly the HD-LP/dvcpro HD EX recording cannot be played back in the older HD150 or 130 vtr’s only the newer 1200,1400,1700 series.
I personally am awaiting detailed feedback about the robustness of using the HD-LP/dvcpro HD EX mode in the field under “real world battle conditions” versus the Varicam “DVCPRO HD” recording mode.
Tony Salgado
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The EX mode is the same tape speed as PRO50. I doubt there is any issue recording in the field. These tape transport systems have been out for several years now. The HDX-400 uses the same EX recording. My experience has been that Panasonic’s tape transports are very reliable. I would not hesitate to use the new 900 HD camera.
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[tony salgado] “1370 (H) x 744 V, effective 1280 (H) x 720 (V).”
My rule of thumb is that Panasonic doesn’t make a 1920×1080 progresive ccd, regardless of what the brouchers say the kit records or outputs.
I wonder if the internal “upconversion” to 1920x1080i will be from a 1280 x 720 4:2:2 signal? This would involove two passes of subsampling.
Would be nicer if it was direct from a 1280x720p 4:4:4 RGB signal to 1080i and then subsampled to 1280×1080.Or maybe it could also be “cross sampled” new phrase?! direct from 1280×720 4:4:4 RGB to 4:2:2 1280x1080i?
If my maths are correct, there is enough pixels in the 1080i codecs so if they could be rearranged could create a 4:4:4 recording of the original 1280×720 ccd!
For 25p work (see below) there would be pixels to spare.Note that there are two flavours of SMPTE 274
1080i 29.97 Y 1280x1080i Pb/Pr is 640x 1080
1080i 25p Y 1440x1080i Pb/Pr is 720×1080Mike Brennan
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Michael,
At the price point of the camera I highly doubt any of this will occur at the level of high end quality you describe.
Simple math from a sales point overshadows the higher math of high end cross conversion.
Tony Salgado
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