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If we could nail down the true nature of the line twitter and devise an optimal method of delivering 25p without it, I'm sold on the V1E. |
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So it could be that even on static VIDEO, the changing noise accross fields is enough to trigger the deinterlacer into not weaving. "Steve was saying some time ago, this camera doesn't do that ..." I've worried about this. Last night I rechecked the stuff from Japan. The cmos signals pass through a signal-procesing chip on the way to the eip. I now think that in interlace mode a flicker filter is engaged which will also slightly reduce noise. This confirms your finding. Later I'll burn my hd dvd and see what happens when it feeds the signal to the hdtv. |
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it was mentioned that the V1 does indeed have a set level average to avoid twitter. Sony confirmed the feature a while back. |
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A flicker filter is a much more precise way of handling flicker. |
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There's a flicker switch but I thought it was for shooting 50Hz in a 60Hz country or vice versa, same as the Z1. |
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Not "our" twitter. |
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Good news. The 25p timeline that I exported as 1080/60i through compressor did play -- with some dropped frames -- on my HD DVD player.
Four 25p S=8 clips: 1) no flicker filter: bad flicker -- just like original 2) minimum flicker filter -- less flicker 3) medium flicker filter -- even less flicker 4) maximum flicker filter -- very very little flicker Looking at these results it seem with FCP it is possible to clean the signal such that when played from an hd dvd player to my HDTV -- it looks good. And, unlike the S=3, the bark on the tree is very detailed. Sony's S=3 recommendation does not show a lot of research. It seems a panic fix. However, I think S=8 is just too high. I think S=5 or S=6 would provide more than enough detail and enable the filter to remove all of it. In fact, for a film look, the image needs to be a bit softer. If not 5, no more than 6. I'm also wondering if I had made a 1080/50i disc -- would my Toshiba play it. And, would my HDTV show it. I'm wondering how multi-system these units might be. So if you upload an S=5 clip I'll try it. Anyway, I think it's clear there is an HD production solution for 25p. Piotr, for all the work you've done, Sony should give you a V1. Thank you for all your help. |
Steve, thank you very much for your work! I'll upload an S=5 clip later today. It may sound dumb, but do I get it right you've engaged a flicker filter in FCP? Is the "Reduce interlace flicker" its counterpart in Vegas?
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I also tried to make a 50i hd dvd. Compressor will not let me -- no 50i support. When I get your new clip, I'll try a 25p. However, I suspect that the burning software may reject it. Right now I'm going to see if the burning software will work with 24p. I fear not. |
Steve, the weather today is too dull for comparative shooting; I do have ready S=5 clips on disk but the shortest is just above the 100 MB limit of the server I've been using. Can you suggest any other host for a 107 MB file - if so, I could upload it immediately? Can your e-mail server accept an over 100 MB file?
Of course I can trim it, but this would require recompression... |
Steve,
Which HD-DVD model are you using? Does it have 1080p output? |
OK, so here is the link to a raw clip with sharpness=5:
http://rapidshare.com/files/19694265/s_5.m2t I also encoded it using Vegas Flicker Reduction switch; please compare it with your FCP flicker switch and assess which of its levels it is closest to. Here is the link: http://rapidshare.com/files/19712604...lter_Vegas.m2t Finally, I encoded it again using the smallest possible amount of the Gaussian Blurr (V=0.001), and this - while showing noticeable softening of the image - eliminates all twitter, even with VLC bobbing, which we have esablished as most closely mimicking the "live" ipnut from camera. Here is the link: http://rapidshare.com/files/19727858...1_in_Vegas.m2t My opinion is that - with 25PsF playing fine with sharpness up to 12, provided no deinterlacing kicks in - we should try to find a way to deliver it that way, rather than reduce the resolution (even if vertical only). Sony should definitely speak their standpoint on this. |
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from my work with this issue in SD there simply is no way to deliver 50i (or 60i I'd have to suppose) with V res greater than half the number of lines. Barry Green makes much of this in his support for progressive scan but I think the point missed is that even if you've acquired in P there's no way to force display devices to display it properly. SD CRT TVs only do I and I can assure you flicker can be a huge problem if you don't carefully watch what you're doing. HD CRT displays will do exactly the same thing. LCD displays that attempt to emulate interlace display will also manage to create flicker. Someone correct me if I'm wrong but this 'bob' display system is close to what a real interlace display does. The difference would seem to be that bob will cause the edges to appear to roll or bob, a proper interlaced display will make them blink. A fine line only one scan line high is always going to flicker on a 50i display. When the CRT writes that line, it's only displayed for as long as the phosphor persistance lasts. It's another 40mS before it gets displayed again. Something blinking at 25Hz is well under the point where persistance of vision kicks in, it's more of a problem where the duty cycle is very low, that's why the problem is worse on CRTs than LCDs, the poor response times of LCDs helps but as you've seen it's still not enough to totally avoid the problem. R60 displays will do a little better but still not good enough to eliminate the problem. The only correct way to display 25p is what is effectively 50p, merge the fields and display the same frame twice. This is almost the same as what a film projector does with a two blade shutter. None of this is really the cameras fault, it's delivering a perfectly good 25p image, you might argue it's too good but I'd rather have the res in the first place, it's going to make many things easier in post. The down side is you need to factor in at some point having to reduce the V res depending on your delivery. |
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"Barry Green makes much of this in his support for progressive scan but I think the point missed is that even if you've acquired in P there's no way to force display devices to display it properly." With 720p60 the monitor simply skips the deinterlacer and shows the P video exactly as it came from the CCDs. It looks perfect. I've used 720p since day 1 of HDV and I've never had a problem. The fact is CineAlta is an acquistion format and I perhaps all PsF formats should be used that way. Or, at least that's true for R50 V1 video. The R50 V1 has way too much V. rez and too much aliasing in P mode. There really is a "problem" with the V1E/P. Turning S to 3 is a very bad fix for real production work. Euro Sony should get on top of this with a White Paper. |
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Maybe, depends how you want to deliver it and / or do with it. Wouldn't as much V res as possible be better for keying, display from computer systems or a film out? Has anyone put a V1U and V1E upto a res chart to compare them? Also lets not forget the V1U in 30p, is it having the same issues? And we can still shoot 25p to deliver 24p very easily. Is even 24p guaranteed to be displayed correctly anyway. I realise you've got more of a shot with it than anything else but I'm under the impression it can still be problematic. Regarding 720p, I don't think it's a big enough step up from SD in R50 countries to hold much attraction some how. That might be wrong in some ways based on what we're seeing, if 720p always gets displayed correctly then effectively the usable V res is about the same as 1080, if not higher. |
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720p always gets displayed correctly on progressive displays. That's why I'm such a fan of P. The V1 res is only VERY slightly higher than JVC 720p. So there is no real loss going to 720p. Tests have shown P "looks" 1.5X more detailed than I. So until there is 1080p, 720p is a far better format. However, to get to 720p one has to convert files. If one is going to do this then there are two other options: 1) DVCPRO HD at 1080i50 which is 1280x1080 at 4:2:2 at 10-bits. This is a great option as it preserves full V. rez and 1280 is more than enough H. rez for a camcorder with only 960-pixels. You can export from Compressor for HD DVD at 1080p25. I'll soon know if it can be burned. 2) CineForm's new codec gives you 10-bits. You can also convert to 720p25 AIC. This file is 317MB for 30S vs 422MB for DVCPROHD. I would go with DVCPROHD. However, it may be reduction to 720p may reduce V. rez automatically eliminating the need for a Flicker Filter. ------------------- If the flags are set properly and one has a hidef dvd player that outputs 1080p60 -- then 24p will be perfect. The real goal in the USA is now 1080p24 into an LCD that will display it at 24p or 48p. This will duplicate a movie perfectly. How are you easily going to get 25p to 24p without audio problems? |
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24p to 25p, 25p to 24p, 24p to 60i, 60i to 25p, 30p to 24p, 24p to 50i...none of these framerates offer challenges any longer on the audio side, even if they do present difficulties to some degree on the video side. I'd bet Bob does this in his sleep, given the work he does. |
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The question of how to do this in FCP came up on the Sony Vegas forum, from memory there's 3rd party utilities to do the same thing. Probably the safest approach so you don't have a can of worms is to convert as a final step i.e. run a 25p project, render a mixed master and convert that. |
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Bob, are you talking about Vegas? If so, Spot's solution seems the easier way. Of course, I wasn't really asking about Vegas -- because with Vegas unable to record 25PsF back to HDV, it isn't an NLE I would recommend for R50 users who want to shoot 25p. I was hoping there were some FCP or Premiere lurkers in R50 areas. Somebody is reading all these posts. :) |
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Someone wrote to me that editing V1 footage shot in 25p mode in a 50i project in PPro (without AspectHD) resulted in pure 25p output. But I've read otherwise since. I don't understand a thing... |
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If you record it back as 50i or 25PsF what comes out the HD component from your deck is exactly the same isn't it? If you capture it back all you have to do is tell your NLE it's Progressive, hardly a difficult task, certainly not with Vegas and I'd guess with most other NLEs as well, after all we've been getting telecined film that way since day one in R50 land. I'd hazard a guess most people just process it as 50i, the only downside being any temporal FXs will come out truly interlaced, it's indeed better to tell the NLE to keep everything progressive. You'll face the exactly same issues with 25F once it's captured for that matter. Personally I wouldn't recommend going back to HDV anyway, one pass of HDV compression is bad enough. |
Does any of you guys have access to an HDTV with FireWire input? Since feeding 25PsF live (before or after tape) into VCL using i.link doesn't create twitter, it'd be an interesting test!
As a side note: does any of the current, early HD/Blu-Ray DVD players have i.link outputs? |
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If I have followed the meanderings correctly there is an inference that because the V1E is not sending a progressive flag via hdmi that HD DVD and Blu-ray players will not do it either. There seems to be a misunderstanding of the Blu-ray specs. 25P will be supported via 50i. 25P is not listed in the specs as 25PsF is 50i and the only true progressive mode that is supported is 24P. That really is progressive encoded material and will be supported across all regions. In PAL land we'll watch BD at normal speed at last. So how will TVs know not to deinterlace 25PsF? There are two methods, cadence detection and flags. I am 99% certain of the facts but I have emailed a friend who is a very skilled DVD author using Scenarist. I am hoping he has some detailed knowledge of BD and will confirm what I say and give a greater insight. TT |
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If you can trust the figures from the Texas shootout the XL-H1 reads 540 lines vertical res. I doubt the Canon A1 is any higher. This would probably explain why the Canon doesn't have the same issue. I think Steve was saying the V1 reads 700+ I've just tried converting 25p to 24p using Vegas. I'm doing it the long way as this avoids any interpolation. It is covered quite well in the documantation. In brief you measure the number of frames using the ruler at 25p, change the project to 24p, move the cursor to the original frame number and ctl-Drag the end of the clip to the cursor. You've slowed down the clip as needed, no different to changing the speed on a projector. The 24p looks every bit as good as the 25p on the Vegas preview monitor. Except I'm having no end of fun trying to render it to anything without it falling to bits on fast motion. It looks like pulldown is being added but I'm compressing frames instead of fields, the macroblocking is really bad. Need to do more research on this. |
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There is no such thing as "HDV" compression. HDV is only the marketing name attached to one Profile/Level of MPEG-2 encoding. There is little difference between the MPEG-2 recorded to HD DVD or BD and the MPEG-2 HDV recorded back to tape. So if you fear re-encoding to HDV you equally will fear encoding for an HD DVD or BD disc. Same "stuff" in both cases. That's why you can take an HDV file and make an HD DVD without any re-encoding. For the next few years it will be a lot smarter to carry an HDV camcorder and your production's tape than it will be to assume you'll find an HD DVD player waiting for you in Asia or Europe -- or even the USA. |
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The shootout had an F9xx at 1000x1000 -- so the V1 really does well. In fact, if not scaled/filtered to 1440, the 3ClearVid system might offer 1000 horizontally. And, Sony just happens to have a 24Mbps version of AVCHD that records 1920x1080. So just when we've bought all our HDV toys ... |
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However, when I deliberately BOB the 24p output in VLC, and send it to my LCD via component - the twitter is still there. Probably my monitor doesn't recognize it properly, either. Of course I'm bobbing it just out of curiosity, as 24p definitely shouldn't use ANY de-interlacing. |
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Piotr, I'm watch your 25p >>> 60i on HD DVD and with the Flicker filter set to MEDIUM, 99% of the twitter is gone.
But the tree bark is way too soft. (Of course the light was very soft.) So if 5 is too soft and 8 is too hard -- that leaves 6 or 7. I can go up to MAXIMUM and have a bit of twitter, but still great detail if you use 7 or almost no twitter and good detail. My instincts tell me 7 was chosen by Sony for a very reason. So 7 seems an obvious choice. But for a film look, you may want a softer look. Just don't use 5 or 8. Your garage has the perfect ultra thin lines for testing. Not very many things are so thin! I guess I bet 7 will be OK for most shooting. Nothing prevents presets for NORM and presets for brick buildings, etc. Post both when you get a sunny day. |
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I'll be posting raw clips with S=6 and 7 at the first opportunity. |
Here is a clip with sharpness 6:
http://rapidshare.com/files/19857440/25p_s_6.m2t And here - the same fine lines on the garage, but with sharpness set at 7: http://rapidshare.com/files/19857444/25p_s_7.m2t Guys, I'll repeat my question from another topic here, as I'm about to order my gear for the V1: does the Manfrotto MN523Pro lanc controller wotk flawlessly with the V1/FX7? Thanks! |
OK, finally got Vegas to do the 25p to 24p thing, well that was the easy part.
Finding out how to render it to 24p with pulldown had me confused for while but here it is: http://rapidshare.com/files/19937797...wn_Test-01.m2t Sorry kind of big (66MB) file. Shot at S=7, 1/25th some time ago now. Telling Vegas to remove pulldown on file open seems to yield perfect 23.976 although it's only 2:3 pulldown so I guess that means there'll still be judder frames in there. Haven't looked at it on a full 1080 monitor as yet but didn't notice any nasties at half res, so far I'm pretty happy with the camera. |
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Thanks Michael. |
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Open a 1080 50i project. Manually change the project properties to Field Order None (Progressive). Make certain you have Quantize to Frames On. Drop the m2t file from the V1 into the project. Set the ruler to Absolute Frames. Move the cursor to the last frame. Either copy the cursor position (left most box under the T/L) to the clipboard or just write down the frame number. This has to be accurate! Now change the project properties to 24fps. Move the cursor to the same position as it was before i.e. the same frame number. You can Paste the number back into the cursor position box or type it in. This should be a little to the right of where it was. Now Ctl-Drag the end of the clip to the cursor. You now have 24p! Sorry if that sound complex still, but the idea is to measure how many frames the original video had and keep the number of frames the same in a 24p project. This means the speed and length will change BUT there's no resampling, all frames stay intact. Then I rendered to 1080 60i HDV but in the MainConcept mpeg encoder set the frame rate to 23.976 + 2-3 Pulldown and moved the quality slider to 15. Vegas will render the file with a .m2t extension and although I haven't tried as yet you should be able to PTT this file. |
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But it's not simply that 24p is easier to sense, the rules for creating 1080-line buffers from 540-line fields are ABSOLUTE. There is no need for bob or weave or anything. The fields all wind-up back in the original frames where they came from. Despite this, the majority of HDTV can't sense the cadence perfectly. So if you want perfect P, you need to shoot 720p. Which is why the option of converting 25PsF to 720p50 DVCPRO HD is so attractive. You get 4:2:2 and no loss is rez. Recording back to a VTR can be done by FireWire. D-5 accepts it. |
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