Ron Shook
Forum Replies Created
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Paul,
[Paul Thurston] “Does this mean that 4:2:2 images captured with an HD camcorder should not be used for filmout or TV? The answer is: they should be used. Since the only people who will ever notice the difference between motion portrayal in 4:4:4 and 4:2:2 color space will probably only be… a video engineer.”
This has been a superb thread and your explanation puts the capper on it. Thanks!!
Because of the entire thread discussion, I think that I now have an understanding of why I, like Craig and others have expressed, tend to feel that 30p looks in some ways more filmlike than 24p when run through a complete YUV, 4:2:2 production/post-production chain. Or maybe it doesn’t look more filmlike, because there are other things going on, of course, but it looks better to me, if it is destined to be video all the way. As John points out 24p in the film projection theater, whether coming from film or video, benefits from multi-blade projection which tames the judder/flicker of 24p.
And it tames the judder/flicker without resorting to artificial cadence pull-down. For video that won’t ever be optically projected, 30p tames the judder/flicker pretty good, again without pull-down.
Of course what I’m talkin’ about applies to NTSC. How Mark deals with the flicker of 25p PAL, I dunno? I suspect that a considerably higher percentage of folks can see flicker at 25p than at 30p.
Thanks to all,
Ron Shook
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Don,
[Don Greening] “Bummer.”
You’d need two encoding chips to do this, I’d think, and thus didn’t really expect it in this little camera.
Ron Shook
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Mark,
[Mark Palmos] “enough to see the blur I mean…”
I can finally see your footage. Had no joy before. Yeah you can see the blur, but it’s not as bad as I’d feared. Still better than SD.
Ron Shook
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Michael,
[Michael Palmer] “it outputs the same signal as HDV.”
A further clarification would be nice. I’m sure I read that you can only output the 25mbps HDV via firewire, but can you be outputting that while recording 35mbps to the SxS cards? I’d guess not, which means you would need be recording to cards in HDV if you needed to record to the cards. Can anyone say precisely the perameters?
Ron Shook
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Randy,
[Randy strome] “Downloaded VLC, and although no error is diplayed, no video will play.”
Same with me. If he uploads it straight from the card, will it play with VLC or do I need to get the clip brower?
Ron Shook
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Mark,
[Mark Palmos] “hey there ron
RH mouse click and save link as…
” target=”_blank”>https://www.finalcutpro.tv/748_0025_01.mov”I did this that and it’ll play only audio. QT claims that there is some component missing but doesn’t say which one and presents me with a list of 10 or 15 components. QT player says that it is completely up to date. What codec was used on this file?
What gives? Anyone else have trouble playing this file on a Windoz machine?
Ron Shook
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Randy,
[Randy strome] “720 24P with a smaller spatial and temporal resolution should cut out enough data to allow for detail to be maintained to a relatively high degree even in pans.”
Right you are. At 720p you’re talking 4 rather than 6 times the pixel resolution of DV and of course 24p data is less than half the data of 60p. I don’t have the camera so I can’t test, but Mark or someone else should give it a try and let us know. I suspect that panning a lot of detail will not exhibit such a resoluton loss as Mark reports in his initial tests.
If you ever get a chance try the same panning test at 720p60 with a 200 series JVC HDV camcorder. Like the EX1 it’s nearly impossible to break the codec into blocking artifacts and such, but you’re lucky to get SD resolution out of it in some instances. The JVC codec is the standard 720p HDV at less than 19mbps. It’s kind of rule of thumb that with a long GOP MPEG2 codec, small increases in the mbps rates can sometimes result in dramatically better performance and the Sony codec is nearly twice the data rate of the 720p HDV codec.
[Randy strome] “How well does the codec adjust?”
Sony usually does as good or better than anyone else with compression codecs, but really you’ll have to tell me. (g)
Ron Shook
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Mark,
[Mark Palmos] “but im comparing a first impression of my ex1 with my lowly XL-1 and with the xl1 i dont see the instant degradation when panning.”
I would expect those results when the DV codec on the XL1 is intra frame in SD at 25 mbps while the EX1 codec is inter frame (GOP) pushing 6 times the pixels at 35 mbps. The EX1 codec is certainly several times more efficient than the DV codec, but several times is not 6 times and somethings gotta give, and that would be resolution.
[Mark Palmos] “A pan OF the subject is more telling… preferably a wide angle shot of a leafy landscape!”
This is the worst case scenario for EX1’s type of compression. I’d suggest that it probably still matches or comes very close to matching the HVX200’s lower resolution to start with, but it’s not gonna look as good as when the camera is stable and not moving.
Ron Shook
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Mark,
[Mark Palmos] “this one seems very nice and very affordable.”
It certainly is affordable, but I’d try before buying as I’m not sure bracing on the chest wouldn’t result in too much breathing instability, particularly if you were rushing around.
I’d think that this is the probably one of the best, but it ain’t nearly as affordable and would more call for a zoom controller which from what I gather from a few posts here wouldn’t be such a bad thing:
https://www.varizoom.com/products/supports/vzdvtraveler.html
Ron Shook
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Mark,
[Mark Palmos] “2/ maybe its my imagination, but shooting at 100th of a second 1080 50i HQ even a very gradual pan shows significant softening of the edges once the pan starts. When it stops again, everything is sharp. At the speed I was panning I wouldnt have expected the softening to be as extreme at 100th of a second. This happens regardless of Interlaced or Progressive.”
I think that I can answer this question adequately, and no, it’s not your imagination. Several things are at work here. First of all a shutter speed of 100th of a second is not that fast. It oughta be a bit better at a significantly faster shutter speed.
Secondly, and probably the bigger culprit, you are seeing the limitations of the long GOP Mpeg2 codec. The Sony 35mbps codec is better than it has any right to be, IMO, but it’s still compression defined over multiple frames of video. Particularly on a pan of a detailed subject where everything in the frame is changing with each frame, however slowly, it’s impossible for the codec to keep up with that amount of change, so the algorythm automatically cuts the detail to avoid blocking artifacts. You hear folks say the codec is nearly impossible to break, but they are essentially talking about blocking and other highly visible artifacts. Some situations, usually involving Pans, the codec has to break down the detail to keep up and avoid the more visible garbage. You’ll see much less problem if you have a subject that takes up far less than the whole frame, moving through a stationary shot. There’s considerably less to change from frame to frame and the long GOP algorythm is more successful at preserving the detail.
This speaks directly to the Sony/Pany controversy over the relative benefits of interframe (long GOP), v.s., intraframe compression. All other things being equal, although in most instances the opposite is true, the XDCam 35 mbps interframe codec is not going to look as good while panning a detailed subject or in subject movement that fills much of the frame as the DVCPro100HD codec because the Pany codec compresses each frame separately.
Matt Devino’s moving shootout footage, illustrates what I’m saying pretty nicely even though we are seeing full res footage that has all been compressed long GOP again for web delivery. In his case, all other things are not equal in that the EX1 has far better native resolution on the camera and in the codec than the HVX 200, yet when you watch the comparison when the respective cameras pan with the skateboarder, there’s very little difference in apparent comparative resolution, the HVX holds it’s own because of the codec differences. Yet on the wide locked frames of the skate through, the background looks sharper with the EX1, while it’s hard to see a lot of difference in the apparent sharpness of the skater himself.
It’d be great to see Matt’s tests natively from each camera. Perhaps he could comment on what he sees prior to compression for web delivery.
[Mark Palmos] “what on earth is so nice about progressive. I mean, ok, when you freeze it looks nicer, ie not interlaced, but when you pan it jerks and looks simply awful… almost as bad as having fields reversed by mistake. If our little EX1 did 1080 50p that would probably be the best of both worlds, but alas. I personally prefer a smoother looking 50i to the jerky 25p. I also know progressive is better for compositing as well as watching on computers, but for watching on a TV monitor, i far prefer interlaced.”
I gotta say that like you I don’t understand the 24/25p or die phenomenon, however things are a little different for us in NTSC land. When 24p goes to TV here pull down or pull up or whatever the heck it is, is applied here to deliver a 1080 60i signal, and that tends to mask some of the judder that you see in 25p but also lowers detail. IMO the most logical way to shoot relatively low action things here in 1080 is 30p where you get some of the best from both worlds.
Ron Shook