Ag-hpx600

[Konstantin Kovalev]

Originally Posted by David Heath

If it's a "CMOS 3100" then one of the first things to ask is whether it has any 720p and/or variable speed capabilities? (Which I don't believe the 3100 does??)

Ideally, I'd like to see full slo-mo up to 60fps at full 1080 resolution - failing that it really should (like the PMW350/500) manage proper slo-mo at 720p.

That would be really nice... And probably much more future-proof than anything else they could do with the camera. 1080 50/60p footage can be converted to any other progressive or interlaced format without loss. Maybe throw in a 48fps mode just for safe measure (people will certainly go bananas over this "feature" after The Hobbit shows).

And also 128gb P2 cards to compensate for the halved recording times....

[David Heath]

Well yes - but what I was really referring to was slo-mo shooting - shoot at 60fps for 24 fps playback. AFAIK that is not possible with the 3100? (As is no 720p mode at all?) Yes, true 1080p/60 as a mode would be fantastic - but bear in mind it would require an acquisition format that at I don't believe is currently defined.

Failing the above, at least let's see the possibility of true 1080 resolution normal shooting, and 60/24 slo-mo 720 - as cameras such as the Sony PMW500 do.

[Konstantin Kovalev]

Originally Posted by David Heath

Well yes - but what I was really referring to was slo-mo shooting - shoot at 60fps for 24 fps playback.

It's not really a camera function, any footage shot at 60p can by slowed down to 2.5x on a 24p timeline, normal 1080p50/60 shooting also means slo-mo capability, it'll just play back at normal speed in-camera.

AFAIK that is not possible with the 3100? (As is no 720p mode at all?) Yes, true 1080p/60 as a mode would be fantastic - but bear in mind it would require an acquisition format that at I don't believe is currently defined.

That is strange, some people say CCD's don't have a scan rate fast enough to render 60p, and yet some high-end Sony cams have 60p. In fact, the Sony HDC3300, although a special case, has up to 90p at 1080 resolution.

And I'm not sure about acquisition format either, but with something as new and not clearly defined as AVC-U, there is no reason to think it can't be done given the inclusion of formats with a much higher bandwidth usage.

[David Heath]

Originally Posted by Konstantin Kovalev

It's not really a camera function, any footage shot at 60p can by slowed down to 2.5x on a 24p timeline, normal 1080p50/60 shooting also means slo-mo capability, it'll just play back at normal speed in-camera.

No, not the same. With something like Sony S&Q what results is identical to a file shot at 24fps in the normal codec. If it's 35Mbs at 24p, then the RECORDED bitrate goes up in proportion to the frame rate (so 70Mbs at 48fps, etc) - the REPLAY bitrate will always be the standard 35Mbs. 1080p/50(60) is likely to have a higher compression rate per frame than comparable 1080p/25 - the higher frame rate serves to smooth out the flaws in normal playback, but it won't be the same after slow-down.

The other point is that S&Q is not simply tied to 60fps/2.5x slo-mo. You may wish just a slight slowing down, and it's quite possible to shoot at (say) 40fps but still end up with the standard 24fps file for replay.

And I'm not sure about acquisition format either, but with something as new and not clearly defined as AVC-U, there is no reason to think it can't be done given the inclusion of formats with a much higher bandwidth usage.

Oh yes, I'm sure it can be done, but point is it would mean the definition of a new codec, or at least a sub-set. The varispeed function (shoot at one frame rate, end up with a 24fps playback file) doesn't need anything new defined.

On a new camera, I'd like to see both, and I'd like to see the varispeed work at full 1080 resolution.

[Konstantin Kovalev]

Originally Posted by David Heath

1080p/50(60) is likely to have a higher compression rate per frame than comparable 1080p/25 - the higher frame rate serves to smooth out the flaws in normal playback, but it won't be the same after slow-down.

In an I-frame codec every single frame gets the same amount of compression, regardless of frame rate or content. The 100mbps rating of AVC-I is only applicable to 1080 30p/60i & 720 60p, any frame rate that is slower will increase recording times because less frames are being recorded, and so at a lower effective bit rate.

24p actually has an 80mbps bit rate, and if we had an AVC-I 100 cam that shot 1080 60p, it's effective bit rate would be 200mbps. At 100mbps the codec is simply set to give each frame roughly 500kb worth of data.

[David Heath]

Originally Posted by Konstantin Kovalev

.......... if we had an AVC-I 100 cam that shot 1080 60p, it's effective bit rate would be 200mbps. At 100mbps the codec is simply set to give each frame roughly 500kb worth of data.

Yes, all that's true as far as it goes, but I doubt if any such 50/60p codec would implement like that - I suspect a manufacturer would not like the idea of doubling the bitrate to give the format. Because the frames are changing much faster, individual flaws within a frame become less noticeable - hence it's more permissible to have a higher compression per frame than at lower frame rates.

Likewise, interframe compression makes even more sense (at least for acquisition) the higher the framerate - a codec can take advantage of the correspondingly smaller differences frame to frame. It's likely that the time interval between I-frames will remain the same - hence doubling the frame rate will mean doubling the number of difference frames between I-frames.

This is why for AVC-HD 28Mbs peak for 1080p/50 is seen as roughly comparable quality to 24Mbs for 25p. Doubling the frame rate shouldn't mean doubling the bitrate.

[Konstantin Kovalev]

Originally Posted by David Heath

Yes, all that's true as far as it goes, but I doubt if any such 50/60p codec would implement like that - I suspect a manufacturer would not like the idea of doubling the bitrate to give the format.

Perhaps not, but AVC-U is currently known to allow up to 200mbps bit rates, which could be used as an excuse for adding that capability.

[Sam Lee]

<<A little off topic, but it seems the 600 is basically a 3100 with CMOS, and future upgrade that will allow you to shoot long-gop in addition to intra. Besides the obvious CMOS vs CCD thing, the 600 is only $4000 cheaper body only.>>>

There's quite a quality jump between HPX-600 and HPX3100. The 3100 has all of the fine color matrix and corrections w/ Film Rec gamma. It looks like real high end broadcast when a decent $28-35K real HD lens is placed on it. HPX600 seems to be just like the HPX500 but w/ updated chips. Colors are just not as pristine somehow w/ the HPX-600.

Panasonic is very careful of keeping the camera's costs and performance in reality check. For example: Most people think that buying the HPX-370 will replace all of their HPX2000, HPX3000 series. They were in for a big surprise. It performed dismally when lighting is not ideal. In real life, lighting is never ideal. So that one example where the more $$ is spent on the camera, the better the quality.

[David Heath]

Originally Posted by Sam Lee

Panasonic is very careful of keeping the camera's costs and performance in reality check. .......... So that one example where the more $$ is spent on the camera, the better the quality.

But as said on the other thread about the HPX600, the cost of the HPX600 is very close to that of the PMW350, probably more expensive when you take memory costs into consideration, and with full reality check the PMW350 sets the bar for such a 2/3" camera.

Yet the PMW350 is (as expected) 2/3" 3 chip - the HPX600 is only single chip, with the quality compromises that makes inevitable. Use a single 1920x1080 chip and that will inevitably decrease the colour resolution and bring the colour aliases well in-band (below 1000lpph) - that's why you're seeing "Colors are just not as pristine somehow."

[Sam Lee]

That explains why it's so muddy looking on the HPX-600. With the exact same lens, I swapped to the HPX-3100 and 3700. Considerable difference in quality. You can instantly see the 3000 series cameras are taking full advantage of high end 2/3" lens w/ colors are popping out on every areas on the frame. And there's no CAC turned on yet. Can't really compare the two as they're different classes of cameras (Single MOS vs/ expensive 3-CCDs). The HPX-600 is definitely tailored to a different market than the 3000 series.

I recall many years ago exact same issue with the HPX-500 and HDX-900. With the exact same 2/3" lens, somehow the HDX-900 footage looked much richer with all of the nuances vs. a flat look on the HPX500. And unfortunately either HPX-500, HPX-600 have 12 pole, 14-bit color matrix adjustment. Just simple presets with limited parameters found on the HPX250, 370.

>> Yet the PMW350 is (as expected) 2/3" 3 chip - the HPX600 is only single chip, with the quality compromises that makes inevitable. Use a single 1920x1080 chip and that will inevitably decrease the colour resolution and bring the colour aliases well in-band (below 1000lpph) - that's why you're seeing "Colors are just not as pristine somehow."<<