Any reviews with hard facts?

[Khoi Pham]

Hello Barry, I don't have the XL2 or DVX to compare the FX1 to but I do have the DSR300 and VX2000, in DV I don't think the XL2 nor DVX could be as good as the DSR300 for obvious reason and I'm sure you will agree with me, I also noticed that the FX1 ability to handle contrast is not all that good compare to my DSR300 and , and I also have seen some frame grab on this site which confirm what I noticed. I also agree that low light performance it not the best either, atleast 12 db below DSR300, BUT what I have seen in the final DVD is diffrent than what you saw, there is no DOUBT in my mind that footage shot on FX1 and delivered on DVD is much better than footage shot on DSR300, so footage shot with XL2 or DVX can not have better picture on final DVD since they are inferior to the bigger CCD and better electronics and lens of the DSR300. You mentioned soft picture with FX1 on final DVD, actually what you saw was a Cleaner picture, most often people think they see a sharper picture when there is a little grain or noise in it, and they think the picture without noise is soft but that is not so, I have looked at and compared footages for many hours before I decided to sell my 2 VX2000 and 2 DSR300, I'm no tech testing expert, I goes by what I see in the final product, but I think the FX1 deserve better that what you have been report on it.
BTW I have one DSR300 with an 18X Canon lens if anybody interest in it. (-:

[Barry Green]

Hi Khoi,

You are not the first one to report something like that. All I'm saying is, these are the tests I've run, these are the results I've gotten, and I don't know how else to do it. And I've listed the testing and methodology so you all can see where I went wrong, if I did.

So if someone wants to take the same footage and demonstrate a reasonable workflow (by which I mean, let's not go and get a $100,000 dedicated hardware resizer, let's keep it in context of the type of desktop video producers who are likely to be using this gear) then by all means I'd like to see it. I just have to re-capture small .m2t's, because all the ones I have now are 70 megabytes or more, and I can't trim them down without recompressing the footage... so I'll have to recapture them in like three-second chunks or something.

And, regarding Marshall Spight's quote:

"The difference between theory and real life is that in theory, there is no difference between theory and real life, but in real life, there is a difference."

That's just brilliant. I think I'll be repeating that quite often, thanks for sharing it!

[Toke Lahti]

<<<-- Originally posted by Barry Green : Whoa -- let's hold up here. HDV has way more detail than DV. Way, way more. If you watch the original HDV source on a 1080i television, the difference is startling. -->>>

I of course meant when converted to dvd, but WHOA again, why hdv doesn't have more detail in dvd than dvd from dv?
Logically it should have like film transfers and other hd formats.

Strong opinions here, little proof.

How many line pairs can dvx, xl2 (pal&ntsc) or fx1 can really reproduce?
How does the amount of details changes with movement?

Lets take a theoretical case that we are using pal dv cameras and progressive display (all displays will be progressive in couple of years).
Fx1's resolution will be 1080x0.7(kell factor) = 756 and progressive pal dv would be 576, so the difference is 24%.

Of course progressive dv cam's resolution can't be that good, because otherwise they would produce interlace flicker with interlaced displays.
So there is lowpass filter, but where it cuts?

After that the difference should be more than 24% so why this doesn't show up with dvd tests?

Does the default sharpness setting cut the details out of fx1 or soft drawing lense? Or mpeg2 compression? Or something else?

[Toke Lahti]

<<<-- Originally posted by Jon Fordham : I am currently scheduled to do a shoot with the FX1 for Heath McKnight this week. As part of my initial tests, I plan on putting my Putora 7A9 chart in front of both the FX1 and the DVX100A. -->>>

Great, Jon!

[John Jay]

Barry,

First off, if you go to www.womble.com and d/l the mpeg-vcr demo, it should allow you to cut up your clips for posting if required, leave the settings as is otherwise it will recompress the footage.

Second, the slight softening in the downconversion is entirely due to the the low pass filter effect of the interpolation. I believe I provided a valid technical description and cure, but if you are still unsure check out
http://kwon3d.com/theory/filtering/lpass.html
The bicubic spline is equivalent to a Butterworth with N=3 which reduces the frequency response of the band-pass near the scan line frequency, and that is why I suggest one with at least N=5 a fifth order interpolation to prevent the slight softening that you see. Alternatively an edge shaprpen will be just as good, and is not a cheat but merely serves to restore the loss of higher frequencies through the filter action of the interpolation. Only after this is done can the image comparison with DV source can be made in fairness.

For example here's how Photoshop describes the bicubic interpoltion method
'Bicubic (Smooth) for the slow but more precise method, resulting in the smoothest tonal gradations'

Third, I have thought of two more benefits ( the nine B's if you like) to downconversion from HDV>DVD so my list is now

B1- reduction of noise by > 50%
B2- removal of the halo effect
B3- reduction of artifacts > 50%
B4- improvement of any slight de-focusing faults
B5- improved colour space going into the mpeg compression for DVD
B6- choice of whether to have interlace or progressive DVD
B7- better framing from cropping if desired without resultion loss
B8- superior full resolution slow motion at 50% speed
B9- 2 stop (12db) improvement in low light response using a triple pixel readout post technique

I'm sure the discussion will continue as others post results

[Graham Hickling]

Quote: And I'm giving the FX1 the benefit of the doubt by making the DVD source from the original HDV footage, not a DV down-rez, because by using DV down-rez, you convert the original 4:2:0 MPEG-2 down to 4:1:1 DV, and then again to 4:2:0 MPEG-2 for the DVD authoring.

But Barry - no-one interested in best-possible quality would down-rez to a DV intermediate! Surely they could go to uncompressed, or one of the high-quality codecs like huffyuv or wavelet, using a high-quality rescaling algorithm and perhaps a touch of (re)sharpening as per John Jay's suggestions?

Having read this thread, I'm left wondering about the quality of the down-rez procedure in the MPEG encoder - could it be a factor in lack of sharpness issue?

[Ken Hodson]

Yes thanks Barry, good post. It has me thinking. And this is what I have come up with.
The Sony FX1 is a hard cam to compare with for this issue. As it shoots interlaced causing it's own problems in down conversion and also using pixel shift to enhance its resolution, so it is not the best example of a true SD to HD or Film downconversion comparison.
That said. Take some 720x480 FX1 DV footage, deinterlace, save as uncompressed. Then take the HDV footage (the same slow pan over some textured scene. Make it an outside shot with lots of distance. Close in shots will not show the difference)deinterlace, save as uncompressed as well. Colour correct the footage extensively, composite in a few objects/titles and FX or what have you. Then downrez. Check out the difference. Especially in the background.
Sharp lines, like your tile idea would be a good example if it was tilted on an angle. This would demonstrate the effective anti-aliasing and colour space increase of the down conversion. Hard lines such as stair railings with high contrast lighting would be a good example as well.
I was skeptical as well untill I saw a DVX progressive compared to a HD10 progressive. Both letterboxed 16:9. I then realized HDV did have a place in the 16:9 SD world.

[Ron Evans]

Since I specifically want to use the FX1 to perform two functions as a wide camera view and possibly alternate camera view by pan/zoom/crop both to output in SD on DVD this issue of the best way to downrez is probably worth a thread of its own at some time. This will be a learning experience just like learning the most effective way to make compatible DVD's was in the last few years. IT might also differentiate between the various NLE's and their choices for downrez algorithms/parameters. Comments from David Newman would be welcome.

Ron Evans