1080i or 720p, which looks better?

Ken Hodson · October 30th, 2004, 08:51 PM

For the FX1's specs read here
http://videosystems.com/mag/video_sonys_hdv_debut/

"Sony developed a new 1/3in., Super HAD CCD for its HDV camcorders. Each CCD has 1,012 (horizontal) by 1,111 (vertical) elements (1,120,000 pixels) that provide an effective pixel count of 1,070,000 pixels (972 horizontal by 1,100 vertical. Vertical smear level is rated at a very low -107dB. Each element has a 2:1 aspect ratio."

JVC HD10. I thought this was all common knowledge by now. There have been many posts discussed in these forums.
The most technical info is probably this article.

"The JVC chip provides 632,640 luma pixels (960?659 pixels)."

http://www.findarticles.com/p/articles/mi_m0HFE/is_5_29/ai_102106333

Tom Roper · October 31st, 2004, 01:31 AM

Ken, I accept the Steve Mullen article. I apologize for misinterpreting your statement also.

The FX1 scales up from 960x1080(pixel shift), the HD10 resolves down to 960x659(luma/alias filters).

Tom Roper · October 31st, 2004, 02:50 AM

Interesting to note in the horizontal, the amount of down-resolving in the HD10 due to the 2 column sliding luma filter, the 2:1 ratio luma/chroma and anti-alias filters...

...is about roughly equal to the green pixel shift up-scaling in the FX1.

There's no contest on the luma/chroma ratio, but from Steve Mullen,

Quote:

"...it is true that while a single CCD delivers two luminance samples for each cluster of four filtered CCD elements, the (conventional 1 CCD) chip is able to provide only a single red, green, and blue sample from the cluster. The JVC CCD is a new design that uses white, green, cyan, and yellow filters to deliver maximum effective vertical resolution.

The 2:1 ratio of luma samples to chroma samples is not that significant because both DV and MPEG-2 compression use color subsampling that reduces chroma resolution even further. NTSC DV compression uses 4:1:1 sampling, while HD MPEG-2 compression uses 4:2:0 sampling."

There, he seems to be saying that mpeg-2 compression (which pertains to the FX1 and HD10 both) plays a larger role in reducing chroma resolution than the 25% caused by the 2 column sliding filter on the JVC single CCD.

If that's so, there's a lot of non-native interpolation within both images caused by mpeg2 compression. Isn't that the whole point of GOPs? I-frames are the only actual native frames, outnumbered by B and P frames that are predictive in that they contain only the changes from the frame before and after?

So how do you put a number on THAT?

And if mpeg2 compression which applies to single and 3 CCD sensors alike, is more of a factor in reducing chroma resolution than single CCD filtering, should you be putting a number at all (like 25%) on single CCDs and not (3) CCDs?

I think there, one could make the case (speaking on resolution), that you can fairly square them off on native CCD sensor elements alone, that for GOP sequences, resolution is 1280x659(JVC HD10) versus 1012x1111(Sony FX1)

I'm talking about a GOP sequence (where mpeg2 governs), not a single I-frame capture where the 2 column sliding filter on the JVC single CCD takes a 25% horizontal resolution hit.

Either way you figure, the difference is only a percentage, but food for thought.

Tom

Graeme Nattress · October 31st, 2004, 07:50 AM

I think what Ken is trying to get at is that the resolution of the CCD is not necessarily what gets recorded to tape, and even if the pixel resolution of the format is played back in full, that might not be accurate to the true resolution of the system.

The only way tot really know is to measure test images, and even then, what do you do about moving shots which stress the MPEG2 compression?? In the end, it's going to be a subjective call.

Graeme

Tom Roper · October 31st, 2004, 10:27 AM

I agree Graeme, especially the second part about moving shots which stress mpeg2 compression.

The camcorder is foremost a motion picture making device, the point being that a fine detail that goes unresolved in one frame due to the two column sliding filter of a single CCD device, does get resolved in the next frame by motion that shifts the fine details into adjacent columns.

And that for either format(1CCD or 3CCD), what gets recorded to tape also might not be accurate to the true resolution of the system due to mpeg2 compression, as you stated.

So, when talking about resolution, why not stick to the objective versus the theoretical? The one thing that we can define unequivocably is the actual element array of CCD sensors behind the lens that gathers the light. That is what we did before pixel counting articles by Steve Mullin raised our awareness of what you stated in the end, will be a subjective call anyway. (On that count, there was never a question from me that the FX1 is a giant leap ahead of the HD10.)

Ken Hodson · October 31st, 2004, 07:40 PM

The mpeg2 compression will effect chroma sampling just as the DV codec did befor it. The FX1 will have an edge in colour resolution due to its 3 chip design, but not a big advantage in luma resolution.

"(On that count, there was never a question from me that the FX1 is a giant leap ahead of the HD10.)"

If interlaced image is a giant leap your welcome to it. I do envy the fully manual controlls though.

Graeme Nattress · October 31st, 2004, 07:58 PM

I would think that yes, 1080i is a big leap over 720p30, which is about the worst frame rate there is. And perhaps the biggest leap (other than manual controls) is that the FX1 footage is not overly sharp like the permanent sharpness lines around everything on the HD10 and especially the HD1 which makes it look like high resolution VHS. And those sharpness lines are something that you can't do anything about in post, whereas 1080i can be very sucessfully de-interlaced or 24p converted, or downconverted to progressive or interlaced PAL or NTSC quite well, which a 30p format will not without extensive and expensive processing.

However, 4:2:0 is ghastly on interlaced images, not that it's not ghastly anyway. Give me 4:1:1 over 4:2:0 any day. I'm going to have to code up a new 4:2:0 chroma reconstruction filter before I can do any kind of processing on HDV footage.

Graeme

Ken Hodson · November 1st, 2004, 01:50 PM

"FX1 footage is not overly sharp like the permanent sharpness lines around everything on the HD10 "

I do not find the HD10 footage to be like this at all. If anything for an HD image it is very soft. I don't know what you are thinking?

"or downconverted to progressive or interlaced PAL or NTSC quite well which a 30p format will not without extensive and expensive processing."

30p is just perfect for putting out anamorphic NTSC DVD's. Where 99.9% of everything I downconvert goes. As well JVC has been demo'ing HD10 footage converted to 25p in Europe using Edios software. Apparently it does a great conversion to PAL. But I live in NTSC land and regardless of what you say, it makes one heck of a NTSC DVD!

"However, 4:2:0 is ghastly on interlaced images"

But works just fine in 720p thanks very much.
I hope you enjoy massive render times befor you can colour correct that 4:2:0 as a deinterlaced image with any level of quality.

Graeme Nattress · November 1st, 2004, 02:00 PM

4:2:0 does not relate to colour correction issues, but to more image manipulation issues, and in that respect affects 720p nearly as much as it effects 1080i.

What I'm thinking about the sharpness is that it's permanently on, and it's visible as nasty edge enhancement, although much worse on the HD1 than the HD10. I don't see anything like that at all on the posted FX1 footage.

As regards to interlaced and progressive, it's a darn site easier and faster to make interlaced progressive than progressive interlaced, so shooting 1080i60 is a lot more flexible in post, in that respect. But as you say, be prepared for render times. It's obviously preferable to shoot in whatever format you want to end up in, rather than have to go in and convert between them.

I think the main issues with the HD10 are lack of manual controls, and it sounds like JVC will be adressing this before too long with their next camera. At that point, it will be "fair" to make some kind of comparison, but before then, you're comparing one obviously flawed (because it's the first of it's kind) camera with another that hardly anyone has been able to use yet, and it's only through kind people posting footage that we can have any idea at all what's going on.

Graeme

Tom Roper · November 1st, 2004, 02:52 PM

Quote:

"or downconverted to progressive or interlaced PAL or NTSC quite well which a 30p format will not without extensive and expensive processing."

30p is just perfect for putting out anamorphic NTSC DVD's. Where 99.9% of everything I downconvert goes. As well JVC has been demo'ing HD10 footage converted to 25p in Europe using Edios software. Apparently it does a great conversion to PAL. But I live in NTSC land and regardless of what you say, it makes one heck of a NTSC DVD!

I don't think the JVC footage (from my HD1) downcoverts very well to NTSC DVD video because of the 30fps progressive 2:2 cadence results in excessive moire for many (U.S. mainly) DVD players.

The problem is not the 30fps progressive with 2:2 cadence format per se, but the fact that proper support for it in U.S. spec DVD players is so spotty. Players using the Faroudja deinterlacing chips in AUTO-2 mode, or Silicone Image chips will do fine, but among the others, it's hit and miss. Yes...the DVDs play, but when the player doesn't adapt to the 2:2 cadence or flags, the video displays excessive moire.

It's not a problem for PAL countries where progressive 2:2 cadence is common, and supported.

DVDs I make look fantastic on my DVD player (Faroudja), but borderline unsatisfactory on other players. It really does depend on the player itself. And since you don't know in advance which player your DVDs for distribution will be played on, you can't be certain that it will look its intended best on every showing.

I can't speak for the case of the FX1 because I haven't tried making an NTSC DVD from the video. But almost all U.S. spec. NTSC DVD players play any DVD movie with aplomb, because the vast majority of the DVDs are 24fps 480 interlaced movies. Almost every U.S. DVD player can be expected to properly play movie titles and support 24fps 480i, with conversion to progressive scan output and 3:2 pulldown.

That leads me to believe that the FX1 1080i interlaced video will convert to 480i NTSC with fewer artifacts and less moire, due to a conventional cadence, and the native output is interlaced.

Yiannis Kall · November 8th, 2004, 02:14 PM

the interlaced video is far more worse than the progressive. I have seen images from the my camera interlaced vs progressive and there is big difference on image quality. So i will wait for the next HDV camera from panasonic or form canon. The video quality of the new sony HDV is not so good at my 70' projector screen. The progressive video from my sony dv has more sharpeness than the interlaced video of sony HDV.
Dont buy it yet wait for the other companies HDV cams and the decide!

October 30th, 2004, 08:51 PM	#16
Ken Hodson Trustee Join Date: Aug 2003 Location: Vancouver BC Canada Posts: 1,315	For the FX1's specs read here http://videosystems.com/mag/video_sonys_hdv_debut/ "Sony developed a new 1/3in., Super HAD CCD for its HDV camcorders. Each CCD has 1,012 (horizontal) by 1,111 (vertical) elements (1,120,000 pixels) that provide an effective pixel count of 1,070,000 pixels (972 horizontal by 1,100 vertical. Vertical smear level is rated at a very low -107dB. Each element has a 2:1 aspect ratio." JVC HD10. I thought this was all common knowledge by now. There have been many posts discussed in these forums. The most technical info is probably this article. "The JVC chip provides 632,640 luma pixels (960?659 pixels)." http://www.findarticles.com/p/articles/mi_m0HFE/is_5_29/ai_102106333 __________________ Damnit Jim, I'm a film maker not a sysytems tech.

October 31st, 2004, 07:50 AM	#19
Graeme Nattress RED Problem Solver Join Date: Sep 2003 Location: Ottawa, Canada Posts: 1,365	I think what Ken is trying to get at is that the resolution of the CCD is not necessarily what gets recorded to tape, and even if the pixel resolution of the format is played back in full, that might not be accurate to the true resolution of the system. The only way tot really know is to measure test images, and even then, what do you do about moving shots which stress the MPEG2 compression?? In the end, it's going to be a subjective call. Graeme __________________ www.nattress.com - filters for FCP

October 31st, 2004, 07:40 PM	#21
Ken Hodson Trustee Join Date: Aug 2003 Location: Vancouver BC Canada Posts: 1,315	The mpeg2 compression will effect chroma sampling just as the DV codec did befor it. The FX1 will have an edge in colour resolution due to its 3 chip design, but not a big advantage in luma resolution. "(On that count, there was never a question from me that the FX1 is a giant leap ahead of the HD10.)" If interlaced image is a giant leap your welcome to it. I do envy the fully manual controlls though. __________________ Damnit Jim, I'm a film maker not a sysytems tech.

October 31st, 2004, 07:58 PM	#22
Graeme Nattress RED Problem Solver Join Date: Sep 2003 Location: Ottawa, Canada Posts: 1,365	I would think that yes, 1080i is a big leap over 720p30, which is about the worst frame rate there is. And perhaps the biggest leap (other than manual controls) is that the FX1 footage is not overly sharp like the permanent sharpness lines around everything on the HD10 and especially the HD1 which makes it look like high resolution VHS. And those sharpness lines are something that you can't do anything about in post, whereas 1080i can be very sucessfully de-interlaced or 24p converted, or downconverted to progressive or interlaced PAL or NTSC quite well, which a 30p format will not without extensive and expensive processing. However, 4:2:0 is ghastly on interlaced images, not that it's not ghastly anyway. Give me 4:1:1 over 4:2:0 any day. I'm going to have to code up a new 4:2:0 chroma reconstruction filter before I can do any kind of processing on HDV footage. Graeme __________________ www.nattress.com - filters for FCP

November 1st, 2004, 01:50 PM	#23
Ken Hodson Trustee Join Date: Aug 2003 Location: Vancouver BC Canada Posts: 1,315	"FX1 footage is not overly sharp like the permanent sharpness lines around everything on the HD10 " I do not find the HD10 footage to be like this at all. If anything for an HD image it is very soft. I don't know what you are thinking? "or downconverted to progressive or interlaced PAL or NTSC quite well which a 30p format will not without extensive and expensive processing." 30p is just perfect for putting out anamorphic NTSC DVD's. Where 99.9% of everything I downconvert goes. As well JVC has been demo'ing HD10 footage converted to 25p in Europe using Edios software. Apparently it does a great conversion to PAL. But I live in NTSC land and regardless of what you say, it makes one heck of a NTSC DVD! "However, 4:2:0 is ghastly on interlaced images" But works just fine in 720p thanks very much. I hope you enjoy massive render times befor you can colour correct that 4:2:0 as a deinterlaced image with any level of quality. __________________ Damnit Jim, I'm a film maker not a sysytems tech.

October 31st, 2004, 01:31 AM	#17
Tom Roper Trustee Join Date: Jun 2004 Location: Denver, Colorado Posts: 1,891	Ken, I accept the Steve Mullen article. I apologize for misinterpreting your statement also. The FX1 scales up from 960x1080(pixel shift), the HD10 resolves down to 960x659(luma/alias filters).

October 31st, 2004, 10:27 AM	#20
Tom Roper Trustee Join Date: Jun 2004 Location: Denver, Colorado Posts: 1,891	I agree Graeme, especially the second part about moving shots which stress mpeg2 compression. The camcorder is foremost a motion picture making device, the point being that a fine detail that goes unresolved in one frame due to the two column sliding filter of a single CCD device, does get resolved in the next frame by motion that shifts the fine details into adjacent columns. And that for either format(1CCD or 3CCD), what gets recorded to tape also might not be accurate to the true resolution of the system due to mpeg2 compression, as you stated. So, when talking about resolution, why not stick to the objective versus the theoretical? The one thing that we can define unequivocably is the actual element array of CCD sensors behind the lens that gathers the light. That is what we did before pixel counting articles by Steve Mullin raised our awareness of what you stated in the end, will be a subjective call anyway. (On that count, there was never a question from me that the FX1 is a giant leap ahead of the HD10.)

November 1st, 2004, 02:00 PM	#24
Graeme Nattress RED Problem Solver Join Date: Sep 2003 Location: Ottawa, Canada Posts: 1,365	4:2:0 does not relate to colour correction issues, but to more image manipulation issues, and in that respect affects 720p nearly as much as it effects 1080i. What I'm thinking about the sharpness is that it's permanently on, and it's visible as nasty edge enhancement, although much worse on the HD1 than the HD10. I don't see anything like that at all on the posted FX1 footage. As regards to interlaced and progressive, it's a darn site easier and faster to make interlaced progressive than progressive interlaced, so shooting 1080i60 is a lot more flexible in post, in that respect. But as you say, be prepared for render times. It's obviously preferable to shoot in whatever format you want to end up in, rather than have to go in and convert between them. I think the main issues with the HD10 are lack of manual controls, and it sounds like JVC will be adressing this before too long with their next camera. At that point, it will be "fair" to make some kind of comparison, but before then, you're comparing one obviously flawed (because it's the first of it's kind) camera with another that hardly anyone has been able to use yet, and it's only through kind people posting footage that we can have any idea at all what's going on. Graeme __________________ www.nattress.com - filters for FCP

November 8th, 2004, 02:14 PM	#26
Yiannis Kall Regular Crew Join Date: Nov 2004 Location: Greece-Athens Posts: 37	the interlaced video is far more worse than the progressive. I have seen images from the my camera interlaced vs progressive and there is big difference on image quality. So i will wait for the next HDV camera from panasonic or form canon. The video quality of the new sony HDV is not so good at my 70' projector screen. The progressive video from my sony dv has more sharpeness than the interlaced video of sony HDV. Dont buy it yet wait for the other companies HDV cams and the decide!