Why is 1080i listed ? at DVinfo.net

Paul Pelalas · February 20th, 2006, 12:46 AM

Why is 1080i listed in the playback specs for the HD100. Am I reading this chart incorrectly ? http://pro.jvc.com/pro/attributes/HD...-hd100_faq.pdf

Robert M Wright · February 20th, 2006, 01:41 AM

It is listed, because the HD100U can output a 1080i signal through component out, during playback. It is converting the 720p recording to 1080i when it does this (to play on monitors with 1080i native resolution).

Constantin Marin · February 20th, 2006, 01:44 AM

Quote:

Originally Posted by Paul Pelalas

Why is 1080i listed in the playback specs for the HD100. Am I reading this chart incorrectly ? http://pro.jvc.com/pro/attributes/HD...-hd100_faq.pdf

1080i means that you can playback a tape recorded in HDV format (720p) and downconvert the signal on the component output to 1080i. In this mode you can eliminate the judder caused by the progressive capture.

Robert M Wright · February 20th, 2006, 01:56 AM

Unless I am completely mistaken, converting 720p source to 1080i output will not eliminate judder. The temporal resolution is still 30fps.

Paul Pelalas · February 20th, 2006, 02:28 AM

Can the 1080i output be recorded ? Would there be any benefit or difference than to converting to 1080i in post, if you wanted to convert to 1080i some clips ?

Robert M Wright · February 20th, 2006, 03:22 AM

I can't really think of any benefit to converting 720p to 1080i in post, unless maybe you were trying to tweek it a little, specifically to display on a 1080i native res monitor/tv. No matter how well it is done, there will always be some degree of degradation when resizing an image.

Robert M Wright · February 20th, 2006, 03:23 AM

Paul -

May I ask, are you considering purchasing a high definition camcorder?

Paul Pelalas · February 20th, 2006, 04:12 AM

Why yes I am considering a High Def cam purchase, can you tell ? Actually, this week I should be placing an order for an HD100. Like any camera purchase I have ever made, I have tryed out the camera, and the others in the same category, I have read, then reread, then reread again, any report, comment, test results, personal and corporate opinions of the products, and viewed as much footage as I possibly could until it was information overload.
After all that I considered the type of work I do, the pros and cons of the workflows of each camera, the look and feel and build of the cameras, the JVC seemed to fit into my workflow.
The reason I had the 1080i question, is that it seems like though I prefer 720p, there may be some clients who want 1080i. Rather than converting , I thought that the component outputs where a live 1080i feed, which is wrong. Like you said it's from playback. So the 1080i feed is of the tape, therefore its of the footage which has been compressed.

Laszlo Horvath · February 20th, 2006, 06:38 AM

Quote:

Originally Posted by Paul Pelalas

Why is 1080i listed in the playback specs for the HD100. Am I reading this chart incorrectly ? http://pro.jvc.com/pro/attributes/HD...-hd100_faq.pdf

1080i component output is only for playback on "1080i only" monitors.
Like my Panasonic 26" tube HDTV which is only 1080i. But the HD100's 720p footages are horrible on this otherwise great TV.
Now I have a 26" LCD.
Laszlo

Robert M Wright · February 20th, 2006, 06:56 AM

I definitely got the impression you have an interest in high definition video, and might be considering the purchase of an HDV camera.

It sounds like you are working hard, to try to get a clearer understanding of the difference between progressive and interlaced video, frame rates and resolutions. It can get a little confusing, especially the way the terms are presented at times.

The HD100U, in HDV mode, shoots only progressive video. That means it is going to acquire entire frames (every line) at once, regardless of how it is actually recorded (using compression or not).

You can record (encode) progressive frames in an interlaced format (the Panasonic DVXs do that, because there actually is no NTSC DV progressive format defined - movies shot with film are prepared for NTSC television broadcast in a similar manner, because NTSC is not a progressive broadcast format), yet it is still progressive in nature because the camera acquires every line of each frame at once, just like a movie camera does, and every line does get recorded.

To record (or broadcast) video using NTSC standards, it has to be 30fps or less, because NTSC has only 60 half frames, by definition. If you wanted to take 60fps progressive video and record or broadcast as NTSC video, then you truly have to convert it to interlaced video, by throwing out half the video information (every other line in each frame). Once you do that, it can't be fully reconstructed, because information has be discarded.

NTSC video is sometimes described as being 30 frames per second, divided into half frames. That is very misleading. True NTSC video, acquired as standard NTSC video with a standard NTSC video camera, is 60 separate half frames acquired in a second. The half frames are separate because they were acquired at separate times, and that is not the same as 30 full frames each acquired at once (like a movie camera's 24), in a second, and then just magically divided in half.

The HD100U records to tape in a progressive format (HDV-720/30p, or in 720/24p, which is very similar, but not officially an HDV standard).

HDTV 720p is not 720/30p or 720/24p. HDTV 720p is 720/60p. If you look at that chart you first posted in this thread, you can see that the HD100U can output a 720/60p signal through component out also. That is for compatibility with HDTVs (just like the 1080i output signal option is).

How a camera acquires video, how video is recorded, and how video is displayed on a TV or a monitor, are three separate things.

Robert M Wright · February 20th, 2006, 07:07 AM

Laslo -

Can you get ABC or Fox HDTV broadcasts ok on your Panasonic tube HDTV?
When you played the HD100 720p video on your Panasonic tube HDTV, did you output it from the camcorder as 720p or as 1080i?

Laszlo Horvath · February 20th, 2006, 08:50 AM

Quote:

Originally Posted by Robert M Wright

Laslo -

Can you get ABC or Fox HDTV broadcasts ok on your Panasonic tube HDTV?
When you played the HD100 720p video on your Panasonic tube HDTV, did you output it from the camcorder as 720p or as 1080i?

When you watch ABC's Fox's 720P/60 broadcost on this 1080i TV, everything is fine.
The only different is the component input on the TV. It's only accept 1080i input. So on the HD100 you need adjust the component output in the Menu to 1080i, otherwise you can't see anything. But again the HD100's 720p footage is very wierd on this TV's 1080i input. That's why I put back to the box (as of right now sitting in my basement. Brand new TV, it's a shame) and I purchesed the 26" Sony Bravia LCD

Laszlo

Sean McHenry · February 20th, 2006, 09:21 AM

One reason to use the 1080i component output - we tape a major PBS production here at my day job in HD. We had been renting several Sony 900s for the show but decided, since we have 2 of the JVC HD100 cameras we are now using the 1080i component output, converting to SDI-HD at 1080i and recording them live in studio to Sony HD decks. These have replaced a very expensive rental for us. We don't use them on critical shots but, to maintain the HD integrity of the process throughout or post process, we use it on an overhead camera shot.

I would say a handful of these shooting as studio cameras only, not using the on board decks, makes good use of the 1080i output option. With a little color correction to get them to match our Sony's, our editor has had nothing but good things to say about using them as alternate cameras.

Sean McHenry

Robert M Wright · February 20th, 2006, 12:08 PM

I'm curious to know if anyone else is experiencing difficulties, playing back from tape on a HD100U to a native 1080i display, like Laszlo did with his Panny tube HDTV.

Robert M Wright · February 20th, 2006, 12:23 PM

Sean - Am I understanding correctly that you are in essence capturing 720/60p direct from the heads with the HD100U, and converting to 1080/60i output (on camera conversion to 1080i)? (Some might not realize that is not the same as converting from 720/30p, by playing back an HD100U HDV recording from tape.) I wonder how that would compare to capturing 1080i (via SDI) straight from the heads of a Canon XL-H1. My thinking is that it would be real close, with the same temporal resolution, the HD100U providing more horizontal resolution and the XL-H1 yielding more vertical resolution.

February 20th, 2006, 12:46 AM	#1
Paul Pelalas Regular Crew Join Date: Aug 2004 Location: New Jersey USA Posts: 41	Why is 1080i listed ? Why is 1080i listed in the playback specs for the HD100. Am I reading this chart incorrectly ? http://pro.jvc.com/pro/attributes/HD...-hd100_faq.pdf

February 20th, 2006, 09:21 AM	#13
Sean McHenry Trustee Join Date: Mar 2004 Location: Hilliard, Ohio Posts: 1,193	One reason to use the 1080i component output - we tape a major PBS production here at my day job in HD. We had been renting several Sony 900s for the show but decided, since we have 2 of the JVC HD100 cameras we are now using the 1080i component output, converting to SDI-HD at 1080i and recording them live in studio to Sony HD decks. These have replaced a very expensive rental for us. We don't use them on critical shots but, to maintain the HD integrity of the process throughout or post process, we use it on an overhead camera shot. I would say a handful of these shooting as studio cameras only, not using the on board decks, makes good use of the 1080i output option. With a little color correction to get them to match our Sony's, our editor has had nothing but good things to say about using them as alternate cameras. Sean McHenry __________________ ‘I don’t know what I’m doing, and I’m shooting on D.V.’ - my hero - David Lynch http://www.DeepBlueEdit.com

February 20th, 2006, 01:41 AM	#2
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	It is listed, because the HD100U can output a 1080i signal through component out, during playback. It is converting the 720p recording to 1080i when it does this (to play on monitors with 1080i native resolution).

February 20th, 2006, 01:56 AM	#4
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	Unless I am completely mistaken, converting 720p source to 1080i output will not eliminate judder. The temporal resolution is still 30fps.

February 20th, 2006, 02:28 AM	#5
Paul Pelalas Regular Crew Join Date: Aug 2004 Location: New Jersey USA Posts: 41	Can the 1080i output be recorded ? Would there be any benefit or difference than to converting to 1080i in post, if you wanted to convert to 1080i some clips ?

February 20th, 2006, 03:22 AM	#6
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	I can't really think of any benefit to converting 720p to 1080i in post, unless maybe you were trying to tweek it a little, specifically to display on a 1080i native res monitor/tv. No matter how well it is done, there will always be some degree of degradation when resizing an image.

February 20th, 2006, 03:23 AM	#7
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	Paul - May I ask, are you considering purchasing a high definition camcorder?

February 20th, 2006, 04:12 AM	#8
Paul Pelalas Regular Crew Join Date: Aug 2004 Location: New Jersey USA Posts: 41	Why yes I am considering a High Def cam purchase, can you tell ? Actually, this week I should be placing an order for an HD100. Like any camera purchase I have ever made, I have tryed out the camera, and the others in the same category, I have read, then reread, then reread again, any report, comment, test results, personal and corporate opinions of the products, and viewed as much footage as I possibly could until it was information overload. After all that I considered the type of work I do, the pros and cons of the workflows of each camera, the look and feel and build of the cameras, the JVC seemed to fit into my workflow. The reason I had the 1080i question, is that it seems like though I prefer 720p, there may be some clients who want 1080i. Rather than converting , I thought that the component outputs where a live 1080i feed, which is wrong. Like you said it's from playback. So the 1080i feed is of the tape, therefore its of the footage which has been compressed.

February 20th, 2006, 06:56 AM	#10
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	I definitely got the impression you have an interest in high definition video, and might be considering the purchase of an HDV camera. It sounds like you are working hard, to try to get a clearer understanding of the difference between progressive and interlaced video, frame rates and resolutions. It can get a little confusing, especially the way the terms are presented at times. The HD100U, in HDV mode, shoots only progressive video. That means it is going to acquire entire frames (every line) at once, regardless of how it is actually recorded (using compression or not). You can record (encode) progressive frames in an interlaced format (the Panasonic DVXs do that, because there actually is no NTSC DV progressive format defined - movies shot with film are prepared for NTSC television broadcast in a similar manner, because NTSC is not a progressive broadcast format), yet it is still progressive in nature because the camera acquires every line of each frame at once, just like a movie camera does, and every line does get recorded. To record (or broadcast) video using NTSC standards, it has to be 30fps or less, because NTSC has only 60 half frames, by definition. If you wanted to take 60fps progressive video and record or broadcast as NTSC video, then you truly have to convert it to interlaced video, by throwing out half the video information (every other line in each frame). Once you do that, it can't be fully reconstructed, because information has be discarded. NTSC video is sometimes described as being 30 frames per second, divided into half frames. That is very misleading. True NTSC video, acquired as standard NTSC video with a standard NTSC video camera, is 60 separate half frames acquired in a second. The half frames are separate because they were acquired at separate times, and that is not the same as 30 full frames each acquired at once (like a movie camera's 24), in a second, and then just magically divided in half. The HD100U records to tape in a progressive format (HDV-720/30p, or in 720/24p, which is very similar, but not officially an HDV standard). HDTV 720p is not 720/30p or 720/24p. HDTV 720p is 720/60p. If you look at that chart you first posted in this thread, you can see that the HD100U can output a 720/60p signal through component out also. That is for compatibility with HDTVs (just like the 1080i output signal option is). How a camera acquires video, how video is recorded, and how video is displayed on a TV or a monitor, are three separate things.

February 20th, 2006, 07:07 AM	#11
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	Laslo - Can you get ABC or Fox HDTV broadcasts ok on your Panasonic tube HDTV? When you played the HD100 720p video on your Panasonic tube HDTV, did you output it from the camcorder as 720p or as 1080i?

February 20th, 2006, 12:08 PM	#14
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	I'm curious to know if anyone else is experiencing difficulties, playing back from tape on a HD100U to a native 1080i display, like Laszlo did with his Panny tube HDTV.

February 20th, 2006, 12:23 PM	#15
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	Sean - Am I understanding correctly that you are in essence capturing 720/60p direct from the heads with the HD100U, and converting to 1080/60i output (on camera conversion to 1080i)? (Some might not realize that is not the same as converting from 720/30p, by playing back an HD100U HDV recording from tape.) I wonder how that would compare to capturing 1080i (via SDI) straight from the heads of a Canon XL-H1. My thinking is that it would be real close, with the same temporal resolution, the HD100U providing more horizontal resolution and the XL-H1 yielding more vertical resolution.