What is this problem? at DVinfo.net

Juni Zhao · October 23rd, 2007, 04:16 PM

http://channeldv.com/public/uncompressed.JPG

This picture was taken from an HDTV screen that was hooked directly from my A1. I used 60i SD and annoyed by the jagged lines. I tried a Sony Z1, almost the same problem. I just wonder if this is the way it is, or something wrong?

Boyd Ostroff · October 23rd, 2007, 06:23 PM

That looks pretty bad to me. However, if I had to guess I'd say the HDTV isn't doing a very good job of scaling the image up to HD resolution. SD material looks pretty bad on my HD LCD screens also. Remember, you only have 720x480 (or 720x576 PAL) pixels to work with. The TV needs to enlarge that to 1920x1080 (or whatever the native resolution is). Since those numbers don't divide evenly there are always some scaling artifacts.

Aside from that, I haven't been all that impressed by the quality of my Z1 when shooting in SD mode. It looks better to my eyes when shooting HDV and downconverting via firewire when capturing.

Richard Hunter · October 24th, 2007, 08:24 AM

What is the resolution of the TV screen? If it is 1366x768 then it could be taking your 1080i video, deinterlacing by discarding one field, which gets it to 540p, and then upscaling to 720p. This would result in artifacts such as the ones you are seeing, although I have to say these are very rough.

Richard

Eric Weiss · October 24th, 2007, 09:33 AM

It's because it is SD content.

Shoot HDV and try it or go into the TV menu area and select
one of the SD display options.

Juni Zhao · October 24th, 2007, 11:03 AM

Quote:

Originally Posted by Richard Hunter

What is the resolution of the TV screen? If it is 1366x768 then it could be taking your 1080i video, deinterlacing by discarding one field, which gets it to 540p, and then upscaling to 720p. This would result in artifacts such as the ones you are seeing, although I have to say these are very rough.

Richard

The TV is just a regular plasma 42" 1080i, so I assume it's 1920x1080. The thing is: when it plays regular commercial DVD it's just nice and smooth. I don't get why there is such a difference....

Juni Zhao · October 24th, 2007, 11:06 AM

OK, I just tried hooking up to an old CRT TV, the result is the same, and I tried a commercial DVD it showed smooth picture.....

Rob Stoner · October 24th, 2007, 11:14 AM

how are you connecting the a1 to the tv? i believe that the only way to get true hd qualty video out of the camera is to hook it up to the tv via component cables rather than the bnc cable. just a thought.

Eric Weiss · October 24th, 2007, 11:19 AM

That's unfortunate.

I've stated many times that SD on the A1 is next to useless.

I wouldn't worry about it too much, most people won't be looking at the lines
with the race cars zooming around. Just shoot HDV in the future and downconvert. You will get a better picture.

Juni Zhao · October 24th, 2007, 12:20 PM

Yes you are absolutely right Eric, I concluded that SD (A1 as well as Z1) is pretty crappy too. Most of the times I can bring the footage back to my digital studio to do editing, but some other times clients just want the tape with SD footage right on the spot, in this case I have to shoot SD. Although I never got any complaints, I just feel unhappy with the artifacts rendered by A1 SD......

Juni Zhao · October 24th, 2007, 12:25 PM

Oh by the way, do you shoot HDV in 60i, 30f, or 24f?
People constantly say that 24p is more filmic, but through my testing the filmic look comes from right exposure, right luminance, and all the color configurations, nothing to do with frame rate or the way of scan. But it's just my personal opinion...

Petri Kaipiainen · October 24th, 2007, 12:39 PM

Why do you say SD on A1 is crappy? To me it looks much better than any prosumer SD cam I have worked with. We are doing almost all our shooting at 16:9 SD with XH-A1 and no client has complaned yet. Actually we are getting clients used to having digibeta originals.

Steven Dempsey · October 24th, 2007, 01:22 PM

Quote:

Originally Posted by Eric Weiss

That's unfortunate.

I've stated many times that SD on the A1 is next to useless.

I wouldn't worry about it too much, most people won't be looking at the lines
with the race cars zooming around. Just shoot HDV in the future and downconvert. You will get a better picture.

I just cannot agree with this. I have shot many projects using SD 30f and the picture is wonderful.

Philip Williams · October 24th, 2007, 01:35 PM

Quote:

Originally Posted by Juni Zhao

The TV is just a regular plasma 42" 1080i, so I assume it's 1920x1080. The thing is: when it plays regular commercial DVD it's just nice and smooth. I don't get why there is such a difference....

It should be noted that commercial DVDs are typically encoded with 24P content and are displayed as progressive frames. Upscaling a progressive image on a 1080i set is likely to provide a superior picture than upscaling an interlaced standard definition picture.

Not saying this to "excuse" the A1 per se, but it is important to note that comparing SD/60i to SD/24P footage on your television is similar to comparing apples and pears.

Juni Zhao · October 24th, 2007, 01:39 PM

Quote:

Originally Posted by Petri Kaipiainen

Why do you say SD on A1 is crappy? To me it looks much better than any prosumer SD cam I have worked with. We are doing almost all our shooting at 16:9 SD with XH-A1 and no client has complaned yet. Actually we are getting clients used to having digibeta originals.

Well this is what my thread is all about. Please take a look at my picture. I am trying to find out why it looked so rough. Again, I didn't do any compression, I just shot in 16:9 SD 60i, then hooked up directly to the TV. I used RCA cables though, I don't think the cable is responsible.

Philip Williams · October 24th, 2007, 01:42 PM

Quote:

Originally Posted by Juni Zhao

I used RCA cables though, I don't think the cable is responsible.

Mmmm... you don't mean the composite video ouput that sends the video out over the yellow RCA cable right? I must have missunderstood, long day...

October 23rd, 2007, 04:16 PM	#1
Juni Zhao Regular Crew Join Date: May 2007 Location: North Andover, Ma Posts: 102	What is this problem? http://channeldv.com/public/uncompressed.JPG This picture was taken from an HDTV screen that was hooked directly from my A1. I used 60i SD and annoyed by the jagged lines. I tried a Sony Z1, almost the same problem. I just wonder if this is the way it is, or something wrong?

October 23rd, 2007, 06:23 PM	#2
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	That looks pretty bad to me. However, if I had to guess I'd say the HDTV isn't doing a very good job of scaling the image up to HD resolution. SD material looks pretty bad on my HD LCD screens also. Remember, you only have 720x480 (or 720x576 PAL) pixels to work with. The TV needs to enlarge that to 1920x1080 (or whatever the native resolution is). Since those numbers don't divide evenly there are always some scaling artifacts. Aside from that, I haven't been all that impressed by the quality of my Z1 when shooting in SD mode. It looks better to my eyes when shooting HDV and downconverting via firewire when capturing.

October 24th, 2007, 08:24 AM	#3
Richard Hunter Trustee Join Date: Dec 2004 Location: Lipa City Batangas, Philippines Posts: 1,110	What is the resolution of the TV screen? If it is 1366x768 then it could be taking your 1080i video, deinterlacing by discarding one field, which gets it to 540p, and then upscaling to 720p. This would result in artifacts such as the ones you are seeing, although I have to say these are very rough. Richard

October 24th, 2007, 09:33 AM	#4
Eric Weiss Major Player Join Date: Mar 2007 Location: Philly,PA Posts: 360	It's because it is SD content. Shoot HDV and try it or go into the TV menu area and select one of the SD display options.

October 24th, 2007, 11:06 AM	#6
Juni Zhao Regular Crew Join Date: May 2007 Location: North Andover, Ma Posts: 102	OK, I just tried hooking up to an old CRT TV, the result is the same, and I tried a commercial DVD it showed smooth picture.....

October 24th, 2007, 11:14 AM	#7
Rob Stoner Regular Crew Join Date: Sep 2007 Location: Milwaukee, Wisconsin Posts: 50	how are you connecting the a1 to the tv? i believe that the only way to get true hd qualty video out of the camera is to hook it up to the tv via component cables rather than the bnc cable. just a thought.

October 24th, 2007, 11:19 AM	#8
Eric Weiss Major Player Join Date: Mar 2007 Location: Philly,PA Posts: 360	That's unfortunate. I've stated many times that SD on the A1 is next to useless. I wouldn't worry about it too much, most people won't be looking at the lines with the race cars zooming around. Just shoot HDV in the future and downconvert. You will get a better picture.

October 24th, 2007, 12:20 PM	#9
Juni Zhao Regular Crew Join Date: May 2007 Location: North Andover, Ma Posts: 102	Yes you are absolutely right Eric, I concluded that SD (A1 as well as Z1) is pretty crappy too. Most of the times I can bring the footage back to my digital studio to do editing, but some other times clients just want the tape with SD footage right on the spot, in this case I have to shoot SD. Although I never got any complaints, I just feel unhappy with the artifacts rendered by A1 SD......

October 24th, 2007, 12:25 PM	#10
Juni Zhao Regular Crew Join Date: May 2007 Location: North Andover, Ma Posts: 102	Oh by the way, do you shoot HDV in 60i, 30f, or 24f? People constantly say that 24p is more filmic, but through my testing the filmic look comes from right exposure, right luminance, and all the color configurations, nothing to do with frame rate or the way of scan. But it's just my personal opinion...

October 24th, 2007, 12:39 PM	#11
Petri Kaipiainen Major Player Join Date: Apr 2007 Location: Espoo Finland Posts: 380	Why do you say SD on A1 is crappy? To me it looks much better than any prosumer SD cam I have worked with. We are doing almost all our shooting at 16:9 SD with XH-A1 and no client has complaned yet. Actually we are getting clients used to having digibeta originals.