Maximizing HD to SD Quality

[Perrone Ford]

Originally Posted by John Peterson

I added unsharp mask (medium strength) to the final output and I don't remember any in camera sharpening being set, but why all the aliasing if it is progressive all the way? There are pronounced horizontal interlacing lines on the video when displayed on a CRT.

John

I just checked. Picture profiles have been off since I bought the camera over a year ago. Doesn't that mean there is no "detail on"? Isn't that where the in camera sharpening would come from if it were turned on?

I will try those settings though. I guess the default settings for the camera produce this problem? Is that right? You must have a picture profile set in order to avoid aliasing in SD DVD even if it is progressive?

I don't know how you monitor, but I am not seeing what you're seeing. The only "faults" I can see is that the shutter speed used is maybe a bit slow, and there is way too much sharpening. Other than that, the video looks fine to me.

Is there any way you can get the original file to me somehow? Or just a second's worth of it?

-P

[Perrone Ford]

Originally Posted by John Peterson

You must have a picture profile set in order to avoid aliasing in SD DVD even if it is progressive?

Let me go try something...

[Perrone Ford]

Ok,

So I grabbed the camera, went around my building and shot a couple 1080/30p clips with the picture profile turned off.

SD Version here: http://www.vimeo.com/6287337

HD Version here: Alias_Twitter Test HD version on Vimeo

Download those and tell me what you see.

[John Peterson]

Originally Posted by Perrone Ford

Ok,

So I grabbed the camera, went around my building and shot a couple 1080/30p clips with the picture profile turned off.

SD Version here: Alias_Twitter Test SD Version on Vimeo

HD Version here: Alias_Twitter Test HD version on Vimeo

Download those and tell me what you see.

For both the SD and HD versions I downloaded the files and loaded them separately into Vegas projects. I matched project properties to the files themselves and changed the default deinterlace method to NONE.

I rendered each of the files to the default DVDA Mpeg2 widescreen video stream template at a CBR of 8000, DC Coefficient 10-Bit, Video Quality - 31,

Brought each into DVDA using a single movie Mpeg-2 720x480-60i, 16:9 (NTSC) template.
Burned each to a DVD and played it through a standard DVD player to a 27 inch CRT television.

Both exhibited severe aliasing with horizontal motion on all objects (especially vertical objects). Twitter was present. I didn't notice the chromatic ghosting I get though, but I think that is part of the aliasing problem.

I tried them on a Plasma TV and the aliasing was gone - replaced by "blurred" edges in the same places where there were aliased edges on the CRT TV.

Thanks for the help Perrone. I e-mailed you regarding sending you an mxf clip.

[Perrone Ford]

Can you monitor to that CRT without burning a DVD? I am curious at this point if you are having issues with the mpeg2 burn process or if the trouble is present BEFORE that compression is done.

Have you looked at these on more than one CRT?

[Jeff Kellam]

Originally Posted by John Peterson

I rendered each of the files to the default DVDA Mpeg2 widescreen video stream template at a CBR of 8000, DC Coefficient 10-Bit, Video Quality - 31,

John:

A direct cosine (DC) coefficient of 10 bit is not usually good. If it had any effect at all, it would exacerbate your exact problem. The DC coefficient only affects adjacent transitional macro block areas with a value greater than zero. 95% of macro blocks have a value of zero. The "Handbook of Image and Video Processing" is an excellent reference for figuring out how to set up the detailed rendering properties.

The only easy explanation I ever found was here:
Subdivision Into Macro Blocks - Review Tom's Hardware : Video Guide Part 3: Video Formats and Compression Methods

[John Peterson]

Originally Posted by Perrone Ford

Can you monitor to that CRT without burning a DVD? I am curious at this point if you are having issues with the mpeg2 burn process or if the trouble is present BEFORE that compression is done.

Have you looked at these on more than one CRT?

I can also see it on the external CRT monitor if I play those clips directly from the timeline. I have to look closely because it is only a 15 inch 4:3 monitor with an Aspect Ratio switch so it is pretty small and the scene moves really fast. Looks like a blurred edge if you don't study it very well,but it is in fact horizontal aliasing.

http://www.ggvideo.com/jvc_tmh150cgu.php

As far as another CRT TV, yes it shows up on all of them (via the DVDs). ith the DVDds I can slow-mo the video to see the horizontal aliasing better.

Are you saying that you don't see what I described on your JVC CRT monitor or on your CRT TV with those same files you gave me?

John

[Perrone Ford]

Originally Posted by John Peterson

Are you saying that you don't see what I described on your JVC CRT monitor or on your CRT TV with those same files you gave me?

John

All I am saying, is that other than the "sharpness" that appears added, I can't see anything on these that I don't see on other DVDs that have been creatd in-house or from other pro sources. BUT, I am not making mpeg2 files. I am just dropping them onto my timeline.

CRTs and Plasma/LCD do not render things the same way. They are progressive by nature. The CRT is going to interlace the footage whether we want it to or not because that is it's nature.

So I really can't say if what youa re seeing is expected and normal, or if it's something else. I suspect that because your issues disappear when you view on a plasma/lcd, that what you are seeing is pretty normal.

[Perrone Ford]

Originally Posted by John Peterson

I can also see it on the external CRT monitor if I play those clips directly from the timeline. I have to look closely because it is only a 15 inch 4:3 monitor with an Aspect Ratio switch so it is pretty small and the scene moves really fast. Looks like a blurred edge if you don't study it very well,but it is in fact horizontal aliasing.

JVC TM-H150CGU 15-Inch High Resolution Color Monitor

This is what I have:
JVC TM-H1900GU 19-Inch Color Monitor (but in 17") Just checked.

Regardless, I may be seeing what you are, but just not as sensitive. How far from the TV are you when viewing this stuff?

[John Peterson]

Originally Posted by Perrone Ford

This is what I have:
JVC TM-H1900GU 19-Inch Color Monitor (but in 17") Just checked.

Regardless, I may be seeing what you are, but just not as sensitive. How far from the TV are you when viewing this stuff?

Four feet from the TV. The editing monitor is right next to me of course.

I guess I am being too fussy, but I am directly comparing it to the SD DVDs I was producing with my VX2000.

I would really like to be certain that there isn't something wrong with the camera itself as I have a three year extended warranty and it has never been in for service since I bought it in June 2008. It hasn't had that much use though.

If you could look at the two .mxf clips that I sent you whenever you have the time (that I created from the original BPAV folders) this videographer would be truly grateful. Let me know if there appears to be something wrong with the camera. They are 1080/30p with ATW and no profiles. Pretty much all default except for the progressive mode.

John

[Perrone Ford]

I looked at the first one. I am going to look at the second one here in a minute. Got an emergency 3 DVD copy job handed to me at 4:15!!! GRrrrr!

[John Peterson]

Originally Posted by Jeff Kellam

John:

A direct cosine (DC) coefficient of 10 bit is not usually good. If it had any effect at all, it would exacerbate your exact problem. The DC coefficient only affects adjacent transitional macro block areas with a value greater than zero. 95% of macro blocks have a value of zero. The "Handbook of Image and Video Processing" is an excellent reference for figuring out how to set up the detailed rendering properties.

The only easy explanation I ever found was here:
Subdivision Into Macro Blocks - Review Tom's Hardware : Video Guide Part 3: Video Formats and Compression Methods

Thanks Jeff,

I'll change it back to the default value of 9-bit.

John

[Perrone Ford]

Originally Posted by John Peterson

Are you saying that you don't see what I described on your JVC CRT monitor or on your CRT TV with those same files you gave me?

Second clip, telephone lines... twitter galore. Aliasing on the telephone pole.

So, I added just a touch of gaussian blur and the twitter stopped and the pole cleaned up a bit. If this MXF is straight out of the camera, then you've got the detail settings in that thing JACKED up.

Do you have access to the camera right now?

[John Peterson]

Originally Posted by Perrone Ford

Second clip, telephone lines... twitter galore. Aliasing on the telephone pole.

So, I added just a touch of gaussian blur and the twitter stopped and the pole cleaned up a bit. If this MXF is straight out of the camera, then you've got the detail settings in that thing JACKED up.

Do you have access to the camera right now?

Yes, I do.

Thanks,
John

[Perrone Ford]

Ok, go make a picture profile like the one I linked you too. I have a bunch in my camera but the one I pointed you too should be a great place to start, and should prevent what you are seeing in this footage. Your camera is not broken, it just has the default settings which really aren't that great.