AC160 SD quality

S

sebastian

Active member
I've owned DVX100A over 8 years and now is time to upgrade...to AC160
3 questions:
1. What do we expect if we record 25p or 50i SD (DV) format with AC160? I mean picture quality compared to DVX100.
Sounds silly but sometimes I'm forced to record to SD. 16:9 footage with DVX100 is not very good because of 4:3 CCD sensors..
2. Maybe a little technical queston but how AC160 really captures/records SD video. Resizes from whole 3MOS sensor?
3. How about composite VIDEO-OUT compared to DVX100? Is there any difference in composite out quality if I shoot for exmple 576p or 1080p.

Sometimes I'm doing live feed from composite out (unfortunately cannot use SDI for that) and recording at the same time to edit this footage later.
Yet I'm not sure if VIDEO OUT is enabled during all recording modes (SD, 720p, 1080p)..
 
I use a USA standard
1) I don't record at that rate but at 60i SD is just as good as DVX100. perhaps a little better since the chip is newer with the ability to tweak the video profile.
2) yes it records an AVI file just like the files you edit with. I don't think it re-sizes anything. I think it just doesn't use all the chip(s) area.
3)video out is just a normal SD signal out. no black on either side. Should be no quality issues but, I don't think composite outputs any HD. So no I don't think video out is enabled during all modes. just SD.
Barry should have a better answer for you if I am wrong
 
Thanks ELN614
In this case there's no big difference if USA or European standard but I guess internal resizing is needed anyways - from 1080p to 576p or 1080p to 480p.
I've asked because DVX100 in 16:9 mode (without special 16:9 lens converter) uses only part of 4:3 CCD sensor's area, but in AC160 we have plenty of pixels to use.
Question is how good is this resizing.
Or AC160 uses only little part of 1920x1080 sensor's area to make SD? Which I doubt because lens is for 1/3" sensor and optical zoom ratings would be way off if less sensor area is used.
This would be like digital zoom in HD mode.

Video out yes.. it can't be any better than composite output can handle, not even near to HD. I'm just concerned that VIDEO OUT is not any worse than with my old DVX100.

There are hundreds of HD videos to download but couldn't find any native (recorded to DV format) SD footage from AC160.
 
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Barry or Jan will have to answer the question of how the SD image is made from the CMOS chip. Since the camera needs to reboot in order to switch between SD and HD I suspect it not a simple internal resizing.
I have never used the "video out" of this camera, but based on owning and using. I doubt you'll see a difference (on the negative side.)
 
I'm answering to my own question.
Yes, these is some difference in DV quality, especially in intelaced 16:9
DVX100 uses only part of it's 4:3 sensor, that's the reason I guess.
I've done some tests:

http://www.rossonex.com/Video/AC160/TestPattern.bmp
These are crops from bigger test pattern stiched together.

Another interesting question was: is it better to shoot stright to DV if client needs only DVD
or is it better to resize from HD footage. Knowing that resizing needs much more work and time
than converting SD to DVD files directly. However, there is some difference in quality.
Seems that AC160A in DV setting uses somekind of "unsharp mask"..
 
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sebastian said:
Another interesting question was: is it better to shoot stright to DV if client needs only DVD
or is it better to resize from HD footage. Knowing that resizing needs much more work and time
than converting SD to DVD files directly. However, there is some difference in quality.
Seems that AC160A in DV setting uses somekind of "unsharp mask"..
Click to expand...

Hi, I always shoot in HD and use TMPGenc to convert to DVD or mpg for all of my clients- it is superb and well worth the effort. I had a client ask me how I managed to get HD onto their training setup which was a std DVD player to a 52" HD screen. While I could see a difference between HD and SD they could not- so I would go the HD route and convert down. Hope this helps.
Cheers!
Rod
 
When I still had my AC-130's I did a test using all the formats and dumped the footage as MPEG2 SD files on a DVD and then compared them. It was almost impossible to tell between the formats BUT the SD was most definitely not as good as the HD format downconverted. Plus if you have all your source in HD it does give you the space to crop if you have to. In Sony Vegas I just let the timeline render from the timeline down to MPEG2 and get great results
 
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