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    Artifacting with Recently Repaired XL2
    #1
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    I shot some footage last weekend in a cyc studio and one clip in particular exhibits bad artifacting; for the life of me I don't know why. I just had this XL2 repaired at Canon (back focus), but they were supposed to have gone over the entire camera.

    http://img831.imageshack.us/img831/7...tifacting1.jpg

    Does anyone know the possible cause of this artifacting and if it can be addressed? I have a few takes of the same scene, but all exhibit the identical problem.

    Any help would be tremendously appreciated.

    Thanks in advance,

    Steve M.


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    #2
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    What software are you using to edit and how was that screenshot taken?

    What mode did you shoot in?

    It looks like either you used a low quality deinterlacer , or didn't interpret the footage correctly (e.g. pulldown removal for progressive modes)


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    Hi PDR,

    I'm using Sony Vegas Version 5.0...yes I know they're up to version 10 already; I am unable to use version 9 or above on this machine as its resource taxing architecture caused a blue-screen and I'm not chancing using it again. That said, Vegas 5.0 still does essentially what I need for SD.

    I shot on the XL2 @ 60i/16:9. Thereís no progressive pull-down with which to contend and Iím confused as to why the footage looks so abysmal. I captured and saved the still from the Vegas timeline in Ďbestí resolution.

    The odd thing is that the playback on my production monitor at the shoot looked fine and playback directly from the XL2 to a 50Ē plasma looks passable as well. I realize I probably pushed the XL2 a bit far in the cyc enviroment with the stark solid colors and background, but I donít think the footage should look this poor. I am concerned about the possibility of my XL2 being improperly adjusted by Canon as Iíd shot in this identical environment previously. Although the footage wasnít as crisp as Iíd like it to be (you may recall my issue with resizing), it didnít display aberrations on par with this. I should also mention that the original back-focus problem was not resolved on Canonís first attempt; I had to drive over 200 round trip miles a second time to get it repaired properly. While I only required a back-focus adjustment, Canon charged me for a full, factory stem-to-stern checkup at $400.00; I donít know whether they tinkered with any settings or circuitry within the camera during the cameraís two visits there.

    Additionally, the original un-altered .avi when played back in WMP looks passable as well; thereís some minor color banding, but nothing like that seen in the V5 timeline. In fact, I tried to render a sample .avi (uncompressed) from the V5 timeline to upload for analysis by other forum members and it looked equally horrible to the still capture.

    It has been suggested that the XL2ís sub 4:2:2 color sampling may be culpable in this scenario by members of the Sony Vegas forums. I am confounded by this anomaly and I donít know whether my capture, the recently repaired XL2 or Sony Vegas is the problem.
    I hope you can offer some insight.

    Thanks again!

    Steve M.


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    The original AVI looks "passable" in WMP, and from the camera directly , because there is deinterlacing on the fly in software or by the TV monitor . The end quality you get depends on the quality of the processing. Some higher end equipment have better interpolation, some do other techniques like line doubling (I'm referring to progressive displays like LCD, plasma) . The only display where interlaced content looks good is a CRT.

    Vegas' deinterlacing quality is horrible, but that shouldn't matter for you if you output an interlaced format (e.g. DVD) . It's basically doing a drop field deinterlace for the screenshot (discards 1 field, and resizes the field) . If you were looking at frames (not fields) you would see combing

    If you were aiming for a progressive output (e.g. web delivery, youtube etc...) , you should use a better deinterlacer. Avisynth offers much higher quality deinterlacers

    If you can post a sample clip to a free hosting site (e.g. mediafire.com) , I can check to see if there is anything else wrong with the clip


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    Hallo Steve,

    The problem is that you shot in 60i and not 24p (or at lest analyze in progressive, while the source is interlaced). 60i means that you have halve the vertical resolution per frame (240p instead of 480p), but double the frames. The de-interlacing is the culprit, but if you need a progressive movie, shoot in progressive mode - there is no better way. The frames you captured is only halve the image (because it's 60i). This explains why it looks good in playback (from the source), but not the frame. You should basically capture 2 frames and combine them to see the "real image" on an interlaced screen (de-interlace). On a progressive screen, you have a problem. Vegas is not to blame. I use FCP and it's the same if I capture a single frame.

    I don't think there is anything wrong with your camera or software. It's just that you should shoot it in progressive (480p). I use the XL2 a lot and don't use interlaced at all because the image quality is too bad for progressive display. In progressive mode, the image is amazing (though I have a PAL version 576p - almost a hundred lines more).

    Hope this helps

    Peet.


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    Peet, Thanks for responding. I must disagree however with your suggestion to shoot in 30p. The footage I’ve acquired is for an exercise video (significant movement) destined for DVD (interlaced format); 60i is the only option unfortunately. It seems that the XL2 does not perform well at 60i and knowing what I now know, I probably should have made a better choice when I made the purchase back in 2007.

    PDR - thanks as always for your input. BTW, forgive the alternate nickname (I was unable to recall my password; my e-mail did not receive the password reset message and I had to re-sign on this forum as a new user log on).
    I'm utterly confused with the XL2 problems I’m having; I should have stuck with Sony!!! The issue I’d mentioned above I can live with, but a newer issue

    I’ve discovered with the 2 days worth of footage I’ve shot has me in a bit of a panic.
    I shot about 8 hours worth of footage on 2 separate days prior to Canon’s factory back-focus repair. While I was disappointed with the overall quality of the 60i footage, it was acceptable (however not stellar) and I edited it for DVD. As I mentioned, I had Canon repair a back-focus problem with the barely-used XL2, which required two round trips to their NJ facility plus $400.00 to remedy. I brought a field monitor and focus chart with me when I picked up the camera on the 2nd attempt to absolutely confirm the repair was properly executed; it seemingly was.
    Three weeks later, I used the repaired camera for 2 days worth of shooting in a rented cyc studio and everything appeared synonymous with the original (pre-repair) footage on my field CRT monitor as I shot and reviewed it. I’ve taken some time away from the project and only recently commenced uploading and editing the post-repair clips in Vegas 5.

    The first indication of a problem emerged when I needed to acquire a still from the timeline. I set the preview quality to “best”, moved the timeline cursor to the set point and I noticed that I was unable to get a clean still. I scratched my head for a minute then I tried right-clicking the clip and setting its field order to “progressive scan.” Upon changing the field order I was able to grab a clean screen still. I’ve never experienced this issue before with the XL2 or any of the Sony cameras I’ve used over the years.

    Concerned, I restored the field order to “lower field first” and rendered out a portion of the segment as an MPEG-2. My fear was realized when I saw that the clip appeared “fuzzy” on playback on the PC. I also rendered the same portion of the segment with the field order set to “progressive scan” and on PC playback it appears noticeably sharper. I went ahead and authored some clips to DVD – several progressive, several lower field first. The progressive clips appear clear on DVD playback, but exhibit the missing fields and cannot be used as such. The interlaced clips appear less clear “confused” as if the fields are somehow misaligned.

    I spent 2 hours on the phone with Canon trying to get an answer as to why this problem now exists when it hadn’t previously. They are only willing to have the camera shipped for inspection or place blame upon anything but the camera or their inept technicians. I am extremely worried about this issue as many of the affected clips are unusable in this “confused” state.

    I don’t shoot video on a daily basis, but I’ve shot and produced quite a few videos over the years and I’ve never experienced this problem or anything like it with the Sony’s I’ve owned and used – PD-150, 250, and rented several 450’s as well. Below are 2 links to uploaded segments: the first is progressive scan and the second is lower field first. None of the clips from the early part of this shoot exhibit this issue and I have no idea what could be the cause. Perhaps you may have some idea?


    Thanks as always,
    Steve M.
    Last edited by Steve Marshall1; 12-22-2010 at 11:12 PM.


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