Forum Archive Home -> Camcorders (DV/HDV/AVCHD) -> Cropping "Letterbox" Problem
Cropping "Letterbox" Problem | ||
| KatCassidy posted 2007 May 09 06:29 | ||
| We've been recording a lot of video to the computer from a Canopus ADVC-110 using Premiere Pro 1.5. The output files are all DV in AVI format.It's mainly 4:3 but also have some 16:9 video. The problem is as such:
When we send the final AVI into Auto GordianKnot for compression to XviD it has all the original black borders. On 4:3 this is several pixels on each side (left, right, top and bottom) but really causes problems with 16:9 as we get the "Letterbox" effect - large black bars at the top and bottom. If we compress the DV AVI to MPEG 2 (.mpg) AGK then crops it correctly. This, however, adds a large wasted time to how long the whole project takes. Note: We are using AGK v2.20 as it has been the only version we have found thet always produces files at our desired size with exceptional quality. Technical note: PAL video. All of our captures are 720x576. When compressing to XviD Our 16:9 videos should be 720x400 (or 720x416) but are coming out at 720x544 in a 4:3 letterbox. | ||
| manono posted 2007 May 09 07:10 | ||
| Hi-
AutoGK doesn't crop AVI sources, except maybe a little bit to keep the AR when resizing. Ideally, if you could cap as MPEG your problem would be solved. Failing that, you can force a crop by entering the hidden options (CTRL-F9) , setting the Threshold to "0", and "Force Cropping Of ..." http://www.autogk.me.uk/modules.php?name=TutorialEN#6 You can find out the crop values by opening the AVI first in VDub(Mod) and testing with the crop filter. And by the way, if your DV is really 16:9, then enable that in the Hidden Options as well, as AutoGK can only recognize 4:3 DV AVIs. However, you had better be sure you know the difference between true 16:9 and widescreen 4:3. If you're getting them with good Aspect Ratio now, even with the uncropped black bars, then they're really widescreen 4:3. Based on what you've said, I suspect everything you have is 4:3. | ||
| KatCassidy posted 2007 May 09 08:38 | ||
Yes, this has worked out fine! Thank you very much
Of course - hence the "letterbox" effect and the reason for needing to crop the video Now onto the next problem we've encountered: When analyzing the source file, AGK seems to perform the analysis at 0.5x speed - ie. it takes 2 hours to analyze a 1 hour video in DV format. When trying to convert an MPG it performs the analysis in a matter of minutes. It compresses the videos in the same amount of time, be it a DV-AVI or an MPG, just the analysis that's killing it. System specs: Celeron 2.6GHz CPU, 512MB PC-400 RAM (or is that PC 4000?) and 40+200GB IDE HDD's. | ||
| manono posted 2007 May 09 08:48 | ||
| Sorry, but I don't know why the analysis of DV AVIs takes so long. About all I can suggest is to upgrade your AutoGK. It's up to v2.40 now.
You said that 2.20 is the only one that produces the right size. But the wrong sized output often (usually) comes from not uninstalling XviD before installing a newer version. My suggestion is to first uninstall XviD in Add/Remove Programs and then install the latest AutoGK. I don't know for sure that the DV AVI analysis step will go faster with the upgrade, but it can't hurt to try. |
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