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prong
Experienced Roboteer
Joined: 19 Jun 2004
Posts: 839
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While the camera does the original encoding to HD the PC then has to process it like any other video codec during editing or playback.
In my experience playing back HD takes a lot more processign power than SD. This makes sense when you reliase while the compressed footage can take up the same space as SD during playback it is getting uncompressed. Since you can have basically 4 times the information being uncompressed and displayed it does take a lot more processing power to accomplish.
If you look at the tech behind HD and bluray DVD players they do a lot more work to output full HD. For example the first Toshiba HD DVD players were esiiantally a highly modified P4 PC dedicated to video plyaback.
Even current computer videocards have on board HD decoding to help with proper HD playback due to the extra processing power needed.
Capturing HD is pretty much just copying it so it is not too strenuous. Once you start wokring with it however while it is the same size it still is much more information being bandied around.
Thanks for the tip on Avid, i will definately give it a try. Having used a varitey of programs including Final Cut Pro etc I have found Premiere to be the most powerful, but certianly not the most user friendly. Mostly however thats due to lots of extra plug ins for effects etc that are not needed for robot editing.
I am happy to blame my old PC for a varitey of troubles and yes the latest version of Premiere ran badly, mostly I suspect due to the low amount of RAM I had. Anyway after an upgrade to a water cooled overclocked quad core with 4GB and dual 10k RPM raptor drives I don't have too many issues.
I disagree that I will maintain the best quality by shooting in the format I wish to export.
For example when i got my camera I tried out a whole bunch of different things to see how the camera performed. The camera CMOS chip captures footage in HD, it has that many pixels. I can either choose to record the information about all those pixels in HD to tape or I can let the camera downconvert to SD and record to tape.
The thing is the camera is downconverting the image for me in hardware on the fly. It does a good job and the SD footage looks great. However, the camera is still down converting the footage to SD from HD. This is exactly the same as is done on the PC except the camera does it real time.
In my experience with my camera I can get a better result downconverting in post. The PC has a lot more procesisng power to put to work in the convert than the camera does and in every case i have tried or seen it does a better job of it. When you think about it that is hardly suprising since it is a full PC vs a hardware coding chip in the camera.
As you said, every time you transcode you incur artifacting. Thats why I let my super powerful PC and latest software do the transcoding for me, not the few years old first gen camera hardware.
There is also the argument that HD footage is more compressed and therefor has more artifacting that SD. In practive however both compression codec cause some artifacting and while the SD codec is less compression the HD codec is more advanced, resulting in similar levels of artifacts once at SD. IN fact i generally find the artifacting from HD that is then downconverted to SD much softer and harder to see than straight up SD compression artifacts. Anyway these effects are almost neglible in the majority of examples i have seen.
Also I have yet to shoot any footage that does not benifit from some post production colour correction / brightness adjustment / white balance etc, however small. In my experience this is best done with HD footage as it always looks better when converted to SD than doing the same effects to SD.
While my moral choices are not in question here I am happy to admit I download and use the latest version of my editing software of choice. I have found that the various updates have made some big diferences in post production editing quality.
Also while this thread is spawned from Robot footage discussion I am not talking about it specifically. Any video production practices I employ are not limited to this one aspect, though i agree that most of the differences are almost entirely negated by other factors such as the polycarb that effects the image a whole lot more.
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Sat Dec 15, 2007 12:09 am |
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