Otis Grapsas
Carbonite Member
Just to confirm though, is it correct to say that other than compression image quality, AVCCAM has no disadvantage compared to AVC-Intra as an editing codec? I know it takes more processor power etc. to render/watch but I mean as far as editing goes.
Doesn't AVC-Intra also work like this?:
AVC-Intra is superior in every imaginable way. 8bit "YUV" captures about 6bits of RGB chroma in natural scenes, and AVC-Intra fixes that because its 10bit encodings can preserve a full 8bit RGB and at very low compression. 8bit RGB is what most modern sensors are capable of after white balance, color correction and a good gamma curve so this is very important. But lets forget AVC-Intra for now.
The GOP formats have a key disadvantage. They are designed for delivery, not for acquisition, and not for stacking encoding cycles. The engineers did not optimise or even consider the performance of the codecs in this use. Each frame is reconstructed from a whole series of frames. Changing something in one frame spreads the deterioration to other frames depending on the compression technique. The quality of each frame is also not constant, it depends on frame changes, and the frame configuration can and will change between sequential transcodings. When you stack encodings in an intraframe codec, you see a deterioration but the motion quality is preserved. On an interframe codec, motion is affected and errors start adding up very fast, in space and time. The GOP codecs I have examined have a noticable motion blur vs the intraframe counterparts even on a single encoding. They don't deal with fast motion or fast shutter speeds very well because they encode frame differences, not full frames. Stack a couple of interframe encoding cycles and the texture will be gone, everything will become noticably soft from the strong filtering, and the lower exposure stops and any flat areas will become very blocky.