Graham Evans wrote:
Aaron Newcomb wrote:
Hi all!
I am getting ready to tape my fourth Cinelerra tutorial which is about
rendering and transcoding. However, most of my rendering is very
simple. Basically I render everything to rawdv (this is changing as I
move toward HD aspect ratios however) and transcode from there into
multiple formats mostly for the web. I thought I would also include
some instruction on transcoding for a DVD since I figure most people
will want to do that as well.
Any thoughts on what else might be useful for people to know about
rendering in Cinelerra?
Lossless rendering with alpha channel - necessary for intermediate
render steps.
Its a while since I got this working but I do remember you need to use
a quicktime box.
Graham
I just checked ... you use component Y'CbCrA 8-bit 4:4:4:4 in a
quicktime container for YUVA-8 bit color model or use Uncompressed RGBA
for the RGBA-8bit color model. These are the only formats which I have
succeeded with so far to properly save alpha channel footage with no
glitches.
Make sure you specify the right color model in the Format dialog
otherwise the resulting render is black or chaotic with no warning why.
I use this technique to render out chromakey footage. As well as using
chromakey HSV (often in several layers) I mask out stray chromakey
glitches (such as when you use a too small back-cloth), blur zoom on the
chromakey effects for nice smooth anti-alias style edge and apply any
other simple corrections which will save me work later. Then I render.
Using the pre-rendered footage I can now begin editing with all speed
and no effects cluttering up the timeline.
Perhaps thats a seperate episode.
Graham
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