> AFAIK mjpeg can handle different colorspaces, including YCbCr, so it seems to > me that transcoding video (footage) to mjpeg doesn't necessarily imply > colorspace conversion, or at least a "lossy" colorspace conversion > (independently of the loss due to the codec itself).
YCbCr is a family of colorspaces. MJPEG uses a different set of primary weightings, and a different scale range than most other video codecs. > In this case, there's a colorspace conversion from 'yuv420p' to 'yuvj420p', > but is it really "lossy" in itself since colorspace "family" and chroma > subsampling are the same (YCbCr and 4:2:0 respectively) ? Yes, it is lossy. The weights, the representation range and the chroma pixel sitings are all different between AVCHD and MJPEG. > Furthermore, am I right to think that colorspace conversion can be avoided in > cinelerra by choosing "YUV-8 Bit" or "YUVA-8 Bit" as Color model in the > project parameters, when working with 8-bits YCbCr footage ? No, unfortunately. You could minimize the loss by working in floating point intermediaries, but Cinelerra doesn't support them AFAIR. The chroma resampling aspects complicate it further (floating point won't save you there). Monty _______________________________________________ Cinelerra mailing list [email protected] https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra
