<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman, new york, times, serif;font-size:12pt"><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;">Please unsubscibe me now<br><br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;">----- Message d'origine ----<br>De : Gregor Riepl <seto-kun@freesurf.ch><br>À : Mailing list for x264 developers <x264-devel@videolan.org><br>Envoyé le : Mercredi, 28 Novembre 2007, 18h38mn 16s<br>Objet : Re: [x264-devel] I444 support<br><br>> Yes, x264 offers very good quality/compression ratio, in particular
at<br>> high compression rates. I would not be so sure this is still true
with<br>> VERY LOW compression like with qp-values of around 0. I don't know, <br>> but<br>> you might very well get a data expansion (even more so with 4:4:4).<br>> Also, at very low compression rates (high data rates) the gain from<br>> temporal prediction (motion compensation) can be very small. So,<br>> consider to use a pure INTRA compression scheme like JPEG2000. For<br>> instance the Kakadu JPEG200 encoder already includes 4:4:4 RGB<br>> compression.<br><br>thanks for the hint. i'll have a look.<br><br>> Finally, of cause I don't know what exactly you try to archive. But,
<br>> if<br>> the material is old and/or analog or if your film scanner (for analog<br>> sources) only has a limited quality, it will definitely not be worth<br>> archiving at very high data rates. In that case you would just waist<br>> expensive storage room to archive a lot of noise...<br><br>ok, let me be a little bit more specific. i'm dealing with cartoon <br>material to be captured from various analog media like laserdisc or <br>35mm (not now, but maybe in the future) and noise is of lesser <br>importance - but i do care about unneccessary loss of information. i <br>suspect that quantisation would even cause less distortion than <br>colorspace conversion. cartoons often exhibit large single-colored <br>areas with sharp edges, or surfaces with simple gradients.<br>compressing and subsampling the color range results in visible <br>jaggyness, especially considering the low resolution of
laserdiscs.<br><br>i did a quick calculation once, don't take my word for it, but a <br>blueray disc can easily accomodate several hours of losslessly <br>compressed video and audio data in low (ntsc) resolution.<br><br>35mm is of course a different matter, to be dealt with later.<br><br>just for the record: there is ffv1, which supposedly supports a broad <br>range of color spaces and doesn't do quantisation. it also (like <br>kakadu) supports only i frames.<br>if at all possible, i want to compare several codecs in terms of speed
<br>and ratio. choosing the best from a handful possibilities is better <br>than having to stick with something that might not be suitable at all.</div><br></div></div><br>
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