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8th May 2013, 19:35 | #1 | Link |
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Optimal Bayer CFA codecs?
Given the growing abundance of digital cinema style cameras on the market, there has been a growing need to capture and record RAW sensor data onto high speed solid-state media. Compressed R'G'B' or Y'U'V' data in the form of (10-bit/8-bit) H.264 Intra or ProRes or DNxHD hasn't been a problem for some time, but 12-/14-/16-bit linear RAW can represent a lot of bandwidth.
If you want to go the mathematically lossless route, what are some the best codecs applicable today in terms of compression ratio and hardware requirements? I've done some research and here's what I've turned out: 1) JPEG-LS (HP Labs LOCO-I) - not that effective on CFA but perhaps it can be further optimized 2) JPEG2000 - popularized by RED even though they've gone the lossy route (3~12:1 compression ratio); there is a 5/3 CDF wavelet transform for lossless compression 3) Various vector prediction techniques - one example 4) Libima - experimental; not sure if it's abandonware 5) CinemaDNG - I believe it supports a HuffYUV style lossless compression mode, at least on the upcoming BMPC Any others to consider? |
8th May 2013, 22:25 | #5 | Link |
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I spoken with him about it- he seems to be not interested. Lossless coding requires different approach, no?
Also 3:1 mode gives in real world way good enough source to start with- there is really no need for lossless mode. RED users use 5:1 or 7:1 even for 100M$ productions. I think 3:1 is a nice compromise. No ffv1 does not understand RAW data, but I managed to unpack RAW data into 16bit TIFF and than encode it. No idea if I broken 12bit DNG or not After debayering it looks fine, so maybe not Last edited by kolak; 8th May 2013 at 23:31. |
8th May 2013, 23:08 | #7 | Link | |
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25th March 2014, 16:27 | #9 | Link |
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Does anyone know how a CFA Bayer data is encoded via lossless jpeg ?
The code in public libraries only has examples for RGB or 4-channel debayered data. I could not find any sample code of lossless jpeg used for RAW bayer compression. DNG SDK does it, but its hard to comprehend. |
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bayer, cfa, codec, color filter array, lossless |
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