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From: | Ken McGaugh |
Subject: | Re: [Openexr-devel] does half round-trip? |
Date: | Tue, 20 Sep 2005 16:48:22 +0100 |
User-agent: | Mozilla Thunderbird 1.0.2 (X11/20050317) |
I was encoding 0->1023 to 0.0->13.0 with the pivot 445->0.18 and negative gammas of 0.6. Paul Miller wrote:
Ken McGaugh wrote:I wrote a small program a while back to test this and it did round-trip without any loss. For every 10-bit code value there was exactly one 16-bit half. But in shake you have the extra step of going through 32-bit float which may introduce some rounding errors.Are you encoding 0->1023 in half as 0->1023, or 0->1 (with super black/white)?Paul Miller wrote:I'm working on an updated Cineon I/O module, and when I use 16 bit int, with the Cineon log data stretched to 0-65535, I can round-trip exactly.However, when I use half as an intermediate format with the cineon linearized between 0->1 (keeping super blacks and super whites), it does not seem to be round-tripping. It's close, and not noticable visually, but Shake's Common node is showing tons of "noise".Is this expected?
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