Fix bug in avifToLinearIEC61966#3218
Merged
Merged
Conversation
maryla-uc
changed the title
wantehchang
approved these changes
May 21, 2026
| { | ||
| if (gamma < -4.5f * 0.018053968510807f) { | ||
| return powf((-gamma + 0.09929682680944f) / -1.09929682680944f, 1.0f / 0.45f); | ||
| return -powf((gamma - 0.09929682680944f) / -1.09929682680944f, 1.0f / 0.45f); |
Member
There was a problem hiding this comment.
Is this bug fix worth documenting in the changelog?
Note: I didn't compare the new code with the spec, but the original code is incorrect mathematically because the base of the power, (-gamma + 0.09929682680944f) / -1.09929682680944f, is negative.
Contributor
Author
There was a problem hiding this comment.
I added a changelog entry, I think it's good hygiene, thanks for reminding me.
Fortunately I think this bug is unlikely to have ever affected anyone. It only affects negative values, and only for transfer function 11 which probably nobody uses. And the transfer functions are only used by the gain map code (creation/tone mapping).
wantehchang
approved these changes
May 22, 2026
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
The negative portion of the curve did not match the spec, and was not the inverse of the fromLinear function.