GoogleChromeLabs/squoosh

WebP2 decoder fails on some images

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#854 opened on Nov 20, 2020

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 (6 comments) (0 reactions) (0 assignees)TypeScript (20,335 stars) (1,431 forks)batch import
codechelp wanted

Description

  1. Open the Squoosh logo in squoosh.
  2. Encode a lossless WP2 (either by setting the quality to 100 in dev or checking lossless in wp2-options). Works fine.
  3. Reduce palette. Fails to decode!

It's possible that the encoder is producing a bad file in this case, I guess.

@surma @RReverser who wants to take this?

Contributor guide

Tech stack
typescript
Domain
frontend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
TypeScriptImage codec concepts
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Investigate the WP2 encoding/decoder logic, particularly the palette reduction step. Look at the codec's encoder output when reducing palette to identify if the encoder produces invalid data. Check for any existing tests or comments about similar issues. Refer to the Squoosh codebase for the WP2 integration.
WebP2 decoder fails on some images · GoogleChromeLabs/squoosh#854 | Good First Issue