properly remove webp metadata (fixes #43) #44
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A Chrome update added metadata to generated WebP, which caused videos generated by Whammy to be invalid. @chrahunt [describes the fix](chrahunt/TagProReplays#78 (comment)): > Okay, I figured out the issue. In Whammy [here](https://github.com/antimatter15/whammy/blob/a1c8e861a3269387ffac519fe6e96c645efb6686/whammy.js#L192) it skips the first 4 bytes of the VP8* chunk, assuming there's no additional metadata. Well now there is, but it isn't what the webp format is expecting. Replacing `4` with `webp.data.indexOf('\x9d\x01\x2a') - 3` did the trick (get to the `start_code` then back up 3 bytes for the `frame_tag` as detailed [here](https://tools.ietf.org/html/rfc6386#section-19.1). I did a local test and was able to generate a webm that ffmpeg approved of.
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On second thought it may be better to just preserve the relevant section of the data here than slice where the frame is actually used. Seems nicer to do the 'parsing' of the webP for consumption by the rest of the extension in |
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This fix was required for me to get anything rendering in the exported webm 👍 |
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A Chrome update added metadata to generated WebP, which caused videos generated by Whammy to be invalid.
@chrahunt describes the fix: