Thanks everyone! This landed as https://chromiumdash.appspot.com/commit/88891c3ee5cec6754e6fe35337620a23e9791c3a
- dale On Wed, Sep 21, 2022 at 8:43 AM Philip Jägenstedt <[email protected]> wrote: > LGTM3, to remove in 108 without deprecation period. > > On Wed, Sep 21, 2022 at 5:25 PM Mike Taylor <[email protected]> > wrote: > >> LGTM2 >> >> On 9/21/22 7:44 AM, Yoav Weiss wrote: >> >> LGTM1 >> >> It seems unlikely that even the (few) developers who access this data are >> somehow relying on it. >> >> On Tue, Sep 20, 2022 at 8:10 PM Dale Curtis <[email protected]> >> wrote: >> >>> On Tue, Sep 20, 2022 at 3:36 AM Yoav Weiss <[email protected]> >>> wrote: >>> >>>> >>>> >>>> On Fri, Sep 16, 2022 at 11:19 PM Dale Curtis <[email protected]> >>>> wrote: >>>> >>>>> Contact emails [email protected] >>>>> >>>>> Explainer None >>>>> >>>>> Specification https://github.com/w3c/webcodecs/issues/508 >>>>> >>>>> Summary >>>>> premultiplyAlpha tells ImageDecoder to multiply the alpha channel into >>>>> the RGB channels of decoded images. It was added to mirror the >>>>> capabilities >>>>> of ImageBitmapOptions, but in retrospect doesn't make sense. >>>>> >>>>> Feature has no observable effects in primary use cases (drawing), but >>>>> may constrain implementations in suboptimal ways. E.g., requiring YUV be >>>>> converted to RGB. See https://github.com/w3c/webcodecs/issues/508 for >>>>> a more detailed description. Per consensus of WebCodecs spec editors and >>>>> lack of usage (0.000000339% - 0.00000687% of page loads per a UseCounter >>>>> in >>>>> M105), we propose deprecating and removing this feature starting with >>>>> M108. >>>>> >>>> >>>> What would breakage look like? What would happen to callers who still >>>> pass that option? >>>> >>> >>> If they're just drawing the frames into canvas, webgl, etc there is no >>> observable difference or breakage (this is the common use case) - since the >>> draw stage takes care of any alpha blending. If they're accessing the raw >>> pixels via VideoFrame::copyTo() they would notice that the alpha is no >>> longer premultiplied. Depending on what the application is doing with the >>> frames this may mean nothing (i.e., not using images w/ alpha, or didn't >>> care about alpha) or it could result in color changes in the image. >>> >>> >>>> >>>> >>>>> >>>>> Blink component Blink>Media>WebCodecs >>>>> <https://bugs.chromium.org/p/chromium/issues/list?q=component:Blink%3EMedia%3EWebCodecs> >>>>> >>>>> TAG review Not applicable >>>>> TAG review status Not applicable >>>>> >>>>> Risks >>>>> It's possible that there exists some client which was accessing raw >>>>> pixel data in JavaScript may observe that the alpha channel is no longer >>>>> premultiplied into RGB channels. Clients wishing for this functionality >>>>> can >>>>> either do the multiply themselves or use createImageBitmap() to do this. >>>>> >>>>> Interoperability and Compatibility >>>>> >>>>> >>>>> *Gecko*: Positive Firefox co-editor supports removal. >>>>> >>>> >>>> I don't know if we can consider this >>>> <https://github.com/w3c/webcodecs/issues/508#issuecomment-1248720618> >>>> a Mozilla position. At the same time, this seems small enough to not >>>> warrant an explicit issue. (and it's good to have consensus on the issue) >>>> >>> >>> That's a bit surprising. I think that's a pretty strong signal, but >>> defer to the API owners. >>> >> >> That's a strong signal from the person editing the spec, but not an >> official Mozilla position. >> >> >>> >>> >>>> >>>> >>>>> >>>>> *WebKit*: No signal >>>>> >>>>> *Web developers*: No signals >>>>> >>>>> *Other signals*: Microsoft co-editor supports removal. >>>>> >>>>> WebView application risks >>>>> >>>>> Does this intent deprecate or change behavior of existing APIs, such >>>>> that it has potentially high risk for Android WebView-based applications? >>>>> >>>>> >>>>> No. >>>>> >>>>> >>>>> Debuggability >>>>> >>>>> n/a >>>>> >>>>> >>>>> Will this feature be supported on all six Blink platforms (Windows, >>>>> Mac, Linux, Chrome OS, Android, and Android WebView)? Yes >>>>> >>>>> Is this feature fully tested by web-platform-tests >>>>> <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md> >>>>> ? Yes >>>>> >>>>> Flag name n/a >>>>> >>>>> Requires code in //chrome? False >>>>> >>>>> Tracking bug >>>>> https://bugs.chromium.org/p/chromium/issues/detail?id=1340190 >>>>> >>>>> Launch bug >>>>> https://bugs.chromium.org/p/chromium/issues/detail?id=1340190 >>>>> >>>>> Estimated milestones >>>>> >>>>> M108 >>>>> >>>>> >>>>> Anticipated spec changes >>>>> >>>>> Open questions about a feature may be a source of future web compat or >>>>> interop issues. Please list open issues (e.g. links to known github issues >>>>> in the project for the feature specification) whose resolution may >>>>> introduce web compat/interop risk (e.g., changing to naming or structure >>>>> of >>>>> the API in a non-backward-compatible way). >>>>> https://github.com/w3c/webcodecs/pull/562 >>>>> >>>>> Link to entry on the Chrome Platform Status >>>>> https://chromestatus.com/feature/4560781148946432 >>>>> >>>>> This intent message was generated by Chrome Platform Status >>>>> <https://chromestatus.com/>. >>>>> -- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "blink-dev" group. >>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to [email protected]. >>>>> To view this discussion on the web visit >>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAPUDrwc%3D7%2B2KC73kKTUdWUmvQNubFtZGphhh8DXgQXnr%2BJc_LQ%40mail.gmail.com >>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAPUDrwc%3D7%2B2KC73kKTUdWUmvQNubFtZGphhh8DXgQXnr%2BJc_LQ%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>> . >>>>> >>>> -- >> You received this message because you are subscribed to the Google Groups >> "blink-dev" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAL5BFfVQSA6gRu8eVfRyu8TPwXQhqduSVDZemsX0%3DGV4nY2jfg%40mail.gmail.com >> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAL5BFfVQSA6gRu8eVfRyu8TPwXQhqduSVDZemsX0%3DGV4nY2jfg%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "blink-dev" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/096e70e9-197e-4859-3196-6f3277e94f7a%40chromium.org >> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/096e70e9-197e-4859-3196-6f3277e94f7a%40chromium.org?utm_medium=email&utm_source=footer> >> . >> > -- You received this message because you are subscribed to the Google Groups "blink-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAPUDrwfpEBz6yH7a62WzkREKa4FWOZGh3awH99_RtcJ0-5kX5g%40mail.gmail.com.
