I *think* I grok what this is for, and I'm still pretty frustrated that there isn't a crisp summary along the lines of "this parameter helps sites implement custom bitrate vs. quality vs. CPU use tradeoffs for different kinds of media and streams, which are important to customers like X, Y, and Z".
Eugene, Philipp: it's important that the Blink process show that we are shipping important features that solve real problems, particularly when we're in the position of shipping first. We *want* to trust the WebRTC/media community to work with us to launch API changes quickly, and demonstrating need is part of that. Can you respond with an overview (perhaps in the form of an Explainer), and/or perhaps have potential users of this API chime in? Best, Alex On Wednesday, July 19, 2023 at 8:14:16 AM UTC-7 Yoav Weiss wrote: > On Wed, Jul 19, 2023 at 2:51 PM Philipp Hancke < > [email protected]> wrote: > >> Am Mi., 19. Juli 2023 um 14:25 Uhr schrieb Yoav Weiss < >> [email protected]>: >> >>> >>> >>> On Thu, Jul 13, 2023 at 10:53 PM 'Eugene Zemtsov' via blink-dev < >>> [email protected]> wrote: >>> >>>> Any new feedback or resolution on this one? >>>> >>>> On Fri, Jul 7, 2023 at 5:53 AM Sangwhan Moon <[email protected]> wrote: >>>> >>>>> (resending from correct email) >>>>> >>>>> On 2023年07月07日 00時32分12秒 (+09:00), Mike Taylor wrote: >>>>> >>>>> On 7/5/23 8:57 PM, 'Eugene Zemtsov' via blink-dev wrote: >>>>> >>>>> Intent to Implement and Ship: Per-frame quantizer in VideoEncoder >>>>> >>>>> Contact emails >>>>> >>>>> [email protected] >>>>> >>>>> Explainer >>>>> >>>>> None >>>>> >>>>> >>> I think an explainer can be significantly helpful in helping us >>> understand how developers will be using this feature and what use cases >>> it'd cover. >>> Could you write one or add an inline explanation outlining that? >>> >> >> Explaining that is tough without going into the details "what is >> quantization for video codecs. See >> https://www.vcodex.com/h264avc-4x4-transform-and-quantization/ >> for a very detailed explanation for H264. >> >> the tl;dr is that folks who encode video like tuning all kinds of knobs >> to get the "best" result and qp is one of those. >> > > An explainer doesn't have to assume folks reading it don't know what > quantization means :) > > Basically, clicking through the specs, it's still not clear to me if the > quantization values are provided as a single int that quantization tables > are supposed to be divided by. a "quality" int that represents a certain > quantization table, or something else entirely. Clarity on that would be > great. > > >> >>> >>>> >>>>> Specification >>>>> >>>>> https://www.w3.org/TR/webcodecs/#video-encoder-bitrate-mode >>>>> >>>>> Summary >>>>> >>>>> Adds "quantizer" VideoEncoderBitrateMode for VideoEncoder. This allows >>>>> to specify a quantizer parameter for each frame for AV1, VP9, and AVC >>>>> video >>>>> codecs. The quantizer parameter is set via codec specific extensions for >>>>> VideoEncoderEncodeOptions. >>>>> >>>>> Assuming I know very little about video codecs, what use cases does >>>>> this enable for developers? >>>>> >>>>> >>>>> >>>>> Blink component >>>>> >>>>> Blink>Media>WebCodecs >>>>> <https://bugs.chromium.org/p/chromium/issues/list?q=component:Blink%3EMedia%3EWebCodecs> >>>>> >>>>> TAG review >>>>> >>>>> None. >>>>> >>>>> Previously WebCodecs API had TAG review as a whole: >>>>> >>>>> https://github.com/w3ctag/design-reviews/issues/612 >>>>> >>>>> This is a new addition since that review, but it's a trivial addition >>>>> (IMHO) so a new review request isn't needed. >>>>> >>>>> >>>>> I agree, I don't see anything particularly contentious in the proposal >>>>> that would warrant a full review. >>>>> >>>>> >>>>> >>>>> TAG review status >>>>> >>>>> Not applicable >>>>> >>>>> Risks >>>>> >>>>> Interoperability and Compatibility >>>>> >>>>> Gecko: Neutral ( >>>>> https://github.com/mozilla/standards-positions/issues/837#issuecomment-1614666364) >>>>> >>>>> Paul Adenot (Mozilla) expressed that minor changes to WebCodecs spec >>>>> don't >>>>> need to go through the full "Request for Mozilla Position" process >>>>> assuming >>>>> they were approved by the Media Working Group. >>>>> >>>>> WebKit: Positive ( >>>>> https://www.w3.org/2023/03/07-mediawg-minutes.html#t02) The issue was >>>>> discussed on 07 March 2023 by w3c Media working group. Jer Noble (Apple) >>>>> was actively participating and provided input for spec details. >>>>> >>>>> Can we request a formal position from WebKit, at least to let them >>>>> know we're intending to ship? >>>>> >>>>> >>>>> Web developers: Positive (https://github.com/w3c/webcodecs/issues/56) >>>>> People ask for this on GitHub >>>>> >>>>> Other signals: >>>>> >>>>> 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? >>>>> >>>>> >>>>> >>>>> 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 >>>>> >>>>> Tracking bug >>>>> >>>>> https://bugs.chromium.org/p/chromium/issues/detail?id=1424154 >>>>> >>>>> Estimated milestones >>>>> >>>>> Shipping on desktop >>>>> >>>>> 117 >>>>> >>>>> Shipping on Android >>>>> >>>>> 117 >>>>> >>>>> >>>>> >>>>> >>>>> Link to entry on the Chrome Platform Status >>>>> >>>>> https://chromestatus.com/feature/5783986600673280 >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> -- >>>>> Thanks, >>>>> Eugene Zemtsov. >>>>> -- >>>>> 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/CAK8JDrF0PKfpVbaYWX-hR0wJ%2Bb9H4YtwFBUc6Y6JGSmFT7pVgQ%40mail.gmail.com >>>>> >>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAK8JDrF0PKfpVbaYWX-hR0wJ%2Bb9H4YtwFBUc6Y6JGSmFT7pVgQ%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/0a1d0f96-c5f0-fdf8-44b0-b49c3f180839%40chromium.org >>>>> >>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/0a1d0f96-c5f0-fdf8-44b0-b49c3f180839%40chromium.org?utm_medium=email&utm_source=footer> >>>>> . >>>>> >>>>> >>>> >>>> -- >>>> Thanks, >>>> Eugene Zemtsov. >>>> >>>> -- >>>> 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/CAK8JDrFxVaQnqU4dGQesuw%2B_AaBV763a0-t%3Dp0273LPNbyespQ%40mail.gmail.com >>>> >>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAK8JDrFxVaQnqU4dGQesuw%2B_AaBV763a0-t%3Dp0273LPNbyespQ%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/CAL5BFfUBdFesjccKhgcoQ5Zs%2BJBEqMtNjFthN2UpVsUF_hEC4w%40mail.gmail.com >>> >>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAL5BFfUBdFesjccKhgcoQ5Zs%2BJBEqMtNjFthN2UpVsUF_hEC4w%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/3906141c-de07-4819-bd97-7b11d2bc11a7n%40chromium.org.
