On Wed, Jul 6, 2016 at 4:50 PM, Vignesh Venkatasubramanian <vigne...@google.com> wrote: > On Fri, Jul 1, 2016 at 3:03 PM, Ronald S. Bultje <rsbul...@gmail.com> wrote: >> Hi, >> >> On Fri, Jul 1, 2016 at 5:27 PM, Vignesh Venkatasubramanian < >> vigneshv-at-google....@ffmpeg.org> wrote: >> >>> On Fri, Jul 1, 2016 at 12:48 PM, Ronald S. Bultje <rsbul...@gmail.com> >>> wrote: >>> > Hi, >>> > >>> > On Fri, Jul 1, 2016 at 3:29 PM, Ronald S. Bultje <rsbul...@gmail.com> >>> wrote: >>> > >>> >> Hi, >>> >> >>> >> On Fri, Jul 1, 2016 at 3:12 PM, Vignesh Venkatasubramanian < >>> >> vigneshv-at-google....@ffmpeg.org> wrote: >>> >> >>> >>> On Fri, Jul 1, 2016 at 11:06 AM, James Almer <jamr...@gmail.com> >>> wrote: >>> >>> > On 7/1/2016 2:53 PM, Ronald S. Bultje wrote: >>> >>> >> Hi, >>> >>> >> >>> >>> >> On Fri, Jul 1, 2016 at 1:40 PM, James Zern < >>> >>> jzern-at-google....@ffmpeg.org> >>> >>> >> wrote: >>> >>> >> >>> >>> >>> On Fri, Jul 1, 2016 at 10:07 AM, Carl Eugen Hoyos < >>> ceho...@ag.or.at> >>> >>> >>> wrote: >>> >>> >>>>> Do we have decoder support (for either vp8 or vp9) for these >>> files? >>> >>> >>>> >>> >>> >>>> No, only encoding and muxing. >>> >>> >>> >>> >>> >>> Seems like a feature request, but no reason to block this one if >>> the >>> >>> >>> vp8 one is here. >>> >>> >> >>> >>> >> >>> >>> >> I'm not sure I have an opinion on this... But it feels strange to >>> allow >>> >>> >> encoding of content we cannot decode. Being ffmpeg, how do we >>> recommend >>> >>> >> people handle the files created with this feature, if not by using >>> >>> ffmpeg >>> >>> >> itself? >>> >>> >>> >>> One plausible reason is that Chrome can decode this. So it will be >>> >>> useful for people who already have ffmpeg in their pipelines and want >>> >>> to create such files. And like James Almer mentioned, this isn't a >>> >>> first. VP8 Alpha has been this way too. >>> >> >>> >> >>> >> The fact that something is the way it is, does not prove that it is >>> >> therefore right, or that we should therefore continue doing it that way >>> in >>> >> other cases. >>> >> >>> >> So you're suggesting that it is perfectly fine for people to use Chrome >>> as >>> >> decoder if FFmpeg is the encoder. What if people don't have Chrome >>> >> installed? Or what if they want a way of UI-less batch-processing such >>> >> files, e.g. what if a service like Youtube/Vimeo wants to allow upload >>> of >>> >> vp8a/vp9a files without invoking Chrome for decoding? >>> >> >>> > >>> > Additional evidence in [1], [2]. >>> > >>> > There absolutely seems to be interest in support for vp8a/vp9a decoding >>> > outside Chrome. I'm not saying you should implement it in all multimedia >>> > frameworks ever created in human history, but doing it in one of them >>> (e.g. >>> > ffmpeg, since it already supports encoding) certainly sounds helpful? >>> > >>> >>> I'm not saying alpha decoder shouldn't ever be implemented in ffmpeg. >>> I'm just saying that it shouldn't be a reason to block this patch. :) >>> Sorry if i wasn't clear before. >> >> >> I totally understand that you would think that, since it means you don't >> have to do anything :). >> >> But there's an issue with this thinking. We're essentially already the >> dumping ground for anything multimedia-related nowadays. After all, we >> maintain it and keep it working (assuming basic tests), things couldn't get >> much easier than that, right? But is it actually useful to anyone? I mean >> not just useful for you, but useful to a wider set of people, at least in >> theory. >> >> If there's no decoder, I would claim that the wider utility of this thing >> is essentially zero. And that's somewhat of a concern. >> >> So, how do we get a decoder? vp8a suggests that just waiting for one to >> spontaneously combust out of thin air just doesn't work. So I'm suggesting >> you provide us with one. It's ok if it uses libvpx instead of ffvp8/9. >> Since vp8a encoding is already in, I won't ask for a vp8a decoder either. >> I'm just asking for a vp9a decoder. It might even be OK if it's implemented >> on top of ffmpeg instead of inside libavcodec (I'm not sure how others feel >> about this), i.e. just something that invokes libavformat to parse a webm >> file, create two decoders to get the yuv and a planes, and then merge them >> together into a yuva420p picture. I'm just asking for something _small_ and >> _simple_ (i.e. not "Chrome") that we can point users to when they ask "how >> do I decode vp9a files". >> >> I asked on IRC (#ffmpeg-devel) and several people concurred: >> >> <BBB> jamrial: so … I’m looking for a second opinion here, like, an >> independent one… am I being too hard on these guys for saying “an encoder >> needs a decoder”? >> <JEEB> BBB: I do tend to agree that in general it goes dec->enc, or both at >> the same time. be it a fully lavc decoder or just utilizing a decoder >> library >> <jamrial> BBB: no, you're not being hard >> >> So it seems I'm not entirely alone in this opinion within the ffmpeg >> developer community. >> > > Alright, i have a working patch for the decoder locally (i will push > that to the ML shortly).
Here it is: http://ffmpeg.org/pipermail/ffmpeg-devel/2016-July/196403.html > In the meantime, let's please unblock this. > It worked this time as it wasn't too complex, but i'm not sure if > conditioning patches like this is always a good idea. :) > >> Ronald >> _______________________________________________ >> ffmpeg-devel mailing list >> ffmpeg-devel@ffmpeg.org >> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > > > -- > Vignesh -- Vignesh _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
