From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-dev-return-6363-cohuck=redhat.com@lists.oasis-open.org Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 19B1F985E91 for ; Thu, 21 Nov 2019 10:55:04 +0000 (UTC) From: Dmitry Sepp Date: Thu, 21 Nov 2019 11:54:57 +0100 Message-ID: <7736193.Whgddqjo8n@os-lin-dmo> In-Reply-To: <20191120112929.gvsne7ykvcyw65lu@sirius.home.kraxel.org> References: <20191105191919.167345-1-dmitry.sepp@opensynergy.com> <20191120112929.gvsne7ykvcyw65lu@sirius.home.kraxel.org> MIME-Version: 1.0 Subject: Re: [virtio-dev] [RFC RESEND] virtio-video: Add virtio video device specification Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: 7Bit To: virtio-dev@lists.oasis-open.org Cc: Gerd Hoffmann , Keiichi Watanabe , Tomasz Figa , Linux Media Mailing List , Alexandre Courbot , Alex Lau , Dylan Reid , =?ISO-8859-1?Q?St=E9phane?= Marchesin , Pawel Osciak , David Stevens , Hans Verkuil , Daniel Vetter List-ID: Hi Gerd, On Mittwoch, 20. November 2019 12:29:29 CET Gerd Hoffmann wrote: > Hi, > > > > > > 3. No support for getting plane requirements from the device (sg vs > > > > > contig, > > > > > size, stride alignment, plane count). > > > > > > > > There is actually a bigger difference that results in that. Vdec > > > > assumes host-allocated buffers coming from a different device, e.g. > > > > virtio-gpu and the host having the right knowledge to allocate the > > > > buffers correctly. This is related to the fact that it's generally > > > > difficult to convey all the allocation constraints in a generic > > > > manner. > > > > > > Yep, buffer handling is tricky, especially when it comes to decoding > > > directly to gpu buffers and also when supporting playback of > > > drm-protected streams where the guest might not be allowed to access > > > the stream data. > > > > Also, if we decide to have a buffer sharing device as Gerd suggested > > in a different thread, > > we'll get less overlaps between video codec feature and camera feature. > > e.g. VIRTIO_VIDEO_T_RESOURCE_* would be simplified. (or removed?) > > Disclaimer: Havn't found the time yet to go over both virtio-video and > virtio-vdec in detail. > > > As Tomasz said, I think virtio-vdec can be modified to support > > encoding as well without big changes. I'm happy to update our > > protocol and driver implementation to support encoding if needed. > > I think it makes sense to have a rough plan first ;) > Is there a virtio-video implementation too? Yes, of course. We will be ready to share the code very soon. Regards, Dmitry. > > When it comes to buffer handling: I don't like that virtio-vdec depends > on virtio-gpu for buffer handling. Allowing sharing buffers between > virtio-vdec and virtio-gpu (and possibly other devices) makes sense as > an optional extension. But IMO the encoder/decoder device should be > able to operate as stand-alone device. > > cheers, > Gerd > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org > For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org