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? 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
