Hi, Kamil > Hello, > > > From: Jonghun Han [mailto:jonghun.han@xxxxxxxxxxx] > > Sent: 06 December 2010 07:57 > > > > Hi, > > > > If MFC(encoder/decoder) has a single node, > > how to know application's object before VIDIOC_S_FMT calling ? > > You're right. No way to know that before. > > > VIDIOC_S_CTRL can be called before VIDIOC_S_FMT. > > For example user wants to use MFC as an *encoder*, > > but user calls VIDIOC_S_CTRL with *decoder* command by mistake. > > In that case driver cannot return fail because it cannot know the > > purpose > > before VIDIOC_S_FMT calling. When VIDIOC_S_FMT is called to use MFC as > > an > > *encoder* > > after VIDIOC_S_CTRL, driver will be confused how to handle it. > > > > But in two nodes solution > > decoder command via VIDIOC_S_CTRL will be failed on encoder device > > node. > > > > > > > -----Original Message----- > > > From: linux-media-owner@xxxxxxxxxxxxxxx [mailto:linux-media- > > > owner@xxxxxxxxxxxxxxx] On Behalf Of Pawel Osciak > > > Sent: Sunday, December 05, 2010 7:55 AM > > > Hi all, > > > I would side with Laurent on this. Judging by formats seems to be > > > enough for this driver and it has great, in my opinion, advantages of > > > a) not overcomplicating things for applications b) not adding new > > > pieces to the API... > > We've had a discussion here with Sylwester Nawrocki and Marek Szyprowski. > > I suppose the application has to detect which video node is MFC anyway, > for example by looking through /sys/class/video4linux or adding rules to > udev. Same way it can choose which of the two node to use, so I don't > think it going to be such a problem. In case of FIMC functionality - > camera capture and m2m transformations are divided between two video > nodes. > > In case of differentiating by format, I agree that it is feasible, but > in my opinion it will overcomplicate the driver. When two nodes are used, > there are going to be separate videobuf2 ops. Those functions that can be > reused, would be reused, otherwise there would be two versions - one for > encoding and one for decoding. Without that most functions would have to > check what the context is doing and act appropriately. This means more > complex code. It will have similar camera capture and m2m style. But we are considering that functions are reused enough b/w encoder & decoder. ---------------------------------------------------------------------- peter Oh, Senior Engineer SW Solution Development Team, System LSI Division, Samsung Electronics, Co., Ltd. Email: jaeryul.oh@xxxxxxxxxxx ----------------------------------------------------------------------- > > What API changes have you had in mind that would be required when using > two video nodes? > > Best regards > -- > Kamil Debski > Linux Platform Group > Samsung Poland R&D Center > > -- > To unsubscribe from this list: send the line "unsubscribe linux-media" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
