On Thursday 19 May 2011 16:06:12 Tomasz Stanislawski wrote: > Laurent Pinchart wrote: > > On Wednesday 18 May 2011 15:03:13 Sylwester Nawrocki wrote: > >> On 05/18/2011 02:31 PM, Hans Verkuil wrote: > >>> On Wednesday, May 18, 2011 14:06:21 Sylwester Nawrocki wrote: > >>>> On 05/16/2011 09:21 AM, Laurent Pinchart wrote: > >>>>> On Saturday 14 May 2011 12:50:32 Hans Verkuil wrote: > >>>>>> On Friday, May 13, 2011 14:43:08 Laurent Pinchart wrote: > >>>>>>> Thinking some more about it, does it make sense to set both crop > >>>>>>> and compose on a single video device node (not talking about > >>>>>>> mem-to-mem, where you use the type to multiplex input/output > >>>>>>> devices on the same node) ? If so, what would the use cases be ? > >>>> > >>>> I can't think of any, one either use crop or compose. > >>> > >>> I can: you crop in the video receiver and compose it into a larger > >>> buffer. > >>> > >>> Actually quite a desirable feature. > >> > >> Yes, right. Don't know why I imagined something different. > >> And we need it in Samsung capture capture interfaces as well. The H/W > >> is capable of cropping and composing with camera interface as a data > >> source similarly as it is done with memory buffers. > > > > The same result could be achieved by adding an offset to the buffer > > address and setting the bytesperline field accordingly, but that would > > only work with userptr buffers. As we're working on an API to share > > buffers between subsystems, I agree that composing into a larger buffer > > is desirable and shouldn't be implemented using offset/stride. > > Hi, > Simulation of cropping on a data source using offset/bytesperline is not > possible for compressed formats like JPEG. I agree with you, but for composing I wonder how you're going to compose an image into a JPEG buffer :-) > I could not find any good definition of bytesperline for macroblock and > planar formats. These problems were the reason of proposing extcrop (aka > selection) API. As I said, I agree that composing shouldn't be implemented using offset/stride, so there's no disagreement. -- Regards, Laurent Pinchart -- 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
