Hi Guennadi, thank you very much for the patch. I am going to apply it in order to start toying with the new capability. I think it is a useful capability. I'll let you know. Again thank you. Paolo 2011/3/30 Guennadi Liakhovetski <g.liakhovetski@xxxxxx>: > On Tue, 29 Mar 2011, Paolo Santinelli wrote: > >> Hi Guennadi, >> >> thank you for the quick answer. >> >> Here is what I mean with dynamic: I take "live" one frame at high >> resolution, for example a picture at VGA or QVGA resolution, then a >> sequence of frames that depict a cropped area (200x200 or 100x100) >> from the original full-resolution frame, and then a new full >> resolution image (VGA or QVGA) and again the sequence of frames that >> depict a cropped area from the original full resolution, and so on. >> That means takes one frame in 640x480 and than takes some frames at >> 100x100 (or 200x200) and so on. > > Ic, so, if you can live with a fixed output format and only change the > input cropping rectangle, the patch set, that I've just sent could give > you a hint, how this can be done. This would work if you're ok with first > obtaining VGA images scaled down to, say, 160x120, and then take 160x120 > cropped frames unscaled. But I'm not sure, this is something, that would > work for you. Otherwise, unless your sensor can upscale cropped images to > VGA output size, you'll also want fast switching between different output > sizes, which you'd have to wait for (or implement yourself;-)) > > Thanks > Guennadi > >> >> The best would be have two different fixed-output image formats, the >> WHOLE IMAGE format ex. 640x480 and the ROI format, 100x100. The ROI >> pictures obtained cropping the a region of the whole image. The >> cropping area could be even wider than 100x100 and then scaled down >> to the 100x100 ROI format. >> >> Probably it is more simple have a cropping area of the same dimension >> of the ROI format, 100x100. >> >> In this way there is a reduction of the computation load of the CPU >> (smaller images). >> >> Thank you very much! >> >> Paolo >> >> 2011/3/29 Guennadi Liakhovetski <g.liakhovetski@xxxxxx>: >> > On Tue, 29 Mar 2011, Paolo Santinelli wrote: >> > >> >> Hi all, >> >> >> >> I am using a PXA270 board running linux 2.6.37 equipped with an ov9655 >> >> Image sensor. I am able to use the cropping and scaling capabilities >> >> V4L2 driver. >> >> The question is : >> >> >> >> Is it possible dynamically change the cropping and scaling values >> >> without close and re-open the camera every time ? >> >> >> >> Now I am using the streaming I/O memory mapping and to dynamically >> >> change the cropping and scaling values I do : >> >> >> >> 1) stop capturing using VIDIOC_STREAMOFF; >> >> 2) unmap all the buffers; >> >> 3) close the device; >> >> 4) open the device; >> >> 5) init the device: VIDIOC_CROPCAP and VIDIOC_S_CROP in order to set >> >> the cropping parameters. VIDIOC_G_FMT and VIDIOC_S_FMT in order to set >> >> the target image width and height, (scaling). >> >> 6) Mapping the buffers: VIDIOC_REQBUFS in order to request buffers and >> >> mmap each buffer using VIDIOC_QUERYBUF and mmap(): >> >> >> >> this procedure works but take 400 ms. >> >> >> >> If I omit steps 3) and 4) (close and re-open the device) I get this errors: >> >> >> >> camera 0-0: S_CROP denied: queue initialised and sizes differ >> >> camera 0-0: S_FMT denied: queue initialised >> >> VIDIOC_S_FMT error 16, Device or resource busy >> >> pxa27x-camera pxa27x-camera.0: PXA Camera driver detached from camera 0 >> >> >> >> Do you have some Idea regarding why I have to close and reopen the >> >> device and regarding a way to speed up these change? >> > >> > Yes, by chance I do;-) First of all you have to make it more precise - >> > what exactly do you mean - dynamic (I call it "live") scaling or cropping? >> > If you want to change output format, that will not be easy ATM, that will >> > require the snapshot mode API, which is not yet even in an RFC state. If >> > you only want to change the cropping and keep the output format (zoom), >> > then I've just implemented that for sh_mobile_ceu_camera. This requires a >> > couple of extensions to the soc-camera core, which I can post tomorrow. >> > But in fact that is also a hack, because the proper way to implement this >> > is to port soc-camera to the Media Controller framework and use the >> > pad-level API. So, I am not sure, whether we want this in the mainline, >> > but if already two of us need it now - before the transition to pad-level >> > operations, maybe it would make sense to mainline this. If, however, you >> > do have to change your output window, maybe you could tell us your >> > use-case, so that we could consider, what's the best way to support that. >> > >> > Thanks >> > Guennadi >> > --- >> > Guennadi Liakhovetski, Ph.D. >> > Freelance Open-Source Software Developer >> > http://www.open-technology.de/ >> > >> >> >> >> -- >> -------------------------------------------------- >> Paolo Santinelli >> ImageLab Computer Vision and Pattern Recognition Lab >> Dipartimento di Ingegneria dell'Informazione >> Universita' di Modena e Reggio Emilia >> via Vignolese 905/B, 41125, Modena, Italy >> >> Cell. +39 3472953357, Office +39 059 2056270, Fax +39 059 2056129 >> email: <mailto:paolo.santinelli@xxxxxxxxxx> paolo.santinelli@xxxxxxxxxx >> URL: <http://imagelab.ing.unimo.it/> http://imagelab.ing.unimo.it >> -------------------------------------------------- >> > > --- > Guennadi Liakhovetski, Ph.D. > Freelance Open-Source Software Developer > http://www.open-technology.de/ > -- -------------------------------------------------- Paolo Santinelli ImageLab Computer Vision and Pattern Recognition Lab Dipartimento di Ingegneria dell'Informazione Universita' di Modena e Reggio Emilia via Vignolese 905/B, 41125, Modena, Italy Cell. +39 3472953357, Office +39 059 2056270, Fax +39 059 2056129 email: <mailto:paolo.santinelli@xxxxxxxxxx> paolo.santinelli@xxxxxxxxxx URL: <http://imagelab.ing.unimo.it/> http://imagelab.ing.unimo.it -------------------------------------------------- -- 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
