From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-bk0-f46.google.com ([209.85.214.46]:65516 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751928Ab2EAUI7 (ORCPT ); Tue, 1 May 2012 16:08:59 -0400 Received: by bkcji2 with SMTP id ji2so1171251bkc.19 for ; Tue, 01 May 2012 13:08:57 -0700 (PDT) Message-ID: <4FA042D8.207@gmail.com> Date: Tue, 01 May 2012 22:08:56 +0200 From: Sylwester Nawrocki MIME-Version: 1.0 To: "Aguirre, Sergio" CC: Linux Media Mailing List Subject: Re: [Query] About V4L2_CAP_VIDEO_CAPTURE_MPLANE device types References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Hi Sergio, On 05/01/2012 09:08 PM, Aguirre, Sergio wrote: > Hi all, > > I wonder if there's an example app for v4l2 devices with > V4L2_CAP_VIDEO_CAPTURE_MPLANE capability? > (like capture.c in V4L2 API docs) There isn't at the V4L2 API docs, it probably makes sense to add one though. I'll try to find a time to prepare a patch for that. A very simple application with V4L2_CAP_VIDEO_CAPTURE_MPLANE support can be found here: http://thread.gmane.org/gmane.comp.video.dri.devel/65997 It might be not that straightforward since there is the DMABUF memory type used. Some more applications using multi-plane API are available at: http://git.infradead.org/users/kmpark/public-apps An MMAP memory example can be found here: http://git.infradead.org/users/kmpark/public-apps/blob/9c057b001e8873861a70f7025214003837a0860b:/v4l2-mfc-example/mfc.c Please see mfc_dec_setup_capture function. > Also, does it have to be mutually exclusive with a > V4L2_CAP_VIDEO_CAPTURE device? No, the driver could support both. But it generally makes sense to implement only _mplane ioctls at drivers. The multi/single-plane conversion should be done in user space. There were some patches for libv4l to support that (http://www.spinics.net/lists/linux-media/msg35080.html), but such conversions are not yet supported in the v4l libraries yet AFAIK. I'm also not sure how is V4L2_CAP_VIDEO_CAPTURE_MPLANE handled in standard GStreamer plugins like v4l2src at the moment, having only multi-plane interface at the driver might cause additional problems there. -- Regards, Sylwester