From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from moutng.kundenserver.de ([212.227.17.10]:59268 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752823Ab2D1ViB convert rfc822-to-8bit (ORCPT ); Sat, 28 Apr 2012 17:38:01 -0400 Date: Sat, 28 Apr 2012 23:37:59 +0200 (CEST) From: Guennadi Liakhovetski To: =?ISO-8859-1?Q?Ezequiel_Garc=EDa?= cc: linux-media Subject: Re: video capture driver interlacing question (easycap) In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-media-owner@vger.kernel.org List-ID: Hi Ezequiel On Sat, 28 Apr 2012, Ezequiel García wrote: > On Thu, Apr 26, 2012 at 5:33 PM, Ezequiel García wrote: > > Hi everyone, > > > > As you may know I'm re-writing from scratch the staging/easycap driver. > > > > Finally, after digging through the labyrinthic staging/easycap code, > > I've reached a point where I'm able to understand isoc packets. > > Despite not having any documentation (I asked several times) from chip vendor, > > I can separate packets in odd and even. > > > > So, instead of receiving frames the device is sending me fields, right? > > > > My doubt now is this: > > * Do I have to *merge* this pair of fields for each frame, or can I > > give it to v4l? > > If affirmative: how should I *merge* them? > > * Is this related to multiplanar buffers (should I use vb2_plane_addr)? > > > > Currently, staging/easycap does some strange and complex conversion, > > from the pair of fields buffers, to get a "frame" buffer (!) but I'm > > not sure if it's the correct way to do it? > > > > I guess I can keep staring at em28xx (together with vivi/uvc/pwc) driver, > > but if someone cares to give me a small hint or point me at a small portion > > of code I'll be grateful. > > > > Thanks, > > Ezequiel. > > Anyone? This might help: http://linuxtv.org/downloads/v4l-dvb-apis/field-order.html i.e., no, you should not merge fields in the driver, IIRC, you just hand them over to the user in separate buffers. Thanks Guennadi --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer http://www.open-technology.de/