From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-wi0-f178.google.com ([209.85.212.178]:43824 "EHLO mail-wi0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965174Ab2JCRst (ORCPT ); Wed, 3 Oct 2012 13:48:49 -0400 Received: by wibhr7 with SMTP id hr7so2797393wib.1 for ; Wed, 03 Oct 2012 10:48:48 -0700 (PDT) From: =?UTF-8?q?Frank=20Sch=C3=A4fer?= To: hdegoede@redhat.com Cc: linux-media@vger.kernel.org, =?UTF-8?q?Frank=20Sch=C3=A4fer?= Subject: [PATCH] libv4lconvert: clarify the behavior and resulting restrictions of v4lconvert_convert() Date: Wed, 3 Oct 2012 19:48:39 +0300 Message-Id: <1349282919-15332-1-git-send-email-fschaefer.oss@googlemail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-media-owner@vger.kernel.org List-ID: Signed-off-by: Frank Schäfer --- lib/include/libv4lconvert.h | 20 ++++++++++++++++++-- 1 Datei geändert, 18 Zeilen hinzugefügt(+), 2 Zeilen entfernt(-) diff --git a/lib/include/libv4lconvert.h b/lib/include/libv4lconvert.h index 167b57d..509655e 100644 --- a/lib/include/libv4lconvert.h +++ b/lib/include/libv4lconvert.h @@ -89,8 +89,24 @@ LIBV4L_PUBLIC int v4lconvert_needs_conversion(struct v4lconvert_data *data, const struct v4l2_format *src_fmt, /* in */ const struct v4l2_format *dest_fmt); /* in */ -/* return value of -1 on error, otherwise the amount of bytes written to - dest */ +/* This function does the following conversions: + - format conversion + - cropping + if enabled: + - processing (auto whitebalance, auto gain, gamma correction) + - horizontal/vertical flipping + - 90 degree (clockwise) rotation + + NOTE: the last 3 steps are enabled/disabled depending on + - the internal device list + - the state of the (software emulated) image controls + + Therefore this function should + - not be used when getting the frames from libv4l + - be called only once per frame + Otherwise this may result in unintended double conversions ! + + Returns the amount of bytes written to dest an -1 on error */ LIBV4L_PUBLIC int v4lconvert_convert(struct v4lconvert_data *data, const struct v4l2_format *src_fmt, /* in */ const struct v4l2_format *dest_fmt, /* in */ -- 1.7.10.4