gstreamer/gst/videocrop/gstvideocropelement.c
2021-03-29 12:45:23 +02:00

76 lines
2.6 KiB
C

/* GStreamer video frame cropping
* Copyright (C) 2006 Tim-Philipp Müller <tim centricular net>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/**
* SECTION:element-videocrop
* @title: videocrop
* @see_also: #GstVideoBox
*
* This element crops video frames, meaning it can remove parts of the
* picture on the left, right, top or bottom of the picture and output
* a smaller picture than the input picture, with the unwanted parts at the
* border removed.
*
* The videocrop element is similar to the videobox element, but its main
* goal is to support a multitude of formats as efficiently as possible.
* Unlike videbox, it cannot add borders to the picture and unlike videbox
* it will always output images in exactly the same format as the input image.
*
* If there is nothing to crop, the element will operate in pass-through mode.
*
* Note that no special efforts are made to handle chroma-subsampled formats
* in the case of odd-valued cropping and compensate for sub-unit chroma plane
* shifts for such formats in the case where the #GstVideoCrop:left or
* #GstVideoCrop:top property is set to an odd number. This doesn't matter for
* most use cases, but it might matter for yours.
*
* ## Example launch line
* |[
* gst-launch-1.0 -v videotestsrc ! videocrop top=42 left=1 right=4 bottom=0 ! ximagesink
* ]|
*
*/
/* TODO:
* - for packed formats, we could avoid memcpy() in case crop_left
* and crop_right are 0 and just create a sub-buffer of the input
* buffer
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gst/gst.h>
#include <gst/video/video.h>
#include "gstvideocropelements.h"
GST_DEBUG_CATEGORY_STATIC (videocrop_debug);
#define GST_CAT_DEFAULT videocrop_debug
void
videocrop_element_init (GstPlugin * plugin)
{
static gsize res = FALSE;
if (g_once_init_enter (&res)) {
GST_DEBUG_CATEGORY_INIT (videocrop_debug, "videocrop", 0, "videocrop");
g_once_init_leave (&res, TRUE);
}
}