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* Copyright (C) 2011 David Schleef <ds@entropywave.com>
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 51 Franklin Street, Suite 500,
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* Boston, MA 02110-1335, USA.
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* SECTION:element-gstzebrastripe
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* The zebrastripe element marks areas of images in a video stream
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* that are brighter than a threshold with a diagonal zebra stripe
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* pattern. Typically, this is used to aid in adjusting the exposure
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* setting on the camera. Setting the threshold to 95 or 100 will
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* show areas that are completely overexposed and clipping. A
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* threshold setting of 70 is often used to properly adjust skin
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* <title>Example launch line</title>
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* gst-launch -v videotestsrc ! zebrastripe ! xvimagesink
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* Marks overexposed areas of the video with zebra stripes.
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* The threshold property is expressed as percentage of full scale,
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* whereas common usage expresses thresholds in terms of IRE. The
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* property setting can be calculated from IRE by using the formula
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* percent = (IRE * 1.075) - 7.5. Note that 100 IRE corresponds to
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* 100 %, and 70 IRE corresponds to 68 %.
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#include <gst/base/gstbasetransform.h>
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#include <gst/video/video.h>
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#include "gstzebrastripe.h"
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GST_DEBUG_CATEGORY_STATIC (gst_zebra_stripe_debug_category);
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#define GST_CAT_DEFAULT gst_zebra_stripe_debug_category
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static void gst_zebra_stripe_set_property (GObject * object,
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guint property_id, const GValue * value, GParamSpec * pspec);
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static void gst_zebra_stripe_get_property (GObject * object,
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guint property_id, GValue * value, GParamSpec * pspec);
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static void gst_zebra_stripe_finalize (GObject * object);
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static gboolean gst_zebra_stripe_start (GstBaseTransform * trans);
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static gboolean gst_zebra_stripe_stop (GstBaseTransform * trans);
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gst_zebra_stripe_prefilter (GstVideoFilter2 * videofilter2, GstBuffer * buf);
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static GstVideoFilter2Functions gst_zebra_stripe_filter_functions[];
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#define DEFAULT_THRESHOLD 90
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/* class initialization */
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#define DEBUG_INIT(bla) \
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GST_DEBUG_CATEGORY_INIT (gst_zebra_stripe_debug_category, "zebrastripe", 0, \
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"debug category for zebrastripe element");
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GST_BOILERPLATE_FULL (GstZebraStripe, gst_zebra_stripe, GstVideoFilter2,
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GST_TYPE_VIDEO_FILTER2, DEBUG_INIT);
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gst_zebra_stripe_base_init (gpointer g_class)
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GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
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gst_element_class_set_details_simple (element_class, "Zebra stripe overlay",
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"Overlays zebra striping on overexposed areas of video",
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"David Schleef <ds@entropywave.com>");
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gst_zebra_stripe_class_init (GstZebraStripeClass * klass)
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GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
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GstVideoFilter2Class *video_filter2_class = GST_VIDEO_FILTER2_CLASS (klass);
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GstBaseTransformClass *base_transform_class =
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GST_BASE_TRANSFORM_CLASS (klass);
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gobject_class->set_property = gst_zebra_stripe_set_property;
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gobject_class->get_property = gst_zebra_stripe_get_property;
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gobject_class->finalize = gst_zebra_stripe_finalize;
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base_transform_class->start = GST_DEBUG_FUNCPTR (gst_zebra_stripe_start);
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base_transform_class->stop = GST_DEBUG_FUNCPTR (gst_zebra_stripe_stop);
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video_filter2_class->prefilter =
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GST_DEBUG_FUNCPTR (gst_zebra_stripe_prefilter);
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g_object_class_install_property (gobject_class, PROP_THRESHOLD,
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g_param_spec_int ("threshold", "Threshold",
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"Threshold above which the video is striped", 0, 100,
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G_PARAM_READWRITE | G_PARAM_CONSTRUCT | G_PARAM_STATIC_STRINGS));
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gst_video_filter2_class_add_functions (video_filter2_class,
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gst_zebra_stripe_filter_functions);
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gst_zebra_stripe_init (GstZebraStripe * zebrastripe,
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GstZebraStripeClass * zebrastripe_class)
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gst_zebra_stripe_set_property (GObject * object, guint property_id,
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const GValue * value, GParamSpec * pspec)
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GstZebraStripe *zebrastripe;
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g_return_if_fail (GST_IS_ZEBRA_STRIPE (object));
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zebrastripe = GST_ZEBRA_STRIPE (object);
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switch (property_id) {
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zebrastripe->threshold = g_value_get_int (value);
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zebrastripe->y_threshold =
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16 + floor (0.5 + 2.19 * zebrastripe->threshold);
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G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
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gst_zebra_stripe_get_property (GObject * object, guint property_id,
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GValue * value, GParamSpec * pspec)
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GstZebraStripe *zebrastripe;
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g_return_if_fail (GST_IS_ZEBRA_STRIPE (object));
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zebrastripe = GST_ZEBRA_STRIPE (object);
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switch (property_id) {
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g_value_set_int (value, zebrastripe->threshold);
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G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
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gst_zebra_stripe_finalize (GObject * object)
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GstZebraStripe *zebrastripe;
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g_return_if_fail (GST_IS_ZEBRA_STRIPE (object));
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zebrastripe = GST_ZEBRA_STRIPE (object);
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/* clean up object here */
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G_OBJECT_CLASS (parent_class)->finalize (object);
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gst_zebra_stripe_start (GstBaseTransform * trans)
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gst_zebra_stripe_stop (GstBaseTransform * trans)
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gst_zebra_stripe_prefilter (GstVideoFilter2 * videofilter2, GstBuffer * buf)
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GstZebraStripe *zebrastripe = GST_ZEBRA_STRIPE (videofilter2);
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gst_zebra_stripe_filter_ip_planarY (GstVideoFilter2 * videofilter2,
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GstBuffer * buf, int start, int end)
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GstZebraStripe *zebrastripe = GST_ZEBRA_STRIPE (videofilter2);
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int width = GST_VIDEO_FILTER2_WIDTH (zebrastripe);
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int threshold = zebrastripe->y_threshold;
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int t = zebrastripe->t;
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ydata = GST_BUFFER_DATA (buf);
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gst_video_format_get_row_stride (GST_VIDEO_FILTER2_FORMAT (videofilter2),
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for (j = start; j < end; j++) {
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guint8 *data = ydata + ystride * j;
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for (i = 0; i < width; i++) {
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if (data[i] >= threshold) {
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if ((i + j + t) & 0x4)
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gst_zebra_stripe_filter_ip_YxYy (GstVideoFilter2 * videofilter2,
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GstBuffer * buf, int start, int end)
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GstZebraStripe *zebrastripe = GST_ZEBRA_STRIPE (videofilter2);
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GstVideoFormat format = GST_VIDEO_FILTER2_FORMAT (zebrastripe);
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int width = GST_VIDEO_FILTER2_WIDTH (zebrastripe);
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int threshold = zebrastripe->y_threshold;
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int t = zebrastripe->t;
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ydata = GST_BUFFER_DATA (buf);
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ystride = gst_video_format_get_row_stride (format, 0, width);
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if (format == GST_VIDEO_FORMAT_UYVY) {
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for (j = start; j < end; j++) {
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guint8 *data = ydata + ystride * j;
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for (i = 0; i < width; i++) {
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if (data[2 * i] >= threshold) {
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if ((i + j + t) & 0x4)
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gst_zebra_stripe_filter_ip_AYUV (GstVideoFilter2 * videofilter2,
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GstBuffer * buf, int start, int end)
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GstZebraStripe *zebrastripe = GST_ZEBRA_STRIPE (videofilter2);
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int width = GST_VIDEO_FILTER2_WIDTH (zebrastripe);
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int threshold = zebrastripe->y_threshold;
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int t = zebrastripe->t;
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ydata = GST_BUFFER_DATA (buf);
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gst_video_format_get_row_stride (GST_VIDEO_FILTER2_FORMAT (videofilter2),
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for (j = start; j < end; j++) {
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guint8 *data = ydata + ystride * j;
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for (i = 0; i < width; i++) {
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if (data[4 * i] >= threshold) {
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if ((i + j + t) & 0x4)
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static GstVideoFilter2Functions gst_zebra_stripe_filter_functions[] = {
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{GST_VIDEO_FORMAT_I420, NULL, gst_zebra_stripe_filter_ip_planarY},
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{GST_VIDEO_FORMAT_YV12, NULL, gst_zebra_stripe_filter_ip_planarY},
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{GST_VIDEO_FORMAT_Y41B, NULL, gst_zebra_stripe_filter_ip_planarY},
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{GST_VIDEO_FORMAT_Y42B, NULL, gst_zebra_stripe_filter_ip_planarY},
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{GST_VIDEO_FORMAT_NV12, NULL, gst_zebra_stripe_filter_ip_planarY},
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{GST_VIDEO_FORMAT_NV21, NULL, gst_zebra_stripe_filter_ip_planarY},
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{GST_VIDEO_FORMAT_YUV9, NULL, gst_zebra_stripe_filter_ip_planarY},
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{GST_VIDEO_FORMAT_YVU9, NULL, gst_zebra_stripe_filter_ip_planarY},
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{GST_VIDEO_FORMAT_Y444, NULL, gst_zebra_stripe_filter_ip_planarY},
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{GST_VIDEO_FORMAT_UYVY, NULL, gst_zebra_stripe_filter_ip_YxYy},
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{GST_VIDEO_FORMAT_YUY2, NULL, gst_zebra_stripe_filter_ip_YxYy},
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{GST_VIDEO_FORMAT_YVYU, NULL, gst_zebra_stripe_filter_ip_YxYy},
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{GST_VIDEO_FORMAT_AYUV, NULL, gst_zebra_stripe_filter_ip_AYUV},
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{GST_VIDEO_FORMAT_UNKNOWN}