gstreamer/ext/zbar/gstzbar.c

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/* GStreamer
* Copyright (C) 2009 Stefan Kost <ensonic@users.sf.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., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:element-zbar
*
* Detect bar codes in the video streams and send them as element messages to
* the #GstBus if .#GstZBar:message property is %TRUE.
*
* The element generate messages named
* <classname>&quot;barcode&quot;</classname>. The structure containes these
* fields:
* <itemizedlist>
* <listitem>
* <para>
* #GstClockTime
* <classname>&quot;timestamp&quot;</classname>:
* the timestamp of the buffer that triggered the message.
* </para>
* </listitem>
* <listitem>
* <para>
* gchar*
* <classname>&quot;type&quot;</classname>:
* the symbol type.
* </para>
* </listitem>
* <listitem>
* <para>
* gchar*
* <classname>&quot;symbol&quot;</classname>:
* the deteted bar code data.
* </para>
* </listitem>
* <listitem>
* <para>
* gint
* <classname>&quot;quality&quot;</classname>:
* an unscaled, relative quantity: larger values are better than smaller
* values.
* </para>
* </listitem>
* </itemizedlist>
*
* <refsect2>
* <title>Example launch lines</title>
* |[
* gst-launch -m v4l2src ! ffmpegcolorspace ! zbar ! ffmpegcolorspace ! xvimagesink
* ]| This pipeline will detect barcodes and send them as messages.
* |[
* gst-launch -m v4l2src ! tee name=t ! queue ! ffmpegcolorspace ! zbar ! fakesink t. ! queue ! xvimagesink
* ]| Same as above, but running the filter on a branch to keep the display in color
* </refsect2>
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "gstzbar.h"
#include <string.h>
#include <math.h>
#include <gst/video/video.h>
GST_DEBUG_CATEGORY_STATIC (zbar_debug);
#define GST_CAT_DEFAULT zbar_debug
/* GstZBar signals and args */
enum
{
/* FILL ME */
LAST_SIGNAL
};
enum
{
PROP_0,
PROP_MESSAGE,
PROP_CACHE
};
#define DEFAULT_CACHE FALSE
#define DEFAULT_MESSAGE TRUE
/* FIXME: add YVU9 and YUV9 once we have a GstVideoFormat for that */
#define ZBAR_YUV_CAPS \
"{ Y800, I420, YV12, NV12, NV21, Y41B, Y42B }"
static GstStaticPadTemplate gst_zbar_src_template =
GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
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GST_STATIC_CAPS (GST_VIDEO_CAPS_MAKE (ZBAR_YUV_CAPS))
);
static GstStaticPadTemplate gst_zbar_sink_template =
GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
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GST_STATIC_CAPS (GST_VIDEO_CAPS_MAKE (ZBAR_YUV_CAPS))
);
static void gst_zbar_finalize (GObject * object);
static void gst_zbar_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_zbar_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static gboolean gst_zbar_start (GstBaseTransform * base);
static gboolean gst_zbar_stop (GstBaseTransform * base);
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static GstFlowReturn gst_zbar_transform_frame_ip (GstVideoFilter * vfilter,
GstVideoFrame * frame);
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#define gst_zbar_parent_class parent_class
G_DEFINE_TYPE (GstZBar, gst_zbar, GST_TYPE_VIDEO_FILTER);
static void
gst_zbar_class_init (GstZBarClass * g_class)
{
GObjectClass *gobject_class;
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GstElementClass *gstelement_class;
GstBaseTransformClass *trans_class;
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GstVideoFilterClass *vfilter_class;
gobject_class = G_OBJECT_CLASS (g_class);
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gstelement_class = GST_ELEMENT_CLASS (g_class);
trans_class = GST_BASE_TRANSFORM_CLASS (g_class);
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vfilter_class = GST_VIDEO_FILTER_CLASS (g_class);
gobject_class->set_property = gst_zbar_set_property;
gobject_class->get_property = gst_zbar_get_property;
gobject_class->finalize = gst_zbar_finalize;
g_object_class_install_property (gobject_class, PROP_MESSAGE,
g_param_spec_boolean ("message", "message",
"Post a barcode message for each detected code",
DEFAULT_MESSAGE, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
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g_object_class_install_property (gobject_class, PROP_CACHE,
g_param_spec_boolean ("cache", "cache",
"Enable or disable the inter-image result cache",
DEFAULT_CACHE,
G_PARAM_READWRITE | GST_PARAM_MUTABLE_READY |
G_PARAM_STATIC_STRINGS));
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gst_element_class_set_details_simple (gstelement_class, "Barcode detector",
"Filter/Analyzer/Video",
"Detect bar codes in the video streams",
"Stefan Kost <ensonic@users.sf.net>");
gst_element_class_add_pad_template (gstelement_class,
gst_static_pad_template_get (&gst_zbar_sink_template));
gst_element_class_add_pad_template (gstelement_class,
gst_static_pad_template_get (&gst_zbar_src_template));
trans_class->start = GST_DEBUG_FUNCPTR (gst_zbar_start);
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trans_class->stop = GST_DEBUG_FUNCPTR (gst_zbar_stop);
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trans_class->transform_ip_on_passthrough = FALSE;
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vfilter_class->transform_frame_ip =
GST_DEBUG_FUNCPTR (gst_zbar_transform_frame_ip);
}
static void
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gst_zbar_init (GstZBar * zbar)
{
zbar->cache = DEFAULT_CACHE;
zbar->message = DEFAULT_MESSAGE;
zbar->scanner = zbar_image_scanner_create ();
}
static void
gst_zbar_finalize (GObject * object)
{
GstZBar *zbar = GST_ZBAR (object);
zbar_image_scanner_destroy (zbar->scanner);
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static void
gst_zbar_set_property (GObject * object, guint prop_id, const GValue * value,
GParamSpec * pspec)
{
GstZBar *zbar;
g_return_if_fail (GST_IS_ZBAR (object));
zbar = GST_ZBAR (object);
switch (prop_id) {
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case PROP_CACHE:
zbar->cache = g_value_get_boolean (value);
break;
case PROP_MESSAGE:
zbar->message = g_value_get_boolean (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_zbar_get_property (GObject * object, guint prop_id, GValue * value,
GParamSpec * pspec)
{
GstZBar *zbar;
g_return_if_fail (GST_IS_ZBAR (object));
zbar = GST_ZBAR (object);
switch (prop_id) {
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case PROP_CACHE:
g_value_set_boolean (value, zbar->cache);
break;
case PROP_MESSAGE:
g_value_set_boolean (value, zbar->message);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static GstFlowReturn
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gst_zbar_transform_frame_ip (GstVideoFilter * vfilter, GstVideoFrame * frame)
{
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GstZBar *zbar = GST_ZBAR (vfilter);
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gpointer data;
gint stride, height;
zbar_image_t *image;
const zbar_symbol_t *symbol;
int n;
image = zbar_image_create ();
/* all formats we support start with an 8-bit Y plane. zbar doesn't need
* to know about the chroma plane(s) */
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data = GST_VIDEO_FRAME_COMP_DATA (frame, 0);
stride = GST_VIDEO_FRAME_COMP_STRIDE (frame, 0);
height = GST_VIDEO_FRAME_HEIGHT (frame);
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zbar_image_set_format (image, GST_MAKE_FOURCC ('Y', '8', '0', '0'));
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zbar_image_set_size (image, stride, height);
zbar_image_set_data (image, (gpointer) data, stride * height, NULL);
/* scan the image for barcodes */
n = zbar_scan_image (zbar->scanner, image);
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if (n == 0)
goto out;
/* extract results */
symbol = zbar_image_first_symbol (image);
for (; symbol; symbol = zbar_symbol_next (symbol)) {
zbar_symbol_type_t typ = zbar_symbol_get_type (symbol);
const char *data = zbar_symbol_get_data (symbol);
gint quality = zbar_symbol_get_quality (symbol);
GST_DEBUG_OBJECT (zbar, "decoded %s symbol \"%s\" at quality %d",
zbar_get_symbol_name (typ), data, quality);
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if (zbar->cache && zbar_symbol_get_count (symbol) != 0)
continue;
if (zbar->message) {
GstMessage *m;
GstStructure *s;
/* post a message */
s = gst_structure_new ("barcode",
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"timestamp", G_TYPE_UINT64, GST_BUFFER_TIMESTAMP (frame->buffer),
"type", G_TYPE_STRING, zbar_get_symbol_name (typ),
"symbol", G_TYPE_STRING, data, "quality", G_TYPE_INT, quality, NULL);
m = gst_message_new_element (GST_OBJECT (zbar), s);
gst_element_post_message (GST_ELEMENT (zbar), m);
}
}
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out:
/* clean up */
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zbar_image_scanner_recycle_image (zbar->scanner, image);
zbar_image_destroy (image);
return GST_FLOW_OK;
}
static gboolean
gst_zbar_start (GstBaseTransform * base)
{
GstZBar *zbar = GST_ZBAR (base);
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/* start the cache if enabled (e.g. for filtering dupes) */
zbar_image_scanner_enable_cache (zbar->scanner, zbar->cache);
return TRUE;
}
static gboolean
gst_zbar_stop (GstBaseTransform * base)
{
GstZBar *zbar = GST_ZBAR (base);
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/* stop the cache if enabled (e.g. for filtering dupes) */
zbar_image_scanner_enable_cache (zbar->scanner, zbar->cache);
return TRUE;
}
static gboolean
plugin_init (GstPlugin * plugin)
{
GST_DEBUG_CATEGORY_INIT (zbar_debug, "zbar", 0, "zbar");
return gst_element_register (plugin, "zbar", GST_RANK_NONE, GST_TYPE_ZBAR);
}
GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
GST_VERSION_MINOR,
zbar,
"zbar barcode scanner",
plugin_init, VERSION, GST_LICENSE, GST_PACKAGE_NAME, GST_PACKAGE_ORIGIN);