gstreamer/gst/videoparsers/gstpngparse.c

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/* GStreamer PNG Parser
* Copyright (C) <2013> Collabora Ltd
* @author Olivier Crete <olivier.crete@collabora.com>
*
* 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.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include "gstpngparse.h"
#include <gst/base/gstbytereader.h>
#define PNG_SIGNATURE G_GUINT64_CONSTANT (0x89504E470D0A1A0A)
GST_DEBUG_CATEGORY (png_parse_debug);
#define GST_CAT_DEFAULT png_parse_debug
static GstStaticPadTemplate srctemplate =
GST_STATIC_PAD_TEMPLATE ("src", GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("image/png, width = (int)[1, MAX], height = (int)[1, MAX],"
"parsed = (boolean) true")
);
static GstStaticPadTemplate sinktemplate =
GST_STATIC_PAD_TEMPLATE ("sink", GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("image/png")
);
#define parent_class gst_png_parse_parent_class
G_DEFINE_TYPE (GstPngParse, gst_png_parse, GST_TYPE_BASE_PARSE);
static gboolean gst_png_parse_start (GstBaseParse * parse);
static GstFlowReturn gst_png_parse_handle_frame (GstBaseParse * parse,
GstBaseParseFrame * frame, gint * skipsize);
static void
gst_png_parse_class_init (GstPngParseClass * klass)
{
GstElementClass *gstelement_class = GST_ELEMENT_CLASS (klass);
GstBaseParseClass *parse_class = GST_BASE_PARSE_CLASS (klass);
GST_DEBUG_CATEGORY_INIT (png_parse_debug, "pngparse", 0, "png parser");
gst_element_class_add_pad_template (gstelement_class,
gst_static_pad_template_get (&srctemplate));
gst_element_class_add_pad_template (gstelement_class,
gst_static_pad_template_get (&sinktemplate));
gst_element_class_set_static_metadata (gstelement_class, "PNG parser",
"Codec/Parser/Video/Image",
"Parses PNG files", "Olivier Crete <olivier.crete@collabora.com>");
/* Override BaseParse vfuncs */
parse_class->start = GST_DEBUG_FUNCPTR (gst_png_parse_start);
parse_class->handle_frame = GST_DEBUG_FUNCPTR (gst_png_parse_handle_frame);
}
static void
gst_png_parse_init (GstPngParse * pngparse)
{
}
static gboolean
gst_png_parse_start (GstBaseParse * parse)
{
GstPngParse *pngparse = GST_PNG_PARSE (parse);
GST_DEBUG_OBJECT (pngparse, "start");
/* the start code and at least 2 empty frames (IHDR and IEND) */
gst_base_parse_set_min_frame_size (parse, 8 + 12 + 12);
pngparse->width = 0;
pngparse->height = 0;
return TRUE;
}
static GstFlowReturn
gst_png_parse_handle_frame (GstBaseParse * parse,
GstBaseParseFrame * frame, gint * skipsize)
{
GstPngParse *pngparse = GST_PNG_PARSE (parse);
GstMapInfo map;
GstByteReader reader;
GstFlowReturn ret = GST_FLOW_OK;
guint64 signature;
guint width = 0, height = 0;
gst_buffer_map (frame->buffer, &map, GST_MAP_READ);
gst_byte_reader_init (&reader, map.data, map.size);
if (!gst_byte_reader_peek_uint64_be (&reader, &signature))
goto beach;
if (signature != PNG_SIGNATURE) {
for (;;) {
guint offset;
offset = gst_byte_reader_masked_scan_uint32 (&reader, 0xffffffff,
0x89504E47, 0, gst_byte_reader_get_remaining (&reader));
if (offset == -1) {
*skipsize = gst_byte_reader_get_remaining (&reader) - 4;
goto beach;
}
gst_byte_reader_skip (&reader, offset);
if (!gst_byte_reader_peek_uint64_be (&reader, &signature))
goto beach;
if (signature == PNG_SIGNATURE) {
/* We're skipping, go out, we'll be back */
*skipsize = gst_byte_reader_get_pos (&reader);
goto beach;
}
gst_byte_reader_skip (&reader, 4);
}
}
gst_byte_reader_skip (&reader, 8);
for (;;) {
guint32 length;
guint32 code;
if (!gst_byte_reader_get_uint32_be (&reader, &length))
goto beach;
if (!gst_byte_reader_get_uint32_le (&reader, &code))
goto beach;
if (code == GST_MAKE_FOURCC ('I', 'H', 'D', 'R')) {
if (!gst_byte_reader_get_uint32_be (&reader, &width))
goto beach;
if (!gst_byte_reader_get_uint32_be (&reader, &height))
goto beach;
length -= 8;
}
if (!gst_byte_reader_skip (&reader, length + 4))
goto beach;
if (code == GST_MAKE_FOURCC ('I', 'E', 'N', 'D')) {
if (pngparse->width != width || pngparse->height != height) {
GstCaps *caps, *sink_caps;
pngparse->height = height;
pngparse->width = width;
caps = gst_caps_new_simple ("image/png",
"width", G_TYPE_INT, width, "height", G_TYPE_INT, height, NULL);
sink_caps =
gst_pad_get_current_caps (GST_BASE_PARSE_SINK_PAD (pngparse));
if (sink_caps) {
GstStructure *st;
gint fr_num, fr_denom;
st = gst_caps_get_structure (sink_caps, 0);
if (st
&& gst_structure_get_fraction (st, "framerate", &fr_num,
&fr_denom)) {
gst_caps_set_simple (caps,
"framerate", GST_TYPE_FRACTION, fr_num, fr_denom, NULL);
} else {
GST_WARNING_OBJECT (pngparse, "No framerate set");
}
}
if (!gst_pad_set_caps (GST_BASE_PARSE_SRC_PAD (parse), caps))
ret = GST_FLOW_NOT_NEGOTIATED;
gst_caps_unref (caps);
if (ret != GST_FLOW_OK)
goto beach;
}
gst_buffer_unmap (frame->buffer, &map);
return gst_base_parse_finish_frame (parse, frame,
gst_byte_reader_get_pos (&reader));
}
}
beach:
gst_buffer_unmap (frame->buffer, &map);
return ret;
}