--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gst_plugins_good/ext/libpng/gstpngdec.c	Fri Apr 16 15:15:52 2010 +0300
@@ -0,0 +1,881 @@
+/* GStreamer
+ * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
+ *
+ * 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-pngdec
+ *
+ * Decodes png images. If there is no framerate set on sink caps, it sends EOS
+ * after the first picture.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "gstpngdec.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <gst/video/video.h>
+#include <gst/gst-i18n-plugin.h>
+
+static const GstElementDetails gst_pngdec_details =
+GST_ELEMENT_DETAILS ("PNG image decoder",
+    "Codec/Decoder/Image",
+    "Decode a png video frame to a raw image",
+    "Wim Taymans <wim@fluendo.com>");
+
+GST_DEBUG_CATEGORY_STATIC (pngdec_debug);
+#define GST_CAT_DEFAULT pngdec_debug
+
+static void gst_pngdec_base_init (gpointer g_class);
+static void gst_pngdec_class_init (GstPngDecClass * klass);
+static void gst_pngdec_init (GstPngDec * pngdec);
+
+static gboolean gst_pngdec_libpng_init (GstPngDec * pngdec);
+static gboolean gst_pngdec_libpng_clear (GstPngDec * pngdec);
+
+static GstStateChangeReturn gst_pngdec_change_state (GstElement * element,
+    GstStateChange transition);
+
+static gboolean gst_pngdec_sink_activate_push (GstPad * sinkpad,
+    gboolean active);
+static gboolean gst_pngdec_sink_activate_pull (GstPad * sinkpad,
+    gboolean active);
+static gboolean gst_pngdec_sink_activate (GstPad * sinkpad);
+
+static GstFlowReturn gst_pngdec_caps_create_and_set (GstPngDec * pngdec);
+
+static void gst_pngdec_task (GstPad * pad);
+static GstFlowReturn gst_pngdec_chain (GstPad * pad, GstBuffer * buffer);
+static gboolean gst_pngdec_sink_event (GstPad * pad, GstEvent * event);
+static gboolean gst_pngdec_sink_setcaps (GstPad * pad, GstCaps * caps);
+
+static GstElementClass *parent_class = NULL;
+
+GType
+gst_pngdec_get_type (void)
+{
+  static GType pngdec_type = 0;
+
+  if (!pngdec_type) {
+    static const GTypeInfo pngdec_info = {
+      sizeof (GstPngDecClass),
+      gst_pngdec_base_init,
+      NULL,
+      (GClassInitFunc) gst_pngdec_class_init,
+      NULL,
+      NULL,
+      sizeof (GstPngDec),
+      0,
+      (GInstanceInitFunc) gst_pngdec_init,
+    };
+
+    pngdec_type = g_type_register_static (GST_TYPE_ELEMENT, "GstPngDec",
+        &pngdec_info, 0);
+  }
+  return pngdec_type;
+}
+
+static GstStaticPadTemplate gst_pngdec_src_pad_template =
+    GST_STATIC_PAD_TEMPLATE ("src",
+    GST_PAD_SRC,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_RGBA ";" GST_VIDEO_CAPS_RGB)
+    );
+
+static GstStaticPadTemplate gst_pngdec_sink_pad_template =
+GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS ("image/png")
+    );
+
+static void
+gst_pngdec_base_init (gpointer g_class)
+{
+  GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
+
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&gst_pngdec_src_pad_template));
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&gst_pngdec_sink_pad_template));
+  gst_element_class_set_details (element_class, &gst_pngdec_details);
+}
+
+static void
+gst_pngdec_class_init (GstPngDecClass * klass)
+{
+  GstElementClass *gstelement_class;
+
+  gstelement_class = (GstElementClass *) klass;
+
+  parent_class = g_type_class_peek_parent (klass);
+
+  gstelement_class->change_state = gst_pngdec_change_state;
+
+  GST_DEBUG_CATEGORY_INIT (pngdec_debug, "pngdec", 0, "PNG image decoder");
+}
+
+static void
+gst_pngdec_init (GstPngDec * pngdec)
+{
+  pngdec->sinkpad =
+      gst_pad_new_from_static_template (&gst_pngdec_sink_pad_template, "sink");
+  gst_pad_set_activate_function (pngdec->sinkpad, gst_pngdec_sink_activate);
+  gst_pad_set_activatepush_function (pngdec->sinkpad,
+      gst_pngdec_sink_activate_push);
+  gst_pad_set_activatepull_function (pngdec->sinkpad,
+      gst_pngdec_sink_activate_pull);
+  gst_pad_set_chain_function (pngdec->sinkpad, gst_pngdec_chain);
+  gst_pad_set_event_function (pngdec->sinkpad, gst_pngdec_sink_event);
+  gst_pad_set_setcaps_function (pngdec->sinkpad, gst_pngdec_sink_setcaps);
+  gst_element_add_pad (GST_ELEMENT (pngdec), pngdec->sinkpad);
+
+  pngdec->srcpad =
+      gst_pad_new_from_static_template (&gst_pngdec_src_pad_template, "src");
+  gst_pad_use_fixed_caps (pngdec->srcpad);
+  gst_element_add_pad (GST_ELEMENT (pngdec), pngdec->srcpad);
+
+  pngdec->buffer_out = NULL;
+  pngdec->png = NULL;
+  pngdec->info = NULL;
+  pngdec->endinfo = NULL;
+  pngdec->setup = FALSE;
+
+  pngdec->color_type = -1;
+  pngdec->width = -1;
+  pngdec->height = -1;
+  pngdec->bpp = -1;
+  pngdec->fps_n = 0;
+  pngdec->fps_d = 1;
+
+  pngdec->in_timestamp = GST_CLOCK_TIME_NONE;
+  pngdec->in_duration = GST_CLOCK_TIME_NONE;
+
+  gst_segment_init (&pngdec->segment, GST_FORMAT_UNDEFINED);
+
+  pngdec->image_ready = FALSE;
+}
+
+static void
+user_error_fn (png_structp png_ptr, png_const_charp error_msg)
+{
+  GST_ERROR ("%s", error_msg);
+}
+
+static void
+user_warning_fn (png_structp png_ptr, png_const_charp warning_msg)
+{
+  GST_WARNING ("%s", warning_msg);
+}
+
+static void
+user_info_callback (png_structp png_ptr, png_infop info)
+{
+  GstPngDec *pngdec = NULL;
+  GstFlowReturn ret = GST_FLOW_OK;
+  size_t buffer_size;
+  GstBuffer *buffer = NULL;
+
+  pngdec = GST_PNGDEC (png_ptr->io_ptr);
+
+  GST_LOG ("info ready");
+
+  /* Generate the caps and configure */
+  ret = gst_pngdec_caps_create_and_set (pngdec);
+  if (ret != GST_FLOW_OK) {
+    goto beach;
+  }
+
+  /* Allocate output buffer */
+  pngdec->rowbytes = png_get_rowbytes (pngdec->png, pngdec->info);
+  buffer_size = pngdec->height * GST_ROUND_UP_4 (pngdec->rowbytes);
+  ret =
+      gst_pad_alloc_buffer_and_set_caps (pngdec->srcpad, GST_BUFFER_OFFSET_NONE,
+      buffer_size, GST_PAD_CAPS (pngdec->srcpad), &buffer);
+  if (ret != GST_FLOW_OK) {
+    goto beach;
+  }
+
+  pngdec->buffer_out = buffer;
+
+beach:
+  pngdec->ret = ret;
+}
+
+static void
+user_endrow_callback (png_structp png_ptr, png_bytep new_row,
+    png_uint_32 row_num, int pass)
+{
+  GstPngDec *pngdec = NULL;
+
+  pngdec = GST_PNGDEC (png_ptr->io_ptr);
+
+  /* FIXME: implement interlaced pictures */
+
+  /* If buffer_out doesn't exist, it means buffer_alloc failed, which 
+   * will already have set the return code */
+  if (GST_IS_BUFFER (pngdec->buffer_out)) {
+    size_t offset = row_num * GST_ROUND_UP_4 (pngdec->rowbytes);
+
+    GST_LOG ("got row %u, copying in buffer %p at offset %" G_GSIZE_FORMAT,
+        (guint) row_num, pngdec->buffer_out, offset);
+    memcpy (GST_BUFFER_DATA (pngdec->buffer_out) + offset, new_row,
+        pngdec->rowbytes);
+    pngdec->ret = GST_FLOW_OK;
+  }
+}
+
+static gboolean
+buffer_clip (GstPngDec * dec, GstBuffer * buffer)
+{
+  gboolean res = TRUE;
+  gint64 cstart, cstop;
+
+
+  if ((!GST_CLOCK_TIME_IS_VALID (GST_BUFFER_TIMESTAMP (buffer))) ||
+      (!GST_CLOCK_TIME_IS_VALID (GST_BUFFER_DURATION (buffer))) ||
+      (dec->segment.format != GST_FORMAT_TIME))
+    goto beach;
+
+  cstart = GST_BUFFER_TIMESTAMP (buffer);
+  cstop = GST_BUFFER_DURATION (buffer);
+
+  if ((res = gst_segment_clip (&dec->segment, GST_FORMAT_TIME,
+              cstart, cstart + cstop, &cstart, &cstop))) {
+    GST_BUFFER_TIMESTAMP (buffer) = cstart;
+    GST_BUFFER_DURATION (buffer) = cstop - cstart;
+  }
+
+beach:
+  return res;
+}
+
+static void
+user_end_callback (png_structp png_ptr, png_infop info)
+{
+  GstPngDec *pngdec = NULL;
+
+  pngdec = GST_PNGDEC (png_ptr->io_ptr);
+
+  GST_LOG_OBJECT (pngdec, "and we are done reading this image");
+
+  if (!pngdec->buffer_out)
+    return;
+
+  if (GST_CLOCK_TIME_IS_VALID (pngdec->in_timestamp))
+    GST_BUFFER_TIMESTAMP (pngdec->buffer_out) = pngdec->in_timestamp;
+  if (GST_CLOCK_TIME_IS_VALID (pngdec->in_duration))
+    GST_BUFFER_DURATION (pngdec->buffer_out) = pngdec->in_duration;
+
+  /* buffer clipping */
+  if (buffer_clip (pngdec, pngdec->buffer_out)) {
+    /* Push our buffer and then EOS if needed */
+    GST_LOG_OBJECT (pngdec, "pushing buffer with ts=%" GST_TIME_FORMAT,
+        GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (pngdec->buffer_out)));
+
+    pngdec->ret = gst_pad_push (pngdec->srcpad, pngdec->buffer_out);
+  } else {
+    GST_LOG_OBJECT (pngdec, "dropped decoded buffer");
+    gst_buffer_unref (pngdec->buffer_out);
+  }
+  pngdec->buffer_out = NULL;
+  pngdec->image_ready = TRUE;
+}
+
+static void
+user_read_data (png_structp png_ptr, png_bytep data, png_size_t length)
+{
+  GstPngDec *pngdec;
+  GstBuffer *buffer;
+  GstFlowReturn ret = GST_FLOW_OK;
+  guint size;
+
+  pngdec = GST_PNGDEC (png_ptr->io_ptr);
+
+  GST_LOG ("reading %" G_GSIZE_FORMAT " bytes of data at offset %d", length,
+      pngdec->offset);
+
+  ret = gst_pad_pull_range (pngdec->sinkpad, pngdec->offset, length, &buffer);
+  if (ret != GST_FLOW_OK)
+    goto pause;
+
+  size = GST_BUFFER_SIZE (buffer);
+
+  if (size != length)
+    goto short_buffer;
+
+  memcpy (data, GST_BUFFER_DATA (buffer), size);
+
+  gst_buffer_unref (buffer);
+
+  pngdec->offset += length;
+
+  return;
+
+  /* ERRORS */
+pause:
+  {
+    GST_INFO_OBJECT (pngdec, "pausing task, reason %s",
+        gst_flow_get_name (ret));
+    gst_pad_pause_task (pngdec->sinkpad);
+    if (GST_FLOW_IS_FATAL (ret) || ret == GST_FLOW_NOT_LINKED) {
+      GST_ELEMENT_ERROR (pngdec, STREAM, FAILED,
+          (_("Internal data stream error.")),
+          ("stream stopped, reason %s", gst_flow_get_name (ret)));
+      gst_pad_push_event (pngdec->srcpad, gst_event_new_eos ());
+    }
+    return;
+  }
+short_buffer:
+  {
+    gst_buffer_unref (buffer);
+    GST_ELEMENT_ERROR (pngdec, STREAM, FAILED,
+        (_("Internal data stream error.")),
+        ("Read %u, needed %" G_GSIZE_FORMAT "bytes", size, length));
+    ret = GST_FLOW_ERROR;
+    goto pause;
+  }
+}
+
+static GstFlowReturn
+gst_pngdec_caps_create_and_set (GstPngDec * pngdec)
+{
+  GstFlowReturn ret = GST_FLOW_OK;
+  GstCaps *caps = NULL, *res = NULL;
+  GstPadTemplate *templ = NULL;
+  gint bpc = 0, color_type;
+  png_uint_32 width, height;
+
+  g_return_val_if_fail (GST_IS_PNGDEC (pngdec), GST_FLOW_ERROR);
+
+  /* Get bits per channel */
+  bpc = png_get_bit_depth (pngdec->png, pngdec->info);
+
+  /* We don't handle 16 bits per color, strip down to 8 */
+  if (bpc == 16) {
+    GST_LOG_OBJECT (pngdec,
+        "this is a 16 bits per channel PNG image, strip down to 8 bits");
+    png_set_strip_16 (pngdec->png);
+  }
+
+  /* Get Color type */
+  color_type = png_get_color_type (pngdec->png, pngdec->info);
+
+#if 0
+  /* We used to have this HACK to reverse the outgoing bytes, but the problem
+   * that originally required the hack seems to have been in ffmpegcolorspace's
+   * RGBA descriptions. It doesn't seem needed now that's fixed, but might
+   * still be needed on big-endian systems, I'm not sure. J.S. 6/7/2007 */
+  if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+    png_set_bgr (pngdec->png);
+#endif
+
+  /* Gray scale converted to RGB and upscaled to 8 bits */
+  if ((color_type == PNG_COLOR_TYPE_GRAY_ALPHA) ||
+      (color_type == PNG_COLOR_TYPE_GRAY)) {
+    GST_LOG_OBJECT (pngdec, "converting grayscale png to RGB");
+    png_set_gray_to_rgb (pngdec->png);
+    if (bpc < 8) {              /* Convert to 8 bits */
+      GST_LOG_OBJECT (pngdec, "converting grayscale image to 8 bits");
+      png_set_gray_1_2_4_to_8 (pngdec->png);
+    }
+  }
+
+  /* Palette converted to RGB */
+  if (color_type == PNG_COLOR_TYPE_PALETTE) {
+    GST_LOG_OBJECT (pngdec, "converting palette png to RGB");
+    png_set_palette_to_rgb (pngdec->png);
+  }
+
+  /* Update the info structure */
+  png_read_update_info (pngdec->png, pngdec->info);
+
+  /* Get IHDR header again after transformation settings */
+
+  png_get_IHDR (pngdec->png, pngdec->info, &width, &height,
+      &bpc, &pngdec->color_type, NULL, NULL, NULL);
+
+  pngdec->width = width;
+  pngdec->height = height;
+
+  GST_LOG_OBJECT (pngdec, "this is a %dx%d PNG image", pngdec->width,
+      pngdec->height);
+
+  switch (pngdec->color_type) {
+    case PNG_COLOR_TYPE_RGB:
+      GST_LOG_OBJECT (pngdec, "we have no alpha channel, depth is 24 bits");
+      pngdec->bpp = 24;
+      break;
+    case PNG_COLOR_TYPE_RGB_ALPHA:
+      GST_LOG_OBJECT (pngdec, "we have an alpha channel, depth is 32 bits");
+      pngdec->bpp = 32;
+      break;
+    default:
+      GST_ELEMENT_ERROR (pngdec, STREAM, NOT_IMPLEMENTED, (NULL),
+          ("pngdec does not support this color type"));
+      ret = GST_FLOW_NOT_SUPPORTED;
+      goto beach;
+  }
+
+  caps = gst_caps_new_simple ("video/x-raw-rgb",
+      "width", G_TYPE_INT, pngdec->width,
+      "height", G_TYPE_INT, pngdec->height,
+      "bpp", G_TYPE_INT, pngdec->bpp,
+      "framerate", GST_TYPE_FRACTION, pngdec->fps_n, pngdec->fps_d, NULL);
+
+  templ = gst_static_pad_template_get (&gst_pngdec_src_pad_template);
+
+  res = gst_caps_intersect (caps, gst_pad_template_get_caps (templ));
+
+  gst_caps_unref (caps);
+  gst_object_unref (templ);
+
+  if (!gst_pad_set_caps (pngdec->srcpad, res))
+    ret = GST_FLOW_NOT_NEGOTIATED;
+
+  GST_DEBUG_OBJECT (pngdec, "our caps %" GST_PTR_FORMAT, res);
+
+  gst_caps_unref (res);
+
+  /* Push a newsegment event */
+  if (pngdec->need_newsegment) {
+    gst_pad_push_event (pngdec->srcpad,
+        gst_event_new_new_segment (FALSE, 1.0, GST_FORMAT_TIME, 0, -1, 0));
+    pngdec->need_newsegment = FALSE;
+  }
+
+beach:
+  return ret;
+}
+
+static void
+gst_pngdec_task (GstPad * pad)
+{
+  GstPngDec *pngdec;
+  GstBuffer *buffer = NULL;
+  size_t buffer_size = 0;
+  gint i = 0;
+  png_bytep *rows, inp;
+  png_uint_32 rowbytes;
+  GstFlowReturn ret = GST_FLOW_OK;
+
+  pngdec = GST_PNGDEC (GST_OBJECT_PARENT (pad));
+
+  GST_LOG_OBJECT (pngdec, "read frame");
+
+  /* Let libpng come back here on error */
+  if (setjmp (png_jmpbuf (pngdec->png))) {
+    ret = GST_FLOW_ERROR;
+    goto pause;
+  }
+
+  /* Set reading callback */
+  png_set_read_fn (pngdec->png, pngdec, user_read_data);
+
+  /* Read info */
+  png_read_info (pngdec->png, pngdec->info);
+
+  /* Generate the caps and configure */
+  ret = gst_pngdec_caps_create_and_set (pngdec);
+  if (ret != GST_FLOW_OK) {
+    goto pause;
+  }
+
+  /* Allocate output buffer */
+  rowbytes = png_get_rowbytes (pngdec->png, pngdec->info);
+  buffer_size = pngdec->height * GST_ROUND_UP_4 (rowbytes);
+  ret =
+      gst_pad_alloc_buffer_and_set_caps (pngdec->srcpad, GST_BUFFER_OFFSET_NONE,
+      buffer_size, GST_PAD_CAPS (pngdec->srcpad), &buffer);
+  if (ret != GST_FLOW_OK)
+    goto pause;
+
+  rows = (png_bytep *) g_malloc (sizeof (png_bytep) * pngdec->height);
+
+  inp = GST_BUFFER_DATA (buffer);
+
+  for (i = 0; i < pngdec->height; i++) {
+    rows[i] = inp;
+    inp += GST_ROUND_UP_4 (rowbytes);
+  }
+
+  /* Read the actual picture */
+  png_read_image (pngdec->png, rows);
+  free (rows);
+
+  /* Push the raw RGB frame */
+  ret = gst_pad_push (pngdec->srcpad, buffer);
+  if (ret != GST_FLOW_OK)
+    goto pause;
+
+  /* And we are done */
+  gst_pad_pause_task (pngdec->sinkpad);
+  gst_pad_push_event (pngdec->srcpad, gst_event_new_eos ());
+  return;
+
+pause:
+  {
+    GST_INFO_OBJECT (pngdec, "pausing task, reason %s",
+        gst_flow_get_name (ret));
+    gst_pad_pause_task (pngdec->sinkpad);
+    if (GST_FLOW_IS_FATAL (ret) || ret == GST_FLOW_NOT_LINKED) {
+      GST_ELEMENT_ERROR (pngdec, STREAM, FAILED,
+          (_("Internal data stream error.")),
+          ("stream stopped, reason %s", gst_flow_get_name (ret)));
+      gst_pad_push_event (pngdec->srcpad, gst_event_new_eos ());
+    }
+  }
+}
+
+static GstFlowReturn
+gst_pngdec_chain (GstPad * pad, GstBuffer * buffer)
+{
+  GstPngDec *pngdec;
+  GstFlowReturn ret = GST_FLOW_OK;
+
+  pngdec = GST_PNGDEC (gst_pad_get_parent (pad));
+
+  GST_LOG_OBJECT (pngdec, "Got buffer, size=%u", GST_BUFFER_SIZE (buffer));
+
+  if (G_UNLIKELY (!pngdec->setup))
+    goto not_configured;
+
+  /* Something is going wrong in our callbacks */
+  ret = pngdec->ret;
+  if (G_UNLIKELY (ret != GST_FLOW_OK)) {
+    GST_WARNING_OBJECT (pngdec, "we have a pending return code of %d", ret);
+    goto beach;
+  }
+
+  /* Let libpng come back here on error */
+  if (setjmp (png_jmpbuf (pngdec->png))) {
+    GST_WARNING_OBJECT (pngdec, "error during decoding");
+    ret = GST_FLOW_ERROR;
+    goto beach;
+  }
+
+  pngdec->in_timestamp = GST_BUFFER_TIMESTAMP (buffer);
+  pngdec->in_duration = GST_BUFFER_DURATION (buffer);
+
+  /* Progressive loading of the PNG image */
+  png_process_data (pngdec->png, pngdec->info, GST_BUFFER_DATA (buffer),
+      GST_BUFFER_SIZE (buffer));
+
+  if (pngdec->image_ready) {
+    if (pngdec->framed) {
+      /* Reset ourselves for the next frame */
+      gst_pngdec_libpng_clear (pngdec);
+      gst_pngdec_libpng_init (pngdec);
+      GST_LOG_OBJECT (pngdec, "setting up callbacks for next frame");
+      png_set_progressive_read_fn (pngdec->png, pngdec,
+          user_info_callback, user_endrow_callback, user_end_callback);
+    } else {
+      GST_LOG_OBJECT (pngdec, "sending EOS");
+      pngdec->ret = gst_pad_push_event (pngdec->srcpad, gst_event_new_eos ());
+    }
+    pngdec->image_ready = FALSE;
+  }
+
+  /* grab new return code */
+  ret = pngdec->ret;
+
+  /* And release the buffer */
+  gst_buffer_unref (buffer);
+
+beach:
+  gst_object_unref (pngdec);
+
+  return ret;
+
+  /* ERRORS */
+not_configured:
+  {
+    GST_LOG_OBJECT (pngdec, "we are not configured yet");
+    ret = GST_FLOW_WRONG_STATE;
+    goto beach;
+  }
+}
+
+static gboolean
+gst_pngdec_sink_setcaps (GstPad * pad, GstCaps * caps)
+{
+  GstStructure *s;
+  GstPngDec *pngdec;
+  gint num, denom;
+
+  pngdec = GST_PNGDEC (gst_pad_get_parent (pad));
+
+  s = gst_caps_get_structure (caps, 0);
+  if (gst_structure_get_fraction (s, "framerate", &num, &denom)) {
+    GST_DEBUG_OBJECT (pngdec, "framed input");
+    pngdec->framed = TRUE;
+    pngdec->fps_n = num;
+    pngdec->fps_d = denom;
+  } else {
+    GST_DEBUG_OBJECT (pngdec, "single picture input");
+    pngdec->framed = FALSE;
+    pngdec->fps_n = 0;
+    pngdec->fps_d = 1;
+  }
+
+  gst_object_unref (pngdec);
+  return TRUE;
+}
+
+static gboolean
+gst_pngdec_sink_event (GstPad * pad, GstEvent * event)
+{
+  GstPngDec *pngdec;
+  gboolean res;
+
+  pngdec = GST_PNGDEC (gst_pad_get_parent (pad));
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_NEWSEGMENT:{
+      gdouble rate, arate;
+      gboolean update;
+      gint64 start, stop, position;
+      GstFormat fmt;
+
+      gst_event_parse_new_segment_full (event, &update, &rate, &arate, &fmt,
+          &start, &stop, &position);
+
+      gst_segment_set_newsegment_full (&pngdec->segment, update, rate, arate,
+          fmt, start, stop, position);
+
+      GST_LOG_OBJECT (pngdec, "NEWSEGMENT (%s)", gst_format_get_name (fmt));
+
+      if (fmt == GST_FORMAT_TIME) {
+        pngdec->need_newsegment = FALSE;
+        res = gst_pad_push_event (pngdec->srcpad, event);
+      } else {
+        gst_event_unref (event);
+        res = TRUE;
+      }
+      break;
+    }
+    case GST_EVENT_FLUSH_STOP:
+    {
+      gst_pngdec_libpng_clear (pngdec);
+      gst_pngdec_libpng_init (pngdec);
+      png_set_progressive_read_fn (pngdec->png, pngdec,
+          user_info_callback, user_endrow_callback, user_end_callback);
+      pngdec->ret = GST_FLOW_OK;
+      gst_segment_init (&pngdec->segment, GST_FORMAT_UNDEFINED);
+      res = gst_pad_push_event (pngdec->srcpad, event);
+      break;
+    }
+    case GST_EVENT_EOS:
+    {
+      GST_LOG_OBJECT (pngdec, "EOS");
+      gst_pngdec_libpng_clear (pngdec);
+      pngdec->ret = GST_FLOW_UNEXPECTED;
+      res = gst_pad_push_event (pngdec->srcpad, event);
+      break;
+    }
+    default:
+      res = gst_pad_push_event (pngdec->srcpad, event);
+      break;
+  }
+
+  gst_object_unref (pngdec);
+  return res;
+}
+
+
+/* Clean up the libpng structures */
+static gboolean
+gst_pngdec_libpng_clear (GstPngDec * pngdec)
+{
+  png_infopp info = NULL, endinfo = NULL;
+
+  g_return_val_if_fail (GST_IS_PNGDEC (pngdec), FALSE);
+
+  GST_LOG ("cleaning up libpng structures");
+
+  if (pngdec->info) {
+    info = &pngdec->info;
+  }
+
+  if (pngdec->endinfo) {
+    endinfo = &pngdec->endinfo;
+  }
+
+  if (pngdec->png) {
+    png_destroy_read_struct (&(pngdec->png), info, endinfo);
+    pngdec->png = NULL;
+    pngdec->info = NULL;
+    pngdec->endinfo = NULL;
+  }
+
+  pngdec->bpp = pngdec->color_type = pngdec->height = pngdec->width = -1;
+  pngdec->offset = 0;
+  pngdec->rowbytes = 0;
+  pngdec->buffer_out = NULL;
+
+  pngdec->setup = FALSE;
+
+  pngdec->in_timestamp = GST_CLOCK_TIME_NONE;
+  pngdec->in_duration = GST_CLOCK_TIME_NONE;
+
+  return TRUE;
+}
+
+static gboolean
+gst_pngdec_libpng_init (GstPngDec * pngdec)
+{
+  g_return_val_if_fail (GST_IS_PNGDEC (pngdec), FALSE);
+
+  if (pngdec->setup)
+    return TRUE;
+
+  GST_LOG ("init libpng structures");
+
+  /* initialize png struct stuff */
+  pngdec->png = png_create_read_struct (PNG_LIBPNG_VER_STRING,
+      (png_voidp) NULL, user_error_fn, user_warning_fn);
+
+  if (pngdec->png == NULL)
+    goto init_failed;
+
+  pngdec->info = png_create_info_struct (pngdec->png);
+  if (pngdec->info == NULL)
+    goto info_failed;
+
+  pngdec->endinfo = png_create_info_struct (pngdec->png);
+  if (pngdec->endinfo == NULL)
+    goto endinfo_failed;
+
+  pngdec->setup = TRUE;
+
+  return TRUE;
+
+  /* ERRORS */
+init_failed:
+  {
+    GST_ELEMENT_ERROR (pngdec, LIBRARY, INIT, (NULL),
+        ("Failed to initialize png structure"));
+    return FALSE;
+  }
+info_failed:
+  {
+    gst_pngdec_libpng_clear (pngdec);
+    GST_ELEMENT_ERROR (pngdec, LIBRARY, INIT, (NULL),
+        ("Failed to initialize info structure"));
+    return FALSE;
+  }
+endinfo_failed:
+  {
+    gst_pngdec_libpng_clear (pngdec);
+    GST_ELEMENT_ERROR (pngdec, LIBRARY, INIT, (NULL),
+        ("Failed to initialize endinfo structure"));
+    return FALSE;
+  }
+}
+
+static GstStateChangeReturn
+gst_pngdec_change_state (GstElement * element, GstStateChange transition)
+{
+  GstStateChangeReturn ret;
+  GstPngDec *pngdec;
+
+  pngdec = GST_PNGDEC (element);
+
+  switch (transition) {
+    case GST_STATE_CHANGE_READY_TO_PAUSED:
+      gst_pngdec_libpng_init (pngdec);
+      pngdec->need_newsegment = TRUE;
+      pngdec->framed = FALSE;
+      pngdec->ret = GST_FLOW_OK;
+      gst_segment_init (&pngdec->segment, GST_FORMAT_UNDEFINED);
+      break;
+    default:
+      break;
+  }
+
+  ret = parent_class->change_state (element, transition);
+  if (ret != GST_STATE_CHANGE_SUCCESS)
+    return ret;
+
+  switch (transition) {
+    case GST_STATE_CHANGE_PAUSED_TO_READY:
+      gst_pngdec_libpng_clear (pngdec);
+      break;
+    default:
+      break;
+  }
+
+  return ret;
+}
+
+/* this function gets called when we activate ourselves in push mode. */
+static gboolean
+gst_pngdec_sink_activate_push (GstPad * sinkpad, gboolean active)
+{
+  GstPngDec *pngdec;
+
+  pngdec = GST_PNGDEC (GST_OBJECT_PARENT (sinkpad));
+
+  pngdec->ret = GST_FLOW_OK;
+
+  if (active) {
+    /* Let libpng come back here on error */
+    if (setjmp (png_jmpbuf (pngdec->png)))
+      goto setup_failed;
+
+    GST_LOG ("setting up progressive loading callbacks");
+    png_set_progressive_read_fn (pngdec->png, pngdec,
+        user_info_callback, user_endrow_callback, user_end_callback);
+  }
+  return TRUE;
+
+setup_failed:
+  {
+    GST_LOG ("failed setting up libpng jmpbuf");
+    gst_pngdec_libpng_clear (pngdec);
+    return FALSE;
+  }
+}
+
+/* this function gets called when we activate ourselves in pull mode.
+ * We can perform  random access to the resource and we start a task
+ * to start reading */
+static gboolean
+gst_pngdec_sink_activate_pull (GstPad * sinkpad, gboolean active)
+{
+  if (active) {
+    return gst_pad_start_task (sinkpad, (GstTaskFunction) gst_pngdec_task,
+        sinkpad);
+  } else {
+    return gst_pad_stop_task (sinkpad);
+  }
+}
+
+/* this function is called when the pad is activated and should start
+ * processing data.
+ *
+ * We check if we can do random access to decide if we work push or
+ * pull based.
+ */
+static gboolean
+gst_pngdec_sink_activate (GstPad * sinkpad)
+{
+  if (gst_pad_check_pull_range (sinkpad)) {
+    return gst_pad_activate_pull (sinkpad, TRUE);
+  } else {
+    return gst_pad_activate_push (sinkpad, TRUE);
+  }
+}