y4mdec: Add y4mdec

Feel the y4m love.  It seeks.  It works in pitivi.

4 files changed, 838 insertions, 0 deletions

diff --git a/configure.ac b/configure.ac
index 85fc6a370..8e92c688f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -348,6 +348,7 @@ AG_GST_CHECK_PLUGIN(videomaxrate)
 AG_GST_CHECK_PLUGIN(videomeasure)
 AG_GST_CHECK_PLUGIN(videosignal)
 AG_GST_CHECK_PLUGIN(vmnc)
+AG_GST_CHECK_PLUGIN(y4m)
 
 dnl *** plug-ins to exclude ***
 
@@ -1777,6 +1778,7 @@ gst/videomaxrate/Makefile
 gst/videomeasure/Makefile
 gst/videosignal/Makefile
 gst/vmnc/Makefile
+gst/y4m/Makefile
 gst-libs/Makefile
 gst-libs/gst/Makefile
 gst-libs/gst/interfaces/Makefile
diff --git a/gst/y4m/Makefile.am b/gst/y4m/Makefile.am
new file mode 100644
index 000000000..e8e52421d
--- /dev/null
+++ b/gst/y4m/Makefile.am
@@ -0,0 +1,13 @@
+
+plugin_LTLIBRARIES = libgsty4mdec.la
+
+libgsty4mdec_la_SOURCES = gsty4mdec.c
+libgsty4mdec_la_CFLAGS = $(GST_CFLAGS) $(GST_PLUGINS_BASE_CFLAGS)
+libgsty4mdec_la_LIBADD = \
+	$(GST_BASE_PLUGINS_LIBS) -lgstvideo-@GST_MAJORMINOR@ \
+	$(GST_BASE_LIBS) -lgstbase-@GST_MAJORMINOR@ \
+	$(GST_LIBS)
+libgsty4mdec_la_LDFLAGS = $(GST_PLUGIN_LDFLAGS)
+libgsty4mdec_la_LIBTOOLFLAGS = --tag=disable-static
+
+noinst_HEADERS = gsty4mdec.h
diff --git a/gst/y4m/gsty4mdec.c b/gst/y4m/gsty4mdec.c
new file mode 100644
index 000000000..958512fb3
--- /dev/null
+++ b/gst/y4m/gsty4mdec.c
@@ -0,0 +1,747 @@
+/* GStreamer
+ * Copyright (C) 2010 David Schleef <ds@schleef.org>
+ *
+ * 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-gsty4mdec
+ *
+ * The gsty4mdec element decodes uncompressed video in YUV4MPEG format.
+ *
+ * <refsect2>
+ * <title>Example launch line</title>
+ * |[
+ * gst-launch -v filesrc location=file.y4m ! y4mdec ! xvimagesink
+ * ]|
+ * </refsect2>
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gst/gst.h>
+#include <gst/video/video.h>
+#include "gsty4mdec.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+#define MAX_SIZE 32768
+
+GST_DEBUG_CATEGORY (y4mdec_debug);
+#define GST_CAT_DEFAULT y4mdec_debug
+
+/* prototypes */
+
+
+static void gst_y4m_dec_set_property (GObject * object,
+    guint property_id, const GValue * value, GParamSpec * pspec);
+static void gst_y4m_dec_get_property (GObject * object,
+    guint property_id, GValue * value, GParamSpec * pspec);
+static void gst_y4m_dec_dispose (GObject * object);
+static void gst_y4m_dec_finalize (GObject * object);
+
+static GstFlowReturn gst_y4m_dec_chain (GstPad * pad, GstBuffer * buffer);
+static gboolean gst_y4m_dec_sink_event (GstPad * pad, GstEvent * event);
+
+static gboolean gst_y4m_dec_src_event (GstPad * pad, GstEvent * event);
+static gboolean gst_y4m_dec_src_query (GstPad * pad, GstQuery * query);
+
+static GstStateChangeReturn
+gst_y4m_dec_change_state (GstElement * element, GstStateChange transition);
+
+enum
+{
+  PROP_0
+};
+
+/* pad templates */
+
+static GstStaticPadTemplate gst_y4m_dec_sink_template =
+GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS ("application/x-yuv4mpeg, y4mversion=2")
+    );
+
+static GstStaticPadTemplate gst_y4m_dec_src_template =
+GST_STATIC_PAD_TEMPLATE ("src",
+    GST_PAD_SRC,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("{I420,Y42B,Y444}"))
+    );
+
+/* class initialization */
+
+GST_BOILERPLATE (GstY4mDec, gst_y4m_dec, GstElement, GST_TYPE_ELEMENT);
+
+static void
+gst_y4m_dec_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_y4m_dec_src_template));
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&gst_y4m_dec_sink_template));
+
+  gst_element_class_set_details_simple (element_class,
+      "YUV4MPEG demuxer/decoder", "Codec/Demuxer",
+      "Demuxes/decodes YUV4MPEG streams", "David Schleef <ds@schleef.org>");
+}
+
+static void
+gst_y4m_dec_class_init (GstY4mDecClass * klass)
+{
+  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+  GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
+
+  gobject_class->set_property = gst_y4m_dec_set_property;
+  gobject_class->get_property = gst_y4m_dec_get_property;
+  gobject_class->dispose = gst_y4m_dec_dispose;
+  gobject_class->finalize = gst_y4m_dec_finalize;
+  element_class->change_state = GST_DEBUG_FUNCPTR (gst_y4m_dec_change_state);
+
+}
+
+static void
+gst_y4m_dec_init (GstY4mDec * y4mdec, GstY4mDecClass * y4mdec_class)
+{
+  y4mdec->adapter = gst_adapter_new ();
+
+  y4mdec->sinkpad =
+      gst_pad_new_from_static_template (&gst_y4m_dec_sink_template, "sink");
+  gst_pad_set_event_function (y4mdec->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_y4m_dec_sink_event));
+  gst_pad_set_chain_function (y4mdec->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_y4m_dec_chain));
+  gst_element_add_pad (GST_ELEMENT (y4mdec), y4mdec->sinkpad);
+
+  y4mdec->srcpad = gst_pad_new_from_static_template (&gst_y4m_dec_src_template,
+      "src");
+  gst_pad_set_event_function (y4mdec->srcpad,
+      GST_DEBUG_FUNCPTR (gst_y4m_dec_src_event));
+  gst_pad_set_query_function (y4mdec->srcpad,
+      GST_DEBUG_FUNCPTR (gst_y4m_dec_src_query));
+  gst_pad_use_fixed_caps (y4mdec->srcpad);
+  gst_element_add_pad (GST_ELEMENT (y4mdec), y4mdec->srcpad);
+
+}
+
+void
+gst_y4m_dec_set_property (GObject * object, guint property_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstY4mDec *y4mdec;
+
+  g_return_if_fail (GST_IS_Y4M_DEC (object));
+  y4mdec = GST_Y4M_DEC (object);
+
+  switch (property_id) {
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+      break;
+  }
+}
+
+void
+gst_y4m_dec_get_property (GObject * object, guint property_id,
+    GValue * value, GParamSpec * pspec)
+{
+  GstY4mDec *y4mdec;
+
+  g_return_if_fail (GST_IS_Y4M_DEC (object));
+  y4mdec = GST_Y4M_DEC (object);
+
+  switch (property_id) {
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+      break;
+  }
+}
+
+void
+gst_y4m_dec_dispose (GObject * object)
+{
+  GstY4mDec *y4mdec;
+
+  g_return_if_fail (GST_IS_Y4M_DEC (object));
+  y4mdec = GST_Y4M_DEC (object);
+
+  /* clean up as possible.  may be called multiple times */
+  if (y4mdec->adapter) {
+    g_object_unref (y4mdec->adapter);
+    y4mdec->adapter = NULL;
+  }
+
+  G_OBJECT_CLASS (parent_class)->dispose (object);
+}
+
+void
+gst_y4m_dec_finalize (GObject * object)
+{
+  GstY4mDec *y4mdec;
+
+  g_return_if_fail (GST_IS_Y4M_DEC (object));
+  y4mdec = GST_Y4M_DEC (object);
+
+  /* clean up object here */
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+static GstStateChangeReturn
+gst_y4m_dec_change_state (GstElement * element, GstStateChange transition)
+{
+  GstY4mDec *y4mdec;
+  GstStateChangeReturn ret;
+
+  g_return_val_if_fail (GST_IS_Y4M_DEC (element), GST_STATE_CHANGE_FAILURE);
+  y4mdec = GST_Y4M_DEC (element);
+
+  switch (transition) {
+    case GST_STATE_CHANGE_NULL_TO_READY:
+      break;
+    case GST_STATE_CHANGE_READY_TO_PAUSED:
+      break;
+    case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
+      break;
+    default:
+      break;
+  }
+
+  ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
+
+  switch (transition) {
+    case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
+      break;
+    case GST_STATE_CHANGE_PAUSED_TO_READY:
+      break;
+    case GST_STATE_CHANGE_READY_TO_NULL:
+      break;
+    default:
+      break;
+  }
+
+  return ret;
+}
+
+static GstClockTime
+gst_y4m_dec_frames_to_timestamp (GstY4mDec * y4mdec, int frame_index)
+{
+  return gst_util_uint64_scale (frame_index, GST_SECOND * y4mdec->fps_d,
+      y4mdec->fps_n);
+}
+
+static int
+gst_y4m_dec_timestamp_to_frames (GstY4mDec * y4mdec, GstClockTime timestamp)
+{
+  return gst_util_uint64_scale (timestamp, y4mdec->fps_n,
+      GST_SECOND * y4mdec->fps_d);
+}
+
+static int
+gst_y4m_dec_bytes_to_frames (GstY4mDec * y4mdec, gint64 bytes)
+{
+  if (bytes < y4mdec->header_size)
+    return 0;
+  return (bytes - y4mdec->header_size) / (y4mdec->frame_size + 6);
+}
+
+static gint64
+gst_y4m_dec_frames_to_bytes (GstY4mDec * y4mdec, int frame_index)
+{
+  return y4mdec->header_size + (y4mdec->frame_size + 6) * frame_index;
+}
+
+static GstClockTime
+gst_y4m_dec_bytes_to_timestamp (GstY4mDec * y4mdec, gint64 bytes)
+{
+  return gst_y4m_dec_frames_to_timestamp (y4mdec,
+      gst_y4m_dec_bytes_to_frames (y4mdec, bytes));
+}
+
+
+static gboolean
+gst_y4m_dec_parse_header (GstY4mDec * y4mdec, char *header)
+{
+  char *end;
+  int format = -1;
+  int interlaced_char;
+
+  if (memcmp (header, "YUV4MPEG2 ", 10) != 0) {
+    return FALSE;
+  }
+
+  header += 10;
+  while (*header) {
+    GST_DEBUG_OBJECT (y4mdec, "parsing at '%s'", header);
+    switch (*header) {
+      case ' ':
+        header++;
+        break;
+      case 'C':
+        header++;
+        format = strtoul (header, &end, 10);
+        if (end == header)
+          goto error;
+        header = end;
+        break;
+      case 'W':
+        header++;
+        y4mdec->width = strtoul (header, &end, 10);
+        if (end == header)
+          goto error;
+        header = end;
+        break;
+      case 'H':
+        header++;
+        y4mdec->height = strtoul (header, &end, 10);
+        if (end == header)
+          goto error;
+        header = end;
+        break;
+      case 'I':
+        header++;
+        if (header[0] == 0) {
+          GST_WARNING_OBJECT (y4mdec, "Expecting interlaced flag");
+          return FALSE;
+        }
+        interlaced_char = header[0];
+        header++;
+        break;
+      case 'F':
+        header++;
+        y4mdec->fps_n = strtoul (header, &end, 10);
+        if (end == header)
+          goto error;
+        header = end;
+        if (header[0] != ':') {
+          GST_WARNING_OBJECT (y4mdec, "Expecting :");
+          return FALSE;
+        }
+        header++;
+        y4mdec->fps_d = strtoul (header, &end, 10);
+        if (end == header)
+          goto error;
+        header = end;
+        break;
+      case 'A':
+        header++;
+        y4mdec->par_n = strtoul (header, &end, 10);
+        if (end == header)
+          goto error;
+        header = end;
+        if (header[0] != ':') {
+          GST_WARNING_OBJECT (y4mdec, "Expecting :");
+          return FALSE;
+        }
+        header++;
+        y4mdec->par_d = strtoul (header, &end, 10);
+        if (end == header)
+          goto error;
+        header = end;
+        break;
+      default:
+        GST_WARNING_OBJECT (y4mdec, "Unknown y4m header field '%c', ignoring",
+            *header);
+        while (*header && *header != ' ')
+          header++;
+        break;
+    }
+  }
+
+  switch (format) {
+    case 420:
+      y4mdec->format = GST_VIDEO_FORMAT_I420;
+      break;
+    case 422:
+      y4mdec->format = GST_VIDEO_FORMAT_Y42B;
+      break;
+    case 444:
+      y4mdec->format = GST_VIDEO_FORMAT_Y444;
+      break;
+    default:
+      GST_WARNING_OBJECT (y4mdec, "unknown y4m format %d", format);
+      return FALSE;
+  }
+
+  if (y4mdec->width <= 0 || y4mdec->width > MAX_SIZE ||
+      y4mdec->height <= 0 || y4mdec->height > MAX_SIZE) {
+    GST_WARNING_OBJECT (y4mdec, "Dimensions %dx%d out of range",
+        y4mdec->width, y4mdec->height);
+    return FALSE;
+  }
+
+  y4mdec->frame_size = gst_video_format_get_size (y4mdec->format,
+      y4mdec->width, y4mdec->height);
+
+  switch (interlaced_char) {
+    case 0:
+    case '?':
+    case 'p':
+      y4mdec->interlaced = FALSE;
+      break;
+    case 't':
+    case 'b':
+      y4mdec->interlaced = TRUE;
+      y4mdec->tff = (interlaced_char == 't');
+      break;
+    default:
+      GST_WARNING_OBJECT (y4mdec, "Unknown interlaced char '%c'",
+          interlaced_char);
+      return FALSE;
+      break;
+  }
+
+  if (y4mdec->fps_n == 0)
+    y4mdec->fps_n = 1;
+  if (y4mdec->fps_d == 0)
+    y4mdec->fps_d = 1;
+  if (y4mdec->par_n == 0)
+    y4mdec->par_n = 1;
+  if (y4mdec->par_d == 0)
+    y4mdec->par_d = 1;
+
+  return TRUE;
+error:
+  GST_WARNING_OBJECT (y4mdec, "Expecting number y4m header at '%s'", header);
+  return FALSE;
+}
+
+static GstFlowReturn
+gst_y4m_dec_chain (GstPad * pad, GstBuffer * buffer)
+{
+  GstY4mDec *y4mdec;
+  int n_avail;
+  GstFlowReturn flow_ret = GST_FLOW_OK;
+#define MAX_HEADER_LENGTH 80
+  char header[MAX_HEADER_LENGTH];
+  int i;
+  int len;
+
+  y4mdec = GST_Y4M_DEC (gst_pad_get_parent (pad));
+
+  GST_DEBUG_OBJECT (y4mdec, "chain");
+
+  if (GST_BUFFER_IS_DISCONT (buffer)) {
+    GST_DEBUG ("got discont");
+    gst_adapter_clear (y4mdec->adapter);
+  }
+
+  gst_adapter_push (y4mdec->adapter, buffer);
+  n_avail = gst_adapter_available (y4mdec->adapter);
+
+  if (!y4mdec->have_header) {
+    gboolean ret;
+    GstCaps *caps;
+
+    if (n_avail < MAX_HEADER_LENGTH)
+      return GST_FLOW_OK;
+
+    gst_adapter_copy (y4mdec->adapter, (guint8 *) header, 0, MAX_HEADER_LENGTH);
+
+    header[MAX_HEADER_LENGTH - 1] = 0;
+    for (i = 0; i < MAX_HEADER_LENGTH; i++) {
+      if (header[i] == 0x0a)
+        header[i] = 0;
+    }
+
+    ret = gst_y4m_dec_parse_header (y4mdec, header);
+    if (!ret) {
+      GST_ELEMENT_ERROR (y4mdec, STREAM, DECODE,
+          ("Failed to parse YUV4MPEG header"), (NULL));
+      return GST_FLOW_ERROR;
+    }
+
+    y4mdec->header_size = strlen (header) + 1;
+    gst_adapter_flush (y4mdec->adapter, y4mdec->header_size);
+
+    caps = gst_video_format_new_caps_interlaced (y4mdec->format,
+        y4mdec->width, y4mdec->height,
+        y4mdec->fps_n, y4mdec->fps_d,
+        y4mdec->par_n, y4mdec->par_d, y4mdec->interlaced);
+    ret = gst_pad_set_caps (y4mdec->srcpad, caps);
+    gst_caps_unref (caps);
+    if (!ret) {
+      GST_DEBUG_OBJECT (y4mdec, "Couldn't set caps on src pad");
+      return GST_FLOW_ERROR;
+    }
+
+    y4mdec->have_header = TRUE;
+  }
+
+  if (y4mdec->have_new_segment) {
+    GstEvent *event;
+    GstClockTime start = gst_y4m_dec_bytes_to_timestamp (y4mdec,
+        y4mdec->segment_start);
+    GstClockTime stop = gst_y4m_dec_bytes_to_timestamp (y4mdec,
+        y4mdec->segment_stop);
+    GstClockTime position = gst_y4m_dec_bytes_to_timestamp (y4mdec,
+        y4mdec->segment_position);
+
+    event = gst_event_new_new_segment (FALSE, 1.0,
+        GST_FORMAT_TIME, start, stop, position);
+
+    gst_pad_push_event (y4mdec->srcpad, event);
+    //gst_event_unref (event);
+
+    y4mdec->have_new_segment = FALSE;
+    y4mdec->frame_index = gst_y4m_dec_bytes_to_frames (y4mdec,
+        y4mdec->segment_position);
+    GST_DEBUG ("new frame_index %d", y4mdec->frame_index);
+
+  }
+
+  while (1) {
+    n_avail = gst_adapter_available (y4mdec->adapter);
+    if (n_avail < MAX_HEADER_LENGTH)
+      break;
+
+    gst_adapter_copy (y4mdec->adapter, (guint8 *) header, 0, MAX_HEADER_LENGTH);
+    header[MAX_HEADER_LENGTH - 1] = 0;
+    for (i = 0; i < MAX_HEADER_LENGTH; i++) {
+      if (header[i] == 0x0a)
+        header[i] = 0;
+    }
+    if (memcmp (header, "FRAME", 5) != 0) {
+      GST_ELEMENT_ERROR (y4mdec, STREAM, DECODE,
+          ("Failed to parse YUV4MPEG frame"), (NULL));
+      flow_ret = GST_FLOW_ERROR;
+      break;
+    }
+
+    len = strlen (header);
+    if (n_avail < y4mdec->frame_size + len + 1) {
+      /* not enough data */
+      GST_DEBUG ("not enough data for frame %d < %d",
+          n_avail, y4mdec->frame_size + len + 1);
+      break;
+    }
+
+    gst_adapter_flush (y4mdec->adapter, len + 1);
+
+    buffer = gst_adapter_take_buffer (y4mdec->adapter, y4mdec->frame_size);
+
+    GST_BUFFER_CAPS (buffer) = gst_caps_ref (GST_PAD_CAPS (y4mdec->srcpad));
+    GST_BUFFER_TIMESTAMP (buffer) =
+        gst_y4m_dec_frames_to_timestamp (y4mdec, y4mdec->frame_index);
+    GST_BUFFER_DURATION (buffer) =
+        gst_y4m_dec_frames_to_timestamp (y4mdec, y4mdec->frame_index) -
+        GST_BUFFER_TIMESTAMP (buffer);
+    if (y4mdec->interlaced && y4mdec->tff) {
+      GST_BUFFER_FLAG_SET (buffer, GST_VIDEO_BUFFER_TFF);
+    }
+
+    y4mdec->frame_index++;
+
+    flow_ret = gst_pad_push (y4mdec->srcpad, buffer);
+    if (flow_ret != GST_FLOW_OK)
+      break;
+  }
+
+  gst_object_unref (y4mdec);
+  GST_DEBUG ("returning %d", flow_ret);
+  return flow_ret;
+}
+
+static gboolean
+gst_y4m_dec_sink_event (GstPad * pad, GstEvent * event)
+{
+  gboolean res;
+  GstY4mDec *y4mdec;
+
+  y4mdec = GST_Y4M_DEC (gst_pad_get_parent (pad));
+
+  GST_DEBUG_OBJECT (y4mdec, "event");
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_FLUSH_START:
+      res = gst_pad_push_event (y4mdec->srcpad, event);
+      break;
+    case GST_EVENT_FLUSH_STOP:
+      res = gst_pad_push_event (y4mdec->srcpad, event);
+      break;
+    case GST_EVENT_NEWSEGMENT:
+    {
+      gboolean update;
+      gdouble rate;
+      gdouble applied_rate;
+      GstFormat format;
+      gint64 start;
+      gint64 stop;
+      gint64 position;
+
+      gst_event_parse_new_segment_full (event, &update, &rate,
+          &applied_rate, &format, &start, &stop, &position);
+
+      GST_DEBUG ("new_segment: update: %d rate: %g applied_rate: %g "
+          "format: %d start: %" G_GUINT64_FORMAT " stop: %" G_GUINT64_FORMAT
+          " position %" G_GUINT64_FORMAT,
+          update, rate, applied_rate, format, start, stop, position);
+
+      if (format == GST_FORMAT_BYTES) {
+        y4mdec->segment_start = start;
+        y4mdec->segment_stop = stop;
+        y4mdec->segment_position = position;
+        y4mdec->have_new_segment = TRUE;
+      }
+
+      res = TRUE;
+      //res = gst_pad_push_event (y4mdec->srcpad, event);
+    }
+      break;
+    case GST_EVENT_EOS:
+      res = gst_pad_push_event (y4mdec->srcpad, event);
+      break;
+    default:
+      res = gst_pad_push_event (y4mdec->srcpad, event);
+      break;
+  }
+
+  gst_object_unref (y4mdec);
+  return res;
+}
+
+static gboolean
+gst_y4m_dec_src_event (GstPad * pad, GstEvent * event)
+{
+  gboolean res;
+  GstY4mDec *y4mdec;
+
+  y4mdec = GST_Y4M_DEC (gst_pad_get_parent (pad));
+
+  GST_DEBUG_OBJECT (y4mdec, "event");
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_SEEK:
+    {
+      gdouble rate;
+      GstFormat format;
+      GstSeekFlags flags;
+      GstSeekType start_type, stop_type;
+      gint64 start, stop;
+      int framenum;
+      guint64 byte;
+
+      gst_event_parse_seek (event, &rate, &format, &flags, &start_type,
+          &start, &stop_type, &stop);
+
+      if (format != GST_FORMAT_TIME) {
+        res = FALSE;
+        break;
+      }
+
+      framenum = gst_y4m_dec_timestamp_to_frames (y4mdec, start);
+      GST_DEBUG ("seeking to frame %d", framenum);
+
+      byte = gst_y4m_dec_frames_to_bytes (y4mdec, framenum);
+      GST_DEBUG ("offset %d", (int) byte);
+
+      gst_event_unref (event);
+      event = gst_event_new_seek (rate, GST_FORMAT_BYTES, flags,
+          start_type, byte, stop_type, -1);
+
+      res = gst_pad_push_event (y4mdec->sinkpad, event);
+    }
+      break;
+    default:
+      res = gst_pad_push_event (y4mdec->sinkpad, event);
+      break;
+  }
+
+  gst_object_unref (y4mdec);
+  return res;
+}
+
+static gboolean
+gst_y4m_dec_src_query (GstPad * pad, GstQuery * query)
+{
+  GstY4mDec *y4mdec = GST_Y4M_DEC (gst_pad_get_parent (pad));
+  gboolean res = FALSE;
+
+  switch (GST_QUERY_TYPE (query)) {
+    case GST_QUERY_DURATION:
+    {
+      GstFormat format;
+      GstPad *peer;
+
+      GST_DEBUG ("duration query");
+
+      gst_query_parse_duration (query, &format, NULL);
+
+      if (format != GST_FORMAT_TIME) {
+        res = FALSE;
+        GST_DEBUG_OBJECT (y4mdec, "not handling duration query in format %d",
+            format);
+        break;
+      }
+
+      peer = gst_pad_get_peer (y4mdec->sinkpad);
+      if (peer) {
+        GstQuery *peer_query = gst_query_new_duration (GST_FORMAT_BYTES);
+
+        res = gst_pad_query (peer, peer_query);
+        if (res) {
+          gint64 duration;
+          int n_frames;
+
+          gst_query_parse_duration (peer_query, &format, &duration);
+
+          n_frames = gst_y4m_dec_bytes_to_frames (y4mdec, duration);
+          GST_DEBUG ("duration in frames %d", n_frames);
+
+          duration = gst_y4m_dec_frames_to_timestamp (y4mdec, n_frames);
+          GST_DEBUG ("duration in time %" GST_TIME_FORMAT,
+              GST_TIME_ARGS (duration));
+
+          gst_query_set_duration (query, GST_FORMAT_TIME, duration);
+          res = TRUE;
+        }
+
+        gst_query_unref (peer_query);
+        gst_object_unref (peer);
+      }
+      break;
+    }
+    default:
+      res = gst_pad_query_default (pad, query);
+      break;
+  }
+
+  gst_object_unref (y4mdec);
+  return res;
+}
+
+
+static gboolean
+plugin_init (GstPlugin * plugin)
+{
+
+  gst_element_register (plugin, "y4mdec", GST_RANK_SECONDARY,
+      gst_y4m_dec_get_type ());
+
+  GST_DEBUG_CATEGORY_INIT (y4mdec_debug, "y4mdec", 0, "y4mdec element");
+
+  return TRUE;
+}
+
+
+GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
+    GST_VERSION_MINOR,
+    "y4mdec",
+    "FIXME", plugin_init, VERSION, "LGPL", PACKAGE_NAME, GST_PACKAGE_ORIGIN)
diff --git a/gst/y4m/gsty4mdec.h b/gst/y4m/gsty4mdec.h
new file mode 100644
index 000000000..590a2d642
--- /dev/null
+++ b/gst/y4m/gsty4mdec.h
@@ -0,0 +1,76 @@
+/* GStreamer
+ * Copyright (C) 2010 REAL_NAME <EMAIL_ADDRESS>
+ *
+ * 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.
+ */
+
+#ifndef _GST_Y4M_DEC_H_
+#define _GST_Y4M_DEC_H_
+
+#include <gst/gst.h>
+#include <gst/base/gstadapter.h>
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_Y4M_DEC   (gst_y4m_dec_get_type())
+#define GST_Y4M_DEC(obj)   (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_Y4M_DEC,GstY4mDec))
+#define GST_Y4M_DEC_CLASS(klass)   (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_Y4M_DEC,GstY4mDecClass))
+#define GST_IS_Y4M_DEC(obj)   (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_Y4M_DEC))
+#define GST_IS_Y4M_DEC_CLASS(obj)   (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_Y4M_DEC))
+
+typedef struct _GstY4mDec GstY4mDec;
+typedef struct _GstY4mDecClass GstY4mDecClass;
+
+struct _GstY4mDec
+{
+  GstElement base_y4mdec;
+
+  GstPad *sinkpad;
+  GstPad *srcpad;
+  GstAdapter *adapter;
+
+  /* state */
+  gboolean have_header;
+  int frame_index;
+  int header_size;
+
+  gboolean have_new_segment;
+  gint64 segment_start;
+  gint64 segment_stop;
+  gint64 segment_position;
+
+  int width;
+  int height;
+  GstVideoFormat format;
+  gboolean interlaced;
+  gboolean tff;
+  int fps_n;
+  int fps_d;
+  int par_n;
+  int par_d;
+  int frame_size;
+};
+
+struct _GstY4mDecClass
+{
+  GstElementClass base_y4mdec_class;
+};
+
+GType gst_y4m_dec_get_type (void);
+
+G_END_DECLS
+
+#endif