gst/rtp/: Add a jpeg depayloader.

Original commit message from CVS:
* gst/rtp/Makefile.am:
* gst/rtp/gstrtp.c: (plugin_init):
* gst/rtp/gstrtpjpegdepay.c: (gst_rtp_jpeg_depay_base_init),
(gst_rtp_jpeg_depay_class_init), (gst_rtp_jpeg_depay_init),
(gst_rtp_jpeg_depay_finalize), (MakeTables), (MakeQuantHeader),
(MakeHuffmanHeader), (MakeDRIHeader), (MakeHeaders),
(gst_rtp_jpeg_depay_setcaps), (gst_rtp_jpeg_depay_process),
(gst_rtp_jpeg_depay_change_state),
(gst_rtp_jpeg_depay_plugin_init):
* gst/rtp/gstrtpjpegdepay.h:
Add a jpeg depayloader.
* gst/rtp/gstrtpjpegpay.c:
Set the default properties on the payloader to better defaults.

6 files changed, 703 insertions, 4 deletions

diff --git a/ChangeLog b/ChangeLog
index e77e43fc..870cead2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,20 @@
+2008-11-14  Wim Taymans  <wim.taymans@collabora.co.uk>
+
+	* gst/rtp/Makefile.am:
+	* gst/rtp/gstrtp.c: (plugin_init):
+	* gst/rtp/gstrtpjpegdepay.c: (gst_rtp_jpeg_depay_base_init),
+	(gst_rtp_jpeg_depay_class_init), (gst_rtp_jpeg_depay_init),
+	(gst_rtp_jpeg_depay_finalize), (MakeTables), (MakeQuantHeader),
+	(MakeHuffmanHeader), (MakeDRIHeader), (MakeHeaders),
+	(gst_rtp_jpeg_depay_setcaps), (gst_rtp_jpeg_depay_process),
+	(gst_rtp_jpeg_depay_change_state),
+	(gst_rtp_jpeg_depay_plugin_init):
+	* gst/rtp/gstrtpjpegdepay.h:
+	Add a jpeg depayloader.
+
+	* gst/rtp/gstrtpjpegpay.c:
+	Set the default properties on the payloader to better defaults.
+
 2008-11-14  Stefan Kost  <ensonic@users.sf.net>
 
 	* sys/v4l2/gstv4l2.c:
diff --git a/gst/rtp/Makefile.am b/gst/rtp/Makefile.am
index d677930b..534f6108 100644
--- a/gst/rtp/Makefile.am
+++ b/gst/rtp/Makefile.am
@@ -32,6 +32,7 @@ libgstrtp_la_SOURCES = \
 	gstrtph263pay.c \
 	gstrtph264depay.c \
 	gstrtph264pay.c \
+	gstrtpjpegdepay.c \
 	gstrtpjpegpay.c \
 	gstrtpL16depay.c \
 	gstrtpL16pay.c \
@@ -102,6 +103,7 @@ noinst_HEADERS =			\
 		 gstrtph263pay.h 	\
 		 gstrtph264depay.h 	\
 		 gstrtph264pay.h 	\
+		 gstrtpjpegdepay.h 	\
 		 gstrtpjpegpay.h 	\
 		 gstrtpmp1sdepay.h 	\
 		 gstrtpmp2tdepay.h 	\
diff --git a/gst/rtp/gstrtp.c b/gst/rtp/gstrtp.c
index b7e000a0..22022c60 100644
--- a/gst/rtp/gstrtp.c
+++ b/gst/rtp/gstrtp.c
@@ -49,6 +49,7 @@
 #include "gstrtph263pay.h"
 #include "gstrtph264depay.h"
 #include "gstrtph264pay.h"
+#include "gstrtpjpegdepay.h"
 #include "gstrtpjpegpay.h"
 #include "gstrtpL16depay.h"
 #include "gstrtpL16pay.h"
@@ -159,6 +160,9 @@ plugin_init (GstPlugin * plugin)
   if (!gst_rtp_h264_pay_plugin_init (plugin))
     return FALSE;
 
+  if (!gst_rtp_jpeg_depay_plugin_init (plugin))
+    return FALSE;
+
   if (!gst_rtp_jpeg_pay_plugin_init (plugin))
     return FALSE;
 
diff --git a/gst/rtp/gstrtpjpegdepay.c b/gst/rtp/gstrtpjpegdepay.c
new file mode 100644
index 00000000..17fbe120
--- /dev/null
+++ b/gst/rtp/gstrtpjpegdepay.c
@@ -0,0 +1,614 @@
+/* GStreamer
+ * Copyright (C) <2008> Wim Taymans <wim.taymans@gmail.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., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#include <gst/rtp/gstrtpbuffer.h>
+
+#include <string.h>
+#include "gstrtpjpegdepay.h"
+
+GST_DEBUG_CATEGORY_STATIC (rtpjpegdepay_debug);
+#define GST_CAT_DEFAULT (rtpjpegdepay_debug)
+
+/* elementfactory information */
+static const GstElementDetails gst_rtp_jpegdepay_details =
+GST_ELEMENT_DETAILS ("RTP JPEG depayloader",
+    "Codec/Depayloader/Network",
+    "Extracts JPEG video from RTP packets (RFC 2435)",
+    "Wim Taymans <wim.taymans@gmail.com>");
+
+static GstStaticPadTemplate gst_rtp_jpeg_depay_src_template =
+GST_STATIC_PAD_TEMPLATE ("src",
+    GST_PAD_SRC,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS ("image/jpeg")
+    );
+
+static GstStaticPadTemplate gst_rtp_jpeg_depay_sink_template =
+    GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS ("application/x-rtp, "
+        "media = (string) \"video\", "
+        "payload = (int) " GST_RTP_PAYLOAD_DYNAMIC_STRING ", "
+        "clock-rate = (int) 90000, " "encoding-name = (string) \"JPEG\";"
+        "application/x-rtp, "
+        "media = (string) \"video\", "
+        "payload = (int) " GST_RTP_PAYLOAD_JPEG_STRING ", "
+        "clock-rate = (int) 90000")
+    );
+
+GST_BOILERPLATE (GstRtpJPEGDepay, gst_rtp_jpeg_depay, GstBaseRTPDepayload,
+    GST_TYPE_BASE_RTP_DEPAYLOAD);
+
+static void gst_rtp_jpeg_depay_finalize (GObject * object);
+
+static gboolean gst_rtp_jpeg_depay_setcaps (GstBaseRTPDepayload * depayload,
+    GstCaps * caps);
+static GstBuffer *gst_rtp_jpeg_depay_process (GstBaseRTPDepayload * depayload,
+    GstBuffer * buf);
+
+static GstStateChangeReturn gst_rtp_jpeg_depay_change_state (GstElement *
+    element, GstStateChange transition);
+
+static void
+gst_rtp_jpeg_depay_base_init (gpointer klass)
+{
+  GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
+
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&gst_rtp_jpeg_depay_src_template));
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&gst_rtp_jpeg_depay_sink_template));
+
+  gst_element_class_set_details (element_class, &gst_rtp_jpegdepay_details);
+}
+
+static void
+gst_rtp_jpeg_depay_class_init (GstRtpJPEGDepayClass * klass)
+{
+  GObjectClass *gobject_class;
+  GstElementClass *gstelement_class;
+  GstBaseRTPDepayloadClass *gstbasertpdepayload_class;
+
+  gobject_class = (GObjectClass *) klass;
+  gstelement_class = (GstElementClass *) klass;
+  gstbasertpdepayload_class = (GstBaseRTPDepayloadClass *) klass;
+
+  gobject_class->finalize = gst_rtp_jpeg_depay_finalize;
+
+  parent_class = g_type_class_peek_parent (klass);
+
+  gstelement_class->change_state = gst_rtp_jpeg_depay_change_state;
+
+  gstbasertpdepayload_class->set_caps = gst_rtp_jpeg_depay_setcaps;
+  gstbasertpdepayload_class->process = gst_rtp_jpeg_depay_process;
+
+  GST_DEBUG_CATEGORY_INIT (rtpjpegdepay_debug, "rtpjpegdepay", 0,
+      "JPEG Video RTP Depayloader");
+}
+
+static void
+gst_rtp_jpeg_depay_init (GstRtpJPEGDepay * rtpjpegdepay,
+    GstRtpJPEGDepayClass * klass)
+{
+  rtpjpegdepay->adapter = gst_adapter_new ();
+}
+
+static void
+gst_rtp_jpeg_depay_finalize (GObject * object)
+{
+  GstRtpJPEGDepay *rtpjpegdepay;
+
+  rtpjpegdepay = GST_RTP_JPEG_DEPAY (object);
+
+  g_object_unref (rtpjpegdepay->adapter);
+  rtpjpegdepay->adapter = NULL;
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+/*
+ * Table K.1 from JPEG spec.
+ */
+static const int jpeg_luma_quantizer[64] = {
+  16, 11, 10, 16, 24, 40, 51, 61,
+  12, 12, 14, 19, 26, 58, 60, 55,
+  14, 13, 16, 24, 40, 57, 69, 56,
+  14, 17, 22, 29, 51, 87, 80, 62,
+  18, 22, 37, 56, 68, 109, 103, 77,
+  24, 35, 55, 64, 81, 104, 113, 92,
+  49, 64, 78, 87, 103, 121, 120, 101,
+  72, 92, 95, 98, 112, 100, 103, 99
+};
+
+/*
+ * Table K.2 from JPEG spec.
+ */
+static const int jpeg_chroma_quantizer[64] = {
+  17, 18, 24, 47, 99, 99, 99, 99,
+  18, 21, 26, 66, 99, 99, 99, 99,
+  24, 26, 56, 99, 99, 99, 99, 99,
+  47, 66, 99, 99, 99, 99, 99, 99,
+  99, 99, 99, 99, 99, 99, 99, 99,
+  99, 99, 99, 99, 99, 99, 99, 99,
+  99, 99, 99, 99, 99, 99, 99, 99,
+  99, 99, 99, 99, 99, 99, 99, 99
+};
+
+/* Call MakeTables with the Q factor and a guint8[128] return array
+ */
+static void
+MakeTables (GstRtpJPEGDepay * rtpjpegdepay, gint Q, guint8 qtable[128])
+{
+  gint i;
+  guint factor;
+
+  factor = CLAMP (Q, 1, 99);
+
+  if (Q < 50)
+    Q = 5000 / factor;
+  else
+    Q = 200 - factor * 2;
+
+  for (i = 0; i < 64; i++) {
+    gint lq = (jpeg_luma_quantizer[i] * Q + 50) / 100;
+    gint cq = (jpeg_chroma_quantizer[i] * Q + 50) / 100;
+
+    /* Limit the quantizers to 1 <= q <= 255 */
+    qtable[i] = CLAMP (lq, 1, 255);
+    qtable[i + 64] = CLAMP (cq, 1, 255);
+  }
+}
+
+static const guint8 lum_dc_codelens[] = {
+  0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0
+};
+
+static const guint8 lum_dc_symbols[] = {
+  0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
+};
+
+static const guint8 lum_ac_codelens[] = {
+  0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d
+};
+
+static const guint8 lum_ac_symbols[] = {
+  0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,
+  0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,
+  0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,
+  0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0,
+  0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16,
+  0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,
+  0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
+  0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
+  0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
+  0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
+  0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
+  0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
+  0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
+  0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
+  0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
+  0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,
+  0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,
+  0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,
+  0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,
+  0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
+  0xf9, 0xfa
+};
+
+static const guint8 chm_dc_codelens[] = {
+  0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0
+};
+
+static const guint8 chm_dc_symbols[] = {
+  0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
+};
+
+static const guint8 chm_ac_codelens[] = {
+  0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77
+};
+
+static const guint8 chm_ac_symbols[] = {
+  0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,
+  0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,
+  0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,
+  0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0,
+  0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34,
+  0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,
+  0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38,
+  0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
+  0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
+  0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
+  0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,
+  0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
+  0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96,
+  0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5,
+  0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,
+  0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,
+  0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,
+  0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,
+  0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9,
+  0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
+  0xf9, 0xfa
+};
+
+static guint8 *
+MakeQuantHeader (guint8 * p, guint8 * qt, gint size, gint tableNo)
+{
+  *p++ = 0xff;
+  *p++ = 0xdb;                  /* DQT */
+  *p++ = 0;                     /* length msb */
+  *p++ = size + 3;              /* length lsb */
+  *p++ = tableNo;
+  memcpy (p, qt, size);
+
+  return (p + size);
+}
+
+static guint8 *
+MakeHuffmanHeader (guint8 * p, const guint8 * codelens, int ncodes,
+    const guint8 * symbols, int nsymbols, int tableNo, int tableClass)
+{
+  *p++ = 0xff;
+  *p++ = 0xc4;                  /* DHT */
+  *p++ = 0;                     /* length msb */
+  *p++ = 3 + ncodes + nsymbols; /* length lsb */
+  *p++ = (tableClass << 4) | tableNo;
+  memcpy (p, codelens, ncodes);
+  p += ncodes;
+  memcpy (p, symbols, nsymbols);
+  p += nsymbols;
+
+  return (p);
+}
+
+static guint8 *
+MakeDRIHeader (guint8 * p, guint16 dri)
+{
+  *p++ = 0xff;
+  *p++ = 0xdd;                  /* DRI */
+  *p++ = 0x0;                   /* length msb */
+  *p++ = 4;                     /* length lsb */
+  *p++ = dri >> 8;              /* dri msb */
+  *p++ = dri & 0xff;            /* dri lsb */
+
+  return (p);
+}
+
+/*
+ *  Arguments:
+ *    type, width, height: as supplied in RTP/JPEG header
+ *    qt: quantization tables as either derived from
+ *        the Q field using MakeTables() or as specified
+ *        in section 4.2.
+ *    dri: restart interval in MCUs, or 0 if no restarts.
+ *
+ *    p: pointer to return area
+ *
+ *  Return value:
+ *    The length of the generated headers.
+ *
+ *    Generate a frame and scan headers that can be prepended to the
+ *    RTP/JPEG data payload to produce a JPEG compressed image in
+ *    interchange format (except for possible trailing garbage and
+ *    absence of an EOI marker to terminate the scan).
+ */
+static guint
+MakeHeaders (guint8 * p, int type, int width, int height, guint8 * qt,
+    guint precision, guint16 dri)
+{
+  guint8 *start = p;
+  gint size;
+
+  *p++ = 0xff;
+  *p++ = 0xd8;                  /* SOI */
+
+  size = ((precision & 1) ? 128 : 64);
+  p = MakeQuantHeader (p, qt, size, 0);
+  qt += size;
+
+  size = ((precision & 2) ? 128 : 64);
+  p = MakeQuantHeader (p, qt, size, 1);
+  qt += size;
+
+  if (dri != 0)
+    p = MakeDRIHeader (p, dri);
+
+  *p++ = 0xff;
+  *p++ = 0xc0;                  /* SOF */
+  *p++ = 0;                     /* length msb */
+  *p++ = 17;                    /* length lsb */
+  *p++ = 8;                     /* 8-bit precision */
+  *p++ = height >> 8;           /* height msb */
+  *p++ = height;                /* height lsb */
+  *p++ = width >> 8;            /* width msb */
+  *p++ = width;                 /* width lsb */
+  *p++ = 3;                     /* number of components */
+  *p++ = 0;                     /* comp 0 */
+  if (type == 0)
+    *p++ = 0x21;                /* hsamp = 2, vsamp = 1 */
+  else
+    *p++ = 0x22;                /* hsamp = 2, vsamp = 2 */
+  *p++ = 0;                     /* quant table 0 */
+  *p++ = 1;                     /* comp 1 */
+  *p++ = 0x11;                  /* hsamp = 1, vsamp = 1 */
+  *p++ = 1;                     /* quant table 1 */
+  *p++ = 2;                     /* comp 2 */
+  *p++ = 0x11;                  /* hsamp = 1, vsamp = 1 */
+  *p++ = 1;                     /* quant table 1 */
+
+  p = MakeHuffmanHeader (p, lum_dc_codelens,
+      sizeof (lum_dc_codelens), lum_dc_symbols, sizeof (lum_dc_symbols), 0, 0);
+  p = MakeHuffmanHeader (p, lum_ac_codelens,
+      sizeof (lum_ac_codelens), lum_ac_symbols, sizeof (lum_ac_symbols), 0, 1);
+  p = MakeHuffmanHeader (p, chm_dc_codelens,
+      sizeof (chm_dc_codelens), chm_dc_symbols, sizeof (chm_dc_symbols), 1, 0);
+  p = MakeHuffmanHeader (p, chm_ac_codelens,
+      sizeof (chm_ac_codelens), chm_ac_symbols, sizeof (chm_ac_symbols), 1, 1);
+
+  *p++ = 0xff;
+  *p++ = 0xda;                  /* SOS */
+  *p++ = 0;                     /* length msb */
+  *p++ = 12;                    /* length lsb */
+  *p++ = 3;                     /* 3 components */
+  *p++ = 0;                     /* comp 0 */
+  *p++ = 0;                     /* huffman table 0 */
+  *p++ = 1;                     /* comp 1 */
+  *p++ = 0x11;                  /* huffman table 1 */
+  *p++ = 2;                     /* comp 2 */
+  *p++ = 0x11;                  /* huffman table 1 */
+  *p++ = 0;                     /* first DCT coeff */
+  *p++ = 63;                    /* last DCT coeff */
+  *p++ = 0;                     /* sucessive approx. */
+
+  return (p - start);
+};
+
+static gboolean
+gst_rtp_jpeg_depay_setcaps (GstBaseRTPDepayload * depayload, GstCaps * caps)
+{
+  GstStructure *structure;
+  GstRtpJPEGDepay *rtpjpegdepay;
+  GstCaps *outcaps;
+  gint clock_rate;
+  gboolean res;
+
+  rtpjpegdepay = GST_RTP_JPEG_DEPAY (depayload);
+
+  structure = gst_caps_get_structure (caps, 0);
+
+  if (!gst_structure_get_int (structure, "clock-rate", &clock_rate))
+    clock_rate = 90000;
+  depayload->clock_rate = clock_rate;
+
+  outcaps =
+      gst_caps_new_simple ("image/jpeg", "framerate", GST_TYPE_FRACTION, 0, 1,
+      NULL);
+  res = gst_pad_set_caps (depayload->srcpad, outcaps);
+  gst_caps_unref (outcaps);
+
+  return res;
+}
+
+static GstBuffer *
+gst_rtp_jpeg_depay_process (GstBaseRTPDepayload * depayload, GstBuffer * buf)
+{
+  GstRtpJPEGDepay *rtpjpegdepay;
+  GstBuffer *outbuf;
+  gint payload_len, header_len;
+  guint8 *payload;
+  guint frag_offset;
+  gint Q;
+  guint type, width, height;
+  guint16 dri, precision, length;
+  guint8 *qtable;
+
+  rtpjpegdepay = GST_RTP_JPEG_DEPAY (depayload);
+
+  if (GST_BUFFER_IS_DISCONT (buf)) {
+    gst_adapter_clear (rtpjpegdepay->adapter);
+  }
+
+  payload_len = gst_rtp_buffer_get_payload_len (buf);
+
+  if (payload_len < 8)
+    goto empty_packet;
+
+  payload = gst_rtp_buffer_get_payload (buf);
+  header_len = 0;
+
+  /*  0                   1                   2                   3
+   *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   * | Type-specific |              Fragment Offset                  |
+   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   * |      Type     |       Q       |     Width     |     Height    |
+   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   */
+  frag_offset = (payload[1] << 16) | (payload[2] << 8) | payload[3];
+  type = payload[4];
+  Q = payload[5];
+  width = payload[6] * 8;
+  height = payload[7] * 8;
+
+  GST_DEBUG_OBJECT (rtpjpegdepay, "frag %u, type %u, Q %d, width %u, height %u",
+      frag_offset, type, Q, width, height);
+
+  header_len += 8;
+  payload += 8;
+  payload_len -= 8;
+
+  dri = 0;
+  if (type > 63) {
+    if (payload_len < 4)
+      goto empty_packet;
+
+    /*  0                   1                   2                   3
+     *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+     * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     * |       Restart Interval        |F|L|       Restart Count       |
+     * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     */
+    dri = (payload[0] << 8) | payload[1];
+
+    GST_DEBUG_OBJECT (rtpjpegdepay, "DRI %" G_GUINT16_FORMAT, dri);
+
+    payload += 4;
+    header_len += 4;
+    payload_len -= 4;
+  }
+
+  if (Q >= 128 && frag_offset == 0) {
+    if (payload_len < 4)
+      goto empty_packet;
+
+    /*  0                   1                   2                   3
+     *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+     * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     * |      MBZ      |   Precision   |             Length            |
+     * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     * |                    Quantization Table Data                    |
+     * |                              ...                              |
+     * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     */
+    precision = payload[1];
+    length = (payload[2] << 8) | payload[3];
+
+    GST_DEBUG_OBJECT (rtpjpegdepay, "precision %04x, length %" G_GUINT16_FORMAT,
+        precision, length);
+
+    if (Q == 255 && length == 0)
+      goto empty_packet;
+
+    payload += 4;
+    header_len += 4;
+    payload_len -= 4;
+
+    if (length > payload_len)
+      goto empty_packet;
+
+    qtable = payload;
+
+    payload += length;
+    header_len += length;
+    payload_len -= length;
+  } else {
+    length = 0;
+    qtable = NULL;
+    precision = 0;
+  }
+
+  if (frag_offset == 0) {
+    guint size;
+
+    /* first packet */
+    if (length == 0) {
+      if (Q < 128) {
+        /* no quant table, see if we have one cached */
+        qtable = rtpjpegdepay->qtables[Q];
+        if (!qtable) {
+          GST_DEBUG_OBJECT (rtpjpegdepay, "making Q %d table", Q);
+          /* make and cache the table */
+          qtable = g_new (guint8, 128);
+          MakeTables (rtpjpegdepay, Q, qtable);
+          rtpjpegdepay->qtables[Q] = qtable;
+        } else {
+          GST_DEBUG_OBJECT (rtpjpegdepay, "using cached table for Q %d", Q);
+        }
+        /* all 8 bit quantizers */
+        precision = 0;
+      }
+    }
+    /* max header length, should be big enough */
+    outbuf = gst_buffer_new_and_alloc (1000);
+    size = MakeHeaders (GST_BUFFER_DATA (outbuf), type,
+        width, height, qtable, precision, dri);
+
+    GST_DEBUG_OBJECT (rtpjpegdepay, "pushing %u bytes header", size);
+
+    GST_BUFFER_SIZE (outbuf) = size;
+
+    gst_adapter_push (rtpjpegdepay->adapter, outbuf);
+
+  }
+
+  /* take JPEG data, push in the adapter */
+  GST_DEBUG_OBJECT (rtpjpegdepay, "pushing data at offset %d", header_len);
+  outbuf = gst_rtp_buffer_get_payload_subbuffer (buf, header_len, -1);
+  gst_adapter_push (rtpjpegdepay->adapter, outbuf);
+  outbuf = NULL;
+
+  if (gst_rtp_buffer_get_marker (buf)) {
+    guint avail;
+
+    /* last buffer take all data out of the adapter */
+    avail = gst_adapter_available (rtpjpegdepay->adapter);
+    outbuf = gst_adapter_take_buffer (rtpjpegdepay->adapter, avail);
+
+    GST_DEBUG_OBJECT (rtpjpegdepay, "last buffer, returning %u bytes", avail);
+  }
+
+  return outbuf;
+
+  /* ERRORS */
+empty_packet:
+  {
+    GST_ELEMENT_WARNING (rtpjpegdepay, STREAM, DECODE,
+        ("Empty Payload."), (NULL));
+    return NULL;
+  }
+}
+
+static GstStateChangeReturn
+gst_rtp_jpeg_depay_change_state (GstElement * element,
+    GstStateChange transition)
+{
+  GstRtpJPEGDepay *rtpjpegdepay;
+  GstStateChangeReturn ret;
+
+  rtpjpegdepay = GST_RTP_JPEG_DEPAY (element);
+
+  switch (transition) {
+    case GST_STATE_CHANGE_NULL_TO_READY:
+      break;
+    default:
+      break;
+  }
+
+  ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
+
+  switch (transition) {
+    case GST_STATE_CHANGE_READY_TO_NULL:
+      break;
+    default:
+      break;
+  }
+  return ret;
+}
+
+gboolean
+gst_rtp_jpeg_depay_plugin_init (GstPlugin * plugin)
+{
+  return gst_element_register (plugin, "rtpjpegdepay",
+      GST_RANK_MARGINAL, GST_TYPE_RTP_JPEG_DEPAY);
+}
diff --git a/gst/rtp/gstrtpjpegdepay.h b/gst/rtp/gstrtpjpegdepay.h
new file mode 100644
index 00000000..9cbdf68d
--- /dev/null
+++ b/gst/rtp/gstrtpjpegdepay.h
@@ -0,0 +1,62 @@
+/* GStreamer
+ * Copyright (C) <2005> Wim Taymans <wim@fluendo.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., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifndef __GST_RTP_JPEG_DEPAY_H__
+#define __GST_RTP_JPEG_DEPAY_H__
+
+#include <gst/gst.h>
+#include <gst/base/gstadapter.h>
+#include <gst/rtp/gstbasertpdepayload.h>
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_RTP_JPEG_DEPAY \
+  (gst_rtp_jpeg_depay_get_type())
+#define GST_RTP_JPEG_DEPAY(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_RTP_JPEG_DEPAY,GstRtpJPEGDepay))
+#define GST_RTP_JPEG_DEPAY_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_RTP_JPEG_DEPAY,GstRtpJPEGDepayClass))
+#define GST_IS_RTP_JPEG_DEPAY(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_RTP_JPEG_DEPAY))
+#define GST_IS_RTP_JPEG_DEPAY_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_RTP_JPEG_DEPAY))
+
+typedef struct _GstRtpJPEGDepay GstRtpJPEGDepay;
+typedef struct _GstRtpJPEGDepayClass GstRtpJPEGDepayClass;
+
+struct _GstRtpJPEGDepay
+{
+  GstBaseRTPDepayload depayload;
+
+  GstAdapter *adapter;
+
+  /* cached quant tables */
+  guint8 * qtables[255];
+};
+
+struct _GstRtpJPEGDepayClass
+{
+  GstBaseRTPDepayloadClass parent_class;
+};
+
+gboolean gst_rtp_jpeg_depay_plugin_init (GstPlugin * plugin);
+
+G_END_DECLS
+
+#endif /* __GST_RTP_JPEG_DEPAY_H__ */
diff --git a/gst/rtp/gstrtpjpegpay.c b/gst/rtp/gstrtpjpegpay.c
index d59eebec..1810eff8 100644
--- a/gst/rtp/gstrtpjpegpay.c
+++ b/gst/rtp/gstrtpjpegpay.c
@@ -45,9 +45,9 @@
 
 /* elementfactory information */
 static const GstElementDetails gst_rtp_jpeg_pay_details =
-GST_ELEMENT_DETAILS ("RTP packet payloader",
+GST_ELEMENT_DETAILS ("RTP JPEG payloader",
     "Codec/Payloader/Network",
-    "Payload-encodes JPEG pictures into a RTP packet",
+    "Payload-encodes JPEG pictures into RTP packets (RFC 2435)",
     "Axis Communications <dev-gstreamer@axis.com>");
 
 static GstStaticPadTemplate gst_rtp_jpeg_pay_sink_template =
@@ -86,13 +86,13 @@ GST_DEBUG_CATEGORY_STATIC (rtpjpegpay_debug);
  * DEFAULT_JPEG_QUALITY:
  *
  */
-#define DEFAULT_JPEG_QUALITY 0
+#define DEFAULT_JPEG_QUALITY 255
 
 /**
  * DEFAULT_JPEG_TYPE:
  *
  */
-#define DEFAULT_JPEG_TYPE    0
+#define DEFAULT_JPEG_TYPE    1
 
 typedef enum _RtpJpegMarker RtpJpegMarker;