rtp: New QDM2 rtp depayloader.

Reverse-engineered by comparing:
* A rtp hinted file provided by DarwinStreamingServer
* The output procued by DSS for that same file

Also used various streaming sources available on the internet to fine-tune
the code.

The header/codec_data extraction methods are from FFMpeg (LGPL).

gst/rtp/Makefile.am

@@ -50,6 +50,7 @@ libgstrtp_la_SOURCES = \
 	gstrtpmp4gpay.c \
 	gstrtpmp4adepay.c \
 	gstrtpmp4apay.c \
+	gstrtpqdmdepay.c \
 	gstrtpsirenpay.c \
 	gstrtpsirendepay.c \
 	gstrtpspeexdepay.c \
@@ -127,6 +128,7 @@ noinst_HEADERS =			\
 		 gstrtpmp4apay.h        \
 		 gstrtpdepay.h		\
 		 gstasteriskh263.h	\
+		 gstrtpqdmdepay.h	\
 		 gstrtpsirenpay.h 	\
 		 gstrtpsirendepay.h 	\
 		 gstrtpspeexdepay.h	\

gst/rtp/gstrtp.c

@@ -67,6 +67,7 @@
 #include "gstrtpmp4apay.h"
 #include "gstrtpmp4gdepay.h"
 #include "gstrtpmp4gpay.h"
+#include "gstrtpqdmdepay.h"
 #include "gstrtpsirenpay.h"
 #include "gstrtpsirendepay.h"
 #include "gstrtpspeexpay.h"
@@ -220,6 +221,9 @@ plugin_init (GstPlugin * plugin)
   if (!gst_rtp_mp4g_pay_plugin_init (plugin))
     return FALSE;
 
+  if (!gst_rtp_qdm2_depay_plugin_init (plugin))
+    return FALSE;
+
   if (!gst_rtp_siren_pay_plugin_init (plugin))
     return FALSE;
 

gst/rtp/gstrtpqdmdepay.c

@@ -0,0 +1,412 @@
+/* GStreamer
+ * Copyright (C) <2009> Edward Hervey <bilboed@bilboed.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 <string.h>
+
+#include <gst/rtp/gstrtpbuffer.h>
+#include "gstrtpqdmdepay.h"
+
+/* elementfactory information */
+static const GstElementDetails gst_rtp_qdm2depay_details =
+GST_ELEMENT_DETAILS ("RTP QDM2 depayloader",
+    "Codec/Depayloader/Network",
+    "Extracts QDM2 audio from RTP packets (no RFC)",
+    "Edward Hervey <bilboed@bilboed.com>");
+
+static GstStaticPadTemplate gst_rtp_qdm2_depay_src_template =
+GST_STATIC_PAD_TEMPLATE ("src",
+    GST_PAD_SRC,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS ("audio/x-qdm2")
+    );
+
+static GstStaticPadTemplate gst_rtp_qdm2_depay_sink_template =
+GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS ("application/x-rtp, "
+        "media = (string) \"audio\", "
+        "payload = (int) " GST_RTP_PAYLOAD_DYNAMIC_STRING ", "
+        "encoding-name = (string)\"X-QDM\"")
+    );
+
+GST_BOILERPLATE (GstRtpQDM2Depay, gst_rtp_qdm2_depay, GstBaseRTPDepayload,
+    GST_TYPE_BASE_RTP_DEPAYLOAD);
+
+static const guint8 headheader[20] = {
+  0x0, 0x0, 0x0, 0xc, 0x66, 0x72, 0x6d, 0x61,
+  0x51, 0x44, 0x4d, 0x32, 0x0, 0x0, 0x0, 0x24,
+  0x51, 0x44, 0x43, 0x41
+};
+static void gst_rtp_qdm2_depay_finalize (GObject * object);
+
+static GstStateChangeReturn gst_rtp_qdm2_depay_change_state (GstElement *
+    element, GstStateChange transition);
+
+static GstBuffer *gst_rtp_qdm2_depay_process (GstBaseRTPDepayload * depayload,
+    GstBuffer * buf);
+gboolean gst_rtp_qdm2_depay_setcaps (GstBaseRTPDepayload * filter,
+    GstCaps * caps);
+
+static void
+gst_rtp_qdm2_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_qdm2_depay_src_template));
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&gst_rtp_qdm2_depay_sink_template));
+
+
+  gst_element_class_set_details (element_class, &gst_rtp_qdm2depay_details);
+}
+
+static void
+gst_rtp_qdm2_depay_class_init (GstRtpQDM2DepayClass * klass)
+{
+  GObjectClass *gobject_class;
+  GstElementClass *gstelement_class;
+  GstBaseRTPDepayloadClass *gstbasertpdepayload_class;
+
+  gobject_class = (GObjectClass *) klass;
+  gstelement_class = (GstElementClass *) klass;
+  gstbasertpdepayload_class = (GstBaseRTPDepayloadClass *) klass;
+
+  parent_class = g_type_class_peek_parent (klass);
+
+  gstbasertpdepayload_class->process = gst_rtp_qdm2_depay_process;
+  gstbasertpdepayload_class->set_caps = gst_rtp_qdm2_depay_setcaps;
+
+  gobject_class->finalize = gst_rtp_qdm2_depay_finalize;
+
+  gstelement_class->change_state = gst_rtp_qdm2_depay_change_state;
+}
+
+static void
+gst_rtp_qdm2_depay_init (GstRtpQDM2Depay * rtpqdm2depay,
+    GstRtpQDM2DepayClass * klass)
+{
+  rtpqdm2depay->adapter = gst_adapter_new ();
+}
+
+static void
+gst_rtp_qdm2_depay_finalize (GObject * object)
+{
+  GstRtpQDM2Depay *rtpqdm2depay;
+
+  rtpqdm2depay = GST_RTP_QDM2_DEPAY (object);
+
+  g_object_unref (rtpqdm2depay->adapter);
+  rtpqdm2depay->adapter = NULL;
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+// only on the sink
+gboolean
+gst_rtp_qdm2_depay_setcaps (GstBaseRTPDepayload * filter, GstCaps * caps)
+{
+  GstStructure *structure = gst_caps_get_structure (caps, 0);
+  gint clock_rate;
+
+  if (!gst_structure_get_int (structure, "clock-rate", &clock_rate))
+    clock_rate = 44100;         // default
+  filter->clock_rate = clock_rate;
+
+  /* will set caps later */
+
+  return TRUE;
+}
+
+static void
+flush_data (GstRtpQDM2Depay * depay)
+{
+  guint i;
+  guint avail;
+
+  if ((avail = gst_adapter_available (depay->adapter)))
+    gst_adapter_flush (depay->adapter, avail);
+
+  GST_DEBUG ("Flushing %d packets", depay->nbpackets);
+
+  for (i = 0; depay->packets[i]; i++) {
+    QDM2Packet *pack = depay->packets[i];
+    guint32 crc;
+    int i;
+    GstBuffer *buf;
+    guint8 *data;
+
+    /* CRC is the sum of everything (including first bytes)
+     * minus the 2 bytes reserved for the checksum */
+
+    GST_DEBUG ("Packet #%d size:%d", i, pack->offs);
+
+    data = pack->data;
+
+    if (G_UNLIKELY (data == NULL))
+      continue;
+
+    /* type 2 */
+    if (depay->packetsize > 0xff) {
+      crc = data[0] = 0x82;
+      crc -= 3;
+      GST_WRITE_UINT16_BE (data + 1, depay->packetsize - 3);
+      i = 5;
+    } else {
+      crc = data[0] = 0x2;
+      data[1] = depay->packetsize - 2;
+      i = 4;
+      crc -= 2;
+    }
+    crc += depay->packetsize;
+
+    /* Calculate CRC */
+    for (; i < depay->packetsize; i++)
+      crc += data[i];
+
+    /* FIXME : Figure out why there's a difference of 0x1fe (0xff << 1) */
+    if (depay->packetsize > 0xff)
+      crc -= 510;
+
+    if (depay->packetsize > 0xff)
+      GST_WRITE_UINT16_BE (data + 3, crc);
+    else
+      GST_WRITE_UINT16_BE (data + 2, crc);
+
+    GST_DEBUG ("CRC is 0x%x", crc);
+
+/*     gst_util_dump_mem (data, depay->packetsize); */
+
+    buf = gst_buffer_new ();
+    GST_BUFFER_DATA (buf) = data;
+    GST_BUFFER_MALLOCDATA (buf) = data;
+    GST_BUFFER_SIZE (buf) = depay->packetsize;
+
+    gst_adapter_push (depay->adapter, buf);
+
+    if (pack->data) {
+      pack->data = NULL;
+    }
+  }
+}
+
+static void
+add_packet (GstRtpQDM2Depay * depay, guint32 pid, guint32 len, guint8 * data)
+{
+  QDM2Packet *packet;
+
+  if (G_UNLIKELY (!depay->configured))
+    return;
+
+  GST_DEBUG ("pid:%d, len:%d, data:%p", pid, len, data);
+
+  if (G_UNLIKELY (depay->packets[pid] == NULL)) {
+    depay->packets[pid] = g_malloc0 (sizeof (QDM2Packet));
+    depay->nbpackets = MAX (depay->nbpackets, pid + 1);
+  }
+  packet = depay->packets[pid];
+
+  GST_DEBUG ("packet:%p", packet);
+  GST_DEBUG ("packet->data:%p", packet->data);
+
+  if (G_UNLIKELY (packet->data == NULL)) {
+    packet->data = g_malloc0 (depay->packetsize);
+    /* We leave space for the header/crc */
+    if (depay->packetsize > 0xff)
+      packet->offs = 5;
+    else
+      packet->offs = 4;
+  }
+
+  /* Finally copy the data over */
+  memcpy (packet->data + packet->offs, data, len);
+  packet->offs += len;
+}
+
+static GstBuffer *
+gst_rtp_qdm2_depay_process (GstBaseRTPDepayload * depayload, GstBuffer * buf)
+{
+  GstRtpQDM2Depay *rtpqdm2depay;
+  GstBuffer *outbuf;
+
+  rtpqdm2depay = GST_RTP_QDM2_DEPAY (depayload);
+
+  {
+    gint payload_len;
+    guint8 *payload;
+    guint avail;
+    guint pos = 0;
+
+    payload_len = gst_rtp_buffer_get_payload_len (buf);
+    if (payload_len < 3)
+      goto bad_packet;
+
+    payload = gst_rtp_buffer_get_payload (buf);
+
+    GST_DEBUG ("Payload size %d 0x%x", payload_len, payload_len);
+
+/*     gst_util_dump_mem (payload, payload_len); */
+
+    while (pos < payload_len) {
+      switch (payload[pos]) {
+        case 0x80:{
+          GST_DEBUG ("Unrecognized 0x80 marker, skipping 12 bytes");
+          pos += 12;
+        }
+          break;
+        case 0xff:
+          /* HEADERS */
+          GST_DEBUG ("Headers");
+          /* Store the incoming timestamp */
+          rtpqdm2depay->ptimestamp = rtpqdm2depay->timestamp;
+          rtpqdm2depay->timestamp = GST_BUFFER_TIMESTAMP (buf);
+          /* flush the internal data if needed */
+          flush_data (rtpqdm2depay);
+          if (G_UNLIKELY (!rtpqdm2depay->configured)) {
+            guint8 *ourdata;
+            GstBuffer *codecdata;
+            GstCaps *caps;
+
+            /* First bytes are unknown */
+/* 	    gst_util_dump_mem (payload + pos, 32); */
+            ourdata = payload + pos + 10;
+            pos += 10;
+            rtpqdm2depay->channs = GST_READ_UINT32_BE (payload + pos + 4);
+            rtpqdm2depay->samplerate = GST_READ_UINT32_BE (payload + pos + 8);
+            rtpqdm2depay->bitrate = GST_READ_UINT32_BE (payload + pos + 12);
+            rtpqdm2depay->blocksize = GST_READ_UINT32_BE (payload + pos + 16);
+            rtpqdm2depay->framesize = GST_READ_UINT32_BE (payload + pos + 20);
+            rtpqdm2depay->packetsize = GST_READ_UINT32_BE (payload + pos + 24);
+            /* 16 bit empty block (0x02 0x00) */
+            pos += 30;
+            GST_DEBUG
+                ("channs:%d, samplerate:%d, bitrate:%d, blocksize:%d, framesize:%d, packetsize:%d",
+                rtpqdm2depay->channs, rtpqdm2depay->samplerate,
+                rtpqdm2depay->bitrate, rtpqdm2depay->blocksize,
+                rtpqdm2depay->framesize, rtpqdm2depay->packetsize);
+            /* FIXME : SET CAPS ! */
+            /* audio/x-qdm2, codec_data, samplesize=(int)16, rate=(int), channels=(int) */
+            codecdata = gst_buffer_new_and_alloc (48);
+            memcpy (GST_BUFFER_DATA (codecdata), headheader, 20);
+            memcpy (GST_BUFFER_DATA (codecdata) + 20, ourdata, 28);
+
+            caps = gst_caps_new_simple ("audio/x-qdm2",
+                "samplesize", G_TYPE_INT, 16,
+                "rate", G_TYPE_INT, rtpqdm2depay->samplerate,
+                "channels", G_TYPE_INT, rtpqdm2depay->channs,
+                "codec_data", GST_TYPE_BUFFER, codecdata, NULL);
+            gst_pad_set_caps (GST_BASE_RTP_DEPAYLOAD_SRCPAD (depayload), caps);
+            gst_caps_unref (caps);
+            rtpqdm2depay->configured = TRUE;
+          } else {
+            GST_DEBUG ("Already configured, skipping headers");
+            pos += 40;
+          }
+          break;
+        default:{
+          /* Shuffled packet contents */
+          guint packetid = payload[pos++];
+          guint packettype = payload[pos++];
+          guint packlen = payload[pos++];
+          guint hsize = 2;
+
+          GST_DEBUG ("Packet id:%d, type:0x%x, len:%d",
+              packetid, packettype, packlen);
+
+          /* Packets bigger than 0xff bytes have a type with the high bit set */
+          if (G_UNLIKELY (packettype & 0x80)) {
+            packettype &= 0x7f;
+            packlen <<= 8;
+            packlen |= payload[pos++];
+            hsize = 3;
+            GST_DEBUG ("Packet id:%d, type:0x%x, len:%d",
+                packetid, packettype, packlen);
+          }
+
+          if (packettype > 0x17) {
+            GST_ERROR ("HOUSTON WE HAVE A PROBLEM !!!!");
+          }
+          add_packet (rtpqdm2depay, packetid, packlen + hsize,
+              payload + pos - hsize);
+          pos += packlen;
+        }
+      }
+    }
+
+    GST_DEBUG ("final pos %d", pos);
+
+    avail = gst_adapter_available (rtpqdm2depay->adapter);
+    if (G_UNLIKELY (avail)) {
+      outbuf = gst_adapter_take_buffer (rtpqdm2depay->adapter, avail);
+      GST_BUFFER_TIMESTAMP (outbuf) = rtpqdm2depay->ptimestamp;
+      return outbuf;
+    }
+  }
+  return NULL;
+
+  /* ERRORS */
+bad_packet:
+  {
+    GST_ELEMENT_WARNING (rtpqdm2depay, STREAM, DECODE,
+        (NULL), ("Packet was too short"));
+    return NULL;
+  }
+}
+
+static GstStateChangeReturn
+gst_rtp_qdm2_depay_change_state (GstElement * element,
+    GstStateChange transition)
+{
+  GstRtpQDM2Depay *rtpqdm2depay;
+  GstStateChangeReturn ret;
+
+  rtpqdm2depay = GST_RTP_QDM2_DEPAY (element);
+
+  switch (transition) {
+    case GST_STATE_CHANGE_NULL_TO_READY:
+      break;
+    case GST_STATE_CHANGE_READY_TO_PAUSED:
+      gst_adapter_clear (rtpqdm2depay->adapter);
+      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_qdm2_depay_plugin_init (GstPlugin * plugin)
+{
+  return gst_element_register (plugin, "rtpqdm2depay",
+      GST_RANK_MARGINAL, GST_TYPE_RTP_QDM2_DEPAY);
+}

gst/rtp/gstrtpqdmdepay.h

@@ -0,0 +1,82 @@
+/* GStreamer
+ * Copyright (C) <2009> Edward Hervey <bilboed@bilboed.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_QDM2_DEPAY_H__
+#define __GST_RTP_QDM2_DEPAY_H__
+
+#include <gst/gst.h>
+#include <gst/base/gstadapter.h>
+#include <gst/rtp/gstbasertpdepayload.h>
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_RTP_QDM2_DEPAY \
+  (gst_rtp_qdm2_depay_get_type())
+#define GST_RTP_QDM2_DEPAY(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_RTP_QDM2_DEPAY,GstRtpQDM2Depay))
+#define GST_RTP_QDM2_DEPAY_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_RTP_QDM2_DEPAY,GstRtpQDM2DepayClass))
+#define GST_IS_RTP_QDM2_DEPAY(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_RTP_QDM2_DEPAY))
+#define GST_IS_RTP_QDM2_DEPAY_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_RTP_QDM2_DEPAY))
+
+typedef struct _GstRtpQDM2Depay GstRtpQDM2Depay;
+typedef struct _GstRtpQDM2DepayClass GstRtpQDM2DepayClass;
+
+typedef struct _QDM2Packet {
+  guint8* data;
+  guint offs;		/* Starts at 4 to give room for the prefix */
+} QDM2Packet;
+
+#define MAX_SCRAMBLED_PACKETS 64
+
+struct _GstRtpQDM2Depay
+{
+  GstBaseRTPDepayload depayload;
+
+  GstAdapter *adapter;
+
+  gboolean configured;
+
+  GstClockTime timestamp; /* Timestamp of current incoming data */
+  GstClockTime ptimestamp; /* Timestamp of data stored in the adapter */
+
+  guint32 channs;
+  guint32 samplerate;
+  guint32 bitrate;
+  guint32 blocksize;
+  guint32 framesize;
+  guint32 packetsize;
+
+  guint nbpackets;	/* Number of packets to unscramble */
+
+  QDM2Packet *packets[MAX_SCRAMBLED_PACKETS];
+};
+
+struct _GstRtpQDM2DepayClass
+{
+  GstBaseRTPDepayloadClass parent_class;
+};
+
+gboolean gst_rtp_qdm2_depay_plugin_init (GstPlugin * plugin);
+
+G_END_DECLS
+
+#endif /* __GST_RTP_QDM2_DEPAY_H__ */