g726pay: add RFC compliant packetizing

Shuffle the input bits according to RFC 3551 for G726 payloads.
Add option to force the previous behaviour.

Fixes #567140

2 files changed, 269 insertions, 8 deletions

diff --git a/gst/rtp/gstrtpg726pay.c b/gst/rtp/gstrtpg726pay.c
index babf3a28..9903a7c8 100644
--- a/gst/rtp/gstrtpg726pay.c
+++ b/gst/rtp/gstrtpg726pay.c
@@ -30,6 +30,18 @@
 
 #include "gstrtpg726pay.h"
 
+GST_DEBUG_CATEGORY_STATIC (rtpg726pay_debug);
+#define GST_CAT_DEFAULT (rtpg726pay_debug)
+
+#define DEFAULT_FORCE_AAL2      TRUE
+
+enum
+{
+  PROP_0,
+  PROP_FORCE_AAL2,
+  PROP_LAST
+};
+
 static const GstElementDetails gst_rtp_g726_pay_details =
 GST_ELEMENT_DETAILS ("RTP G.726 payloader",
     "Codec/Payloader/Network",
@@ -55,11 +67,19 @@ GST_STATIC_PAD_TEMPLATE ("src",
         "media = (string) \"audio\", "
         "payload = (int) " GST_RTP_PAYLOAD_DYNAMIC_STRING ", "
         "clock-rate = (int) 8000, "
-        "encoding-name = (string) { \"G726-16\", \"G726-24\", \"G726-32\", \"G726-40\" } ")
+        "encoding-name = (string) { \"G726-16\", \"G726-24\", \"G726-32\", \"G726-40\", "
+        "    \"AAL2-G726-16\", \"AAL2-G726-24\", \"AAL2-G726-32\", \"AAL2-G726-40\" } ")
     );
 
+static void gst_rtp_g726_pay_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec);
+static void gst_rtp_g726_pay_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec);
+
 static gboolean gst_rtp_g726_pay_setcaps (GstBaseRTPPayload * payload,
     GstCaps * caps);
+static GstFlowReturn gst_rtp_g726_pay_handle_buffer (GstBaseRTPPayload *
+    payload, GstBuffer * buffer);
 
 GST_BOILERPLATE (GstRtpG726Pay, gst_rtp_g726_pay, GstBaseRTPAudioPayload,
     GST_TYPE_BASE_RTP_AUDIO_PAYLOAD);
@@ -83,9 +103,19 @@ gst_rtp_g726_pay_class_init (GstRtpG726PayClass * klass)
 
   gstbasertppayload_class = (GstBaseRTPPayloadClass *) klass;
 
-  parent_class = g_type_class_peek_parent (klass);
+  gobject_class->set_property = gst_rtp_g726_pay_set_property;
+  gobject_class->get_property = gst_rtp_g726_pay_get_property;
+
+  g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_FORCE_AAL2,
+      g_param_spec_boolean ("force-aal2", "Force AAL2",
+          "Force AAL2 encoding for compatibility with bad depayloaders",
+          DEFAULT_FORCE_AAL2, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
 
   gstbasertppayload_class->set_caps = gst_rtp_g726_pay_setcaps;
+  gstbasertppayload_class->handle_buffer = gst_rtp_g726_pay_handle_buffer;
+
+  GST_DEBUG_CATEGORY_INIT (rtpg726pay_debug, "rtpg726pay", 0,
+      "G.726 RTP Payloader");
 }
 
 static void
@@ -97,6 +127,8 @@ gst_rtp_g726_pay_init (GstRtpG726Pay * rtpg726pay, GstRtpG726PayClass * klass)
 
   GST_BASE_RTP_PAYLOAD (rtpg726pay)->clock_rate = 8000;
 
+  rtpg726pay->force_aal2 = DEFAULT_FORCE_AAL2;
+
   /* sample based codec */
   gst_base_rtp_audio_payload_set_sample_based (basertpaudiopayload);
 }
@@ -105,16 +137,25 @@ static gboolean
 gst_rtp_g726_pay_setcaps (GstBaseRTPPayload * payload, GstCaps * caps)
 {
   gchar *encoding_name;
-  GstStructure *structure = gst_caps_get_structure (caps, 0);
+  GstStructure *structure;
   GstBaseRTPAudioPayload *basertpaudiopayload;
-  gint bitrate;
+  GstRtpG726Pay *pay;
+  GstCaps *peercaps;
 
   basertpaudiopayload = GST_BASE_RTP_AUDIO_PAYLOAD (payload);
+  pay = GST_RTP_G726_PAY (payload);
 
-  if (!gst_structure_get_int (structure, "bitrate", &bitrate))
-    bitrate = 32000;
+  structure = gst_caps_get_structure (caps, 0);
 
-  switch (bitrate) {
+  if (!gst_structure_get_int (structure, "bitrate", &pay->bitrate))
+    pay->bitrate = 32000;
+
+  GST_DEBUG_OBJECT (payload, "using bitrate %d", pay->bitrate);
+
+  pay->aal2 = FALSE;
+
+  /* first see what we can do with the bitrate */
+  switch (pay->bitrate) {
     case 16000:
       encoding_name = g_strdup ("G726-16");
       gst_base_rtp_audio_payload_set_samplebits_options (basertpaudiopayload,
@@ -139,6 +180,65 @@ gst_rtp_g726_pay_setcaps (GstBaseRTPPayload * payload, GstCaps * caps)
       goto invalid_bitrate;
   }
 
+  GST_DEBUG_OBJECT (payload, "selected base encoding %s", encoding_name);
+
+  /* now see if we need to produce AAL2 or not */
+  peercaps = gst_pad_peer_get_caps (payload->srcpad);
+  if (peercaps) {
+    GstCaps *filter, *intersect;
+    gchar *capsstr;
+
+    GST_DEBUG_OBJECT (payload, "have peercaps %" GST_PTR_FORMAT, peercaps);
+
+    capsstr = g_strdup_printf ("application/x-rtp, "
+        "media = (string) \"audio\", "
+        "clock-rate = (int) 8000, "
+        "encoding-name = (string) %s; "
+        "application/x-rtp, "
+        "media = (string) \"audio\", "
+        "clock-rate = (int) 8000, "
+        "encoding-name = (string) AAL2-%s", encoding_name, encoding_name);
+    filter = gst_caps_from_string (capsstr);
+    g_free (capsstr);
+
+    /* intersect to filter */
+    intersect = gst_caps_intersect (peercaps, filter);
+    gst_caps_unref (peercaps);
+
+    GST_DEBUG_OBJECT (payload, "intersected to %" GST_PTR_FORMAT, intersect);
+
+    if (!intersect)
+      goto no_format;
+    if (gst_caps_is_empty (intersect)) {
+      gst_caps_unref (intersect);
+      goto no_format;
+    }
+
+    structure = gst_caps_get_structure (intersect, 0);
+
+    /* now see what encoding name we settled on, we need to dup because the
+     * string goes away when we unref the intersection below. */
+    encoding_name =
+        g_strdup (gst_structure_get_string (structure, "encoding-name"));
+
+    /* if we managed to negotiate to AAL2, we definatly are going to do AAL2
+     * encoding. Else we only encode AAL2 when explicitly set by the
+     * property. */
+    if (g_str_has_prefix (encoding_name, "AAL2-"))
+      pay->aal2 = TRUE;
+    else
+      pay->aal2 = pay->force_aal2;
+
+    GST_DEBUG_OBJECT (payload, "final encoding %s, AAL2 %d", encoding_name,
+        pay->aal2);
+
+    gst_caps_unref (intersect);
+  } else {
+    /* downstream can do anything but we prefer the better supported non-AAL2 */
+    pay->aal2 = pay->force_aal2;
+    GST_DEBUG_OBJECT (payload, "no peer caps, AAL2 %d", pay->aal2);
+  }
+
   gst_basertppayload_set_options (payload, "audio", TRUE, encoding_name, 8000);
   gst_basertppayload_set_outcaps (payload, NULL);
 
@@ -149,9 +249,166 @@ gst_rtp_g726_pay_setcaps (GstBaseRTPPayload * payload, GstCaps * caps)
   /* ERRORS */
 invalid_bitrate:
   {
-    GST_ERROR_OBJECT (payload, "invalid bitrate %d specified", bitrate);
+    GST_ERROR_OBJECT (payload, "invalid bitrate %d specified", pay->bitrate);
     return FALSE;
   }
+no_format:
+  {
+    GST_ERROR_OBJECT (payload, "could not negotiate format");
+    return FALSE;
+  }
+}
+
+static GstFlowReturn
+gst_rtp_g726_pay_handle_buffer (GstBaseRTPPayload * payload, GstBuffer * buffer)
+{
+  GstFlowReturn res;
+  GstRtpG726Pay *pay;
+
+  pay = GST_RTP_G726_PAY (payload);
+
+  if (!pay->aal2) {
+    guint8 *data, tmp;
+    guint len;
+
+    /* for non AAL2, we need to reshuffle the bytes, we can do this in-place
+     * when the buffer is writable. */
+    buffer = gst_buffer_make_writable (buffer);
+
+    data = GST_BUFFER_DATA (buffer);
+    len = GST_BUFFER_SIZE (buffer);
+
+    GST_LOG_OBJECT (pay, "packing %u bytes of data", len);
+
+    /* we need to reshuffle the bytes, output is of the form:
+     * A B C D .. with the number of bits depending on the bitrate. */
+    switch (pay->bitrate) {
+      case 16000:
+      {
+        /*  0               
+         *  0 1 2 3 4 5 6 7 
+         * +-+-+-+-+-+-+-+-+-
+         * |D D|C C|B B|A A| ...
+         * |0 1|0 1|0 1|0 1|
+         * +-+-+-+-+-+-+-+-+-
+         */
+        while (len > 0) {
+          tmp = *data;
+          *data++ = ((tmp & 0xc0) >> 6) |
+              ((tmp & 0x30) >> 2) | ((tmp & 0x0c) << 2) | ((tmp & 0x03) << 6);
+          len--;
+        }
+        break;
+      }
+      case 24000:
+      {
+        /*  0                   1                   2
+         *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
+         * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
+         * |C C|B B B|A A A|F|E E E|D D D|C|H H H|G G G|F F| ...
+         * |1 2|0 1 2|0 1 2|2|0 1 2|0 1 2|0|0 1 2|0 1 2|0 1|
+         * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
+         */
+        while (len > 2) {
+          tmp = *data;
+          *data++ = ((tmp & 0xc0) >> 6) |
+              ((tmp & 0x38) >> 1) | ((tmp & 0x07) << 5);
+          tmp = *data;
+          *data++ = ((tmp & 0x80) >> 7) |
+              ((tmp & 0x70) >> 3) | ((tmp & 0x0e) << 4) | ((tmp & 0x01) << 7);
+          tmp = *data;
+          *data++ = ((tmp & 0xe0) >> 5) |
+              ((tmp & 0x1c) >> 2) | ((tmp & 0x03) << 6);
+          len -= 3;
+        }
+        break;
+      }
+      case 32000:
+      {
+        /*  0                   1
+         *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+         * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
+         * |B B B B|A A A A|D D D D|C C C C| ...
+         * |0 1 2 3|0 1 2 3|0 1 2 3|0 1 2 3|
+         * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
+         */
+        while (len > 0) {
+          tmp = *data;
+          *data++ = ((tmp & 0xf0) >> 4) | ((tmp & 0x0f) << 4);
+          len--;
+        }
+        break;
+      }
+      case 40000:
+      {
+        /*  0                   1                   2                   3                   4
+         *  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 2 3 4 5 6 7 8 9 0
+         * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
+         * |B B B|A A A A A|D|C C C C C|B B|E E E E|D D D D|G G|F F F F F|E|H H H H H|G G G|
+         * |2 3 4|0 1 2 3 4|4|0 1 2 3 4|0 1|1 2 3 4|0 1 2 3|3 4|0 1 2 3 4|0|0 1 2 3 4|0 1 2|   
+         * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
+         */
+        while (len > 4) {
+          tmp = *data;
+          *data++ = ((tmp & 0xe0) >> 5) | ((tmp & 0x1f) << 3);
+          tmp = *data;
+          *data++ = ((tmp & 0x80) >> 7) |
+              ((tmp & 0x7c) >> 2) | ((tmp & 0x03) << 6);
+          tmp = *data;
+          *data++ = ((tmp & 0xf0) >> 4) | ((tmp & 0x0f) << 4);
+          tmp = *data;
+          *data++ = ((tmp & 0xc0) >> 6) |
+              ((tmp & 0x3e) << 2) | ((tmp & 0x01) << 7);
+          tmp = *data;
+          *data++ = ((tmp & 0xf8) >> 3) | ((tmp & 0x07) << 5);
+          len -= 5;
+        }
+        break;
+      }
+    }
+  }
+
+  res =
+      GST_BASE_RTP_PAYLOAD_CLASS (parent_class)->handle_buffer (payload,
+      buffer);
+
+  return res;
+}
+
+static void
+gst_rtp_g726_pay_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstRtpG726Pay *rtpg726pay;
+
+  rtpg726pay = GST_RTP_G726_PAY (object);
+
+  switch (prop_id) {
+    case PROP_FORCE_AAL2:
+      rtpg726pay->force_aal2 = g_value_get_boolean (value);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+gst_rtp_g726_pay_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec)
+{
+  GstRtpG726Pay *rtpg726pay;
+
+  rtpg726pay = GST_RTP_G726_PAY (object);
+
+  switch (prop_id) {
+    case PROP_FORCE_AAL2:
+      g_value_set_boolean (value, rtpg726pay->force_aal2);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
 }
 
 gboolean
diff --git a/gst/rtp/gstrtpg726pay.h b/gst/rtp/gstrtpg726pay.h
index 43eaf63f..1d9856b9 100644
--- a/gst/rtp/gstrtpg726pay.h
+++ b/gst/rtp/gstrtpg726pay.h
@@ -36,6 +36,10 @@ typedef struct _GstRtpG726PayClass GstRtpG726PayClass;
 struct _GstRtpG726Pay
 {
   GstBaseRTPAudioPayload audiopayload;
+
+  gboolean aal2;
+  gboolean force_aal2;
+  gint bitrate;
 };
 
 struct _GstRtpG726PayClass