rtph263pdepay: Fix picture header for non-writable payload

Under certain conditions gst_rtp_buffer_get_payload() returns a copy of
the payload. In this case the payload modifications will not affect the
rtp buffer. So instead of modifying the payload buffer directly we
should modify the buffer that actually gets pushed on the adapter.

gst/rtp/gstrtph263pdepay.c

@@ -287,12 +287,8 @@ gst_rtp_h263p_depay_process (GstRTPBaseDepayload * depayload,
     goto too_small;
 
   if (P) {
-    /* FIXME, have to make the packet writable hear. Better to reset these
-     * bytes when we copy the packet below */
     rtph263pdepay->wait_start = FALSE;
     header_len -= 2;
-    payload[header_len] = 0;
-    payload[header_len + 1] = 0;
   }
 
   if (rtph263pdepay->wait_start)
@@ -304,7 +300,6 @@ gst_rtp_h263p_depay_process (GstRTPBaseDepayload * depayload,
   /* FIXME do not ignore the VRC header (See RFC 2429 section 4.2) */
   /* FIXME actually use the RTP picture header when it is lost in the network */
   /* for now strip off header */
-  payload += header_len;
   payload_len -= header_len;
 
   if (M) {
@@ -317,6 +312,8 @@ gst_rtp_h263p_depay_process (GstRTPBaseDepayload * depayload,
 
     outbuf =
         gst_rtp_buffer_get_payload_subbuffer (rtp, header_len, payload_len);
+    if (P)
+      gst_buffer_memset (outbuf, 0, 0, 2);
     gst_adapter_push (rtph263pdepay->adapter, outbuf);
     outbuf = NULL;
 
@@ -341,6 +338,8 @@ gst_rtp_h263p_depay_process (GstRTPBaseDepayload * depayload,
 
     outbuf =
         gst_rtp_buffer_get_payload_subbuffer (rtp, header_len, payload_len);
+    if (P)
+      gst_buffer_memset (outbuf, 0, 0, 2);
     gst_adapter_push (rtph263pdepay->adapter, outbuf);
   }
   return NULL;

tests/check/elements/rtph263.c

@@ -142,6 +142,106 @@ GST_START_TEST (test_h263pay_mode_b_snow)
 }
 GST_END_TEST;
 
+/* gst_rtp_buffer_get_payload() may return a copy of the payload. This test
+ * makes sure that the rtph263pdepay also produces the correct output in this
+ * case. */
+GST_START_TEST (test_h263pdepay_fragmented_memory_non_writable_buffer)
+{
+  GstHarness *h;
+  GstBuffer *header_buf, *payload_buf, *buf;
+  GstRTPBuffer rtp = GST_RTP_BUFFER_INIT;
+  guint8 header[] = {
+    0x04, 0x00 };
+  guint8 payload[] = {
+    0x80, 0x02, 0x1c, 0xb8, 0x01, 0x00, 0x11, 0xe0, 0x44, 0xc4 };
+  guint8 frame[] = {
+    0x00, 0x00, 0x80, 0x02, 0x1c, 0xb8, 0x01, 0x00, 0x11, 0xe0, 0x44, 0xc4 };
+
+  h = gst_harness_new ("rtph263pdepay");
+  gst_harness_set_src_caps_str (h, "application/x-rtp, media=video, "
+      "clock-rate=90000, encoding-name=H263-1998");
+
+  /* Packet with M=1, P=1 */
+  header_buf = gst_rtp_buffer_new_allocate (sizeof (header), 0, 0);
+  gst_rtp_buffer_map (header_buf, GST_MAP_WRITE, &rtp);
+  gst_rtp_buffer_set_marker (&rtp, TRUE);
+  memcpy (gst_rtp_buffer_get_payload (&rtp), header, sizeof (header));
+  gst_rtp_buffer_unmap (&rtp);
+
+  payload_buf = gst_buffer_new_allocate (NULL, sizeof (payload), NULL);
+  gst_buffer_fill (payload_buf, 0, payload, sizeof (payload));
+  buf = gst_buffer_append (header_buf, payload_buf);
+
+  gst_harness_push (h, gst_buffer_ref (buf));
+  gst_buffer_unref (buf);
+
+  buf = gst_harness_pull (h);
+  fail_unless (gst_buffer_memcmp (buf, 0, frame, sizeof (frame)) == 0);
+  gst_buffer_unref (buf);
+
+  gst_harness_teardown (h);
+}
+GST_END_TEST;
+
+/* gst_rtp_buffer_get_payload() may return a copy of the payload. This test
+ * makes sure that the rtph263pdepay also produces the correct output in this
+ * case. */
+GST_START_TEST (test_h263pdepay_fragmented_memory_non_writable_buffer_split_frame)
+{
+  GstHarness *h;
+  GstBuffer *header_buf, *payload_buf, *buf;
+  GstRTPBuffer rtp = GST_RTP_BUFFER_INIT;
+  guint8 header[] = {
+    0x04, 0x00 };
+  guint8 payload[] = {
+    0x80, 0x02, 0x1c, 0xb8, 0x01, 0x00, 0x11, 0xe0, 0x44, 0xc4 };
+  guint8 frame[] = {
+    0x00, 0x00, 0x80, 0x02, 0x1c, 0xb8, 0x01, 0x00, 0x11, 0xe0, 0x44, 0xc4 };
+
+  h = gst_harness_new ("rtph263pdepay");
+  gst_harness_set_src_caps_str (h, "application/x-rtp, media=video, "
+      "clock-rate=90000, encoding-name=H263-1998");
+
+  /* First packet, M=0, P=1 */
+  header_buf = gst_rtp_buffer_new_allocate (sizeof (header), 0, 0);
+  gst_rtp_buffer_map (header_buf, GST_MAP_WRITE, &rtp);
+  gst_rtp_buffer_set_marker (&rtp, FALSE);
+  gst_rtp_buffer_set_seq (&rtp, 0);
+  memcpy (gst_rtp_buffer_get_payload (&rtp), header, sizeof (header));
+  gst_rtp_buffer_unmap (&rtp);
+
+  payload_buf = gst_buffer_new_allocate (NULL, sizeof (payload), NULL);
+  gst_buffer_fill (payload_buf, 0, payload, sizeof (payload));
+  buf = gst_buffer_append (header_buf, payload_buf);
+
+  gst_harness_push (h, gst_buffer_ref (buf));
+  gst_buffer_unref (buf);
+  fail_unless_equals_int (gst_harness_buffers_received (h), 0);
+
+  /* Second packet, M=1, P=1 */
+  header_buf = gst_rtp_buffer_new_allocate (sizeof (header), 0, 0);
+  gst_rtp_buffer_map (header_buf, GST_MAP_WRITE, &rtp);
+  gst_rtp_buffer_set_marker (&rtp, TRUE);
+  gst_rtp_buffer_set_seq (&rtp, 1);
+  memcpy (gst_rtp_buffer_get_payload (&rtp), header, sizeof (header));
+  gst_rtp_buffer_unmap (&rtp);
+
+  payload_buf = gst_buffer_new_allocate (NULL, sizeof (payload), NULL);
+  gst_buffer_memset (payload_buf, 0, 0, 10);
+  buf = gst_buffer_append (header_buf, payload_buf);
+
+  gst_harness_push (h, gst_buffer_ref (buf));
+  gst_buffer_unref (buf);
+  fail_unless_equals_int (gst_harness_buffers_received (h), 1);
+
+  buf = gst_harness_pull (h);
+  fail_unless (gst_buffer_memcmp (buf, 0, frame, sizeof (frame)) == 0);
+  gst_buffer_unref (buf);
+
+  gst_harness_teardown (h);
+}
+GST_END_TEST;
+
 static Suite *
 rtph263_suite (void)
 {
@@ -156,6 +256,10 @@ rtph263_suite (void)
   suite_add_tcase (s, (tc_chain = tcase_create ("h263pay")));
   tcase_add_test (tc_chain, test_h263pay_mode_b_snow);
 
+  suite_add_tcase (s, (tc_chain = tcase_create ("h263pdepay")));
+  tcase_add_test (tc_chain, test_h263pdepay_fragmented_memory_non_writable_buffer);
+  tcase_add_test (tc_chain, test_h263pdepay_fragmented_memory_non_writable_buffer_split_frame);
+
   return s;
 }