RTP: reorder for better readability

modules/access/rtp/session.c

@@ -376,80 +376,13 @@ drop:
 }
 
 
-static void
-rtp_decode (demux_t *demux, const rtp_session_t *session, rtp_source_t *src)
-{
-    block_t *block = src->blocks;
-
-    assert (block);
-    src->blocks = block->p_next;
-    block->p_next = NULL;
-
-    /* Discontinuity detection */
-    uint16_t delta_seq = rtp_seq (block) - (src->last_seq + 1);
-    if (delta_seq != 0)
-    {
-        if (delta_seq >= 0x8000)
-        {   /* Trash too late packets (and PIM Assert duplicates) */
-            msg_Dbg (demux, "ignoring late packet (sequence: %"PRIu16")",
-                      rtp_seq (block));
-            goto drop;
-        }
-        msg_Warn (demux, "%"PRIu16" packet(s) lost", delta_seq);
-        block->i_flags |= BLOCK_FLAG_DISCONTINUITY;
-    }
-    src->last_seq = rtp_seq (block);
-
-    /* Match the payload type */
-    void *pt_data;
-    const rtp_pt_t *pt = rtp_find_ptype (session, src, block, &pt_data);
-    if (pt == NULL)
-    {
-        msg_Dbg (demux, "unknown payload (%"PRIu8")",
-                 rtp_ptype (block));
-        goto drop;
-    }
-
-    /* Computes the PTS from the RTP timestamp and payload RTP frequency.
-     * DTS is unknown. Also, while the clock frequency depends on the payload
-     * format, a single source MUST only use payloads of a chosen frequency.
-     * Otherwise it would be impossible to compute consistent timestamps. */
-    const uint32_t timestamp = rtp_timestamp (block);
-    block->i_pts = src->ref_ntp
-       + CLOCK_FREQ * (int32_t)(timestamp - src->ref_rtp) / pt->frequency;
-    /* TODO: proper inter-medias/sessions sync (using RTCP-SR) */
-    src->ref_ntp = block->i_pts;
-    src->ref_rtp = timestamp;
-
-    /* CSRC count */
-    size_t skip = 12u + (block->p_buffer[0] & 0x0F) * 4;
-
-    /* Extension header (ignored for now) */
-    if (block->p_buffer[0] & 0x10)
-    {
-        skip += 4;
-        if (block->i_buffer < skip)
-            goto drop;
-
-        skip += 4 * GetWBE (block->p_buffer + skip - 2);
-    }
-
-    if (block->i_buffer < skip)
-        goto drop;
-
-    block->p_buffer += skip;
-    block->i_buffer -= skip;
-
-    pt->decode (demux, pt_data, block);
-    return;
-
-drop:
-    block_Release (block);
-}
-
+static void rtp_decode (demux_t *, const rtp_session_t *, rtp_source_t *);
 
 /**
- * Dequeues an RTP packet and pass it to decoder. Not cancellation-safe(?).
+ * Dequeues RTP packets and pass them to decoder. Not cancellation-safe(?).
+ * A packet is decoded if it is the next in sequence order, or if we have
+ * given up waiting on the missing packets (time out) from the last one
+ * already decoded.
  *
  * @param demux VLC demux object
  * @param session RTP session receiving the packet
@@ -527,3 +460,78 @@ bool rtp_dequeue (demux_t *demux, const rtp_session_t *session,
     }
     return pending;
 }
+
+
+/**
+ * Decodes one RTP packet.
+ */
+static void
+rtp_decode (demux_t *demux, const rtp_session_t *session, rtp_source_t *src)
+{
+    block_t *block = src->blocks;
+
+    assert (block);
+    src->blocks = block->p_next;
+    block->p_next = NULL;
+
+    /* Discontinuity detection */
+    uint16_t delta_seq = rtp_seq (block) - (src->last_seq + 1);
+    if (delta_seq != 0)
+    {
+        if (delta_seq >= 0x8000)
+        {   /* Trash too late packets (and PIM Assert duplicates) */
+            msg_Dbg (demux, "ignoring late packet (sequence: %"PRIu16")",
+                      rtp_seq (block));
+            goto drop;
+        }
+        msg_Warn (demux, "%"PRIu16" packet(s) lost", delta_seq);
+        block->i_flags |= BLOCK_FLAG_DISCONTINUITY;
+    }
+    src->last_seq = rtp_seq (block);
+
+    /* Match the payload type */
+    void *pt_data;
+    const rtp_pt_t *pt = rtp_find_ptype (session, src, block, &pt_data);
+    if (pt == NULL)
+    {
+        msg_Dbg (demux, "unknown payload (%"PRIu8")",
+                 rtp_ptype (block));
+        goto drop;
+    }
+
+    /* Computes the PTS from the RTP timestamp and payload RTP frequency.
+     * DTS is unknown. Also, while the clock frequency depends on the payload
+     * format, a single source MUST only use payloads of a chosen frequency.
+     * Otherwise it would be impossible to compute consistent timestamps. */
+    const uint32_t timestamp = rtp_timestamp (block);
+    block->i_pts = src->ref_ntp
+       + CLOCK_FREQ * (int32_t)(timestamp - src->ref_rtp) / pt->frequency;
+    /* TODO: proper inter-medias/sessions sync (using RTCP-SR) */
+    src->ref_ntp = block->i_pts;
+    src->ref_rtp = timestamp;
+
+    /* CSRC count */
+    size_t skip = 12u + (block->p_buffer[0] & 0x0F) * 4;
+
+    /* Extension header (ignored for now) */
+    if (block->p_buffer[0] & 0x10)
+    {
+        skip += 4;
+        if (block->i_buffer < skip)
+            goto drop;
+
+        skip += 4 * GetWBE (block->p_buffer + skip - 2);
+    }
+
+    if (block->i_buffer < skip)
+        goto drop;
+
+    block->p_buffer += skip;
+    block->i_buffer -= skip;
+
+    pt->decode (demux, pt_data, block);
+    return;
+
+drop:
+    block_Release (block);
+}