From 7e363149f323f745b4147aa469208bdbb8465db6 Mon Sep 17 00:00:00 2001
From: Wim Taymans <wim.taymans@collabora.co.uk>
Date: Wed, 17 Mar 2010 16:23:24 +0100
Subject: [PATCH] mp4gdepay: improve constantDuration guessing

When no constantDuration has been given in the caps, try to derive one from the
timestamp difference between packets. Also keep doing this for each packet
because some broken streams might simply provide wrong timestamps.
---
 gst/rtp/gstrtpmp4gdepay.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/gst/rtp/gstrtpmp4gdepay.c b/gst/rtp/gstrtpmp4gdepay.c
index 939e3f1a8e..8a3b5486f8 100644
--- a/gst/rtp/gstrtpmp4gdepay.c
+++ b/gst/rtp/gstrtpmp4gdepay.c
@@ -441,6 +441,8 @@ gst_rtp_mp4g_depay_process (GstBaseRTPDepayload * depayload, GstBuffer * buf)
     payload_len = gst_rtp_buffer_get_payload_len (buf);
     payload = gst_rtp_buffer_get_payload (buf);
 
+    GST_DEBUG_OBJECT (rtpmp4gdepay, "received payload of %d", payload_len);
+
     rtptime = gst_rtp_buffer_get_timestamp (buf);
     M = gst_rtp_buffer_get_marker (buf);
 
@@ -526,8 +528,11 @@ gst_rtp_mp4g_depay_process (GstBaseRTPDepayload * depayload, GstBuffer * buf)
         if (i == 0) {
           AU_index = gst_bs_parse_read (&bs, rtpmp4gdepay->indexlength);
 
+          GST_DEBUG_OBJECT (rtpmp4gdepay, "AU index %u", AU_index);
+
           if (AU_index == 0 && rtpmp4gdepay->prev_AU_index == 0) {
             gint diff;
+            gint cd;
 
             /* if we see two consecutive packets with AU_index of 0, we can
              * assume we have constantDuration packets. Since we don't have
@@ -540,15 +545,17 @@ gst_rtp_mp4g_depay_process (GstBaseRTPDepayload * depayload, GstBuffer * buf)
               diff = -(rtpmp4gdepay->prev_rtptime - rtptime);
 
             /* if no constantDuration was given, make one */
-            if (rtpmp4gdepay->constantDuration == 0) {
-              rtpmp4gdepay->constantDuration = diff / num_AU_headers;
-              GST_DEBUG_OBJECT (depayload, "guessing constantDuration %d",
-                  rtpmp4gdepay->constantDuration);
+            if (rtpmp4gdepay->constantDuration != 0) {
+              cd = rtpmp4gdepay->constantDuration;
+              GST_DEBUG_OBJECT (depayload, "using constantDuration %d", cd);
+            } else {
+              cd = diff / num_AU_headers;
+              GST_DEBUG_OBJECT (depayload, "guessing constantDuration %d", cd);
             }
 
-            if (rtpmp4gdepay->constantDuration > 0) {
+            if (cd > 0) {
               /* get the number of packets by dividing with the duration */
-              diff /= rtpmp4gdepay->constantDuration;
+              diff /= cd;
             } else {
               diff = 0;
             }
@@ -558,6 +565,8 @@ gst_rtp_mp4g_depay_process (GstBaseRTPDepayload * depayload, GstBuffer * buf)
 
             AU_index = rtpmp4gdepay->last_AU_index;
 
+            GST_DEBUG_OBJECT (rtpmp4gdepay, "diff %d, AU index %u", diff,
+                AU_index);
           } else {
             rtpmp4gdepay->prev_AU_index = AU_index;
             rtpmp4gdepay->last_AU_index = AU_index;