From ffc06e17f036c183df6037f9654eeae870d14e54 Mon Sep 17 00:00:00 2001
From: Wim Taymans <wim.taymans@collabora.co.uk>
Date: Thu, 3 Jun 2010 19:23:01 +0200
Subject: [PATCH] mp4gdepay: calculate the frame duration correctly

When we calculate the frame duration, we need to use the amount of
frames in the _previous_ packet, not the current packet. The frame duration is
needed to correctly de-interleave interleaved streams. This fixes the case where
there are a variable number of frames in a packet.

Fixes #620494
---
 gst/rtp/gstrtpmp4gdepay.c | 8 ++++++++
 gst/rtp/gstrtpmp4gdepay.h | 1 +
 2 files changed, 9 insertions(+)

diff --git a/gst/rtp/gstrtpmp4gdepay.c b/gst/rtp/gstrtpmp4gdepay.c
index 4d8aee272c..8307becca6 100644
--- a/gst/rtp/gstrtpmp4gdepay.c
+++ b/gst/rtp/gstrtpmp4gdepay.c
@@ -544,7 +544,13 @@ gst_rtp_mp4g_depay_process (GstBaseRTPDepayload * depayload, GstBuffer * buf)
             if (rtpmp4gdepay->constantDuration != 0) {
               cd = rtpmp4gdepay->constantDuration;
               GST_DEBUG_OBJECT (depayload, "using constantDuration %d", cd);
+            } else if (rtpmp4gdepay->prev_AU_num > 0) {
+              /* use number of packets and of previous frame */
+              cd = diff / rtpmp4gdepay->prev_AU_num;
+              GST_DEBUG_OBJECT (depayload, "guessing constantDuration %d", cd);
             } else {
+              /* assume this frame has the same number of packets as the
+               * previous one */
               cd = diff / num_AU_headers;
               GST_DEBUG_OBJECT (depayload, "guessing constantDuration %d", cd);
             }
@@ -592,6 +598,7 @@ gst_rtp_mp4g_depay_process (GstBaseRTPDepayload * depayload, GstBuffer * buf)
             }
           }
           rtpmp4gdepay->prev_rtptime = rtptime;
+          rtpmp4gdepay->prev_AU_num = num_AU_headers;
         } else {
           AU_index_delta =
               gst_bs_parse_read (&bs, rtpmp4gdepay->indexdeltalength);
@@ -709,6 +716,7 @@ gst_rtp_mp4g_depay_change_state (GstElement * element,
       rtpmp4gdepay->prev_AU_index = -1;
       rtpmp4gdepay->prev_rtptime = -1;
       rtpmp4gdepay->last_AU_index = -1;
+      rtpmp4gdepay->prev_AU_num = -1;
       break;
     default:
       break;
diff --git a/gst/rtp/gstrtpmp4gdepay.h b/gst/rtp/gstrtpmp4gdepay.h
index 2d19413274..cd088e5b19 100644
--- a/gst/rtp/gstrtpmp4gdepay.h
+++ b/gst/rtp/gstrtpmp4gdepay.h
@@ -65,6 +65,7 @@ struct _GstRtpMP4GDepay
   guint last_AU_index;
   guint next_AU_index;
   guint32 prev_rtptime;
+  guint prev_AU_num;
 
   GQueue *packets;