From 8c3671fae67daa68caabab790f8b62984d8994dc Mon Sep 17 00:00:00 2001
From: Klaus Schmidinger <vdr@tvdr.de>
Date: Wed, 19 Feb 2025 15:39:16 +0100
Subject: [PATCH] Fixed cPtsIndex::FindFrameNumber() to handle the case where
 Pts points to an I-frame

---
 HISTORY     |  3 ++-
 dvbplayer.c | 18 ++++++++----------
 2 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/HISTORY b/HISTORY
index 8fa7dcdc..949f1bdd 100644
--- a/HISTORY
+++ b/HISTORY
@@ -10034,7 +10034,7 @@ Video Disk Recorder Revision History
   (suggested by Stefan Hofmann).
 - Added vdrrootdir and incdir to vdr.pc (thanks to Stefan Hofmann).
 
-2025-02-18:
+2025-02-19:
 
 - Removed all DEPRECATED_* code.
 - Fixed error checking in case the fps value can't be determined by the frame parser.
@@ -10086,3 +10086,4 @@ Video Disk Recorder Revision History
 - Fixed progress display when switching from "pause" to "slow back" (reported by Andreas
   Baierl).
 - Fixed spurious fast frames when switching from "slow back" to "slow forward".
+- Fixed cPtsIndex::FindFrameNumber() to handle the case where Pts points to an I-frame.
diff --git a/dvbplayer.c b/dvbplayer.c
index d890f87a..5af036e4 100644
--- a/dvbplayer.c
+++ b/dvbplayer.c
@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: dvbplayer.c 5.6 2025/02/18 17:06:15 kls Exp $
+ * $Id: dvbplayer.c 5.7 2025/02/19 15:39:16 kls Exp $
  */
 
 #include "dvbplayer.h"
@@ -98,24 +98,22 @@ int cPtsIndex::FindFrameNumber(uint32_t Pts, bool Forward)
   if (w == r)
      return lastFound; // replay always starts at an I frame
   bool Valid = false;
-  int d;
   int FrameNumber = 0;
-  int UnplayedIFrame = 2; // GOPs may intersect, so we're looping until we found two unplayed I frames
+  int UnplayedIFrame = 2; // GOPs may intersect, so we loop until we processed a complete unplayed GOP
   for (int i = r; i != w && UnplayedIFrame; ) {
-      d = Pts - pi[i].pts;
-      if (d > 0x7FFFFFFF)
-         d = 0xFFFFFFFF - d; // handle rollover
-      if (d > 0) {
+      int32_t d = int32_t(Pts - pi[i].pts); // typecast handles rollover
+      if (d >= 0) {
          if (pi[i].independent) {
             FrameNumber = pi[i].index; // an I frame's index represents its frame number
             Valid = true;
+            if (d == 0)
+               UnplayedIFrame = 1; // if Pts is at an I frame we only need to check up to the next I frame
             }
          else
             FrameNumber++; // for every played non-I frame, increase frame number
          }
-      else
-        if (pi[i].independent)
-           --UnplayedIFrame;
+      else if (pi[i].independent)
+         --UnplayedIFrame;
       if (++i >= PTSINDEX_ENTRIES)
          i = 0;
       }