From 48c18ca4ed4517b3e2a7697dc791cd38bb268c85 Mon Sep 17 00:00:00 2001
From: Isaac Connor <isaac@zoneminder.com>
Date: Fri, 23 Dec 2022 09:02:41 -0500
Subject: [PATCH] Attempt to better handle 32bit wrap around in the pts in the
 input stream.

---
 src/zm_ffmpeg_camera.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/zm_ffmpeg_camera.cpp b/src/zm_ffmpeg_camera.cpp
index cb6c9dff8..d9a16f3c7 100644
--- a/src/zm_ffmpeg_camera.cpp
+++ b/src/zm_ffmpeg_camera.cpp
@@ -188,6 +188,7 @@ int FfmpegCamera::Capture(std::shared_ptr<ZMPacket> &zm_packet) {
   start_read_time = std::chrono::steady_clock::now();
   int ret;
   AVFormatContext *formatContextPtr;
+  int64_t lastPTS;
 
   if ( mSecondFormatContext and
       (
@@ -197,12 +198,14 @@ int FfmpegCamera::Capture(std::shared_ptr<ZMPacket> &zm_packet) {
       ) ) {
     // if audio stream is behind video stream, then read from audio, otherwise video
     formatContextPtr = mSecondFormatContext;
+    lastPTS = mLastAudioPTS;
     Debug(4, "Using audio input because audio PTS %" PRId64 " < video PTS %" PRId64,
         av_rescale_q(mLastAudioPTS, mAudioStream->time_base, AV_TIME_BASE_Q),
         av_rescale_q(mLastVideoPTS, mVideoStream->time_base, AV_TIME_BASE_Q)
         );
   } else {
     formatContextPtr = mFormatContext;
+    lastPTS = mLastVideoPTS;
     Debug(4, "Using video input because %" PRId64 " >= %" PRId64,
         (mAudioStream?av_rescale_q(mLastAudioPTS, mAudioStream->time_base, AV_TIME_BASE_Q):0),
         av_rescale_q(mLastVideoPTS, mVideoStream->time_base, AV_TIME_BASE_Q)
@@ -224,6 +227,11 @@ int FfmpegCamera::Capture(std::shared_ptr<ZMPacket> &zm_packet) {
     }
     return -1;
   }
+  if ((packet->pts < 0) and (lastPTS >=0)) {
+    // 32-bit wrap around?
+    Info("Suspected 32bit wraparound in input pts. %"PRId64, packet->pts);
+    return -1;
+  }
 
   av_packet_guard pkt_guard{packet};