From ecee80c4ef4be669d5b5d8343c858d5ebd1f673c Mon Sep 17 00:00:00 2001
From: Isaac Connor <isaac@zoneminder.com>
Date: Thu, 7 Apr 2022 13:12:34 -0400
Subject: [PATCH] Implement last_dts[] because next_dts[] isn't actually
 useful. This fixes another ffmpeg deprecation problem by keep our own copy of
 cur_dts

---
 src/zm_videostore.cpp | 26 +++++++++++++++++---------
 src/zm_videostore.h   |  2 ++
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/src/zm_videostore.cpp b/src/zm_videostore.cpp
index b94de982a..32c84d2cd 100644
--- a/src/zm_videostore.cpp
+++ b/src/zm_videostore.cpp
@@ -349,6 +349,8 @@ bool VideoStore::open() {
 #else
   avcodec_copy_context(video_out_stream->codec, video_out_ctx);
 #endif
+  last_dts[video_out_stream->index] = AV_NOPTS_VALUE;
+
   video_out_stream->time_base = video_in_stream ? video_in_stream->time_base : AV_TIME_BASE_Q;
   if (monitor->GetOptVideoWriter() == Monitor::PASSTHROUGH) {
     // Only set orientation if doing passthrough, otherwise the frame image will be rotated
@@ -470,6 +472,7 @@ bool VideoStore::open() {
 
     // We will assume that subsequent stream allocations will increase the index
     max_stream_index = audio_out_stream->index;
+    last_dts[audio_out_stream->index] = AV_NOPTS_VALUE;
   }  // end if audio_in_stream
 
   //max_stream_index is 0-based, so add 1
@@ -1313,15 +1316,19 @@ int VideoStore::write_packet(AVPacket *pkt, AVStream *stream) {
   pkt->stream_index = stream->index;
 
   if (pkt->dts == AV_NOPTS_VALUE) {
-    Error("undefined dts");
-//    Debug(1, "undef dts, fixing by setting to stream cur_dts %" PRId64, stream->cur_dts);
-//    pkt->dts = stream->cur_dts;
-  } else if (pkt->dts < next_dts[stream->index]) {
-    Debug(1, "non increasing dts, fixing. our dts %" PRId64 " stream next_dts %" PRId64, pkt->dts, next_dts[stream->index]);
-    pkt->dts = next_dts[stream->index];
+    if (last_dts[stream->index] == AV_NOPTS_VALUE) {
+      last_dts[stream->index] = 0;
+    } 
+    pkt->dts = last_dts[stream->index];
+  } else if (pkt->dts < last_dts[stream->index]) {
+    Warning("non increasing dts, fixing. our dts %" PRId64 " stream %d next_dts %" PRId64,
+        pkt->dts, stream->index, next_dts[stream->index]);
+    pkt->dts = last_dts[stream->index];
   }
 
-  if (pkt->dts > pkt->pts) {
+  if (pkt->pts == AV_NOPTS_VALUE) {
+    pkt->pts = pkt->dts;
+  } else if (pkt->dts > pkt->pts) {
     Warning("pkt.dts(%" PRId64 ") must be <= pkt.pts(%" PRId64 ")."
             "Decompression must happen before presentation.",
             pkt->dts, pkt->pts);
@@ -1334,8 +1341,9 @@ int VideoStore::write_packet(AVPacket *pkt, AVStream *stream) {
 
   ZM_DUMP_STREAM_PACKET(stream, (*pkt), "finished pkt");
   next_dts[stream->index] = pkt->dts + pkt->duration;
-  Debug(3, "next_dts for stream %d has become %" PRId64,
-      stream->index, next_dts[stream->index]);
+  last_dts[stream->index] = pkt->dts;
+  Debug(3, "next_dts for stream %d has become %" PRId64 " last_dts %" PRId64,
+      stream->index, next_dts[stream->index], last_dts[stream->index]);
 
   int ret = av_interleaved_write_frame(oc, pkt);
   if (ret != 0) {
diff --git a/src/zm_videostore.h b/src/zm_videostore.h
index b67d1d0f4..a73018293 100644
--- a/src/zm_videostore.h
+++ b/src/zm_videostore.h
@@ -7,6 +7,7 @@
 #include "zm_swscale.h"
 
 #include <memory>
+#include <map>
 
 extern "C"  {
 #ifdef HAVE_LIBSWRESAMPLE
@@ -100,6 +101,7 @@ class VideoStore {
 
     // These are for out, should start at zero.  We assume they do not wrap because we just aren't going to save files that big.
     int64_t *next_dts;
+    std::map<int, int64_t> last_dts;
     int64_t audio_next_pts;
 
     int max_stream_index;