From 2d6439449a7f212270bddb308cbed616699a06d4 Mon Sep 17 00:00:00 2001
From: jcdr428 <jessiedeer@hotmail.com>
Date: Mon, 25 Sep 2023 17:13:09 +0100
Subject: [PATCH] Fix CLPI for H.264 BFF (Bottom Field First) streams

Fixes issue #700.
---
 tsMuxer/h264StreamReader.cpp | 5 ++++-
 tsMuxer/h264StreamReader.h   | 1 +
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/tsMuxer/h264StreamReader.cpp b/tsMuxer/h264StreamReader.cpp
index 505c7a2b..63d0ac1d 100644
--- a/tsMuxer/h264StreamReader.cpp
+++ b/tsMuxer/h264StreamReader.cpp
@@ -14,6 +14,7 @@ H264StreamReader::H264StreamReader()
     m_frameNum = 0;
     m_lastMessageLen = -1;
     m_forceLsbDiv = 0;
+    m_fieldFirst = 0;
     prevPicOrderCntMsb = prevPicOrderCntLsb = 0;
     m_iFramePtsOffset = 0;
     m_isFirstFrame = true;
@@ -672,6 +673,8 @@ void H264StreamReader::additionalStreamCheck(uint8_t *buff, uint8_t *end)
                 int picOrder = calcPicOrder(slice);
                 if (slice.isIDR())
                     frameNum = -1;
+                if (slice.isIFrame())
+                    m_fieldFirst = slice.bottom_field_flag;
                 checkPyramid(++frameNum, &picOrder, true);
             }
             break;
@@ -1079,7 +1082,7 @@ int H264StreamReader::processSliceNal(uint8_t *buff)
     if (slice.first_mb_in_slice != 0)
         return 0;
 
-    if (slice.bottom_field_flag == 1)  // insrease PTS/DTS only for whole frame
+    if (m_fieldFirst != slice.bottom_field_flag)  // insrease PTS/DTS only for whole frame
         return 0;
 
     if (detectPrimaryPicType(slice, buff) != 0)
diff --git a/tsMuxer/h264StreamReader.h b/tsMuxer/h264StreamReader.h
index dc31ab7b..248df682 100644
--- a/tsMuxer/h264StreamReader.h
+++ b/tsMuxer/h264StreamReader.h
@@ -92,6 +92,7 @@ class H264StreamReader final : public MPEGStreamReader
     int prevPicOrderCntMsb;
     int prevPicOrderCntLsb;
     int m_forceLsbDiv;
+    int m_fieldFirst;
     int m_lastMessageLen;
     bool m_isFirstFrame;
     SeiMethod m_insertSEIMethod;