From 1e9f10487127845580c651613dca699c1af2fdba Mon Sep 17 00:00:00 2001
From: Brian Matherly <brian.matherly@yahoo.com>
Date: Tue, 5 Dec 2023 20:49:25 -0600
Subject: [PATCH] Add a loop range feature to MLT Producer

---
 src/framework/mlt.vers       |  7 ++++++-
 src/framework/mlt_producer.c | 33 +++++++++++++++++++++++++++++++++
 src/framework/mlt_producer.h |  1 +
 src/mlt++/MltProducer.cpp    |  5 +++++
 src/mlt++/MltProducer.h      |  1 +
 src/mlt++/mlt++.vers         |  7 +++++++
 6 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/src/framework/mlt.vers b/src/framework/mlt.vers
index a55580dd4..093a638a0 100644
--- a/src/framework/mlt.vers
+++ b/src/framework/mlt.vers
@@ -687,4 +687,9 @@ MLT_7.22.0 {
     mlt_property_is_color;
     mlt_property_is_numeric;
     mlt_property_is_rect;
-} MLT_7.18.0;
\ No newline at end of file
+} MLT_7.18.0;
+
+MLT_7.24.0 {
+  global:
+    mlt_producer_set_loop_range;
+} MLT_7.22.0;
diff --git a/src/framework/mlt_producer.c b/src/framework/mlt_producer.c
index 904c9e029..a4bd6ccac 100644
--- a/src/framework/mlt_producer.c
+++ b/src/framework/mlt_producer.c
@@ -356,6 +356,14 @@ int mlt_producer_seek(mlt_producer self, mlt_position position)
         // Do not bounds check a link.
     } else if (position < 0 || mlt_producer_get_playtime(self) == 0) {
         position = 0;
+    } else if (mlt_properties_exists(MLT_PRODUCER_PROPERTIES(self), "_loop_start")) {
+        int loopStart = mlt_properties_get_int(MLT_PRODUCER_PROPERTIES(self), "_loop_start");
+        int loopEnd = mlt_properties_get_int(MLT_PRODUCER_PROPERTIES(self), "_loop_end");
+        if (loopStart >= 0 && loopEnd > 0 && loopStart < loopEnd) {
+            if (position > loopEnd || position < loopStart) {
+                position = loopStart;
+            }
+        }
     } else if (use_points && (eof == NULL || !strcmp(eof, "pause"))
                && position >= mlt_producer_get_playtime(self)) {
         mlt_producer_set_speed(self, 0);
@@ -1304,3 +1312,28 @@ int mlt_producer_probe(mlt_producer self)
     }
     return 0;
 }
+
+/** Set the loop range for the producer.
+ *
+ * When the loop range is set, the producer will automatically seek to the start frame
+ * after it provides the end frame. Set start to -1 to disable looping.
+ *
+ * \public \memberof mlt_producer_s
+ * \param self a producer
+ * \param start the frame number for the beginning of the loop
+ * \param end the frame number for the end of the loop
+ */
+
+void mlt_producer_set_loop_range(mlt_producer self, int start, int end)
+{
+    if (!self)
+        return;
+    mlt_properties properties = MLT_PRODUCER_PROPERTIES(self);
+    if (start < 0 || end < 0) {
+        mlt_properties_clear(properties, "_loop_start");
+        mlt_properties_clear(properties, "_loop_end");
+    } else {
+        mlt_properties_set_int(properties, "_loop_start", start);
+        mlt_properties_set_int(properties, "_loop_end", end);
+    }
+}
diff --git a/src/framework/mlt_producer.h b/src/framework/mlt_producer.h
index 9b7bcff7b..7d4d6e2c5 100644
--- a/src/framework/mlt_producer.h
+++ b/src/framework/mlt_producer.h
@@ -145,5 +145,6 @@ extern void mlt_producer_close(mlt_producer self);
 int64_t mlt_producer_get_creation_time(mlt_producer self);
 void mlt_producer_set_creation_time(mlt_producer self, int64_t creation_time);
 extern int mlt_producer_probe(mlt_producer self);
+extern void mlt_producer_set_loop_range(mlt_producer self, int start, int end);
 
 #endif
diff --git a/src/mlt++/MltProducer.cpp b/src/mlt++/MltProducer.cpp
index a837194df..56d851b31 100644
--- a/src/mlt++/MltProducer.cpp
+++ b/src/mlt++/MltProducer.cpp
@@ -266,3 +266,8 @@ bool Producer::probe()
 {
     return mlt_producer_probe(get_producer());
 }
+
+void Producer::set_loop_range(int start, int end)
+{
+    return mlt_producer_set_loop_range(get_producer(), start, end);
+}
diff --git a/src/mlt++/MltProducer.h b/src/mlt++/MltProducer.h
index 7afefbc36..d7a5ee525 100644
--- a/src/mlt++/MltProducer.h
+++ b/src/mlt++/MltProducer.h
@@ -78,6 +78,7 @@ class MLTPP_DECLSPEC Producer : public Service
     int64_t get_creation_time();
     void set_creation_time(int64_t creation_time);
     bool probe();
+    void set_loop_range(int start, int end);
 };
 } // namespace Mlt
 
diff --git a/src/mlt++/mlt++.vers b/src/mlt++/mlt++.vers
index 5d5510d47..a2a92f314 100644
--- a/src/mlt++/mlt++.vers
+++ b/src/mlt++/mlt++.vers
@@ -733,3 +733,10 @@ MLT_7.14.0 {
       "Mlt::Chain::attach_normalizers()";
     };
 } MLT_7.12.0;
+
+MLT_7.24.0 {
+  global:
+    extern "C++" {
+      "Mlt::Producer::set_loop_range(int, int)";
+    };
+} MLT_7.14.0;
\ No newline at end of file