From b4f835c4ef6e0e0bbe6adef8235381e56f3f91df Mon Sep 17 00:00:00 2001
From: Paul B Mahol <onemda@gmail.com>
Date: Fri, 27 Jan 2023 23:34:02 +0100
Subject: [PATCH 1/4] avfilter/framesync: calculate frame duration too

Signed-off-by: Paul B Mahol <onemda@gmail.com>
---
 libavfilter/framesync.c | 20 ++++++++++++++++----
 libavfilter/framesync.h | 15 +++++++++++++++
 2 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/libavfilter/framesync.c b/libavfilter/framesync.c
index ee91e4cf68..71d67ca742 100644
--- a/libavfilter/framesync.c
+++ b/libavfilter/framesync.c
@@ -173,8 +173,10 @@ int ff_framesync_configure(FFFrameSync *fs)
                fs->time_base.num, fs->time_base.den);
     }
 
-    for (i = 0; i < fs->nb_in; i++)
+    for (i = 0; i < fs->nb_in; i++) {
         fs->in[i].pts = fs->in[i].pts_next = AV_NOPTS_VALUE;
+        fs->in[i].duration = fs->in[i].duration_next = 0;
+    }
     fs->sync_level = UINT_MAX;
     framesync_sync_level_update(fs);
 
@@ -184,7 +186,7 @@ int ff_framesync_configure(FFFrameSync *fs)
 static int framesync_advance(FFFrameSync *fs)
 {
     unsigned i;
-    int64_t pts;
+    int64_t pts, duration;
     int ret;
 
     while (!(fs->frame_ready || fs->eof)) {
@@ -193,9 +195,12 @@ static int framesync_advance(FFFrameSync *fs)
             return ret;
 
         pts = INT64_MAX;
+        duration = 0;
         for (i = 0; i < fs->nb_in; i++)
-            if (fs->in[i].have_next && fs->in[i].pts_next < pts)
+            if (fs->in[i].have_next && fs->in[i].pts_next < pts) {
                 pts = fs->in[i].pts_next;
+                duration = fs->in[i].duration_next;
+            }
         if (pts == INT64_MAX) {
             framesync_eof(fs);
             break;
@@ -211,8 +216,10 @@ static int framesync_advance(FFFrameSync *fs)
                 av_frame_free(&fs->in[i].frame);
                 fs->in[i].frame      = fs->in[i].frame_next;
                 fs->in[i].pts        = fs->in[i].pts_next;
+                fs->in[i].duration   = fs->in[i].duration_next;
                 fs->in[i].frame_next = NULL;
                 fs->in[i].pts_next   = AV_NOPTS_VALUE;
+                fs->in[i].duration_next = 0;
                 fs->in[i].have_next  = 0;
                 fs->in[i].state      = fs->in[i].frame ? STATE_RUN : STATE_EOF;
                 if (fs->in[i].sync == fs->sync_level && fs->in[i].frame)
@@ -228,6 +235,7 @@ static int framesync_advance(FFFrameSync *fs)
                      fs->in[i].before == EXT_STOP))
                     fs->frame_ready = 0;
         fs->pts = pts;
+        fs->duration = duration;
     }
     return 0;
 }
@@ -241,14 +249,17 @@ static int64_t framesync_pts_extrapolate(FFFrameSync *fs, unsigned in,
 
 static void framesync_inject_frame(FFFrameSync *fs, unsigned in, AVFrame *frame)
 {
-    int64_t pts;
+    int64_t pts, duration;
 
     av_assert0(!fs->in[in].have_next);
     av_assert0(frame);
     pts = av_rescale_q(frame->pts, fs->in[in].time_base, fs->time_base);
+    duration = av_rescale_q(frame->duration, fs->in[in].time_base, fs->time_base);
     frame->pts = pts;
+    frame->duration = duration;
     fs->in[in].frame_next = frame;
     fs->in[in].pts_next   = pts;
+    fs->in[in].duration_next = duration;
     fs->in[in].have_next  = 1;
 }
 
@@ -400,6 +411,7 @@ int ff_framesync_dualinput_get(FFFrameSync *fs, AVFrame **f0, AVFrame **f1)
     }
     av_assert0(mainpic);
     mainpic->pts = av_rescale_q(fs->pts, fs->time_base, ctx->outputs[0]->time_base);
+    mainpic->duration = av_rescale_q(fs->duration, fs->time_base, ctx->outputs[0]->time_base);
     if (ctx->is_disabled)
         secondpic = NULL;
     *f0 = mainpic;
diff --git a/libavfilter/framesync.h b/libavfilter/framesync.h
index 233f50a0eb..6a2866afc8 100644
--- a/libavfilter/framesync.h
+++ b/libavfilter/framesync.h
@@ -131,11 +131,21 @@ typedef struct FFFrameSyncIn {
      */
     int64_t pts;
 
+    /**
+     * duration of the current frame
+     */
+    int64_t duration;
+
     /**
      * PTS of the next frame, for internal use
      */
     int64_t pts_next;
 
+    /**
+     * duration of the next frame, for internal use
+     */
+    int64_t duration_next;
+
     /**
      * Boolean flagging the next frame, for internal use
      */
@@ -188,6 +198,11 @@ typedef struct FFFrameSync {
      */
     int64_t pts;
 
+    /**
+     * Duration of the current event
+     */
+    int64_t duration;
+
     /**
      * Callback called when a frame event is ready
      */
-- 
2.39.1