diff --git a/lib/upipe-modules/upipe_sync.c b/lib/upipe-modules/upipe_sync.c
index 338405d75..0dfa9b966 100644
--- a/lib/upipe-modules/upipe_sync.c
+++ b/lib/upipe-modules/upipe_sync.c
@@ -1,7 +1,8 @@
 /*
- * Copyright (C) 2017 Open Broadcast Systems Ltd
+ * Copyright (C) 2017-2021 Open Broadcast Systems Ltd
  *
  * Authors: Rafaël Carré
+ *          Kieran Kunhya
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
@@ -96,6 +97,9 @@ struct upipe_sync {
     /** ntsc */
     uint8_t frame_idx;
 
+    /* framesync */
+    int frame_sync;
+
     /** public upipe structure */
     struct upipe upipe;
 };
@@ -469,7 +473,7 @@ static bool sync_channel(struct upipe *upipe)
             } else {
                 float f = (float)((int64_t)pts - (int64_t)video_pts) * 1000 / UCLOCK_FREQ;
                 upipe_notice_va(upipe_sync_sub_to_upipe(upipe_sync_sub),
-                        "DROP %.2f, duration in CLOCK %" PRIu64 "", f, duration);
+                        "DROP %.2f, duration in CLOCK %" PRIu64 " samples %zu", f, duration, samples);
                 ulist_delete(uchain_uref);
                 uref_free(uref);
                 upipe_sync_sub->samples -= samples;
@@ -713,7 +717,8 @@ static void output_sound(struct upipe *upipe, const struct urational *fps,
 
             src_samples -= uref_samples;
             samples -= uref_samples;
-            upipe_sync_sub->samples -= uref_samples;
+            if (upipe_sync_sub->samples >= uref_samples)
+                upipe_sync_sub->samples -= uref_samples;
             //upipe_notice_va(upipe_sub, "pop, samples %" PRIu64, upipe_sync_sub->samples);
 
             if (src_samples == 0) {
@@ -747,44 +752,52 @@ static void cb(struct upump *upump)
     struct upipe_sync *upipe_sync = upipe_sync_from_upipe(upipe);
 
     uint64_t now = uclock_now(upipe_sync->uclock);
-    if (now - upipe_sync->ticks_per_frame > upipe_sync->pts)
-        upipe_dbg_va(upipe, "cb after %" PRId64 "ms",
-        (int64_t)((int64_t)now - (int64_t)upipe_sync->pts) / 27000);
+
+    if (upipe_sync->frame_sync) {
+        if (now - upipe_sync->ticks_per_frame > upipe_sync->pts)
+            upipe_dbg_va(upipe, "cb after %" PRId64 "ms",
+            (int64_t)((int64_t)now - (int64_t)upipe_sync->pts) / 27000);
+    }
 
     now = upipe_sync->pts; // the upump was scheduled for now
     struct uchain *uchain = NULL;
-    for (;;) {
-        uchain = ulist_peek(&upipe_sync->urefs);
-        upipe_throw(upipe, UPROBE_SYNC_PICTURE, UPIPE_SYNC_SIGNATURE, !!uchain);
-        if (!uchain)
-            break;
-
-        struct uref *uref = uref_from_uchain(uchain);
-        uint64_t pts = 0;
-        uref_clock_get_pts_sys(uref, &pts);
-        pts += upipe_sync->latency;
+    if (upipe_sync->frame_sync) {
+        for (;;) {
+            uchain = ulist_peek(&upipe_sync->urefs);
+            upipe_throw(upipe, UPROBE_SYNC_PICTURE, UPIPE_SYNC_SIGNATURE, !!uchain);
+            if (!uchain)
+                break;
+
+            struct uref *uref = uref_from_uchain(uchain);
+            uint64_t pts = 0;
+            uref_clock_get_pts_sys(uref, &pts);
+            pts += upipe_sync->latency;
+
+            /* frame duration */
+            const uint64_t ticks = upipe_sync->ticks_per_frame;
+
+            if (pts < now - ticks / 2) {
+                /* frame pts too much in the past */
+                upipe_warn_va(upipe, "too late");
+            } else if (pts > now + ticks / 2) {
+                upipe_warn_va(upipe, "video too early: %.2f > %.2f",
+                    pts_to_time(pts), pts_to_time(now + ticks / 2)
+                );
+                uchain = NULL; /* do not drop */
+                break;
+            } else {
+                break; // ok
+            }
 
-        /* frame duration */
-        const uint64_t ticks = upipe_sync->ticks_per_frame;
-
-        if (pts < now - ticks / 2) {
-            /* frame pts too much in the past */
-            upipe_warn_va(upipe, "too late");
-        } else if (pts > now + ticks / 2) {
-            upipe_warn_va(upipe, "video too early: %.2f > %.2f",
-                pts_to_time(pts), pts_to_time(now + ticks / 2)
-            );
-            uchain = NULL; /* do not drop */
-            break;
-        } else {
-            break; // ok
+            ulist_pop(&upipe_sync->urefs);
+            uref_free(uref);
+            upipe_sync->buffered_frames--;
+            int64_t u = pts - now;
+            upipe_err_va(upipe, "Drop pic (pts-now == %" PRId64 "ms)", u / 27000);
         }
-
-        ulist_pop(&upipe_sync->urefs);
-        uref_free(uref);
-        upipe_sync->buffered_frames--;
-        int64_t u = pts - now;
-        upipe_err_va(upipe, "Drop pic (pts-now == %" PRId64 "ms)", u / 27000);
+    }
+    else {
+        upipe_dbg_va(upipe, "queued %zu", ulist_depth(&upipe_sync->urefs));
     }
 
     /* sync audio */
@@ -795,56 +808,65 @@ static void cb(struct upump *upump)
     /* output audio */
     output_sound(upipe_sync_to_upipe(upipe_sync), &upipe_sync->fps, NULL);
 
-    /* output pic */
-    if (uchain) {
-        ulist_pop(&upipe_sync->urefs);
-        /* buffer picture */
-        uref_free(upipe_sync->uref);
-        upipe_sync->buffered_frames--;
-        upipe_sync->uref = uref_from_uchain(uchain);
-    } else {
-        upipe_dbg_va(upipe, "no picture, repeating last one");
-    }
-
     struct uref *uref = NULL;
-    if (upipe_sync->uref) {
-        uref = uref_dup(upipe_sync->uref);
-        uref_clock_set_pts_sys(uref, upipe_sync->pts - upipe_sync->latency);
-    }
+    if (upipe_sync->frame_sync) {
+        /* output pic */
+        if (uchain) {
+            ulist_pop(&upipe_sync->urefs);
+            /* buffer picture */
+            uref_free(upipe_sync->uref);
+            upipe_sync->buffered_frames--;
+            upipe_sync->uref = uref_from_uchain(uchain);
+        } else {
+            upipe_dbg_va(upipe, "no picture, repeating last one");
+        }
 
-    if (0) {
-        now = uclock_now(upipe_sync->uclock);
-        upipe_notice_va(upipe,
-                "output %.2f now %.2f latency %" PRIu64,
-                pts_to_time(upipe_sync->pts - upipe_sync->latency),
-                pts_to_time(now),
-                upipe_sync->latency / 27000
-            );
+        if (upipe_sync->uref) {
+            uref = uref_dup(upipe_sync->uref);
+            uref_clock_set_pts_sys(uref, upipe_sync->pts - upipe_sync->latency);
+        }
+
+        if (0) {
+            now = uclock_now(upipe_sync->uclock);
+            upipe_notice_va(upipe,
+                    "output %.2f now %.2f latency %" PRIu64,
+                    pts_to_time(upipe_sync->pts - upipe_sync->latency),
+                    pts_to_time(now),
+                    upipe_sync->latency / 27000
+                );
+        }
+    }
+    else {
+        uchain = ulist_pop(&upipe_sync->urefs);
+        uref = uref_from_uchain(uchain);
     }
 
     if (uref)
         upipe_sync_output(upipe, uref, NULL);
 
-    /* increment pts */
-    upipe_sync->pts += upipe_sync->ticks_per_frame;
-
-    /* schedule next pic */
-    now = uclock_now(upipe_sync->uclock);
-    if (now != UINT64_MAX && now > upipe_sync->pts) {
-        uint64_t diff = now - upipe_sync->pts;
-        diff += upipe_sync->ticks_per_frame - 1;
-        diff /= upipe_sync->ticks_per_frame;
-        upipe_err_va(upipe, "skipping %"PRIu64" beats", diff);
-        upipe_sync->pts += diff * upipe_sync->ticks_per_frame;
-    }
+    /* In non framesync mode scheduling is based on when video frame arrives */
+    if (upipe_sync->frame_sync) {
+        /* increment pts */
+        upipe_sync->pts += upipe_sync->ticks_per_frame;
 
-    uint64_t wait;
-    if (now == UINT64_MAX)
-        wait = upipe_sync->ticks_per_frame;
-    else
-        wait = upipe_sync->pts - now;
+        /* schedule next pic */
+        now = uclock_now(upipe_sync->uclock);
+        if (now != UINT64_MAX && now > upipe_sync->pts) {
+            uint64_t diff = now - upipe_sync->pts;
+            diff += upipe_sync->ticks_per_frame - 1;
+            diff /= upipe_sync->ticks_per_frame;
+            upipe_err_va(upipe, "skipping %"PRIu64" beats", diff);
+            upipe_sync->pts += diff * upipe_sync->ticks_per_frame;
+        }
+
+        uint64_t wait;
+        if (now == UINT64_MAX)
+            wait = upipe_sync->ticks_per_frame;
+        else
+            wait = upipe_sync->pts - now;
 
-    upipe_sync_wait_upump(upipe, wait, cb);
+        upipe_sync_wait_upump(upipe, wait, cb);
+    }
 }
 
 /** @internal @This receives data.
@@ -883,7 +905,7 @@ static void upipe_sync_sub_input(struct upipe *upipe, struct uref *uref,
     size_t samples = 0;
     uref_sound_size(uref, &samples, NULL);
     upipe_sync_sub->samples += samples;
-    //upipe_notice_va(upipe, "push, samples %" PRIu64, upipe_sync_sub->samples);
+    upipe_notice_va(upipe, "push in samples %zu, queued samples %" PRIu64, samples, upipe_sync_sub->samples);
 
     ulist_add(&upipe_sync_sub->urefs, uref_to_uchain(uref));
 
@@ -928,46 +950,63 @@ static void upipe_sync_input(struct upipe *upipe, struct uref *uref,
         return;
     }
     pts += upipe_sync->latency;
-
     uint64_t now = uclock_now(upipe_sync->uclock);
 
-    /* reject late pics */
-    if (now != UINT64_MAX && now > pts) {
-        uint64_t cr = 0;
-        uref_clock_get_cr_sys(uref, &cr);
-        upipe_err_va(upipe, "%s() picture too late by %" PRIu64 "ms, drop pic, recept %" PRIu64 "",
-            __func__, (now - pts) / 27000, (now - cr) / 27000);
-        uref_free(uref);
-        return;
-    }
+    uint64_t wait;
+    if (upipe_sync->frame_sync) {
+        /* reject late pics */
+        if (now != UINT64_MAX && now > pts) {
+            uint64_t cr = 0;
+            uref_clock_get_cr_sys(uref, &cr);
+            upipe_err_va(upipe, "%s() picture too late by %" PRIu64 "ms, drop pic, recept %" PRIu64 "",
+                __func__, (now - pts) / 27000, (now - cr) / 27000);
+            uref_free(uref);
+            return;
+        }
 
-    //upipe_dbg_va(upipe, "push PTS in %" PRIu64 " ms", (pts - now) / 27000);
+        //upipe_dbg_va(upipe, "push PTS in %" PRIu64 " ms", (pts - now) / 27000);
 
-    /* buffer pic */
-    ulist_add(&upipe_sync->urefs, uref_to_uchain(uref));
-    upipe_sync->buffered_frames++;
+        /* buffer pic */
+        ulist_add(&upipe_sync->urefs, uref_to_uchain(uref));
+        upipe_sync->buffered_frames++;
 
-    /* limit buffered frames */
-    if (unlikely(upipe_sync->buffered_frames >= MAX_VIDEO_FRAMES)) {
-        ulist_uref_flush(&upipe_sync->urefs);
-        upipe_sync->buffered_frames = 0;
-    }
+        /* limit buffered frames */
+        if (unlikely(upipe_sync->buffered_frames >= MAX_VIDEO_FRAMES)) {
+            ulist_uref_flush(&upipe_sync->urefs);
+            upipe_sync->buffered_frames = 0;
+        }
 
-    /* timer already active */
-    if (upipe_sync->upump)
-        return;
+        /* timer already active */
+        if (upipe_sync->upump)
+            return;
 
-    /* need upump mgr */
-    if (!ubase_check(upipe_sync_check_upump_mgr(upipe_sync_to_upipe(upipe_sync))))
-        return;
+        /* need upump mgr */
+        if (!ubase_check(upipe_sync_check_upump_mgr(upipe_sync_to_upipe(upipe_sync))))
+            return;
 
-    /* start timer */
-    uint64_t wait;
-    if (now == UINT64_MAX)
-        wait = upipe_sync->ticks_per_frame;
-    else
+        /* start timer */
+        if (now == UINT64_MAX)
+            wait = upipe_sync->ticks_per_frame;
+        else
+            wait = pts - now;
+    }
+    else {
         wait = pts - now;
 
+        /* too old frames */
+        if (now > pts + upipe_sync->ticks_per_frame) {
+            uref_free(uref);
+            return;
+        }
+
+        /* buffer pic */
+        ulist_add(&upipe_sync->urefs, uref_to_uchain(uref));
+
+        /* need upump mgr */
+        if (!ubase_check(upipe_sync_check_upump_mgr(upipe_sync_to_upipe(upipe_sync))))
+            return;
+    }
+
     upipe_sync->pts = pts;
     upipe_sync_wait_upump(upipe_sync_to_upipe(upipe_sync), wait, cb);
 }
@@ -997,6 +1036,7 @@ static struct upipe *upipe_sync_alloc(struct upipe_mgr *mgr,
     upipe_sync->buffered_frames = 0;
     upipe_sync->uref = NULL;
     ulist_init(&upipe_sync->urefs);
+    upipe_sync->frame_sync = 1; /* Old frame sync behaviour by default */
 
     upipe_sync_init_urefcount(upipe);
     upipe_sync_init_uclock(upipe);
@@ -1059,6 +1099,28 @@ static int upipe_sync_set_flow_def(struct upipe *upipe, struct uref *flow_def)
     return UBASE_ERR_NONE;
 }
 
+/** @internal @This sets the content of an sync option.
+ *
+ * @param upipe description structure of the pipe
+ * @param option name of the option
+ * @param content content of the option
+ * @return an error code
+ */
+static int upipe_sync_set_option(struct upipe *upipe,
+                                 const char *option, const char *content)
+{
+    struct upipe_sync *upipe_sync = upipe_sync_from_upipe(upipe);
+    if (!option || !content)
+        return UBASE_ERR_INVALID;
+
+    if (!strcmp(option, "frame-sync"))
+        upipe_sync->frame_sync = atoi(content);
+    else
+        return UBASE_ERR_INVALID;
+
+    return UBASE_ERR_NONE;
+}
+
 /** @internal @This processes control commands.
  *
  * @param upipe description structure of the pipe
@@ -1081,7 +1143,11 @@ static int upipe_sync_control(struct upipe *upipe, int command, va_list args)
            return UBASE_ERR_NONE;
         case UPIPE_ATTACH_UPUMP_MGR:
            return upipe_sync_attach_upump_mgr(upipe);
-
+        case UPIPE_SET_OPTION: {
+            const char *option = va_arg(args, const char *);
+            const char *content = va_arg(args, const char *);
+            return upipe_sync_set_option(upipe, option, content);
+        }
         default:
             return UBASE_ERR_UNHANDLED;
     }