@carl Added a test to the branch which captures at least part of this. I think that fails because Player::use_video() doesn't do anything for left-eye images (awaiting the right).

@carl Potential fix on branch, need to send a build to test.

Could you please try this build: https://dcpomatic.com/temp/3056-3d-crash/1fa1a2d/osx-10.10/DCP-o-matic%203056-3d-crash-1fa1a2d5e%20macOS10.10+.dmg
and see if it solves the problem?

@stereo3d ping

Thanks!

Hopefully fixed by the fix for 0003164.

For reference the proposed fix I made for this bug was

commit 0fe862a41368e6de5572ac5451285395248ca109
Author: Carl Hetherington <cth@carlh.net>
Date:   Thu Jul 3 15:38:52 2025 +0200

    Insert black for missing 3D eyes in the Shuffler (#3056).

diff --git a/src/lib/shuffler.cc b/src/lib/shuffler.cc
index 318166a07..aa3be6506 100644
--- a/src/lib/shuffler.cc
+++ b/src/lib/shuffler.cc
@@ -22,6 +22,8 @@
 #include "content_video.h"
 #include "dcpomatic_assert.h"
 #include "dcpomatic_log.h"
+#include "image.h"
+#include "raw_image_proxy.h"
 #include "shuffler.h"
 #include <iostream>
 #include <string>
@@ -91,13 +93,42 @@ Shuffler::video(weak_ptr<Piece> weak_piece, ContentVideo video)
            break;
        }

+       optional<Eyes> extra;
+
        if (_store.size() > _max_size) {
            LOG_WARNING("Shuffler is full after receiving frame at {}; 3D sync may be incorrect.", to_string(video.time));
+           /* Now that we've given up waiting for the correct frames to arrive, we may need to insert some extra
+            * left/right eyes so that the player doesn't wait forever for lefts/rights that will never come.
+            * Set extra to the extra eye that we should insert based on what we'll emit now and what's coming next.
+            */
+           auto const& this_frame = _store.front();
+           auto const& next_frame = *std::next(_store.begin());
+           if (this_frame.second.eyes == next_frame.second.eyes) {
+               extra = this_frame.second.eyes == Eyes::LEFT ? Eyes::RIGHT : Eyes::LEFT;
+           }
+       }
+
+       auto emit_black = [this](Eyes eyes) {
+           LOG_DEBUG_THREE_D("Shuffler emits extra time=%1 eyes=%2 store=%3", to_string(_store.front().second.time), static_cast<int>(eyes), _store.size());
+           auto image = std::make_shared<Image>(AV_PIX_FMT_RGB24, dcp::Size(64, 64), Image::Alignment::COMPACT);
+           image->make_black();
+           auto proxy = std::make_shared<RawImageProxy>(image);
+           ContentVideo black(proxy, _store.front().second.time, eyes, _store.front().second.part);
+           Video(_store.front().first, black);
+       };
+
+       if (extra && *extra == Eyes::LEFT) {
+           emit_black(*extra);
        }

        LOG_DEBUG_THREE_D("Shuffler emits time={} eyes={} store={}", to_string(_store.front().second.time), static_cast<int>(_store.front().second.eyes), _store.size());
        Video(_store.front().first, _store.front().second);
        _last = _store.front().second;
+
+       if (extra && *extra == Eyes::RIGHT) {
+           emit_black(*extra);
+       }
+
        _store.pop_front();
    }
 }
diff --git a/test/shuffler_test.cc b/test/shuffler_test.cc
index 118b626ac..7afaf2716 100644
--- a/test/shuffler_test.cc
+++ b/test/shuffler_test.cc
@@ -180,6 +180,7 @@ BOOST_AUTO_TEST_CASE(shuffler_test6)
 {
    Shuffler s;
    s.Video.connect(boost::bind(&receive, _1, _2));
+   pending_cv.clear();

    push(s, 0, Eyes::LEFT);
    check(0, Eyes::LEFT, __LINE__);
@@ -196,3 +197,23 @@ BOOST_AUTO_TEST_CASE(shuffler_test6)
    push(s, 3, Eyes::RIGHT);
    check(3, Eyes::RIGHT, __LINE__);
 }
+
+
+BOOST_AUTO_TEST_CASE(shuffler_full_test)
+{
+   Shuffler s;
+   s.Video.connect(boost::bind(&receive, _1, _2));
+
+   push(s, 0, Eyes::LEFT);
+   check(0, Eyes::LEFT, __LINE__);
+
+   for (int i = 1; i < 65; ++i) {
+       push(s, i, Eyes::LEFT);
+   }
+   BOOST_CHECK(pending_cv.empty());
+
+   push(s, 64, Eyes::LEFT);
+   check(1, Eyes::LEFT, __LINE__);
+   check(1, Eyes::RIGHT, __LINE__);
+}
+