0000001  0x00007ffff5e39781 in boost::optional_detail::optional_base<dcp::ArrayData>::optional_base(boost::optional_detail::optional_base<dcp::ArrayData> const&) (this=0x7fffd2715f50, rhs=...) at /usr/include/boost/optional/optional.hpp:198
0000002  0x00007ffff5e39677 in boost::optional<dcp::ArrayData>::optional(boost::optional<dcp::ArrayData> const&) (this=0x7fffd2715f50) at /usr/include/boost/optional/optional.hpp:965
0000003  0x00007ffff5e396a2 in dcpomatic::Font::Content::Content(dcpomatic::Font::Content const&) (this=0x7fffd2715f50) at ../src/lib/font.h:85
0000004  0x00007ffff5e3dd0f in dcpomatic::Font::content() const (this=0x0) at ../src/lib/font.h:92
0000005  0x00007ffff5e39ec4 in FontConfig::make_font_available[abi:cxx11](std::shared_ptr<dcpomatic::Font>) (this=0x7fffcc01ac20, font=std::shared_ptr<dcpomatic::Font> (empty) = {...}) at ../src/lib/font_config.cc:59
0000006  0x00007ffff5fd40e9 in setup_layout(std::__cxx11::list<StringText, std::allocator<StringText> >, dcp::Size, dcpomatic::DCPTime, int) (subtitles=std::__cxx11::list = {...}, target=..., time=..., frame_rate=24)
    at ../src/lib/render_text.cc:304
0000007  0x00007ffff5fd4610 in render_line(std::__cxx11::list<StringText, std::allocator<StringText> >, dcp::Size, dcpomatic::DCPTime, int) (subtitles=std::__cxx11::list = {...}, target=..., time=..., frame_rate=24)
    at ../src/lib/render_text.cc:327
0000008  0x00007ffff5fd5369 in render_text(std::__cxx11::list<StringText, std::allocator<StringText> >, dcp::Size, dcpomatic::Time<dcpomatic::DCPTimeDifferentiator, dcpomatic::ContentTimeDifferentiator>, int)
    (subtitles=std::__cxx11::list = {...}, target=..., time=..., frame_rate=24) at ../src/lib/render_text.cc:419
0000009  0x00007ffff5f335fe in Player::open_subtitles_for_frame(dcpomatic::Time<dcpomatic::DCPTimeDifferentiator, dcpomatic::ContentTimeDifferentiator>) const (this=0x555555fdda18, time=...) at ../src/lib/player.cc:943
0000010 0x00007ffff5f393eb in Player::do_emit_video(std::shared_ptr<PlayerVideo>, dcpomatic::Time<dcpomatic::DCPTimeDifferentiator, dcpomatic::ContentTimeDifferentiator>)
    (this=0x555555fdda18, pv=std::shared_ptr<PlayerVideo> (use count 2, weak count 0) = {...}, time=...) at ../src/lib/player.cc:1452
0000011 0x00007ffff5f391fb in Player::emit_video(std::shared_ptr<PlayerVideo>, dcpomatic::Time<dcpomatic::DCPTimeDifferentiator, dcpomatic::ContentTimeDifferentiator>)
    (this=0x555555fdda18, pv=std::shared_ptr<PlayerVideo> (use count 3, weak count 0) = {...}, time=...) at ../src/lib/player.cc:1441
0000012 0x00007ffff5f34c6d in Player::video(std::weak_ptr<Piece>, ContentVideo) (this=0x555555fdda18, weak_piece=std::weak_ptr<Piece> (use count 4, weak count 8) = {...}, video=...) at ../src/lib/player.cc:1115
0000013 0x00007ffff5f73dfd in boost::_mfi::mf2<void, Player, std::weak_ptr<Piece>, ContentVideo>::operator()(Player*, std::weak_ptr<Piece>, ContentVideo) const
    (this=0x555556228900, p=0x555555fdda18, a1=std::weak_ptr<Piece> (use count 4, weak count 8) = {...}, a2=...) at /usr/include/boost/bind/mem_fn_template.hpp:280
0000014 0x00007ffff5f71269 in boost::_bi::list3<boost::_bi::value<Player*>, boost::_bi::value<std::weak_ptr<Piece> >, boost::arg<1> >::operator()<boost::_mfi::mf2<void, Player, std::weak_ptr<Piece>, ContentVideo>, boost::_bi::rrlist1<ContentVideo> >(boost::_bi::type<void>, boost::_mfi::mf2<void, Player, std::weak_ptr<Piece>, ContentVideo>&, boost::_bi::rrlist1<ContentVideo>&, int) (this=0x555556228910, f=..., a=...) at /usr/include/boost/bind/bind.hpp:398
0000015 0x00007ffff5f6c6ef in boost::_bi::bind_t<void, boost::_mfi::mf2<void, Player, std::weak_ptr<Piece>, ContentVideo>, boost::_bi::list3<boost::_bi::value<Player*>, boost::_bi::value<std::weak_ptr<Piece> >, boost::arg<1> > >::operator()<ContentVideo>(ContentVideo&&) (this=0x555556228900, a1=...) at /usr/include/boost/bind/bind.hpp:1306
0000016 0x00007ffff5f6833f in boost::detail::function::void_function_obj_invoker1<boost::_bi::bind_t<void, boost::_mfi::mf2<void, Player, std::weak_ptr<Piece>, ContentVideo>, boost::_bi::list3<boost::_bi::value<Player*>, boost::_bi::value<std::weak_ptr<Piece> >, boost::arg<1> > >, void, ContentVideo>::invoke(boost::detail::function::function_buffer&, ContentVideo) (function_obj_ptr=..., a0=...) at /usr/include/boost/function/function_template.hpp:158
0000017 0x00007ffff6082a85 in boost::function1<void, ContentVideo>::operator()(ContentVideo) const (this=0x5555567954b8, a0=...) at /usr/include/boost/function/function_template.hpp:763
0000018 0x00007ffff6082997 in boost::signals2::detail::call_with_tuple_args<boost::signals2::detail::void_type>::m_invoke<boost::function<void (ContentVideo)>, 0u, ContentVideo&>(boost::function<void (ContentVideo)>&, boost::signals2::detail::unsigned_meta_array<0u>, std::tuple<ContentVideo&> const&, boost::enable_if<boost::is_void<boost::function<void (ContentVideo)>::result_type>, void>::type*) const (this=0x7fffd2716d57, func=..., args=std::tuple containing = {...})
    at /usr/include/boost/signals2/detail/variadic_slot_invoker.hpp:105
0000019 0x00007ffff608292e in boost::signals2::detail::call_with_tuple_args<boost::signals2::detail::void_type>::operator()<boost::function<void (ContentVideo)>, ContentVideo&, 1ul>(boost::function<void (ContentVideo)>&, std::tuple<ContentVideo&> const&, mpl_::size_t<1ul>) const (this=0x7fffd2716d57, func=..., args=std::tuple containing = {...}) at /usr/include/boost/signals2/detail/variadic_slot_invoker.hpp:90
0000020 0x00007ffff60828c5 in boost::signals2::detail::variadic_slot_invoker<boost::signals2::detail::void_type, ContentVideo>::operator()<boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<void (ContentVideo), boost::function<void (ContentVideo)> >, boost::signals2::mutex> > >(boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<void (ContentVideo), boost::function<void (ContentVideo)> >, boost::signals2::mutex> > const&) const (this=0x7fffd2717090, connectionBody=...)
    at /usr/include/boost/signals2/detail/variadic_slot_invoker.hpp:133
0000021 0x00007ffff6082799 in boost::signals2::detail::slot_call_iterator_t<boost::signals2::detail::variadic_slot_invoker<boost::signals2::detail::void_type, ContentVideo>, std::_List_iterator<boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<void (ContentVideo), boost::function<void (ContentVideo)> >, boost::signals2::mutex> > >, boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<void (ContentVideo), boost::function<void (ContentVideo)> >, boost::signals2::mutex> >::dereference() const (this=0x7fffd2716e40)
    at /usr/include/boost/signals2/detail/slot_call_iterator.hpp:110
0000022 0x00007ffff60826d4 in boost::iterators::iterator_core_access::dereference<boost::signals2::detail::slot_call_iterator_t<boost::signals2::detail::variadic_slot_invoker<boost::signals2::detail::void_type, ContentVideo>, std::_List_iterator<boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<void (ContentVideo), boost::function<void (ContentVideo)> >, boost::signals2::mutex> > >, boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<void (ContentVideo), boost::function<void (ContentVideo)> >, boost::signals2::mutex> > >(boost::signals2::detail::slot_call_iterator_t<boost::signals2::detail::variadic_slot_invoker<boost::signals2::detail::void_type, ContentVideo>, std::_List_iterator<boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<void (ContentVideo), boost::function<void (ContentVideo)> >, boost::signals2::mutex> > >, boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<void (ContentVideo), boost::function<void (ContentVideo)> >, boost::signals2::mutex> > const&) (f=...) at /usr/include/boost/iterator/iterator_facade.hpp:550
0000023 0x00007ffff6082578 in boost::iterators::detail::iterator_facade_base<boost::signals2::detail::slot_call_iterator_t<boost::signals2::detail::variadic_slot_invoker<boost::signals2::detail::void_type, ContentVideo>, std::_List_iterator<boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<void (ContentVideo), boost::function<void (ContentVideo)> >, boost::signals2::mutex> > >, boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<void (ContentVideo), boost::function<void (ContentVideo)> >, boost::signals2::mutex> >, boost::signals2::detail::void_type, boost::iterators::single_pass_traversal_tag, boost::signals2::detail::void_type const&, long, false, false>::operator*() const (this=0x7fffd2716e40) at /usr/include/boost/iterator/iterator_facade.hpp:656
0000024 0x00007ffff6082127 in boost::signals2::optional_last_value<void>::operator()<boost::signals2::detail::slot_call_iterator_t<boost::signals2::detail::variadic_slot_invoker<boost::signals2::detail::void_type, ContentVideo>, std::_List_iterator<boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<void