[decklink] #484 Possible race condition with move-assignment of packaged_task avoided...

diff --git a/modules/decklink/consumer/decklink_consumer.cpp b/modules/decklink/consumer/decklink_consumer.cpp
index c9761c3c170c10b7ac4869c93f106dc8b6dfe493..3378068762d8e1fb74c73bb717816fb921bf9c80 100644 (file)
--- a/modules/decklink/consumer/decklink_consumer.cpp
+++ b/modules/decklink/consumer/decklink_consumer.cpp
@@ -20,7 +20,7 @@
 */
 
 #include "../StdAfx.h"
 */
 
 #include "../StdAfx.h"

- 
+

 #include "decklink_consumer.h"
 
 #include "../util/util.h"
 #include "decklink_consumer.h"
 
 #include "../util/util.h"


@@ -56,11 +56,12 @@
 #include <boost/lexical_cast.hpp>
 #include <boost/circular_buffer.hpp>
 #include <boost/property_tree/ptree.hpp>
 #include <boost/lexical_cast.hpp>
 #include <boost/circular_buffer.hpp>
 #include <boost/property_tree/ptree.hpp>

+#include <boost/thread/mutex.hpp>

 
 #include <future>
 
 
 #include <future>
 

-namespace caspar { namespace decklink { 
-       
+namespace caspar { namespace decklink {
+

 struct configuration
 {
        enum class keyer_t
 struct configuration
 {
        enum class keyer_t


@@ -86,7 +87,7 @@ struct configuration
        bool                                            key_only                        = false;
        int                                                     base_buffer_depth       = 3;
        core::audio_channel_layout      out_channel_layout      = core::audio_channel_layout::invalid();
        bool                                            key_only                        = false;
        int                                                     base_buffer_depth       = 3;
        core::audio_channel_layout      out_channel_layout      = core::audio_channel_layout::invalid();

-       
+

        int buffer_depth() const
        {
                return base_buffer_depth + (latency == latency_t::low_latency ? 0 : 1);
        int buffer_depth() const
        {
                return base_buffer_depth + (latency == latency_t::low_latency ? 0 : 1);


@@ -151,25 +152,25 @@ void set_keyer(
        {
                BOOL value = true;
                if (SUCCEEDED(attributes->GetFlag(BMDDeckLinkSupportsInternalKeying, &value)) && !value)
        {
                BOOL value = true;
                if (SUCCEEDED(attributes->GetFlag(BMDDeckLinkSupportsInternalKeying, &value)) && !value)

-                       CASPAR_LOG(error) << print << L" Failed to enable internal keyer.";     
+                       CASPAR_LOG(error) << print << L" Failed to enable internal keyer.";

                else if (FAILED(decklink_keyer->Enable(FALSE)))
                else if (FAILED(decklink_keyer->Enable(FALSE)))

-                       CASPAR_LOG(error) << print << L" Failed to enable internal keyer.";                     
+                       CASPAR_LOG(error) << print << L" Failed to enable internal keyer.";

                else if (FAILED(decklink_keyer->SetLevel(255)))
                        CASPAR_LOG(error) << print << L" Failed to set key-level to max.";
                else
                else if (FAILED(decklink_keyer->SetLevel(255)))
                        CASPAR_LOG(error) << print << L" Failed to set key-level to max.";
                else

-                       CASPAR_LOG(info) << print << L" Enabled internal keyer.";               
+                       CASPAR_LOG(info) << print << L" Enabled internal keyer.";

        }
        else if (keyer == configuration::keyer_t::external_keyer)
        {
                BOOL value = true;
                if (SUCCEEDED(attributes->GetFlag(BMDDeckLinkSupportsExternalKeying, &value)) && !value)
        }
        else if (keyer == configuration::keyer_t::external_keyer)
        {
                BOOL value = true;
                if (SUCCEEDED(attributes->GetFlag(BMDDeckLinkSupportsExternalKeying, &value)) && !value)

-                       CASPAR_LOG(error) << print << L" Failed to enable external keyer.";     
-               else if (FAILED(decklink_keyer->Enable(TRUE)))                  
-                       CASPAR_LOG(error) << print << L" Failed to enable external keyer.";     
+                       CASPAR_LOG(error) << print << L" Failed to enable external keyer.";
+               else if (FAILED(decklink_keyer->Enable(TRUE)))
+                       CASPAR_LOG(error) << print << L" Failed to enable external keyer.";

                else if (FAILED(decklink_keyer->SetLevel(255)))
                        CASPAR_LOG(error) << print << L" Failed to set key-level to max.";
                else
                else if (FAILED(decklink_keyer->SetLevel(255)))
                        CASPAR_LOG(error) << print << L" Failed to set key-level to max.";
                else

-                       CASPAR_LOG(info) << print << L" Enabled external keyer.";                       
+                       CASPAR_LOG(info) << print << L" Enabled external keyer.";

        }
 }
 
        }
 }
 


@@ -202,14 +203,14 @@ public:
 
                needs_to_copy_ = will_attempt_dma && dma_transfer_from_gl_buffer_impossible;
        }
 
                needs_to_copy_ = will_attempt_dma && dma_transfer_from_gl_buffer_impossible;
        }

-       
+

        // IUnknown
 
        virtual HRESULT STDMETHODCALLTYPE QueryInterface(REFIID, LPVOID*)
        {
                return E_NOINTERFACE;
        }
        // IUnknown
 
        virtual HRESULT STDMETHODCALLTYPE QueryInterface(REFIID, LPVOID*)
        {
                return E_NOINTERFACE;
        }

-       
+

        virtual ULONG STDMETHODCALLTYPE AddRef()
        {
                return ++ref_count_;
        virtual ULONG STDMETHODCALLTYPE AddRef()
        {
                return ++ref_count_;


@@ -229,7 +230,7 @@ public:
        virtual long STDMETHODCALLTYPE GetRowBytes()                {return static_cast<long>(format_desc_.width*4);}
        virtual BMDPixelFormat STDMETHODCALLTYPE GetPixelFormat()   {return bmdFormat8BitBGRA;}
        virtual BMDFrameFlags STDMETHODCALLTYPE GetFlags()                      {return bmdFrameFlagDefault;}
        virtual long STDMETHODCALLTYPE GetRowBytes()                {return static_cast<long>(format_desc_.width*4);}
        virtual BMDPixelFormat STDMETHODCALLTYPE GetPixelFormat()   {return bmdFormat8BitBGRA;}
        virtual BMDFrameFlags STDMETHODCALLTYPE GetFlags()                      {return bmdFrameFlagDefault;}

-               
+

        virtual HRESULT STDMETHODCALLTYPE GetBytes(void** buffer)
        {
                try
        virtual HRESULT STDMETHODCALLTYPE GetBytes(void** buffer)
        {
                try


@@ -268,11 +269,11 @@ public:
 
                return S_OK;
        }
 
                return S_OK;
        }

-               
+

        virtual HRESULT STDMETHODCALLTYPE GetTimecode(BMDTimecodeFormat format, IDeckLinkTimecode** timecode) {return S_FALSE;}
        virtual HRESULT STDMETHODCALLTYPE GetAncillaryData(IDeckLinkVideoFrameAncillary** ancillary)              {return S_FALSE;}
 
        virtual HRESULT STDMETHODCALLTYPE GetTimecode(BMDTimecodeFormat format, IDeckLinkTimecode** timecode) {return S_FALSE;}
        virtual HRESULT STDMETHODCALLTYPE GetAncillaryData(IDeckLinkVideoFrameAncillary** ancillary)              {return S_FALSE;}
 

-       // decklink_frame       
+       // decklink_frame

 
        const core::audio_buffer& audio_data()
        {
 
        const core::audio_buffer& audio_data()
        {


@@ -358,7 +359,7 @@ struct key_video_context : public IDeckLinkVideoOutputCallback, boost::noncopyab
 
 template <typename Configuration>
 struct decklink_consumer : public IDeckLinkVideoOutputCallback, boost::noncopyable
 
 template <typename Configuration>
 struct decklink_consumer : public IDeckLinkVideoOutputCallback, boost::noncopyable

-{              
+{

        const int                                                                                       channel_index_;
        const configuration                                                                     config_;
 
        const int                                                                                       channel_index_;
        const configuration                                                                     config_;
 


@@ -372,7 +373,7 @@ struct decklink_consumer : public IDeckLinkVideoOutputCallback, boost::noncopyab
        std::exception_ptr                                                                      exception_;
 
        tbb::atomic<bool>                                                                       is_running_;
        std::exception_ptr                                                                      exception_;
 
        tbb::atomic<bool>                                                                       is_running_;

-               
+

        const std::wstring                                                                      model_name_                             = get_model_name(decklink_);
        bool                                                                                            will_attempt_dma_;
        const core::video_format_desc                                           format_desc_;
        const std::wstring                                                                      model_name_                             = get_model_name(decklink_);
        bool                                                                                            will_attempt_dma_;
        const core::video_format_desc                                           format_desc_;


@@ -385,13 +386,14 @@ struct decklink_consumer : public IDeckLinkVideoOutputCallback, boost::noncopyab
        long long                                                                                       audio_scheduled_                = 0;
 
        int                                                                                                     preroll_count_                  = 0;
        long long                                                                                       audio_scheduled_                = 0;
 
        int                                                                                                     preroll_count_                  = 0;

-               
+

        boost::circular_buffer<std::vector<int32_t>>            audio_container_                { buffer_size_ + 1 };
 
        tbb::concurrent_bounded_queue<core::const_frame>        frame_buffer_;
        boost::circular_buffer<std::vector<int32_t>>            audio_container_                { buffer_size_ + 1 };
 
        tbb::concurrent_bounded_queue<core::const_frame>        frame_buffer_;

-       
+

        spl::shared_ptr<diagnostics::graph>                                     graph_;
        caspar::timer                                                                           tick_timer_;
        spl::shared_ptr<diagnostics::graph>                                     graph_;
        caspar::timer                                                                           tick_timer_;

+       boost::mutex                                                                            send_completion_mutex_;

        std::packaged_task<bool ()>                                                     send_completion_;
        reference_signal_detector                                                       reference_signal_detector_      { output_ };
        tbb::atomic<int64_t>                                                            current_presentation_delay_;
        std::packaged_task<bool ()>                                                     send_completion_;
        reference_signal_detector                                                       reference_signal_detector_      { output_ };
        tbb::atomic<int64_t>                                                            current_presentation_delay_;


@@ -403,7 +405,7 @@ public:
                        const configuration& config,
                        const core::video_format_desc& format_desc,
                        const core::audio_channel_layout& in_channel_layout,
                        const configuration& config,
                        const core::video_format_desc& format_desc,
                        const core::audio_channel_layout& in_channel_layout,

-                       int channel_index) 
+                       int channel_index)

                : channel_index_(channel_index)
                , config_(config)
                , format_desc_(format_desc)
                : channel_index_(channel_index)
                , config_(config)
                , format_desc_(format_desc)


@@ -412,13 +414,13 @@ public:
                is_running_ = true;
                current_presentation_delay_ = 0;
                scheduled_frames_completed_ = 0;
                is_running_ = true;
                current_presentation_delay_ = 0;
                scheduled_frames_completed_ = 0;

-                               
+

                frame_buffer_.set_capacity(1);
 
                if (config.keyer == configuration::keyer_t::external_separate_device_keyer)
                        key_context_.reset(new key_video_context<Configuration>(config, print()));
 
                frame_buffer_.set_capacity(1);
 
                if (config.keyer == configuration::keyer_t::external_separate_device_keyer)
                        key_context_.reset(new key_video_context<Configuration>(config, print()));
 

-               graph_->set_color("tick-time", diagnostics::color(0.0f, 0.6f, 0.9f));   
+               graph_->set_color("tick-time", diagnostics::color(0.0f, 0.6f, 0.9f));

                graph_->set_color("late-frame", diagnostics::color(0.6f, 0.3f, 0.3f));
                graph_->set_color("dropped-frame", diagnostics::color(0.3f, 0.6f, 0.3f));
                graph_->set_color("flushed-frame", diagnostics::color(0.4f, 0.3f, 0.8f));
                graph_->set_color("late-frame", diagnostics::color(0.6f, 0.3f, 0.3f));
                graph_->set_color("dropped-frame", diagnostics::color(0.3f, 0.6f, 0.3f));
                graph_->set_color("flushed-frame", diagnostics::color(0.4f, 0.3f, 0.8f));


@@ -432,18 +434,18 @@ public:
 
                graph_->set_text(print());
                diagnostics::register_graph(graph_);
 
                graph_->set_text(print());
                diagnostics::register_graph(graph_);

-               
+

                enable_video(get_display_mode(output_, format_desc_.format, bmdFormat8BitBGRA, bmdVideoOutputFlagDefault, will_attempt_dma_));
                enable_video(get_display_mode(output_, format_desc_.format, bmdFormat8BitBGRA, bmdVideoOutputFlagDefault, will_attempt_dma_));

-                               
+

                if(config.embedded_audio)
                        enable_audio();
                if(config.embedded_audio)
                        enable_audio();

-               
-               set_latency(configuration_, config.latency, print());                           
+
+               set_latency(configuration_, config.latency, print());

                set_keyer(attributes_, keyer_, config.keyer, print());
 
                if(config.embedded_audio)
                set_keyer(attributes_, keyer_, config.keyer, print());
 
                if(config.embedded_audio)

-                       output_->BeginAudioPreroll();           
-               
+                       output_->BeginAudioPreroll();
+

                for (int n = 0; n < buffer_size_; ++n)
                {
                        if (config.embedded_audio)
                for (int n = 0; n < buffer_size_; ++n)
                {
                        if (config.embedded_audio)


@@ -463,11 +465,11 @@ public:
        }
 
        ~decklink_consumer()
        }
 
        ~decklink_consumer()

-       {               
+       {

                is_running_ = false;
                frame_buffer_.try_push(core::const_frame::empty());
 
                is_running_ = false;
                frame_buffer_.try_push(core::const_frame::empty());
 

-               if(output_ != nullptr) 
+               if(output_ != nullptr)

                {
                        output_->StopScheduledPlayback(0, nullptr, 0);
                        if(config_.embedded_audio)
                {
                        output_->StopScheduledPlayback(0, nullptr, 0);
                        if(config_.embedded_audio)


@@ -475,22 +477,22 @@ public:
                        output_->DisableVideoOutput();
                }
        }
                        output_->DisableVideoOutput();
                }
        }

-       
+

        void enable_audio()
        {
                if(FAILED(output_->EnableAudioOutput(bmdAudioSampleRate48kHz, bmdAudioSampleType32bitInteger, out_channel_layout_.num_channels, bmdAudioOutputStreamTimestamped)))
                                CASPAR_THROW_EXCEPTION(caspar_exception() << msg_info(print() + L" Could not enable audio output."));
        void enable_audio()
        {
                if(FAILED(output_->EnableAudioOutput(bmdAudioSampleRate48kHz, bmdAudioSampleType32bitInteger, out_channel_layout_.num_channels, bmdAudioOutputStreamTimestamped)))
                                CASPAR_THROW_EXCEPTION(caspar_exception() << msg_info(print() + L" Could not enable audio output."));

-                               
+

                CASPAR_LOG(info) << print() << L" Enabled embedded-audio.";
        }
 
        void enable_video(BMDDisplayMode display_mode)
        {
                CASPAR_LOG(info) << print() << L" Enabled embedded-audio.";
        }
 
        void enable_video(BMDDisplayMode display_mode)
        {

-               if(FAILED(output_->EnableVideoOutput(display_mode, bmdVideoOutputFlagDefault))) 
+               if(FAILED(output_->EnableVideoOutput(display_mode, bmdVideoOutputFlagDefault)))

                        CASPAR_THROW_EXCEPTION(caspar_exception() << msg_info(print() + L" Could not enable fill video output."));
                        CASPAR_THROW_EXCEPTION(caspar_exception() << msg_info(print() + L" Could not enable fill video output."));

-               
+

                if(FAILED(output_->SetScheduledFrameCompletionCallback(this)))
                if(FAILED(output_->SetScheduledFrameCompletionCallback(this)))

-                       CASPAR_THROW_EXCEPTION(caspar_exception() 
+                       CASPAR_THROW_EXCEPTION(caspar_exception()

                                                                        << msg_info(print() + L" Failed to set fill playback completion callback.")
                                                                        << boost::errinfo_api_function("SetScheduledFrameCompletionCallback"));
 
                                                                        << msg_info(print() + L" Failed to set fill playback completion callback.")
                                                                        << boost::errinfo_api_function("SetScheduledFrameCompletionCallback"));
 


@@ -500,17 +502,17 @@ public:
 
        void start_playback()
        {
 
        void start_playback()
        {

-               if(FAILED(output_->StartScheduledPlayback(0, format_desc_.time_scale, 1.0))) 
+               if(FAILED(output_->StartScheduledPlayback(0, format_desc_.time_scale, 1.0)))

                        CASPAR_THROW_EXCEPTION(caspar_exception() << msg_info(print() + L" Failed to schedule fill playback."));
 
                if (key_context_ && FAILED(key_context_->output_->StartScheduledPlayback(0, format_desc_.time_scale, 1.0)))
                        CASPAR_THROW_EXCEPTION(caspar_exception() << msg_info(print() + L" Failed to schedule key playback."));
        }
                        CASPAR_THROW_EXCEPTION(caspar_exception() << msg_info(print() + L" Failed to schedule fill playback."));
 
                if (key_context_ && FAILED(key_context_->output_->StartScheduledPlayback(0, format_desc_.time_scale, 1.0)))
                        CASPAR_THROW_EXCEPTION(caspar_exception() << msg_info(print() + L" Failed to schedule key playback."));
        }

-       
+

        virtual HRESULT STDMETHODCALLTYPE QueryInterface(REFIID, LPVOID*)       {return E_NOINTERFACE;}
        virtual ULONG STDMETHODCALLTYPE AddRef()                                        {return 1;}
        virtual ULONG STDMETHODCALLTYPE Release()                               {return 1;}
        virtual HRESULT STDMETHODCALLTYPE QueryInterface(REFIID, LPVOID*)       {return E_NOINTERFACE;}
        virtual ULONG STDMETHODCALLTYPE AddRef()                                        {return 1;}
        virtual ULONG STDMETHODCALLTYPE Release()                               {return 1;}

-       
+

        virtual HRESULT STDMETHODCALLTYPE ScheduledPlaybackHasStopped()
        {
                is_running_ = false;
        virtual HRESULT STDMETHODCALLTYPE ScheduledPlaybackHasStopped()
        {
                is_running_ = false;


@@ -522,7 +524,7 @@ public:
        {
                if(!is_running_)
                        return E_FAIL;
        {
                if(!is_running_)
                        return E_FAIL;

-               
+

                try
                {
                        auto tick_time = tick_timer_.elapsed()*format_desc_.fps * 0.5;
                try
                {
                        auto tick_time = tick_timer_.elapsed()*format_desc_.fps * 0.5;


@@ -568,10 +570,14 @@ public:
 
                        frame_buffer_.pop(frame);
 
 
                        frame_buffer_.pop(frame);
 

-                       if (send_completion_.valid())

                        {
                        {

-                               send_completion_();
-                               send_completion_ = std::packaged_task<bool ()>();
+                               boost::lock_guard<boost::mutex> lock(send_completion_mutex_);
+
+                               if (send_completion_.valid())
+                               {
+                                       send_completion_();
+                                       send_completion_ = std::packaged_task<bool()>();
+                               }

                        }
 
                        if (config_.embedded_audio)
                        }
 
                        if (config_.embedded_audio)


@@ -603,7 +609,7 @@ public:
 
                audio_scheduled_ += sample_frame_count;
        }
 
                audio_scheduled_ += sample_frame_count;
        }

-                       
+

        void schedule_next_video(core::const_frame frame)
        {
                if (key_context_)
        void schedule_next_video(core::const_frame frame)
        {
                if (key_context_)


@@ -628,14 +634,16 @@ public:
                });
 
                if(exception != nullptr)
                });
 
                if(exception != nullptr)

-                       std::rethrow_exception(exception);              
+                       std::rethrow_exception(exception);

 
                if(!is_running_)
                        CASPAR_THROW_EXCEPTION(caspar_exception() << msg_info(print() + L" Is not running."));
 
                if(!is_running_)
                        CASPAR_THROW_EXCEPTION(caspar_exception() << msg_info(print() + L" Is not running."));

-               
+

                if (frame_buffer_.try_push(frame))
                        return make_ready_future(true);
 
                if (frame_buffer_.try_push(frame))
                        return make_ready_future(true);
 

+               boost::lock_guard<boost::mutex> lock(send_completion_mutex_);
+

                send_completion_ = std::packaged_task<bool ()>([frame, this] () mutable -> bool
                {
                        frame_buffer_.push(frame);
                send_completion_ = std::packaged_task<bool ()>([frame, this] () mutable -> bool
                {
                        frame_buffer_.push(frame);


@@ -645,7 +653,7 @@ public:
 
                return send_completion_.get_future();
        }
 
                return send_completion_.get_future();
        }

-       
+

        std::wstring print() const
        {
                if (config_.keyer == configuration::keyer_t::external_separate_device_keyer)
        std::wstring print() const
        {
                if (config_.keyer == configuration::keyer_t::external_separate_device_keyer)


@@ -693,26 +701,26 @@ public:
        }
 
        // frame_consumer
        }
 
        // frame_consumer

-       
+

        void initialize(const core::video_format_desc& format_desc, const core::audio_channel_layout& channel_layout, int channel_index) override
        {
                format_desc_ = format_desc;
                executor_.invoke([=]
                {
                        consumer_.reset();
        void initialize(const core::video_format_desc& format_desc, const core::audio_channel_layout& channel_layout, int channel_index) override
        {
                format_desc_ = format_desc;
                executor_.invoke([=]
                {
                        consumer_.reset();

-                       consumer_.reset(new decklink_consumer<Configuration>(config_, format_desc, channel_layout, channel_index));                     
+                       consumer_.reset(new decklink_consumer<Configuration>(config_, format_desc, channel_layout, channel_index));

                });
        }
                });
        }

-       
+

        std::future<bool> send(core::const_frame frame) override
        {
                return consumer_->send(frame);
        }
        std::future<bool> send(core::const_frame frame) override
        {
                return consumer_->send(frame);
        }

-       
+

        std::wstring print() const override
        {
                return consumer_ ? consumer_->print() : L"[decklink_consumer]";
        std::wstring print() const override
        {
                return consumer_ ? consumer_->print() : L"[decklink_consumer]";

-       }               
+       }

 
        std::wstring name() const override
        {
 
        std::wstring name() const override
        {


@@ -813,12 +821,12 @@ spl::shared_ptr<core::frame_consumer> create_consumer(
 {
        if (params.size() < 1 || !boost::iequals(params.at(0), L"DECKLINK"))
                return core::frame_consumer::empty();
 {
        if (params.size() < 1 || !boost::iequals(params.at(0), L"DECKLINK"))
                return core::frame_consumer::empty();

-       
+

        configuration config;
        configuration config;

-               
+

        if (params.size() > 1)
                config.device_index = boost::lexical_cast<int>(params.at(1));
        if (params.size() > 1)
                config.device_index = boost::lexical_cast<int>(params.at(1));

-       
+

        if (contains_param(L"INTERNAL_KEY", params))
                config.keyer = configuration::keyer_t::internal_keyer;
        else if (contains_param(L"EXTERNAL_KEY", params))
        if (contains_param(L"INTERNAL_KEY", params))
                config.keyer = configuration::keyer_t::internal_keyer;
        else if (contains_param(L"EXTERNAL_KEY", params))


@@ -915,18 +923,18 @@ developer@blackmagic-design.com
 
 -----------------------------------------------------------------------------
 
 
 -----------------------------------------------------------------------------
 

-Thanks for your inquiry. The minimum number of frames that you can preroll 
-for scheduled playback is three frames for video and four frames for audio. 
+Thanks for your inquiry. The minimum number of frames that you can preroll
+for scheduled playback is three frames for video and four frames for audio.

 As you mentioned if you preroll less frames then playback will not start or
 As you mentioned if you preroll less frames then playback will not start or

-playback will be very sporadic. From our experience with Media Express, we 
-recommended that at least seven frames are prerolled for smooth playback. 
+playback will be very sporadic. From our experience with Media Express, we
+recommended that at least seven frames are prerolled for smooth playback.

 
 Regarding the bmdDeckLinkConfigLowLatencyVideoOutput flag:
 There can be around 3 frames worth of latency on scheduled output.
 When the bmdDeckLinkConfigLowLatencyVideoOutput flag is used this latency is
 
 Regarding the bmdDeckLinkConfigLowLatencyVideoOutput flag:
 There can be around 3 frames worth of latency on scheduled output.
 When the bmdDeckLinkConfigLowLatencyVideoOutput flag is used this latency is

-reduced  or removed for scheduled playback. If the DisplayVideoFrameSync() 
-method is used, the bmdDeckLinkConfigLowLatencyVideoOutput setting will 
-guarantee that the provided frame will be output as soon the previous 
+reduced  or removed for scheduled playback. If the DisplayVideoFrameSync()
+method is used, the bmdDeckLinkConfigLowLatencyVideoOutput setting will
+guarantee that the provided frame will be output as soon the previous

 frame output has been completed.
 ################################################################################
 */
 frame output has been completed.
 ################################################################################
 */


@@ -943,10 +951,10 @@ developer@blackmagic-design.com
 
 -----------------------------------------------------------------------------
 
 
 -----------------------------------------------------------------------------
 

-Thanks for your inquiry. You could try subclassing IDeckLinkMutableVideoFrame 
-and providing a pointer to your video buffer when GetBytes() is called. 
-This may help to keep copying to a minimum. Please ensure that the pixel 
-format is in bmdFormat10BitYUV, otherwise the DeckLink API / driver will 
+Thanks for your inquiry. You could try subclassing IDeckLinkMutableVideoFrame
+and providing a pointer to your video buffer when GetBytes() is called.
+This may help to keep copying to a minimum. Please ensure that the pixel
+format is in bmdFormat10BitYUV, otherwise the DeckLink API / driver will

 have to colourspace convert which may result in additional copying.
 ################################################################################
 */
 have to colourspace convert which may result in additional copying.
 ################################################################################
 */