mfvideosrc: Add support for DirectShow capture filter

Adding DirecShow video capture filter mode, in addition
to existing MediaFoundation and WinRT(UWP) mode, to support
DirectShow only filters (not KS driver compatible)
such as custom virtual camera filters.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3350>

subprojects/gst-plugins-bad/sys/mediafoundation/gstmfcapturedshow.h

@@ -0,0 +1,36 @@
+/* GStreamer
+ * Copyright (C) 2022 Seungha Yang <seungha@centricular.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#pragma once
+
+#include <gst/gst.h>
+#include "gstmfsourceobject.h"
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_MF_CAPTURE_DSHOW (gst_mf_capture_dshow_get_type())
+G_DECLARE_FINAL_TYPE (GstMFCaptureDShow, gst_mf_capture_dshow,
+    GST, MF_CAPTURE_DSHOW, GstMFSourceObject);
+
+GstMFSourceObject * gst_mf_capture_dshow_new (GstMFSourceType type,
+                                              gint device_index,
+                                              const gchar * device_name,
+                                              const gchar * device_path);
+
+G_END_DECLS

subprojects/gst-plugins-bad/sys/mediafoundation/gstmfdevice.cpp

@@ -31,6 +31,7 @@
 
 #if GST_MF_WINAPI_DESKTOP
 #include "gstwin32devicewatcher.h"
+#include "gstmfcapturedshow.h"
 
 #ifndef INITGUID
 #include <initguid.h>
@@ -265,11 +266,11 @@ gst_mf_device_provider_finalize (GObject * object)
   G_OBJECT_CLASS (gst_mf_device_provider_parent_class)->finalize (object);
 }
 
-static GList *
+static void
-gst_mf_device_provider_probe (GstDeviceProvider * provider)
+gst_mf_device_provider_probe_internal (GstDeviceProvider * provider,
+    gboolean try_dshow, GList ** list)
 {
   GstMFDeviceProvider *self = GST_MF_DEVICE_PROVIDER (provider);
-  GList *list = nullptr;
   gint i;
 
   for (i = 0;; i++) {
@@ -280,8 +281,18 @@ gst_mf_device_provider_probe (GstDeviceProvider * provider)
     gchar *device_name = nullptr;
     gchar *device_path = nullptr;
 
+#if GST_MF_WINAPI_DESKTOP
+    if (try_dshow) {
+      obj = gst_mf_capture_dshow_new (GST_MF_SOURCE_TYPE_VIDEO, i,
+          nullptr, nullptr);
+    } else {
       obj = gst_mf_source_object_new (GST_MF_SOURCE_TYPE_VIDEO,
           i, nullptr, nullptr, nullptr);
+    }
+#else
+    obj = gst_mf_source_object_new (GST_MF_SOURCE_TYPE_VIDEO,
+        i, nullptr, nullptr, nullptr);
+#endif
     if (!obj)
       break;
 
@@ -314,7 +325,7 @@ gst_mf_device_provider_probe (GstDeviceProvider * provider)
         "display-name", device_name, "caps", caps,
         "device-class", "Source/Video", "properties", props, nullptr);
 
-    list = g_list_append (list, device);
+    *list = g_list_append (*list, device);
 
   next:
     if (caps)
@@ -325,6 +336,17 @@ gst_mf_device_provider_probe (GstDeviceProvider * provider)
     g_free (device_name);
     gst_object_unref (obj);
   }
+}
+
+static GList *
+gst_mf_device_provider_probe (GstDeviceProvider * provider)
+{
+  GList *list = nullptr;
+
+  gst_mf_device_provider_probe_internal (provider, FALSE, &list);
+#if GST_MF_WINAPI_DESKTOP
+  gst_mf_device_provider_probe_internal (provider, TRUE, &list);
+#endif
 
   return list;
 }

subprojects/gst-plugins-bad/sys/mediafoundation/gstmfsourceobject.cpp

@@ -232,6 +232,21 @@ gst_mf_source_object_create (GstMFSourceObject * object, GstBuffer ** buffer)
   return klass->create (object, buffer);
 }
 
+GstFlowReturn
+gst_mf_source_object_get_sample (GstMFSourceObject * object,
+    GstSample ** sample)
+{
+  GstMFSourceObjectClass *klass;
+
+  g_return_val_if_fail (GST_IS_MF_SOURCE_OBJECT (object), GST_FLOW_ERROR);
+  g_return_val_if_fail (sample != nullptr, GST_FLOW_ERROR);
+
+  klass = GST_MF_SOURCE_OBJECT_GET_CLASS (object);
+  g_assert (klass->get_sample != nullptr);
+
+  return klass->get_sample (object, sample);
+}
+
 void
 gst_mf_source_object_set_flushing (GstMFSourceObject * object,
     gboolean flushing)

subprojects/gst-plugins-bad/sys/mediafoundation/gstmfsourceobject.h

@@ -72,6 +72,9 @@ struct _GstMFSourceObjectClass
   GstFlowReturn (*create)      (GstMFSourceObject * object,
                                 GstBuffer ** buffer);
 
+  GstFlowReturn (*get_sample)  (GstMFSourceObject * object,
+                                GstSample ** sample);
+
   gboolean      (*unlock)      (GstMFSourceObject * object);
 
   gboolean      (*unlock_stop) (GstMFSourceObject * object);
@@ -96,6 +99,10 @@ GstFlowReturn   gst_mf_source_object_fill         (GstMFSourceObject * object,
 GstFlowReturn   gst_mf_source_object_create       (GstMFSourceObject * object,
                                                    GstBuffer ** buffer);
 
+/* DirectShow filter */
+GstFlowReturn   gst_mf_source_object_get_sample   (GstMFSourceObject * object,
+                                                   GstSample ** sample);
+
 void            gst_mf_source_object_set_flushing (GstMFSourceObject * object,
                                                    gboolean flushing);
 

subprojects/gst-plugins-bad/sys/mediafoundation/gstmfsourcereader.cpp

@@ -990,7 +990,7 @@ gst_mf_source_reader_new (GstMFSourceType type, gint device_index,
   gst_object_ref_sink (self);
 
   if (!self->opened) {
-    GST_WARNING_OBJECT (self, "Couldn't open device");
+    GST_DEBUG_OBJECT (self, "Couldn't open device");
     gst_object_unref (self);
     return nullptr;
   }

subprojects/gst-plugins-bad/sys/mediafoundation/gstmfvideosrc.cpp

@@ -45,6 +45,10 @@
 #include "gstmfsourceobject.h"
 #include <string.h>
 
+#if GST_MF_WINAPI_DESKTOP
+#include "gstmfcapturedshow.h"
+#endif
+
 GST_DEBUG_CATEGORY (gst_mf_video_src_debug);
 #define GST_CAT_DEFAULT gst_mf_video_src_debug
 
@@ -76,6 +80,8 @@ struct _GstMFVideoSrc
   guint64 n_frames;
   GstClockTime latency;
 
+  gboolean use_dshow;
+
   /* properties */
   gchar *device_path;
   gchar *device_name;
@@ -268,6 +274,15 @@ gst_mf_video_src_start (GstBaseSrc * src)
 
   self->n_frames = 0;
   self->latency = 0;
+  self->use_dshow = FALSE;
+
+  if (!self->source) {
+#if GST_MF_WINAPI_DESKTOP
+    self->use_dshow = TRUE;
+    self->source = gst_mf_capture_dshow_new (GST_MF_SOURCE_TYPE_VIDEO,
+        self->device_index, self->device_name, self->device_path);
+#endif
+  }
 
   if (!self->source) {
     GST_ERROR_OBJECT (self, "Couldn't create capture object");
@@ -415,6 +430,7 @@ gst_mf_video_src_create (GstPushSrc * pushsrc, GstBuffer ** buffer)
   GstMFVideoSrc *self = GST_MF_VIDEO_SRC (pushsrc);
   GstFlowReturn ret = GST_FLOW_OK;
   GstBuffer *buf = nullptr;
+  GstSample *sample = nullptr;
   GstClock *clock;
   GstClockTime running_time = GST_CLOCK_TIME_NONE;
   GstClockTimeDiff diff;
@@ -429,7 +445,9 @@ gst_mf_video_src_create (GstPushSrc * pushsrc, GstBuffer ** buffer)
     self->started = TRUE;
   }
 
-  if (GST_VIDEO_INFO_FORMAT (&self->info) != GST_VIDEO_FORMAT_ENCODED) {
+  if (self->use_dshow) {
+    ret = gst_mf_source_object_get_sample (self->source, &sample);
+  } else if (GST_VIDEO_INFO_FORMAT (&self->info) != GST_VIDEO_FORMAT_ENCODED) {
     ret = GST_BASE_SRC_CLASS (parent_class)->alloc (GST_BASE_SRC (self), 0,
         GST_VIDEO_INFO_SIZE (&self->info), &buf);
 
@@ -444,6 +462,23 @@ gst_mf_video_src_create (GstPushSrc * pushsrc, GstBuffer ** buffer)
   if (ret != GST_FLOW_OK)
     return ret;
 
+  /* DirectShow capture object will set caps if it's got updated */
+  if (sample) {
+    if (gst_sample_get_caps (sample)) {
+      if (!gst_base_src_negotiate (GST_BASE_SRC (self))) {
+        GST_ERROR_OBJECT (self, "Failed to negotiate with new caps");
+        gst_sample_unref (sample);
+        return GST_FLOW_NOT_NEGOTIATED;
+      } else {
+        GST_DEBUG_OBJECT (self, "Renegotiated");
+      }
+    }
+
+    buf = gst_sample_get_buffer (sample);
+    gst_buffer_ref (buf);
+    gst_sample_unref (sample);
+  }
+
   GST_BUFFER_OFFSET (buf) = self->n_frames;
   GST_BUFFER_OFFSET_END (buf) = GST_BUFFER_OFFSET (buf) + 1;
   self->n_frames++;

subprojects/gst-plugins-bad/sys/mediafoundation/meson.build

@@ -20,6 +20,7 @@ mf_sources = [
 ]
 
 mf_desktop_sources = [
+  'gstmfcapturedshow.cpp',
   'gstmfsourcereader.cpp',
   'gstwin32devicewatcher.cpp',
 ]