/*

 * GStreamer

 * Copyright (C) 2015 Jan Schmidt <jan@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.

 */

/**

 * SECTION:element-glstereosplit

 * @title: glstereosplit

 *

 * Receive a stereoscopic video stream and split into left/right

 *

 * ## Examples

 * |[

 * gst-launch-1.0 videotestsrc ! glstereosplit name=s ! queue ! glimagesink s. ! queue ! glimagesink

 * ]|

 * FBO (Frame Buffer Object) and GLSL (OpenGL Shading Language) are required.

 *

 */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include "gstglstereosplit.h"

#define GST_CAT_DEFAULT gst_gl_stereosplit_debug

GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);

#define SUPPORTED_GL_APIS GST_GL_API_GLES2 | GST_GL_API_OPENGL | GST_GL_API_OPENGL3

#define DEBUG_INIT \

  GST_DEBUG_CATEGORY_INIT (gst_gl_stereosplit_debug, "glstereosplit", 0, "glstereosplit element");

G_DEFINE_TYPE_WITH_CODE (GstGLStereoSplit, gst_gl_stereosplit,

    GST_TYPE_ELEMENT, DEBUG_INIT);

static GstStaticPadTemplate sink_template = GST_STATIC_PAD_TEMPLATE ("sink",

    GST_PAD_SINK, GST_PAD_ALWAYS,

    GST_STATIC_CAPS (GST_VIDEO_CAPS_MAKE_WITH_FEATURES

        (GST_CAPS_FEATURE_MEMORY_GL_MEMORY, "RGBA"))

    );

static GstStaticPadTemplate src_left_template = GST_STATIC_PAD_TEMPLATE ("left",

    GST_PAD_SRC, GST_PAD_ALWAYS,

    GST_STATIC_CAPS (GST_VIDEO_CAPS_MAKE_WITH_FEATURES

        (GST_CAPS_FEATURE_MEMORY_GL_MEMORY, "RGBA"))

    );

static GstStaticPadTemplate src_right_template =

GST_STATIC_PAD_TEMPLATE ("right",

    GST_PAD_SRC, GST_PAD_ALWAYS,

    GST_STATIC_CAPS (GST_VIDEO_CAPS_MAKE_WITH_FEATURES

        (GST_CAPS_FEATURE_MEMORY_GL_MEMORY,

            "RGBA"))

    );

static void stereosplit_reset (GstGLStereoSplit * self);

static void stereosplit_finalize (GstGLStereoSplit * self);

static void stereosplit_set_context (GstElement * element,

    GstContext * context);

static GstFlowReturn stereosplit_chain (GstPad * pad, GstGLStereoSplit * split,

    GstBuffer * buf);

static GstStateChangeReturn stereosplit_change_state (GstElement * element,

    GstStateChange transition);

static gboolean stereosplit_sink_query (GstPad * pad, GstObject * parent,

    GstQuery * query);

static gboolean stereosplit_sink_event (GstPad * pad, GstObject * parent,

    GstEvent * event);

static gboolean stereosplit_src_query (GstPad * pad, GstObject * parent,

    GstQuery * query);

static gboolean stereosplit_src_event (GstPad * pad, GstObject * parent,

    GstEvent * event);

static gboolean ensure_context (GstGLStereoSplit * self);

static void

gst_gl_stereosplit_class_init (GstGLStereoSplitClass * klass)

{

  GObjectClass *gobject_class = (GObjectClass *) klass;

  GstElementClass *element_class = GST_ELEMENT_CLASS (klass);

  gst_element_class_set_static_metadata (element_class,

      "GLStereoSplit", "Codec/Converter",

      "Splits a stereoscopic stream into separate left/right streams",

      "Jan Schmidt <jan@centricular.com>\n"

      "Matthew Waters <matthew@centricular.com>");

  gobject_class->finalize = (GObjectFinalizeFunc) (stereosplit_finalize);

  element_class->change_state = stereosplit_change_state;

  element_class->set_context = stereosplit_set_context;

  gst_element_class_add_static_pad_template (element_class, &sink_template);

  gst_element_class_add_static_pad_template (element_class, &src_left_template);

  gst_element_class_add_static_pad_template (element_class,

      &src_right_template);

}

static void

gst_gl_stereosplit_init (GstGLStereoSplit * self)

{

  GstPad *pad;

  pad = self->sink_pad =

      gst_pad_new_from_static_template (&sink_template, "sink");

  gst_pad_set_chain_function (pad, (GstPadChainFunction) (stereosplit_chain));

  gst_pad_set_query_function (pad, stereosplit_sink_query);

  gst_pad_set_event_function (pad, stereosplit_sink_event);

  gst_element_add_pad (GST_ELEMENT (self), self->sink_pad);

  pad = self->left_pad =

      gst_pad_new_from_static_template (&src_left_template, "left");

  gst_pad_set_query_function (pad, stereosplit_src_query);

  gst_pad_set_event_function (pad, stereosplit_src_event);

  gst_element_add_pad (GST_ELEMENT (self), self->left_pad);

  pad = self->right_pad =

      gst_pad_new_from_static_template (&src_right_template, "right");

  gst_pad_set_query_function (pad, stereosplit_src_query);

  gst_pad_set_event_function (pad, stereosplit_src_event);

  gst_element_add_pad (GST_ELEMENT (self), self->right_pad);

  self->viewconvert = gst_gl_view_convert_new ();

}

static void

stereosplit_reset (GstGLStereoSplit * self)

{

  if (self->context)

    gst_object_replace ((GstObject **) & self->context, NULL);

  if (self->display)

    gst_object_replace ((GstObject **) & self->display, NULL);

}

static void

stereosplit_finalize (GstGLStereoSplit * self)

{

  GObjectClass *klass = G_OBJECT_CLASS (gst_gl_stereosplit_parent_class);

  if (self->viewconvert)

    gst_object_replace ((GstObject **) & self->viewconvert, NULL);

  klass->finalize ((GObject *) (self));

}

static void

stereosplit_set_context (GstElement * element, GstContext * context)

{

  GstGLStereoSplit *stereosplit = GST_GL_STEREOSPLIT (element);

  gst_gl_handle_set_context (element, context, &stereosplit->display,

      &stereosplit->other_context);

  if (stereosplit->display)

    gst_gl_display_filter_gl_api (stereosplit->display, SUPPORTED_GL_APIS);

  GST_ELEMENT_CLASS (gst_gl_stereosplit_parent_class)->set_context (element,

      context);

}

static GstStateChangeReturn

stereosplit_change_state (GstElement * element, GstStateChange transition)

{

  GstGLStereoSplit *stereosplit = GST_GL_STEREOSPLIT (element);

  GstStateChangeReturn result;

  switch (transition) {

    case GST_STATE_CHANGE_NULL_TO_READY:

      if (!gst_gl_ensure_element_data (element, &stereosplit->display,

              &stereosplit->other_context))

        return GST_STATE_CHANGE_FAILURE;

      gst_gl_display_filter_gl_api (stereosplit->display, SUPPORTED_GL_APIS);

      break;

    default:

      break;

  }

  result =

      GST_ELEMENT_CLASS (gst_gl_stereosplit_parent_class)->change_state

      (element, transition);

  switch (transition) {

    case GST_STATE_CHANGE_READY_TO_NULL:

      if (stereosplit->other_context) {

        gst_object_unref (stereosplit->other_context);

        stereosplit->other_context = NULL;

      }

      if (stereosplit->display) {

        gst_object_unref (stereosplit->display);

        stereosplit->display = NULL;

      }

      break;

    case GST_STATE_CHANGE_PAUSED_TO_READY:

      stereosplit_reset (stereosplit);

      break;

    default:

      break;

  }

  return result;

}

static GstCaps *

stereosplit_transform_caps (GstGLStereoSplit * self, GstPadDirection direction,

    GstCaps * caps, GstCaps * filter)

{

  GstCaps *next_caps;

  /* FIXME: Is this the right way to ensure a context here ? */

  if (!ensure_context (self))

    return NULL;

  next_caps =

      gst_gl_view_convert_transform_caps (self->viewconvert, direction, caps,

      NULL);

  return next_caps;

}

static GstCaps *

strip_mview_fields (GstCaps * incaps, GstVideoMultiviewFlags keep_flags)

{

  GstCaps *outcaps = gst_caps_make_writable (incaps);

  gint i, n;

  n = gst_caps_get_size (outcaps);

  for (i = 0; i < n; i++) {

    GstStructure *st = gst_caps_get_structure (outcaps, i);

    GstVideoMultiviewFlags flags, mask;

    gst_structure_remove_field (st, "multiview-mode");

    if (gst_structure_get_flagset (st, "multiview-flags", (guint *) & flags,

            (guint *) & mask)) {

      flags &= keep_flags;

      mask = keep_flags;

      gst_structure_set (st, "multiview-flags",

          GST_TYPE_VIDEO_MULTIVIEW_FLAGSET, flags, mask, NULL);

    }

  }

  return outcaps;

}

static gboolean stereosplit_do_bufferpool (GstGLStereoSplit * self,

    GstCaps * caps);

static GstCaps *

stereosplit_get_src_caps (GstGLStereoSplit * split,

    GstPad * pad, GstVideoMultiviewMode preferred_mode)

{

  GstCaps *outcaps, *tmp, *templ_caps;

  GValue item = G_VALUE_INIT, list = G_VALUE_INIT;

  /* Get the template format */

  templ_caps = gst_pad_get_pad_template_caps (pad);

  /* And limit down to the preferred mode or mono */

  templ_caps = gst_caps_make_writable (templ_caps);

  g_value_init (&item, G_TYPE_STRING);

  g_value_init (&list, GST_TYPE_LIST);

  g_value_set_static_string (&item,

      gst_video_multiview_mode_to_caps_string (preferred_mode));

  gst_value_list_append_value (&list, &item);

  g_value_set_static_string (&item,

      gst_video_multiview_mode_to_caps_string (GST_VIDEO_MULTIVIEW_MODE_MONO));

  gst_value_list_append_value (&list, &item);

  gst_caps_set_value (templ_caps, "multiview-mode", &list);

  g_value_unset (&list);

  g_value_unset (&item);

  /* And intersect with the peer */

  if ((tmp = gst_pad_peer_query_caps (pad, NULL)) == NULL) {

    gst_caps_unref (templ_caps);

    return NULL;

  }

  outcaps = gst_caps_intersect_full (tmp, templ_caps, GST_CAPS_INTERSECT_FIRST);

  gst_caps_unref (tmp);

  gst_caps_unref (templ_caps);

  GST_DEBUG_OBJECT (split, "Src pad %" GST_PTR_FORMAT " caps %" GST_PTR_FORMAT,

      pad, outcaps);

  return outcaps;

}

static gboolean

stereosplit_set_output_caps (GstGLStereoSplit * split, GstCaps * sinkcaps)

{

  GstCaps *left = NULL, *right = NULL, *tridcaps = NULL;

  GstCaps *tmp, *combined;

  gboolean res = FALSE;

  /* Choose some preferred output caps.

   * Keep input width/height and PAR, preserve preferred output

   * multiview flags for flipping/flopping if any, and set each

   * left right pad to either left/mono and right/mono, as they prefer

   */

  /* Calculate what downstream can collectively support */

  left =

      stereosplit_get_src_caps (split, split->left_pad,

      GST_VIDEO_MULTIVIEW_MODE_LEFT);

  if (left == NULL)

    goto fail;

  right =

      stereosplit_get_src_caps (split, split->right_pad,

      GST_VIDEO_MULTIVIEW_MODE_RIGHT);

  if (right == NULL)

    goto fail;

  tridcaps = stereosplit_transform_caps (split, GST_PAD_SINK, sinkcaps, NULL);

  if (!tridcaps || gst_caps_is_empty (tridcaps)) {

    GST_ERROR_OBJECT (split,

        "Failed to transform input caps %" GST_PTR_FORMAT, sinkcaps);

    goto fail;

  }

  /* Preserve downstream preferred flipping/flopping */

  tmp =

      strip_mview_fields (gst_caps_ref (left),

      GST_VIDEO_MULTIVIEW_FLAGS_LEFT_FLIPPED |

      GST_VIDEO_MULTIVIEW_FLAGS_LEFT_FLOPPED);

  combined = gst_caps_intersect (tridcaps, tmp);

  gst_caps_unref (tridcaps);

  gst_caps_unref (tmp);

  tridcaps = combined;

  tmp =

      strip_mview_fields (gst_caps_ref (right),

      GST_VIDEO_MULTIVIEW_FLAGS_RIGHT_FLIPPED |

      GST_VIDEO_MULTIVIEW_FLAGS_RIGHT_FLOPPED);

  combined = gst_caps_intersect (tridcaps, tmp);

  gst_caps_unref (tridcaps);

  gst_caps_unref (tmp);

  tridcaps = combined;

  if (G_UNLIKELY (gst_caps_is_empty (tridcaps))) {

    gst_caps_unref (tridcaps);

    goto fail;

  }

  /* Now generate the version for each output pad */

  GST_DEBUG_OBJECT (split, "Attempting to set output caps %" GST_PTR_FORMAT,

      tridcaps);

  tmp = gst_caps_intersect (tridcaps, left);

  gst_caps_unref (left);

  left = tmp;

  left = gst_caps_fixate (left);

  if (!gst_pad_set_caps (split->left_pad, left)) {

    GST_ERROR_OBJECT (split,

        "Failed to set left output caps %" GST_PTR_FORMAT, left);

    goto fail;

  }

  tmp = gst_caps_intersect (tridcaps, right);

  gst_caps_unref (right);

  right = tmp;

  right = gst_caps_fixate (right);

  if (!gst_pad_set_caps (split->right_pad, right)) {

    GST_ERROR_OBJECT (split,

        "Failed to set right output caps %" GST_PTR_FORMAT, right);

    goto fail;

  }

  gst_gl_view_convert_set_context (split->viewconvert, split->context);

  tridcaps = gst_caps_make_writable (tridcaps);

  gst_caps_set_simple (tridcaps, "multiview-mode", G_TYPE_STRING,

      "separated", "views", G_TYPE_INT, 2, NULL);

  tridcaps = gst_caps_fixate (tridcaps);

  if (!gst_gl_view_convert_set_caps (split->viewconvert, sinkcaps, tridcaps)) {

    GST_ERROR_OBJECT (split, "Failed to set caps on converter");

    goto fail;

  }

  /* FIXME: Provide left and right caps to do_bufferpool */

  stereosplit_do_bufferpool (split, left);

  res = TRUE;

fail:

  if (left)

    gst_caps_unref (left);

  if (right)

    gst_caps_unref (right);

  if (tridcaps)

    gst_caps_unref (tridcaps);

  return res;

}

static gboolean

_find_local_gl_context (GstGLStereoSplit * split)

{

  if (gst_gl_query_local_gl_context (GST_ELEMENT (split), GST_PAD_SRC,

          &split->context))

    return TRUE;

  if (gst_gl_query_local_gl_context (GST_ELEMENT (split), GST_PAD_SINK,

          &split->context))

    return TRUE;

  return FALSE;

}

static gboolean

ensure_context (GstGLStereoSplit * self)

{

  GError *error = NULL;

  if (!gst_gl_ensure_element_data (self, &self->display, &self->other_context))

    return FALSE;

  gst_gl_display_filter_gl_api (self->display, SUPPORTED_GL_APIS);

  _find_local_gl_context (self);

  if (!self->context) {

    GST_OBJECT_LOCK (self->display);

    do {

      if (self->context)

        gst_object_unref (self->context);

      /* just get a GL context.  we don't care */

      self->context =

          gst_gl_display_get_gl_context_for_thread (self->display, NULL);

      if (!self->context) {

        if (!gst_gl_display_create_context (self->display, self->other_context,

                &self->context, &error)) {

          GST_OBJECT_UNLOCK (self->display);

          goto context_error;

        }

      }

    } while (!gst_gl_display_add_context (self->display, self->context));

    GST_OBJECT_UNLOCK (self->display);

  }

  {

    GstGLAPI current_gl_api = gst_gl_context_get_gl_api (self->context);

    if ((current_gl_api & (SUPPORTED_GL_APIS)) == 0)

      goto unsupported_gl_api;

  }

  return TRUE;

unsupported_gl_api:

  {

    GstGLAPI gl_api = gst_gl_context_get_gl_api (self->context);

    gchar *gl_api_str = gst_gl_api_to_string (gl_api);

    gchar *supported_gl_api_str = gst_gl_api_to_string (SUPPORTED_GL_APIS);

    GST_ELEMENT_ERROR (self, RESOURCE, BUSY,

        ("GL API's not compatible context: %s supported: %s", gl_api_str,

            supported_gl_api_str), (NULL));

    g_free (supported_gl_api_str);

    g_free (gl_api_str);

    return FALSE;

  }

context_error:

  {

    GST_ELEMENT_ERROR (self, RESOURCE, NOT_FOUND, ("%s", error->message),

        (NULL));

    g_clear_error (&error);

    return FALSE;

  }

}

static gboolean

stereosplit_decide_allocation (GstGLStereoSplit * self, GstQuery * query)

{

  if (!ensure_context (self))

    return FALSE;

  return TRUE;

}

static gboolean

stereosplit_propose_allocation (GstGLStereoSplit * self, GstQuery * query)

{

  if (!gst_gl_ensure_element_data (self, &self->display, &self->other_context))

    return FALSE;

  return TRUE;

}

static gboolean

stereosplit_do_bufferpool (GstGLStereoSplit * self, GstCaps * caps)

{

  GstQuery *query;

  query = gst_query_new_allocation (caps, TRUE);

  if (!gst_pad_peer_query (self->left_pad, query)) {

    if (!gst_pad_peer_query (self->right_pad, query)) {

      GST_DEBUG_OBJECT (self, "peer ALLOCATION query failed on both src pads");

    }

  }

  if (!stereosplit_decide_allocation (self, query)) {

    gst_query_unref (query);

    return FALSE;

  }

  gst_query_unref (query);

  return TRUE;

}

static GstFlowReturn

stereosplit_chain (GstPad * pad, GstGLStereoSplit * split, GstBuffer * buf)

{

  GstBuffer *left, *right;

  GstBuffer *split_buffer = NULL;

  GstFlowReturn ret;

  gint i, n_planes;

  n_planes = GST_VIDEO_INFO_N_PLANES (&split->viewconvert->out_info);

  GST_LOG_OBJECT (split, "chaining buffer %" GST_PTR_FORMAT, buf);

  if (gst_gl_view_convert_submit_input_buffer (split->viewconvert,

          GST_BUFFER_IS_DISCONT (buf), buf) != GST_FLOW_OK) {

    GST_ELEMENT_ERROR (split, RESOURCE, NOT_FOUND, ("%s",

            "Failed to 3d convert buffer"),

        ("Could not get submit input buffer"));

    return GST_FLOW_ERROR;

  }

  ret = gst_gl_view_convert_get_output (split->viewconvert, &split_buffer);

  if (ret != GST_FLOW_OK) {

    GST_ELEMENT_ERROR (split, RESOURCE, NOT_FOUND, ("%s",

            "Failed to 3d convert buffer"), ("Could not get output buffer"));

    return GST_FLOW_ERROR;

  }

  if (split_buffer == NULL)

    return GST_FLOW_OK;         /* Need another input buffer */

  left = gst_buffer_new ();

  gst_buffer_copy_into (left, buf,

      GST_BUFFER_COPY_FLAGS | GST_BUFFER_COPY_TIMESTAMPS, 0, -1);

  GST_BUFFER_FLAG_UNSET (left, GST_VIDEO_BUFFER_FLAG_FIRST_IN_BUNDLE);

  gst_buffer_add_parent_buffer_meta (left, split_buffer);

  for (i = 0; i < n_planes; i++) {

    GstMemory *mem = gst_buffer_get_memory (split_buffer, i);

    gst_buffer_append_memory (left, mem);

  }

  ret = gst_pad_push (split->left_pad, gst_buffer_ref (left));

  /* Allow unlinked on the first pad - as long as the 2nd isn't unlinked */

  gst_buffer_unref (left);

  if (G_UNLIKELY (ret != GST_FLOW_OK && ret != GST_FLOW_NOT_LINKED)) {

    gst_buffer_unref (split_buffer);

    return ret;

  }

  right = gst_buffer_new ();

  gst_buffer_copy_into (right, buf,

      GST_BUFFER_COPY_FLAGS | GST_BUFFER_COPY_TIMESTAMPS, 0, -1);

  GST_BUFFER_FLAG_UNSET (left, GST_VIDEO_BUFFER_FLAG_FIRST_IN_BUNDLE);

  gst_buffer_add_parent_buffer_meta (right, split_buffer);

  for (i = n_planes; i < n_planes * 2; i++) {

    GstMemory *mem = gst_buffer_get_memory (split_buffer, i);

    gst_buffer_append_memory (right, mem);

  }

  ret = gst_pad_push (split->right_pad, gst_buffer_ref (right));

  gst_buffer_unref (right);

  gst_buffer_unref (split_buffer);

  return ret;

}

static gboolean

stereosplit_src_query (GstPad * pad, GstObject * parent, GstQuery * query)

{

  GstGLStereoSplit *split = GST_GL_STEREOSPLIT (parent);

  switch (GST_QUERY_TYPE (query)) {

    case GST_QUERY_CONTEXT:

    {

      if (gst_gl_handle_context_query ((GstElement *) split, query,

              split->display, split->context, split->other_context))

        return TRUE;

      return gst_pad_query_default (pad, parent, query);

    }

      /* FIXME: Handle caps query */

    default:

      return gst_pad_query_default (pad, parent, query);

  }

}

static gboolean

stereosplit_src_event (GstPad * pad, GstObject * parent, GstEvent * event)

{

  return gst_pad_event_default (pad, parent, event);

}

static gboolean

stereosplit_sink_query (GstPad * pad, GstObject * parent, GstQuery * query)

{

  GstGLStereoSplit *split = GST_GL_STEREOSPLIT (parent);

  GST_DEBUG_OBJECT (split, "sink query %s",

      gst_query_type_get_name (GST_QUERY_TYPE (query)));

  switch (GST_QUERY_TYPE (query)) {

    case GST_QUERY_CONTEXT:

    {

      if (gst_gl_handle_context_query ((GstElement *) split, query,

              split->display, split->context, split->other_context))

        return TRUE;

      return gst_pad_query_default (pad, parent, query);

    }

    case GST_QUERY_ALLOCATION:

    {

      return stereosplit_propose_allocation (split, query);

    }

    case GST_QUERY_ACCEPT_CAPS:

    {

      GstCaps *possible, *caps;

      gboolean allowed;

      gst_query_parse_accept_caps (query, &caps);

      if (!(possible = gst_pad_query_caps (split->sink_pad, caps)))

        return FALSE;

      allowed = gst_caps_is_subset (caps, possible);

      gst_caps_unref (possible);

      gst_query_set_accept_caps_result (query, allowed);

      return allowed;

    }

    case GST_QUERY_CAPS:

    {

      GstCaps *filter, *left, *right, *combined, *ret, *templ_caps;

      gst_query_parse_caps (query, &filter);

      /* Calculate what downstream can collectively support */

      if (!(left = gst_pad_peer_query_caps (split->left_pad, NULL)))

        return FALSE;

      if (!(right = gst_pad_peer_query_caps (split->right_pad, NULL)))

        return FALSE;

      /* Strip out multiview mode and flags that might break the

       * intersection, since we can convert.

       * We could keep downstream preferred flip/flopping and list

       * separated as preferred in the future which might

       * theoretically allow us an easier conversion, but it's not essential

       */

      left = strip_mview_fields (left, GST_VIDEO_MULTIVIEW_FLAGS_NONE);

      right = strip_mview_fields (right, GST_VIDEO_MULTIVIEW_FLAGS_NONE);

      combined = gst_caps_intersect (left, right);

      gst_caps_unref (left);

      gst_caps_unref (right);

      /* Intersect peer caps with our template formats */

      templ_caps = gst_pad_get_pad_template_caps (split->left_pad);

      ret =

          gst_caps_intersect_full (combined, templ_caps,

          GST_CAPS_INTERSECT_FIRST);

      gst_caps_unref (templ_caps);

      gst_caps_unref (combined);

      combined = ret;

      if (!combined || gst_caps_is_empty (combined)) {

        gst_caps_unref (combined);

        return FALSE;

      }

      /* Convert from the src pad caps to input formats we support */

      ret = stereosplit_transform_caps (split, GST_PAD_SRC, combined, filter);

      gst_caps_unref (combined);

      combined = ret;

      /* Intersect with the sink pad template then */

      templ_caps = gst_pad_get_pad_template_caps (split->sink_pad);

      ret =

          gst_caps_intersect_full (combined, templ_caps,

          GST_CAPS_INTERSECT_FIRST);

      gst_caps_unref (templ_caps);

      GST_LOG_OBJECT (split, "Returning sink pad caps %" GST_PTR_FORMAT, ret);

      gst_query_set_caps_result (query, ret);

      return !gst_caps_is_empty (ret);

    }

    default:

      return gst_pad_query_default (pad, parent, query);

  }

}

static gboolean

stereosplit_sink_event (GstPad * pad, GstObject * parent, GstEvent * event)

{

  GstGLStereoSplit *split = GST_GL_STEREOSPLIT (parent);

  switch (GST_EVENT_TYPE (event)) {

    case GST_EVENT_CAPS:

    {

      GstCaps *caps;

      gst_event_parse_caps (event, &caps);

      return stereosplit_set_output_caps (split, caps);

    }

    default:

      return gst_pad_event_default (pad, parent, event);

  }

}