[longomatch] Select the highest resolution from the camera

[Andoni Morales Alastruey <amorales src gnome org>]

commit a6422f1765b5a4cd0d2bf7df602c5b7921fe5272
Author: Andoni Morales Alastruey <ylatuya gmail com>
Date:   Sat Dec 13 01:46:00 2014 +0100

    Select the highest resolution from the camera
    
    Some capture devices like the AVermedia Extreamcap U3
    do not downscale correctly so we pick the highest resolution
    and scale in software if needed downstream.

 libcesarplayer/gst-camera-capturer.c |   78 ++++++++++++++++++++++------------
 1 files changed, 51 insertions(+), 27 deletions(-)
---
diff --git a/libcesarplayer/gst-camera-capturer.c b/libcesarplayer/gst-camera-capturer.c
index df7a731..9a5ebd3 100644
--- a/libcesarplayer/gst-camera-capturer.c
+++ b/libcesarplayer/gst-camera-capturer.c
@@ -1008,11 +1008,40 @@ gst_camera_capturer_have_type_cb (GstElement * typefind, guint prob,
   return TRUE;
 }
 
+static GstCaps *
+gst_camera_capturer_find_highest_res (GstCaps *caps)
+{
+  gint max_width = 0, max_height = 0, i = 0;
+  gint width, height;
+  gchar *caps_str;
+  GstCaps *rcaps;
+
+  for (i=0; i < gst_caps_get_size (caps); i++) {
+    GstStructure *s = gst_caps_get_structure (caps, i);
+    gst_structure_get_int (s, "width", &width);
+    gst_structure_get_int (s, "height", &height);
+    if (width + height > max_width + max_height) {
+      max_width = width;
+      max_height = height;
+    }
+  }
+  caps_str = g_strdup_printf ("video/x-raw-yuv, width=%d, height=%d;"
+      "video/x-raw-rgb, width=%d, height=%d;"
+      "video/x-dv, systemstream=true, width=%d, height=%d",
+      max_width, max_height, max_width, max_height, max_width, max_height);
+  rcaps = gst_caps_from_string (caps_str);
+  g_free (caps_str);
+  return rcaps;
+}
+
 static gboolean
 gst_camera_capturer_create_video_source (GstCameraCapturer * gcc,
     CaptureSourceType type, GError ** err)
 {
-  GstElement *typefind;
+  GstElement *bin;
+  GstElement *typefind, *source;
+  GstCaps *source_caps, *link_caps;
+  GstPad *source_pad;
   gchar *source_str;
   gchar *filter = "";
 
@@ -1042,24 +1071,9 @@ gst_camera_capturer_create_video_source (GstCameraCapturer * gcc,
       g_assert_not_reached ();
   }
 
-  /* HACK: dshowvideosrc's device must be set before linking the element
-   * since the device is set in getcaps and can't be changed later */
-  if (!g_strcmp0 (gcc->priv->source_element_name, "dshowvideosrc")) {
-    source_str = g_strdup_printf ("%s device-name=\"%s\" name=source ! "
-        "video/x-raw-yuv; video/x-raw-rgb; "
-        "video/x-dv, systemstream=(boolean)True "
-        "! typefind name=typefind", gcc->priv->source_element_name,
-        gcc->priv->device_id);
-  } else {
-    source_str = g_strdup_printf ("%s name=source %s ! typefind name=typefind",
-        gcc->priv->source_element_name, filter);
-  }
-
-  GST_INFO_OBJECT (gcc, "Created video source %s", source_str);
-  gcc->priv->source_bin =
-      gst_parse_bin_from_description (source_str, TRUE, NULL);
-  g_free (source_str);
-  if (!gcc->priv->source_bin) {
+  gcc->priv->source_bin = bin = gst_bin_new ("source");
+  gcc->priv->source = source = gst_element_factory_make (gcc->priv->source_element_name, "video-source");
+  if (!source) {
     g_set_error (err,
         GCC_ERROR,
         GST_ERROR_PLUGIN_LOAD,
@@ -1068,21 +1082,31 @@ gst_camera_capturer_create_video_source (GstCameraCapturer * gcc,
         gcc->priv->source_element_name);
     return FALSE;
   }
+  typefind = gst_element_factory_make ("typefind", "video-source-typefind");
+  gst_bin_add_many (GST_BIN(bin), source, typefind, NULL);
+  source_pad = gst_element_get_static_pad (typefind, "src");
+  gst_element_add_pad (bin, gst_ghost_pad_new ("src", source_pad));
+  gst_object_unref (source_pad);
+
+  /* dshowvideosrc's device must be set before linking the element
+   * since the device is set in getcaps and can't be changed later */
+  gst_camera_capturer_update_device_id (gcc);
 
-  gcc->priv->source =
-      gst_bin_get_by_name (GST_BIN (gcc->priv->source_bin), "source");
-  typefind = gst_bin_get_by_name (GST_BIN (gcc->priv->source_bin), "typefind");
+  /* Some capture devices like the Extremecap U3 don't downscale correctly.
+   * Choose the highest resolution and downscale later if needed */
+  source_pad = gst_element_get_static_pad (source, "src");
+  source_caps = gst_pad_get_caps_reffed (source_pad);
+  link_caps = gst_camera_capturer_find_highest_res (source_caps);
+  gst_object_unref (source_pad);
+  gst_caps_unref (source_caps);
+
+  gst_element_link_filtered (source, typefind, link_caps);
   g_signal_connect (typefind, "have-type",
       G_CALLBACK (gst_camera_capturer_have_type_cb), gcc);
 
-  gst_camera_capturer_update_device_id (gcc);
-
   GST_INFO_OBJECT (gcc, "Created video source %s",
       gcc->priv->source_element_name);
 
-  gst_object_unref (gcc->priv->source);
-  gst_object_unref (typefind);
-
   return TRUE;
 }