exiftag: handle GST_TAG_CAPTURING_LIGHT_SOURCE tag

This exif tag allows to specify the different light conditions
when taking a picture. This tag is defined in:
https://exiftool.org/TagNames/EXIF.html#LightSource

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5571>

girs/GstTag-1.0.gir

@@ -151,6 +151,35 @@ The allowed values are:
       <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/tag/tag.h"/>
       <type name="utf8" c:type="gchar*"/>
     </constant>
+    <constant name="TAG_CAPTURING_LIGHT_SOURCE" value="capturing-light-source" c:type="GST_TAG_CAPTURING_LIGHT_SOURCE" version="1.26">
+      <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/tag/tag.h">Light source used when capturing an image. (string)
+
+The allowed values are:
+  "unknown"
+  "daylight"
+  "fluorescent"
+  "tungsten"
+  "flash"
+  "fine-weather"
+  "cloudy-weather"
+  "shade"
+  "daylight-fluorescent"
+  "day-white-fluorescent"
+  "cool-white-fluorescent"
+  "white-fluorescent"
+  "warm-white-fluorescent"
+  "standard-light-A"
+  "standard-light-B"
+  "standard-light-C"
+  "D55"
+  "D65"
+  "D75"
+  "D50"
+  "iso-studio-tungsten"
+  "other"</doc>
+      <source-position filename="../subprojects/gst-plugins-base/gst-libs/gst/tag/tag.h"/>
+      <type name="utf8" c:type="gchar*"/>
+    </constant>
     <constant name="TAG_CAPTURING_METERING_MODE" value="capturing-metering-mode" c:type="GST_TAG_CAPTURING_METERING_MODE">
       <doc xml:space="preserve" filename="../subprojects/gst-plugins-base/gst-libs/gst/tag/tag.h">Defines the way a camera determines the exposure. (string)
 

subprojects/gst-plugins-bad/tests/check/elements/jifmux.c

@@ -201,6 +201,63 @@ end:
   return -1;
 }
 
+static gint
+__exif_tag_capture_light_source_to_exif_value (const gchar * str)
+{
+  if (str == NULL) {
+    GST_WARNING ("Invalid light source: NULL");
+    return -1;
+  }
+
+  if (strcmp (str, "unknown") == 0)
+    return 0;
+  else if (strcmp (str, "daylight") == 0)
+    return 1;
+  else if (strcmp (str, "flourescent") == 0)
+    return 2;
+  else if (strcmp (str, "tungsten") == 0)
+    return 3;
+  else if (strcmp (str, "flash") == 0)
+    return 4;
+  else if (strcmp (str, "fine-weather") == 0)
+    return 9;
+  else if (strcmp (str, "cloudy-weather") == 0)
+    return 10;
+  else if (strcmp (str, "shade") == 0)
+    return 11;
+  else if (strcmp (str, "daylight-fluorescent") == 0)
+    return 12;
+  else if (strcmp (str, "day-white-fluorescent") == 0)
+    return 13;
+  else if (strcmp (str, "cool-white-fluorescent") == 0)
+    return 14;
+  else if (strcmp (str, "white-fluorescent") == 0)
+    return 15;
+  else if (strcmp (str, "warm-white-fluorescent") == 0)
+    return 16;
+  else if (strcmp (str, "standard-light-A") == 0)
+    return 17;
+  else if (strcmp (str, "standard-light-B") == 0)
+    return 18;
+  else if (strcmp (str, "standard-light-C") == 0)
+    return 19;
+  else if (strcmp (str, "D55") == 0)
+    return 20;
+  else if (strcmp (str, "D65") == 0)
+    return 21;
+  else if (strcmp (str, "D75") == 0)
+    return 22;
+  else if (strcmp (str, "D50") == 0)
+    return 23;
+  else if (strcmp (str, "iso-studio-tungsten") == 0)
+    return 24;
+  else if (strcmp (str, "other") == 0)
+    return 255;
+
+  GST_WARNING ("Invalid light source: %s", str);
+  return -1;
+}
+
 static gint
 __exif_tag_capture_contrast_to_exif_value (const gchar * str)
 {
@@ -347,6 +404,8 @@ GST_COMPARE_GST_STRING_TAG_TO_EXIF_SHORT_FUNC (GST_TAG_CAPTURING_EXPOSURE_MODE,
     capture_exposure_mode);
 GST_COMPARE_GST_STRING_TAG_TO_EXIF_SHORT_FUNC (GST_TAG_CAPTURING_WHITE_BALANCE,
     capture_white_balance);
+GST_COMPARE_GST_STRING_TAG_TO_EXIF_SHORT_FUNC (GST_TAG_CAPTURING_LIGHT_SOURCE,
+    capture_light_source);
 GST_COMPARE_GST_STRING_TAG_TO_EXIF_SHORT_FUNC (GST_TAG_CAPTURING_CONTRAST,
     capture_contrast);
 GST_COMPARE_GST_STRING_TAG_TO_EXIF_SHORT_FUNC
@@ -631,6 +690,8 @@ static const GstExifTagMatch tag_map[] = {
       compare_capture_exposure_mode},
   {GST_TAG_CAPTURING_WHITE_BALANCE, EXIF_TAG_WHITE_BALANCE, EXIF_TYPE_SHORT,
       compare_capture_white_balance},
+  {GST_TAG_CAPTURING_LIGHT_SOURCE, EXIF_TAG_LIGHT_SOURCE, EXIF_TYPE_SHORT,
+      compare_capture_light_source},
   {GST_TAG_CAPTURING_DIGITAL_ZOOM_RATIO, EXIF_TAG_DIGITAL_ZOOM_RATIO,
       EXIF_TYPE_RATIONAL, NULL},
   {GST_TAG_CAPTURING_SCENE_CAPTURE_TYPE, EXIF_TAG_SCENE_CAPTURE_TYPE,
@@ -1145,6 +1206,55 @@ GST_START_TEST (test_jifmux_tags)
   generate_jif_file_with_tags (WHITE_BALANCE_TAG ("manual"), tmpfile);
   libexif_check_tags (WHITE_BALANCE_TAG ("manual"), tmpfile);
 
+#define LIGHT_SOURCE_TAG(t) "taglist," GST_TAG_CAPTURING_LIGHT_SOURCE "=" t
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("unknown"), tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("unknown"), tmpfile);
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("daylight"), tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("daylight"), tmpfile);
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("flourescent"), tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("flourescent"), tmpfile);
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("tungsten"), tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("tungsten"), tmpfile);
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("flash"), tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("flash"), tmpfile);
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("fine-weather"), tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("fine-weather"), tmpfile);
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("cloudy-weather"), tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("cloudy-weather"), tmpfile);
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("shade"), tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("shade"), tmpfile);
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("daylight-fluorescent"),
+      tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("daylight-fluorescent"), tmpfile);
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("day-white-fluorescent"),
+      tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("day-white-fluorescent"), tmpfile);
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("cool-white-fluorescent"),
+      tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("cool-white-fluorescent"), tmpfile);
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("white-fluorescent"), tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("white-fluorescent"), tmpfile);
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("warm-white-fluorescent"),
+      tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("warm-white-fluorescent"), tmpfile);
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("standard-light-A"), tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("standard-light-A"), tmpfile);
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("standard-light-B"), tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("standard-light-B"), tmpfile);
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("standard-light-C"), tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("standard-light-C"), tmpfile);
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("D55"), tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("D55"), tmpfile);
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("D65"), tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("D65"), tmpfile);
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("D75"), tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("D75"), tmpfile);
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("iso-studio-tungsten"),
+      tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("iso-studio-tungsten"), tmpfile);
+  generate_jif_file_with_tags (LIGHT_SOURCE_TAG ("other"), tmpfile);
+  libexif_check_tags (LIGHT_SOURCE_TAG ("other"), tmpfile);
+
 #define GAIN_ADJUSTMENT_TAG(t) "taglist," GST_TAG_CAPTURING_GAIN_ADJUSTMENT "=" t
   generate_jif_file_with_tags (GAIN_ADJUSTMENT_TAG ("none"), tmpfile);
   libexif_check_tags (GAIN_ADJUSTMENT_TAG ("none"), tmpfile);

subprojects/gst-plugins-base/gst-libs/gst/tag/gstexiftag.c

@@ -279,6 +279,7 @@ EXIF_SERIALIZATION_DESERIALIZATION_FUNC (shutter_speed);
 EXIF_SERIALIZATION_DESERIALIZATION_FUNC (source);
 EXIF_SERIALIZATION_DESERIALIZATION_FUNC (speed);
 EXIF_SERIALIZATION_DESERIALIZATION_FUNC (white_balance);
+EXIF_SERIALIZATION_DESERIALIZATION_FUNC (light_source);
 
 EXIF_DESERIALIZATION_FUNC (resolution);
 EXIF_DESERIALIZATION_FUNC (add_to_pending_tags);
@@ -330,6 +331,7 @@ EXIF_DESERIALIZATION_FUNC (add_to_pending_tags);
 #define EXIF_TAG_SCENE_TYPE 0xA301
 #define EXIF_TAG_EXPOSURE_MODE 0xA402
 #define EXIF_TAG_WHITE_BALANCE 0xA403
+#define EXIF_TAG_LIGHT_SOURCE 0x9208
 #define EXIF_TAG_DIGITAL_ZOOM_RATIO 0xA404
 #define EXIF_TAG_FOCAL_LENGTH_IN_35_MM_FILM 0xa405
 #define EXIF_TAG_SCENE_CAPTURE_TYPE 0xA406
@@ -429,6 +431,8 @@ static const GstExifTagMatch tag_map_exif[] = {
       0, serialize_exposure_mode, deserialize_exposure_mode},
   {GST_TAG_CAPTURING_WHITE_BALANCE, EXIF_TAG_WHITE_BALANCE, EXIF_TYPE_SHORT,
       0, serialize_white_balance, deserialize_white_balance},
+  {GST_TAG_CAPTURING_LIGHT_SOURCE, EXIF_TAG_LIGHT_SOURCE, EXIF_TYPE_SHORT,
+      0, serialize_light_source, deserialize_light_source},
   {GST_TAG_CAPTURING_DIGITAL_ZOOM_RATIO, EXIF_TAG_DIGITAL_ZOOM_RATIO,
         EXIF_TYPE_RATIONAL, 0, NULL,
       NULL},
@@ -2125,6 +2129,8 @@ EXIF_SERIALIZATION_DESERIALIZATION_MAP_STRING_TO_INT_FUNC (source,
     capturing_source);
 EXIF_SERIALIZATION_DESERIALIZATION_MAP_STRING_TO_INT_FUNC (white_balance,
     capturing_white_balance);
+EXIF_SERIALIZATION_DESERIALIZATION_MAP_STRING_TO_INT_FUNC (light_source,
+    capturing_light_source);
 
 static void
 serialize_geo_coordinate (GstExifWriter * writer, const GstTagList * taglist,

subprojects/gst-plugins-base/gst-libs/gst/tag/gsttageditingprivate.c

@@ -280,6 +280,115 @@ __exif_tag_capturing_white_balance_from_exif_value (gint value)
   }
 }
 
+gint
+__exif_tag_capturing_light_source_to_exif_value (const gchar * str)
+{
+  if (str == NULL) {
+    GST_WARNING ("Invalid light source: NULL");
+    return -1;
+  }
+
+  if (strcmp (str, "unknown") == 0)
+    return 0;
+  else if (strcmp (str, "daylight") == 0)
+    return 1;
+  else if (strcmp (str, "flourescent") == 0)
+    return 2;
+  else if (strcmp (str, "tungsten") == 0)
+    return 3;
+  else if (strcmp (str, "flash") == 0)
+    return 4;
+  else if (strcmp (str, "fine-weather") == 0)
+    return 9;
+  else if (strcmp (str, "cloudy-weather") == 0)
+    return 10;
+  else if (strcmp (str, "shade") == 0)
+    return 11;
+  else if (strcmp (str, "daylight-fluorescent") == 0)
+    return 12;
+  else if (strcmp (str, "day-white-fluorescent") == 0)
+    return 13;
+  else if (strcmp (str, "cool-white-fluorescent") == 0)
+    return 14;
+  else if (strcmp (str, "white-fluorescent") == 0)
+    return 15;
+  else if (strcmp (str, "warm-white-fluorescent") == 0)
+    return 16;
+  else if (strcmp (str, "standard-light-A") == 0)
+    return 17;
+  else if (strcmp (str, "standard-light-B") == 0)
+    return 18;
+  else if (strcmp (str, "standard-light-C") == 0)
+    return 19;
+  else if (strcmp (str, "D55") == 0)
+    return 20;
+  else if (strcmp (str, "D65") == 0)
+    return 21;
+  else if (strcmp (str, "D75") == 0)
+    return 22;
+  else if (strcmp (str, "D50") == 0)
+    return 23;
+  else if (strcmp (str, "iso-studio-tungsten") == 0)
+    return 24;
+  else if (strcmp (str, "other") == 0)
+    return 255;
+
+  GST_WARNING ("Invalid light source: %s", str);
+  return -1;
+}
+
+const gchar *
+__exif_tag_capturing_light_source_from_exif_value (gint value)
+{
+  switch (value) {
+    case 0:
+      return "unknown";
+    case 1:
+      return "daylight";
+    case 2:
+      return "flourescent";
+    case 4:
+      return "flash";
+    case 9:
+      return "fine-weather";
+    case 10:
+      return "cloudy-weather";
+    case 11:
+      return "shade";
+    case 12:
+      return "daylight-fluorescent";
+    case 13:
+      return "day-white-fluorescent";
+    case 14:
+      return "cool-white-fluorescent";
+    case 15:
+      return "white-fluorescent";
+    case 16:
+      return "warm-white-fluorescent";
+    case 17:
+      return "standard-light-A";
+    case 18:
+      return "standard-light-B";
+    case 19:
+      return "standard-light-C";
+    case 20:
+      return "D55";
+    case 21:
+      return "D65";
+    case 22:
+      return "D75";
+    case 23:
+      return "D50";
+    case 24:
+      return "iso-studio-tungsten";
+    case 255:
+      return "other";
+    default:
+      GST_WARNING ("Invalid light source type: %d", value);
+      return NULL;
+  }
+}
+
 static gint
 __exif_tag_capturing_contrast_sharpness_to_exif_value (const gchar * str,
     const gchar * tag_name)

subprojects/gst-plugins-base/gst-libs/gst/tag/gsttageditingprivate.h

@@ -53,6 +53,9 @@ const gchar * __exif_tag_capturing_gain_adjustment_from_exif_value (gint value);
 gint __exif_tag_capturing_white_balance_to_exif_value (const gchar * str);
 const gchar * __exif_tag_capturing_white_balance_from_exif_value (gint value);
 
+int __exif_tag_capturing_light_source_to_exif_value (const gchar * str);
+const gchar * __exif_tag_capturing_light_source_from_exif_value (gint value);
+
 gint __exif_tag_capturing_contrast_to_exif_value (const gchar * str);
 const gchar * __exif_tag_capturing_contrast_from_exif_value (gint value);
 

subprojects/gst-plugins-base/gst-libs/gst/tag/tag.h

@@ -296,6 +296,39 @@ G_BEGIN_DECLS
  */
 #define GST_TAG_CAPTURING_WHITE_BALANCE       "capturing-white-balance"
 
+/**
+ * GST_TAG_CAPTURING_LIGHT_SOURCE:
+ *
+ * Light source used when capturing an image. (string)
+ *
+ * The allowed values are:
+ *   "unknown"
+ *   "daylight"
+ *   "fluorescent"
+ *   "tungsten"
+ *   "flash"
+ *   "fine-weather"
+ *   "cloudy-weather"
+ *   "shade"
+ *   "daylight-fluorescent"
+ *   "day-white-fluorescent"
+ *   "cool-white-fluorescent"
+ *   "white-fluorescent"
+ *   "warm-white-fluorescent"
+ *   "standard-light-A"
+ *   "standard-light-B"
+ *   "standard-light-C"
+ *   "D55"
+ *   "D65"
+ *   "D75"
+ *   "D50"
+ *   "iso-studio-tungsten"
+ *   "other"
+ *
+ * Since: 1.26
+ */
+#define GST_TAG_CAPTURING_LIGHT_SOURCE        "capturing-light-source"
+
 /**
  * GST_TAG_CAPTURING_CONTRAST:
  *

subprojects/gst-plugins-base/gst-libs/gst/tag/tags.c

@@ -165,6 +165,11 @@ gst_tag_register_tags_internal (gpointer unused)
       G_TYPE_STRING, _("capturing white balance"),
       _("The white balance mode set when capturing an image"), NULL);
 
+  gst_tag_register_static (GST_TAG_CAPTURING_LIGHT_SOURCE, GST_TAG_FLAG_META,
+      G_TYPE_STRING, _("capturing light source"),
+      _("The light source indicates the kind of light when capturing an"
+          "image"), NULL);
+
   gst_tag_register_static (GST_TAG_CAPTURING_CONTRAST, GST_TAG_FLAG_META,
       G_TYPE_STRING, _("capturing contrast"),
       _("The direction of contrast processing applied "