pbutils: add H.264 profile/level extraction functions to codec utils

This adds code to parse the first few bytes of H.264 sequence parameter
set in order to extract the profile and level as const strings. This
code was originally in both qtdemux and matroskademux.

https://bugzilla.gnome.org/show_bug.cgi?id=617314

API: gst_codec_utils_h264_get_level()
API: gst_codec_utils_h264_get_profile()
API: gst_codec_utils_h264_caps_set_level_and_profile()

diff --git a/gst-libs/gst/pbutils/codec-utils.c b/gst-libs/gst/pbutils/codec-utils.c
index 412ca65..700a619 100644 (file)
--- a/gst-libs/gst/pbutils/codec-utils.c
+++ b/gst-libs/gst/pbutils/codec-utils.c
@@ -40,6 +40,19 @@
 #define GST_SIMPLE_CAPS_HAS_FIELD(caps,field) \
     gst_structure_has_field(gst_caps_get_structure((caps),0),(field))
 
+static const gchar *
+digit_to_string (guint digit)
+{
+  static const char itoa[][2] = {
+    "0", "1", "2", "3", "4", "5", "6", "7", "8", "9"
+  };
+
+  if (G_LIKELY (digit < 10))
+    return itoa[digit];
+  else
+    return NULL;
+}
+
 /**
  * gst_codec_utils_aac_get_sample_rate_from_index:
  * @sr_idx: Sample rate index as from the AudioSpecificConfig (MPEG-4
@@ -285,13 +298,7 @@ gst_codec_utils_aac_get_level (const guint8 * audio_config, guint len)
         rcu);
     return NULL;
   } else {
-    /* For fast and convenient int -> string conversion */
-    static const char itoa[][2] = {
-      "0", "1", "2", "3", "4", "5", "6", "7", "8", "9"
-    };
-
-    g_assert (ret < G_N_ELEMENTS (itoa));
-    return itoa[ret];
+    return digit_to_string (ret);
   }
 }
 
@@ -348,3 +355,174 @@ gst_codec_utils_aac_caps_set_level_and_profile (GstCaps * caps,
 
   return (level != NULL && profile != NULL);
 }
+
+/**
+ * gst_codec_utils_h264_get_profile:
+ * @sps: Pointer to the sequence parameter set for the stream.
+ * @len: Length of the data available in @sps.
+ *
+ * Converts the profile indication (<tt>profile_idc</tt>) in the stream's
+ * sequence parameter set into a string. The SPS is expected to have the
+ * following format, as defined in the H.264 specification. The SPS is viewed
+ * as a bitstream here, with bit 0 being the most significant bit of the first
+ * byte.
+ *
+ * Bit 0:7   - Profile indication
+ * Bit 8     - constraint_set0_flag
+ * Bit 9     - constraint_set1_flag
+ * Bit 10    - constraint_set2_flag
+ * Bit 11    - constraint_set3_flag
+ * Bit 12    - constraint_set3_flag
+ * Bit 13:15 - Reserved
+ * Bit 16:24 - Level indication
+ *
+ * Returns: The profile as a const string, or NULL if there is an error.
+ */
+const gchar *
+gst_codec_utils_h264_get_profile (const guint8 * sps, guint len)
+{
+  const gchar *profile = NULL;
+  gint csf1, csf3;
+
+  g_return_val_if_fail (sps != NULL, NULL);
+
+  if (len < 2)
+    return NULL;
+
+  csf1 = (sps[1] & 0x40) >> 6;
+  csf3 = (sps[1] & 0x10) >> 4;
+
+  switch (sps[0]) {
+    case 66:
+      if (csf1)
+        profile = "constrained-baseline";
+      else
+        profile = "baseline";
+      break;
+    case 77:
+      profile = "main";
+      break;
+    case 88:
+      profile = "extended";
+      break;
+    case 100:
+      profile = "high";
+      break;
+    case 110:
+      if (csf3)
+        profile = "high-10-intra";
+      else
+        profile = "high-10";
+      break;
+    case 122:
+      if (csf3)
+        profile = "high-4:2:2-intra";
+      else
+        profile = "high-4:2:2";
+      break;
+    case 244:
+      if (csf3)
+        profile = "high-4:4:4-intra";
+      else
+        profile = "high-4:4:4";
+      break;
+    case 44:
+      profile = "cavlc-4:4:4-intra";
+      break;
+    default:
+      return NULL;
+  }
+
+  return profile;
+}
+
+/**
+ * gst_codec_utils_h264_get_level:
+ * @sps: Pointer to the sequence parameter set for the stream.
+ * @len: Length of the data available in @sps.
+ *
+ * Converts the level indication (<tt>level_idc</tt>) in the stream's
+ * sequence parameter set into a string. The SPS is expected to have the
+ * same format as for @gst_codec_utils_aac_get_profile().
+ *
+ * Returns: The level as a const string, or NULL if there is an error.
+ */
+const gchar *
+gst_codec_utils_h264_get_level (const guint8 * sps, guint len)
+{
+  gint csf3;
+
+  g_return_val_if_fail (sps != NULL, NULL);
+
+  if (len < 3)
+    return NULL;
+
+  csf3 = (sps[1] & 0x10) >> 4;
+
+  if (sps[2] == 11 && csf3)
+    return "1b";
+  else if (sps[2] % 10 == 0)
+    return digit_to_string (sps[2] / 10);
+  else {
+    switch (sps[2]) {
+      case 11:
+        return "1.1";
+      case 12:
+        return "1.2";
+      case 13:
+        return "1.3";
+      case 21:
+        return "2.1";
+      case 22:
+        return "2.2";
+      case 31:
+        return "3.1";
+      case 32:
+        return "3.2";
+      case 41:
+        return "4.1";
+      case 42:
+        return "4.2";
+      case 51:
+        return "5.1";
+      default:
+        return NULL;
+    }
+  }
+}
+
+/**
+ * gst_codec_utils_h264_caps_set_level_and_profile:
+ * @caps: the #GstCaps to which the level and profile are to be added
+ * @sps: Pointer to the sequence parameter set for the stream.
+ * @len: Length of the data available in @sps.
+ *
+ * Sets the level and profile in @caps if it can be determined from @sps. See
+ * #gst_codec_utils_h264_get_level() and #gst_codec_utils_h264_get_profile()
+ * for more details on the parameters.
+ *
+ * Returns: TRUE if the level and profile could be set, FALSE otherwise.
+ */
+gboolean
+gst_codec_utils_h264_caps_set_level_and_profile (GstCaps * caps,
+    const guint8 * sps, guint len)
+{
+  const gchar *level, *profile;
+
+  g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
+  g_return_val_if_fail (GST_CAPS_IS_SIMPLE (caps), FALSE);
+  g_return_val_if_fail (GST_SIMPLE_CAPS_HAS_NAME (caps, "video/x-h264"), FALSE);
+  g_return_val_if_fail (sps != NULL, FALSE);
+
+  level = gst_codec_utils_h264_get_level (sps, len);
+
+  if (level != NULL)
+    gst_caps_set_simple (caps, "level", G_TYPE_STRING, level, NULL);
+
+  profile = gst_codec_utils_h264_get_profile (sps, len);
+
+  if (profile != NULL)
+    gst_caps_set_simple (caps, "profile", G_TYPE_STRING, profile, NULL);
+
+  return (level != NULL && profile != NULL);
+}

diff --git a/gst-libs/gst/pbutils/codec-utils.h b/gst-libs/gst/pbutils/codec-utils.h
index 2a83348..1428b2b 100644 (file)
--- a/gst-libs/gst/pbutils/codec-utils.h
+++ b/gst-libs/gst/pbutils/codec-utils.h
@@ -38,6 +38,16 @@ gboolean      gst_codec_utils_aac_caps_set_level_and_profile (GstCaps      * cap
                                                               const guint8 * audio_config,
                                                               guint          len);
 
+/* H.264 */
+
+const gchar * gst_codec_utils_h264_get_profile (const guint8 * sps, guint len);
+
+const gchar * gst_codec_utils_h264_get_level   (const guint8 * sps, guint len);
+
+gboolean      gst_codec_utils_h264_caps_set_level_and_profile (GstCaps      * caps,
+                                                               const guint8 * sps,
+                                                               guint          len);
+
 G_END_DECLS
 
 #endif /* __GST_PB_UTILS_CODEC_UTILS_H__ */