add --tag-from-json

[fdkaac.git] / README

diff --git a/README b/README
index 007af3adfbfd2ee88a10618e3576bc073f86ffd8..4bd55b3eaaf39d3a209c6faf2cd76f9304df7595 100644 (file)
--- a/README
+++ b/README
@@ -50,3 +50,53 @@ Therefore, only use UTF-8 (without BOM) when setting text tags by this option.
 On the other hand, --tag / --long-tag (and other command line arguments) are
 converted from locale character encoding to UTF-8 on Posix environment.
 On Windows, command line arguments are always treated as Unicode.
+
+Tagging using JSON
+------------------
+With --tag-from-json, fdkaac can read JSON file and set tags from it.
+By default, tags are assumed to be in the root object(dictionary) like this:
+
+{
+  "title": "No Expectations",
+  "artist": "The Rolling Stones",
+  "album": "Beggars Banquet",
+  "track": 2
+}
+
+In this case, you can simply specify the filename like:
+--tag-from-json=/path/to/json
+
+If the object containing tags is placed somewhere else, you can optionally
+specify the path of the object with dotted notation.
+
+{
+  "format" : {
+    "filename" : "Middle Curse.flac",
+    "nb_streams" : 1,
+    "format_name" : "flac",
+    "format_long_name" : "raw FLAC",
+    "start_time" : "N/A",
+    "duration" : "216.146667",
+    "size" : "11851007.000000",
+    "bit_rate" : "438628.000000",
+    "tags" : {
+      "ALBUM" : "Scary World Theory",
+      "ARTIST" : "Lali Puna",
+      "DATE" : "2001",
+      "DISCID" : "9208CC0A",
+      "TITLE" : "Middle Curse",
+      "TRACKTOTAL" : "10",
+      "track" : "2"
+    }
+  }
+}
+
+In this example, tags are placed under the object "format.tags".
+("format" is a child of the root, and "tags" is a child of the "format").
+In this case, you can say:
+--tag-from-json=/path/to/json?format.tags
+
+For your information, ffprobe of ffmpeg project (or avprobe of libav) can
+output media information/metadata in json format like this.
+
+Note that not all tags can be read/written this way.