MediaMetadataRetriever: parse genre tags (0b291937) · Commits · e / os / android_frameworks_base

media/java/android/media/MediaMetadataRetriever.java

+271 −1

Original line number	Diff line number	Diff line
		@@ -28,6 +28,7 @@ import android.graphics.Bitmap;
		import android.net.Uri;
		import android.os.Build;
		import android.os.IBinder;
		import android.text.TextUtils;

		import java.io.FileDescriptor;
		import java.io.FileInputStream;
		@@ -44,6 +45,162 @@ import java.util.Map;
		* frame and meta data from an input media file.
		*/
		public class MediaMetadataRetriever implements AutoCloseable {

		// borrowed from ExoPlayer
		private static final String[] STANDARD_GENRES = new String[] {
		// These are the official ID3v1 genres.
		"Blues",
		"Classic Rock",
		"Country",
		"Dance",
		"Disco",
		"Funk",
		"Grunge",
		"Hip-Hop",
		"Jazz",
		"Metal",
		"New Age",
		"Oldies",
		"Other",
		"Pop",
		"R&B",
		"Rap",
		"Reggae",
		"Rock",
		"Techno",
		"Industrial",
		"Alternative",
		"Ska",
		"Death Metal",
		"Pranks",
		"Soundtrack",
		"Euro-Techno",
		"Ambient",
		"Trip-Hop",
		"Vocal",
		"Jazz+Funk",
		"Fusion",
		"Trance",
		"Classical",
		"Instrumental",
		"Acid",
		"House",
		"Game",
		"Sound Clip",
		"Gospel",
		"Noise",
		"AlternRock",
		"Bass",
		"Soul",
		"Punk",
		"Space",
		"Meditative",
		"Instrumental Pop",
		"Instrumental Rock",
		"Ethnic",
		"Gothic",
		"Darkwave",
		"Techno-Industrial",
		"Electronic",
		"Pop-Folk",
		"Eurodance",
		"Dream",
		"Southern Rock",
		"Comedy",
		"Cult",
		"Gangsta",
		"Top 40",
		"Christian Rap",
		"Pop/Funk",
		"Jungle",
		"Native American",
		"Cabaret",
		"New Wave",
		"Psychadelic",
		"Rave",
		"Showtunes",
		"Trailer",
		"Lo-Fi",
		"Tribal",
		"Acid Punk",
		"Acid Jazz",
		"Polka",
		"Retro",
		"Musical",
		"Rock & Roll",
		"Hard Rock",
		// These were made up by the authors of Winamp and later added to the ID3 spec.
		"Folk",
		"Folk-Rock",
		"National Folk",
		"Swing",
		"Fast Fusion",
		"Bebob",
		"Latin",
		"Revival",
		"Celtic",
		"Bluegrass",
		"Avantgarde",
		"Gothic Rock",
		"Progressive Rock",
		"Psychedelic Rock",
		"Symphonic Rock",
		"Slow Rock",
		"Big Band",
		"Chorus",
		"Easy Listening",
		"Acoustic",
		"Humour",
		"Speech",
		"Chanson",
		"Opera",
		"Chamber Music",
		"Sonata",
		"Symphony",
		"Booty Bass",
		"Primus",
		"Porn Groove",
		"Satire",
		"Slow Jam",
		"Club",
		"Tango",
		"Samba",
		"Folklore",
		"Ballad",
		"Power Ballad",
		"Rhythmic Soul",
		"Freestyle",
		"Duet",
		"Punk Rock",
		"Drum Solo",
		"A capella",
		"Euro-House",
		"Dance Hall",
		// These were made up by the authors of Winamp but have not been added to the ID3 spec.
		"Goa",
		"Drum & Bass",
		"Club-House",
		"Hardcore",
		"Terror",
		"Indie",
		"BritPop",
		"Afro-Punk",
		"Polsk Punk",
		"Beat",
		"Christian Gangsta Rap",
		"Heavy Metal",
		"Black Metal",
		"Crossover",
		"Contemporary Christian",
		"Christian Rock",
		"Merengue",
		"Salsa",
		"Thrash Metal",
		"Anime",
		"Jpop",
		"Synthpop"
		};

		static {
		System.loadLibrary("media_jni");
		native_init();
		@@ -225,6 +382,8 @@ public class MediaMetadataRetriever implements AutoCloseable {
		private native void _setDataSource(MediaDataSource dataSource)
		throws IllegalArgumentException;

		private native @Nullable String nativeExtractMetadata(int keyCode);

		/**
		* Call this method after setDataSource(). This method retrieves the
		* meta data value associated with the keyCode.
		@@ -236,7 +395,118 @@ public class MediaMetadataRetriever implements AutoCloseable {
		* @return The meta data value associate with the given keyCode on success;
		* null on failure.
		*/
		public native @Nullable String extractMetadata(int keyCode);
		public @Nullable String extractMetadata(int keyCode) {
		String meta = nativeExtractMetadata(keyCode);
		if (keyCode == METADATA_KEY_GENRE) {
		// translate numeric genre code(s) to human readable
		meta = convertGenreTag(meta);
		}
		return meta;
		}

		/*
		* The id3v2 spec doesn't specify the syntax of the genre tag very precisely, so
		* some assumptions are made. Using one possible interpretation of the id3v2
		* spec, this method converts an id3 genre tag string to a human readable string,
		* as follows:
		* - if the first character of the tag is a digit, the entire tag is assumed to
		* be an id3v1 numeric genre code. If the tag does not parse to a number, or
		* the number is outside the range of defined standard genres, it is ignored.
		* - if the tag does not start with a digit, it is assumed to be an id3v2 style
		* tag consisting of one or more genres, with each genre being either a parenthesized
		* integer referring to an id3v1 numeric genre code, the special indicators "(CR)" or
		* "(RX)" (for "Cover" or "Remix", respectively), or a custom genre string. When
		* a custom genre string is encountered, it is assumed to continue until the end
		* of the tag, unless it starts with "((" in which case it is assumed to continue
		* until the next close-parenthesis or the end of the tag. Any parse error in the tag
		* causes it to be ignored.
		* The human-readable genre string is not localized, and uses the English genre names
		* from the spec.
		*/
		private String convertGenreTag(String meta) {
		if (TextUtils.isEmpty(meta)) {
		return null;
		}

		if (Character.isDigit(meta.charAt(0))) {
		// assume a single id3v1-style bare number without any extra characters
		try {
		int genreIndex = Integer.parseInt(meta);
		if (genreIndex >= 0 && genreIndex < STANDARD_GENRES.length) {
		return STANDARD_GENRES[genreIndex];
		}
		} catch (NumberFormatException e) {
		// ignore and fall through
		}
		return null;
		} else {
		// assume id3v2-style genre tag, with parenthesized numeric genres
		// and/or literal genre strings, possibly more than one per tag.
		StringBuilder genres = null;
		String nextGenre = null;
		while (true) {
		if (!TextUtils.isEmpty(nextGenre)) {
		if (genres == null) {
		genres = new StringBuilder();
		}
		if (genres.length() != 0) {
		genres.append(", ");
		}
		genres.append(nextGenre);
		nextGenre = null;
		}
		if (TextUtils.isEmpty(meta)) {
		// entire tag has been processed.
		break;
		}
		if (meta.startsWith("(RX)")) {
		nextGenre = "Remix";
		meta = meta.substring(4);
		} else if (meta.startsWith("(CR)")) {
		nextGenre = "Cover";
		meta = meta.substring(4);
		} else if (meta.startsWith("((")) {
		// the id3v2 spec says that custom genres that start with a parenthesis
		// should be "escaped" with another parenthesis, however the spec doesn't
		// specify escaping parentheses inside the custom string. We'll parse any
		// such strings until a closing parenthesis is found, or the end of
		// the tag is reached.
		int closeParenOffset = meta.indexOf(')');
		if (closeParenOffset == -1) {
		// string continues to end of tag
		nextGenre = meta.substring(1);
		meta = "";
		} else {
		nextGenre = meta.substring(1, closeParenOffset + 1);
		meta = meta.substring(closeParenOffset + 1);
		}
		} else if (meta.startsWith("(")) {
		// should be a parenthesized numeric genre
		int closeParenOffset = meta.indexOf(')');
		if (closeParenOffset == -1) {
		return null;
		}
		String genreNumString = meta.substring(1, closeParenOffset);
		try {
		int genreIndex = Integer.parseInt(genreNumString.toString());
		if (genreIndex >= 0 && genreIndex < STANDARD_GENRES.length) {
		nextGenre = STANDARD_GENRES[genreIndex];
		} else {
		return null;
		}
		} catch (NumberFormatException e) {
		return null;
		}
		meta = meta.substring(closeParenOffset + 1);
		} else {
		// custom genre
		nextGenre = meta;
		meta = "";
		}
		}
		return genres == null \|\| genres.length() == 0 ? null : genres.toString();
		}
		}

		/**
		* This method is similar to {@link #getFrameAtTime(long, int, BitmapParams)}

media/jni/android_media_MediaMetadataRetriever.cpp

+1 −1

Original line number	Diff line number	Diff line
		@@ -728,7 +728,7 @@ static const JNINativeMethod nativeMethods[] = {
		(void *)android_media_MediaMetadataRetriever_getFrameAtIndex
		},

		{"extractMetadata", "(I)Ljava/lang/String;",
		{"nativeExtractMetadata", "(I)Ljava/lang/String;",
		(void *)android_media_MediaMetadataRetriever_extractMetadata},
		{"getEmbeddedPicture", "(I)[B",
		(void *)android_media_MediaMetadataRetriever_getEmbeddedPicture},