diff --git a/mp4.go b/mp4.go
index 6523397..a573ad4 100644
--- a/mp4.go
+++ b/mp4.go
@@ -31,6 +31,8 @@ var atoms = atomNames(map[string]string{
 	"\xa9day": "year",
 	"\xa9nam": "title",
 	"\xa9gen": "genre",
+	"gnre":    "genre ID3v1 ID",
+	"geID":    "genre ID",
 	"trkn":    "track",
 	"\xa9wrt": "composer",
 	"\xa9too": "encoder",
@@ -45,6 +47,439 @@ var atoms = atomNames(map[string]string{
 	"disk":    "disc",
 })
 
+// Source: https://exiftool.org/TagNames/QuickTime.html
+var genreIDValues = map[int]string{
+	2:        "Blues",
+	3:        "Comedy",
+	4:        "Children's Music",
+	5:        "Classical",
+	6:        "Country",
+	7:        "Electronic",
+	8:        "Holiday",
+	9:        "Classical|Opera",
+	10:       "Singer/Songwriter",
+	11:       "Jazz",
+	12:       "Latino",
+	13:       "New Age",
+	14:       "Pop",
+	15:       "R&B/Soul",
+	16:       "Soundtrack",
+	17:       "Dance",
+	18:       "Hip-Hop/Rap",
+	19:       "World",
+	20:       "Alternative",
+	21:       "Rock",
+	22:       "Christian & Gospel",
+	23:       "Vocal",
+	24:       "Reggae",
+	25:       "Easy Listening",
+	27:       "J-Pop",
+	28:       "Enka",
+	29:       "Anime",
+	30:       "Kayokyoku",
+	50:       "Fitness & Workout",
+	51:       "Pop|K-Pop",
+	52:       "Karaoke",
+	53:       "Instrumental",
+	1001:     "Alternative|College Rock",
+	1002:     "Alternative|Goth Rock",
+	1003:     "Alternative|Grunge",
+	1004:     "Alternative|Indie Rock",
+	1005:     "Alternative|New Wave",
+	1006:     "Alternative|Punk",
+	1007:     "Blues|Chicago Blues",
+	1009:     "Blues|Classic Blues",
+	1010:     "Blues|Contemporary Blues",
+	1011:     "Blues|Country Blues",
+	1012:     "Blues|Delta Blues",
+	1013:     "Blues|Electric Blues",
+	1014:     "Children's Music|Lullabies",
+	1015:     "Children's Music|Sing-Along",
+	1016:     "Children's Music|Stories",
+	1017:     "Classical|Avant-Garde",
+	1018:     "Classical|Baroque Era",
+	1019:     "Classical|Chamber Music",
+	1020:     "Classical|Chant",
+	1021:     "Classical|Choral",
+	1022:     "Classical|Classical Crossover",
+	1023:     "Classical|Early Music",
+	1024:     "Classical|Impressionist",
+	1025:     "Classical|Medieval Era",
+	1026:     "Classical|Minimalism",
+	1027:     "Classical|Modern Era",
+	1028:     "Classical|Opera",
+	1029:     "Classical|Orchestral",
+	1030:     "Classical|Renaissance",
+	1031:     "Classical|Romantic Era",
+	1032:     "Classical|Wedding Music",
+	1033:     "Country|Alternative Country",
+	1034:     "Country|Americana",
+	1035:     "Country|Bluegrass",
+	1036:     "Country|Contemporary Bluegrass",
+	1037:     "Country|Contemporary Country",
+	1038:     "Country|Country Gospel",
+	1039:     "Country|Honky Tonk",
+	1040:     "Country|Outlaw Country",
+	1041:     "Country|Traditional Bluegrass",
+	1042:     "Country|Traditional Country",
+	1043:     "Country|Urban Cowboy",
+	1044:     "Dance|Breakbeat",
+	1045:     "Dance|Exercise",
+	1046:     "Dance|Garage",
+	1047:     "Dance|Hardcore",
+	1048:     "Dance|House",
+	1049:     "Dance|Jungle/Drum'n'bass",
+	1050:     "Dance|Techno",
+	1051:     "Dance|Trance",
+	1052:     "Jazz|Big Band",
+	1053:     "Jazz|Bop",
+	1054:     "Easy Listening|Lounge",
+	1055:     "Easy Listening|Swing",
+	1056:     "Electronic|Ambient",
+	1057:     "Electronic|Downtempo",
+	1058:     "Electronic|Electronica",
+	1060:     "Electronic|IDM/Experimental",
+	1061:     "Electronic|Industrial",
+	1062:     "Singer/Songwriter|Alternative Folk",
+	1063:     "Singer/Songwriter|Contemporary Folk",
+	1064:     "Singer/Songwriter|Contemporary Singer/Songwriter",
+	1065:     "Singer/Songwriter|Folk-Rock",
+	1066:     "Singer/Songwriter|New Acoustic",
+	1067:     "Singer/Songwriter|Traditional Folk",
+	1068:     "Hip-Hop/Rap|Alternative Rap",
+	1069:     "Hip-Hop/Rap|Dirty South",
+	1070:     "Hip-Hop/Rap|East Coast Rap",
+	1071:     "Hip-Hop/Rap|Gangsta Rap",
+	1072:     "Hip-Hop/Rap|Hardcore Rap",
+	1073:     "Hip-Hop/Rap|Hip-Hop",
+	1074:     "Hip-Hop/Rap|Latin Rap",
+	1075:     "Hip-Hop/Rap|Old School Rap",
+	1076:     "Hip-Hop/Rap|Rap",
+	1077:     "Hip-Hop/Rap|Underground Rap",
+	1078:     "Hip-Hop/Rap|West Coast Rap",
+	1079:     "Holiday|Chanukah",
+	1080:     "Holiday|Christmas",
+	1081:     "Holiday|Christmas: Children's",
+	1082:     "Holiday|Christmas: Classic",
+	1083:     "Holiday|Christmas: Classical",
+	1084:     "Holiday|Christmas: Jazz",
+	1085:     "Holiday|Christmas: Modern",
+	1086:     "Holiday|Christmas: Pop",
+	1087:     "Holiday|Christmas: R&B",
+	1088:     "Holiday|Christmas: Religious",
+	1089:     "Holiday|Christmas: Rock",
+	1090:     "Holiday|Easter",
+	1091:     "Holiday|Halloween",
+	1092:     "Holiday|Holiday: Other",
+	1093:     "Holiday|Thanksgiving",
+	1094:     "Christian & Gospel|CCM",
+	1095:     "Christian & Gospel|Christian Metal",
+	1096:     "Christian & Gospel|Christian Pop",
+	1097:     "Christian & Gospel|Christian Rap",
+	1098:     "Christian & Gospel|Christian Rock",
+	1099:     "Christian & Gospel|Classic Christian",
+	1100:     "Christian & Gospel|Contemporary Gospel",
+	1101:     "Christian & Gospel|Gospel",
+	1103:     "Christian & Gospel|Praise & Worship",
+	1104:     "Christian & Gospel|Southern Gospel",
+	1105:     "Christian & Gospel|Traditional Gospel",
+	1106:     "Jazz|Avant-Garde Jazz",
+	1107:     "Jazz|Contemporary Jazz",
+	1108:     "Jazz|Crossover Jazz",
+	1109:     "Jazz|Dixieland",
+	1110:     "Jazz|Fusion",
+	1111:     "Jazz|Latin Jazz",
+	1112:     "Jazz|Mainstream Jazz",
+	1113:     "Jazz|Ragtime",
+	1114:     "Jazz|Smooth Jazz",
+	1115:     "Latino|Latin Jazz",
+	1116:     "Latino|Contemporary Latin",
+	1117:     "Latino|Pop Latino",
+	1118:     "Latino|Raices",
+	1119:     "Latino|Urbano latino",
+	1120:     "Latino|Baladas y Boleros",
+	1121:     "Latino|Rock y Alternativo",
+	1122:     "Brazilian",
+	1123:     "Latino|Musica Mexicana",
+	1124:     "Latino|Musica tropical",
+	1125:     "New Age|Environmental",
+	1126:     "New Age|Healing",
+	1127:     "New Age|Meditation",
+	1128:     "New Age|Nature",
+	1129:     "New Age|Relaxation",
+	1130:     "New Age|Travel",
+	1131:     "Pop|Adult Contemporary",
+	1132:     "Pop|Britpop",
+	1133:     "Pop|Pop/Rock",
+	1134:     "Pop|Soft Rock",
+	1135:     "Pop|Teen Pop",
+	1136:     "R&B/Soul|Contemporary R&B",
+	1137:     "R&B/Soul|Disco",
+	1138:     "R&B/Soul|Doo Wop",
+	1139:     "R&B/Soul|Funk",
+	1140:     "R&B/Soul|Motown",
+	1141:     "R&B/Soul|Neo-Soul",
+	1142:     "R&B/Soul|Quiet Storm",
+	1143:     "R&B/Soul|Soul",
+	1144:     "Rock|Adult Alternative",
+	1145:     "Rock|American Trad Rock",
+	1146:     "Rock|Arena Rock",
+	1147:     "Rock|Blues-Rock",
+	1148:     "Rock|British Invasion",
+	1149:     "Rock|Death Metal/Black Metal",
+	1150:     "Rock|Glam Rock",
+	1151:     "Rock|Hair Metal",
+	1152:     "Rock|Hard Rock",
+	1153:     "Rock|Metal",
+	1154:     "Rock|Jam Bands",
+	1155:     "Rock|Prog-Rock/Art Rock",
+	1156:     "Rock|Psychedelic",
+	1157:     "Rock|Rock & Roll",
+	1158:     "Rock|Rockabilly",
+	1159:     "Rock|Roots Rock",
+	1160:     "Rock|Singer/Songwriter",
+	1161:     "Rock|Southern Rock",
+	1162:     "Rock|Surf",
+	1163:     "Rock|Tex-Mex",
+	1165:     "Soundtrack|Foreign Cinema",
+	1166:     "Soundtrack|Musicals",
+	1167:     "Comedy|Novelty",
+	1168:     "Soundtrack|Original Score",
+	1169:     "Soundtrack|Soundtrack",
+	1171:     "Comedy|Standup Comedy",
+	1172:     "Soundtrack|TV Soundtrack",
+	1173:     "Vocal|Standards",
+	1174:     "Vocal|Traditional Pop",
+	1175:     "Jazz|Vocal Jazz",
+	1176:     "Vocal|Vocal Pop",
+	1177:     "African|Afro-Beat",
+	1178:     "African|Afro-Pop",
+	1179:     "World|Cajun",
+	1180:     "World|Celtic",
+	1181:     "World|Celtic Folk",
+	1182:     "World|Contemporary Celtic",
+	1183:     "Reggae|Modern Dancehall",
+	1184:     "World|Drinking Songs",
+	1185:     "Indian|Indian Pop",
+	1186:     "World|Japanese Pop",
+	1187:     "World|Klezmer",
+	1188:     "World|Polka",
+	1189:     "World|Traditional Celtic",
+	1190:     "World|Worldbeat",
+	1191:     "World|Zydeco",
+	1192:     "Reggae|Roots Reggae",
+	1193:     "Reggae|Dub",
+	1194:     "Reggae|Ska",
+	1195:     "World|Caribbean",
+	1196:     "World|South America",
+	1197:     "Arabic",
+	1198:     "World|North America",
+	1199:     "World|Hawaii",
+	1200:     "World|Australia",
+	1201:     "World|Japan",
+	1202:     "World|France",
+	1203:     "African",
+	1204:     "World|Asia",
+	1205:     "World|Europe",
+	1206:     "World|South Africa",
+	1207:     "Jazz|Hard Bop",
+	1208:     "Jazz|Trad Jazz",
+	1209:     "Jazz|Cool Jazz",
+	1210:     "Blues|Acoustic Blues",
+	1211:     "Classical|High Classical",
+	1220:     "Brazilian|Axe",
+	1221:     "Brazilian|Bossa Nova",
+	1222:     "Brazilian|Choro",
+	1223:     "Brazilian|Forro",
+	1224:     "Brazilian|Frevo",
+	1225:     "Brazilian|MPB",
+	1226:     "Brazilian|Pagode",
+	1227:     "Brazilian|Samba",
+	1228:     "Brazilian|Sertanejo",
+	1229:     "Brazilian|Baile Funk",
+	1230:     "Alternative|Chinese Alt",
+	1231:     "Alternative|Korean Indie",
+	1232:     "Chinese",
+	1233:     "Chinese|Chinese Classical",
+	1234:     "Chinese|Chinese Flute",
+	1235:     "Chinese|Chinese Opera",
+	1236:     "Chinese|Chinese Orchestral",
+	1237:     "Chinese|Chinese Regional Folk",
+	1238:     "Chinese|Chinese Strings",
+	1239:     "Chinese|Taiwanese Folk",
+	1240:     "Chinese|Tibetan Native Music",
+	1241:     "Hip-Hop/Rap|Chinese Hip-Hop",
+	1242:     "Hip-Hop/Rap|Korean Hip-Hop",
+	1243:     "Korean",
+	1244:     "Korean|Korean Classical",
+	1245:     "Korean|Korean Trad Song",
+	1246:     "Korean|Korean Trad Instrumental",
+	1247:     "Korean|Korean Trad Theater",
+	1248:     "Rock|Chinese Rock",
+	1249:     "Rock|Korean Rock",
+	1250:     "Pop|C-Pop",
+	1251:     "Pop|Cantopop/HK-Pop",
+	1252:     "Pop|Korean Folk-Pop",
+	1253:     "Pop|Mandopop",
+	1254:     "Pop|Tai-Pop",
+	1255:     "Pop|Malaysian Pop",
+	1256:     "Pop|Pinoy Pop",
+	1257:     "Pop|Original Pilipino Music",
+	1258:     "Pop|Manilla Sound",
+	1259:     "Pop|Indo Pop",
+	1260:     "Pop|Thai Pop",
+	1261:     "Vocal|Trot",
+	1262:     "Indian",
+	1263:     "Indian|Bollywood",
+	1264:     "Indian|Regional Indian|Tamil",
+	1265:     "Indian|Regional Indian|Telugu",
+	1266:     "Indian|Regional Indian",
+	1267:     "Indian|Devotional & Spiritual",
+	1268:     "Indian|Sufi",
+	1269:     "Indian|Indian Classical",
+	1270:     "Russian|Russian Chanson",
+	1271:     "World|Dini",
+	1272:     "Turkish|Halk",
+	1273:     "Turkish|Sanat",
+	1274:     "World|Dangdut",
+	1275:     "World|Indonesian Religious",
+	1276:     "World|Calypso",
+	1277:     "World|Soca",
+	1278:     "Indian|Ghazals",
+	1279:     "Indian|Indian Folk",
+	1280:     "Turkish|Arabesque",
+	1281:     "African|Afrikaans",
+	1282:     "World|Farsi",
+	1283:     "World|Israeli",
+	1284:     "Arabic|Khaleeji",
+	1285:     "Arabic|North African",
+	1286:     "Arabic|Arabic Pop",
+	1287:     "Arabic|Islamic",
+	1288:     "Soundtrack|Sound Effects",
+	1289:     "Folk",
+	1290:     "Orchestral",
+	1291:     "Marching",
+	1293:     "Pop|Oldies",
+	1294:     "Country|Thai Country",
+	1295:     "World|Flamenco",
+	1296:     "World|Tango",
+	1297:     "World|Fado",
+	1298:     "World|Iberia",
+	1299:     "Russian",
+	1300:     "Turkish",
+	100000:   "Christian & Gospel",
+	100001:   "Classical|Art Song",
+	100002:   "Classical|Brass & Woodwinds",
+	100003:   "Classical|Solo Instrumental",
+	100004:   "Classical|Contemporary Era",
+	100005:   "Classical|Oratorio",
+	100006:   "Classical|Cantata",
+	100007:   "Classical|Electronic",
+	100008:   "Classical|Sacred",
+	100009:   "Classical|Guitar",
+	100010:   "Classical|Piano",
+	100011:   "Classical|Violin",
+	100012:   "Classical|Cello",
+	100013:   "Classical|Percussion",
+	100014:   "Electronic|Dubstep",
+	100015:   "Electronic|Bass",
+	100016:   "Hip-Hop/Rap|UK Hip-Hop",
+	100017:   "Reggae|Lovers Rock",
+	100018:   "Alternative|EMO",
+	100019:   "Alternative|Pop Punk",
+	100020:   "Alternative|Indie Pop",
+	100021:   "New Age|Yoga",
+	100022:   "Pop|Tribute",
+	100023:   "Pop|Shows",
+	100024:   "Cuban",
+	100025:   "Cuban|Mambo",
+	100026:   "Cuban|Chachacha",
+	100027:   "Cuban|Guajira",
+	100028:   "Cuban|Son",
+	100029:   "Cuban|Bolero",
+	100030:   "Cuban|Guaracha",
+	100031:   "Cuban|Timba",
+	100032:   "Soundtrack|Video Game",
+	100033:   "Indian|Regional Indian|Punjabi|Punjabi Pop",
+	100034:   "Indian|Regional Indian|Bengali|Rabindra Sangeet",
+	100035:   "Indian|Regional Indian|Malayalam",
+	100036:   "Indian|Regional Indian|Kannada",
+	100037:   "Indian|Regional Indian|Marathi",
+	100038:   "Indian|Regional Indian|Gujarati",
+	100039:   "Indian|Regional Indian|Assamese",
+	100040:   "Indian|Regional Indian|Bhojpuri",
+	100041:   "Indian|Regional Indian|Haryanvi",
+	100042:   "Indian|Regional Indian|Odia",
+	100043:   "Indian|Regional Indian|Rajasthani",
+	100044:   "Indian|Regional Indian|Urdu",
+	100045:   "Indian|Regional Indian|Punjabi",
+	100046:   "Indian|Regional Indian|Bengali",
+	100047:   "Indian|Indian Classical|Carnatic Classical",
+	100048:   "Indian|Indian Classical|Hindustani Classical",
+	100049:   "African|Afro House",
+	100050:   "African|Afro Soul",
+	100051:   "African|Afrobeats",
+	100052:   "African|Benga",
+	100053:   "African|Bongo-Flava",
+	100054:   "African|Coupe-Decale",
+	100055:   "African|Gqom",
+	100056:   "African|Highlife",
+	100057:   "African|Kuduro",
+	100058:   "African|Kizomba",
+	100059:   "African|Kwaito",
+	100060:   "African|Mbalax",
+	100061:   "African|Ndombolo",
+	100062:   "African|Shangaan Electro",
+	100063:   "African|Soukous",
+	100064:   "African|Taarab",
+	100065:   "African|Zouglou",
+	100066:   "Turkish|Ozgun",
+	100067:   "Turkish|Fantezi",
+	100068:   "Turkish|Religious",
+	100069:   "Pop|Turkish Pop",
+	100070:   "Rock|Turkish Rock",
+	100071:   "Alternative|Turkish Alternative",
+	100072:   "Hip-Hop/Rap|Turkish Hip-Hop/Rap",
+	100073:   "African|Maskandi",
+	100074:   "Russian|Russian Romance",
+	100075:   "Russian|Russian Bard",
+	100076:   "Russian|Russian Pop",
+	100077:   "Russian|Russian Rock",
+	100078:   "Russian|Russian Hip-Hop",
+	100079:   "Arabic|Levant",
+	100080:   "Arabic|Levant|Dabke",
+	100081:   "Arabic|Maghreb Rai",
+	100082:   "Arabic|Khaleeji|Khaleeji Jalsat",
+	100083:   "Arabic|Khaleeji|Khaleeji Shailat",
+	100084:   "Tarab",
+	100085:   "Tarab|Iraqi Tarab",
+	100086:   "Tarab|Egyptian Tarab",
+	100087:   "Tarab|Khaleeji Tarab",
+	100088:   "Pop|Levant Pop",
+	100089:   "Pop|Iraqi Pop",
+	100090:   "Pop|Egyptian Pop",
+	100091:   "Pop|Maghreb Pop",
+	100092:   "Pop|Khaleeji Pop",
+	100093:   "Hip-Hop/Rap|Levant Hip-Hop",
+	100094:   "Hip-Hop/Rap|Egyptian Hip-Hop",
+	100095:   "Hip-Hop/Rap|Maghreb Hip-Hop",
+	100096:   "Hip-Hop/Rap|Khaleeji Hip-Hop",
+	100097:   "Alternative|Indie Levant",
+	100098:   "Alternative|Indie Egyptian",
+	100099:   "Alternative|Indie Maghreb",
+	100100:   "Electronic|Levant Electronic",
+	100101:   "Electronic|Electro-Cha'abi",
+	100102:   "Electronic|Maghreb Electronic",
+	100103:   "Folk|Iraqi Folk",
+	100104:   "Folk|Khaleeji Folk",
+	100105:   "Dance|Maghreb Dance",
+	50000061: "Spoken Word",
+	50000063: "Disney",
+	50000064: "French Pop",
+	50000066: "German Pop",
+	50000068: "German Folk",
+}
+
 // Detect PNG image if "implicit" class is used
 var pngHeader = []byte{137, 80, 78, 71, 13, 10, 26, 10}
 
@@ -148,10 +583,15 @@ func (m metadataMP4) readAtomData(r io.ReadSeeker, name string, size uint32, pro
 
 		// "data" + size (4 bytes each)
 		b = b[8:]
-
 		if len(b) < 4 {
 			return fmt.Errorf("invalid encoding: expected at least %d bytes, for class, got %d", 4, len(b))
 		}
+
+		if name == "gnre" {
+			m.data[name] = getInt(b[len(b)-1:])
+			return nil
+		}
+
 		class := getInt(b[1:4])
 		var ok bool
 		contentType, ok = atomTypes[class]
@@ -198,10 +638,10 @@ func (m metadataMP4) readAtomData(r io.ReadSeeker, name string, size uint32, pro
 		data = string(b)
 
 	case "uint8":
-		if len(b) < 1 {
+		if len(b) == 0 {
 			return fmt.Errorf("invalid encoding: expected at least %d bytes, for integer tag data, got %d", 1, len(b))
 		}
-		data = getInt(b[:1])
+		data = getInt(b[len(b)-1:])
 
 	case "jpeg", "png":
 		data = &Picture{
@@ -318,7 +758,17 @@ func (m metadataMP4) Composer() string {
 }
 
 func (m metadataMP4) Genre() string {
-	return m.getString(atoms.Name("genre"))
+	genre := m.getString(atoms.Name("genre"))
+	if len(genre) == 0 {
+		genreID := m.getInt(atoms.Name("genre ID"))
+		if genreID == 0 {
+			genreID := m.getInt(atoms.Name("genre ID3v1 ID")) - 1
+			genre = id3v1Genres[genreID]
+		} else {
+			genre = genreIDValues[genreID]
+		}
+	}
+	return genre
 }
 
 func (m metadataMP4) Year() int {