Figure 1
Suno’s interface in ‘Custom’ mode. The user can manually input lyrics and tags (style of the music). Last accessed December 16, 2024.
Figure 2
Udio’s interface (as of February 18, 2025). Custom mode allows for manual adjustments even if the prompts are automatically generated.
Table 1
The subset of the metadata from Suno and Udio we analyzed.
| Field | Suno | Udio |
|---|---|---|
| id | Unique song ID | Unique song ID |
| title | Title of the song | Title of the song |
| tags | Tags derived from the user input | User tags |
| replaced_tags | N/A | Dictionary with tags replacements |
| lyrics | N/A | Song lyrics |
| prompt | Song lyrics | User input |
| gpt_description_prompt | User prompt for lyrics generation | N/A |
| optimized_prompt | N/A | Refined user input |
Table 2
The 15 most popular languages for lyrics in the dataset. The percentage refers to the prevalence in each platform.
| Language | ISO 639‑3 | Udio | Suno |
|---|---|---|---|
| English | eng_Latn | 71.39% | 46.75% |
| German | deu_Latn | 3.68% | 8.87% |
| Russian | rus_Cyrl | 2.99% | 6.68% |
| Spanish | spa_Latn | 3.28% | 4.58% |
| Portuguese | por_Latn | 1.68% | 3.55% |
| Korean | kor_Hang | 3.21% | 3.00% |
| Chinese | yue_Hant | 1.77% | 3.33% |
| Indian | ind_Latn | 0.27% | 3.26% |
| French | fra_Latn | 1.81% | 2.15% |
| Japanese | jpn_Jpan | 1.45% | 1.92% |
| Turkish | tur_Latn | 0.29% | 1.66% |
| Italian | ita_Latn | 1.06% | 1.29% |
| Thai | tha_Thai | 0.05% | 1.26% |
| Vietnamese | vie_Latn | 0.09% | 1.11% |
| Polish | pol_Latn | 0.77% | 0.94% |
| TOTAL | 93.79% | 90.35% |
Figure 3
Clustering of prompts embeddings. The names for each cluster are manually defined after checking their content.
Table 3
Macro‑categories (manually defined) and HDBSCAN clusters (manually renamed) in the lyrics‑embedding space with their respective sizes.
| Category | Clusters |
|---|---|
| abstract (1719) | afrofuturism (26), afrofuturism (64), carpe diem (70), chaos (21), clashing (60), dreams (49), dreams (31), flying (199), spirituality (42), mask (24), mirrors (53), money (26), photo (35), post‑atomic (32), religion (854), shadows (48), tired (37), war (48) |
| animals (708) | animals (74), bees (38), birds (40), butterfly (23), capybara (33), cats (280), dogs (169), fireflies (27), frog (24) |
| celebration (232) | birthday (126), halloween (31), xmas (75) |
| daily life (345) | chores (23), daily work (68), monday (54), monotony (25), rent (37), school (109), weekend (29) |
| dance (515) | beat (31), beat (64), last (49), night (31), night (125), groove (125), heartbeat (29), moonlight (25), swing (36) |
| driving (210) | driving (83), road trip (47), speed (80) |
| family (241) | family (52), father (43), friends (87), mother (59), |
| fantasy (893) | demons (21), fantasy (562), shadows (24), spooky (117), vampire (29), vikings (83), werewolf (57) |
| feelings (809) | break free (109), fade away (26), good ol days (31), happiness (24), loneliness (131), madness (116), old place (46), pain (30), peaceful (28), revenge (23), run free (25), runaway (29), tears (22), weariness (114), yesterday (55) |
| food (784) | candy (60), cheese (522), coffee (101), fruit (101) |
| genre (817) | blues (60), country music (301), emo (195), guitar (52), heavy metal (29), rock ‘n’ roll (50), trap‑like (130) |
| location (679) | america (38), australia (21), beach (28), capitals (23), desert (58), earth (96), egypt (35), forest (65), river (26), sea (289) |
| love (2182) | apology (21), goodbye (85), heartbrake (172), i miss you (45), always (74), breakup (81), burning (37), can’t wait (52), crazy (29), distance (50), dream (31), electric (40), eyes (97), feel (41), forever (26), forever (406), hand (20), holding on (33), letting go (22), longing (80), loss (28), missing (27), stay (37), time (26), togetherness (41), unrequited (292), wait (33), wandering (38), whisper (76), whisper (47), return (95) |
| meme (412) | fck (183), memes (91), pp (118), weed (20) |
| mixed language (769) | chinese (93), hindi (23), indonesian (24), jamaican (86), japanese (355), korean (108), russian (52), spanish (28) |
| motivational (288) | new dawn (50), dreams (40), phoenix (59), rising (61), shine (21), unstoppable (57) |
| other (557) | alphabet (27), boots‑pub? (27), gpt glitch? (25), absurd? (25), poe‑raven (39), short+instr. (414) |
| politics (143) | palestine (29), protest songs (71), trump+biden (43) |
| sports (254) | sports (197), training (57) |
| stars/night (648) | cosmic (460), quiet night (39), stars (32), nightsky (117) |
| technology (899) | AI (663), code (110), crypto (40), digital (55), math (31) |
| time (336) | midnight (32), midnight (130), midnight+love (22), morning (38), sunset (84), time (30) |
| urban (595) | city (135), city (165), lost (22), neons (233), street (40) |
| videogames (126) | helldivers (20), pokemon (42), videogames (64) |
| weather/seasons (949) | autumn (51), frozen (39), moonlight (140), rain (62), rain+dancing (183), rain+love (49), rainy day (39), summer (211), sunshine (155), sunshine+love (20) |
| outliers (25794) | outliers (25794) |
Figure 4
Clusters of lyrics (from both Suno and Udio) obtained from the HDBSCAN algorithm applied to a five‑dimensional UMAP reduction of the embedding space. The scatterplot is then created on a two‑dimensional reduction of the same space. Colors represent macro‑categories and text annotations refer to the specific clusters, as shown in Table 3.
Figure 5
Word cloud for Suno (left) and Udio (right). Font size is scaled according to prevalence.
Table 4
Manually created high‑level taxonomy derived from tags used more than 10 times. For Suno and Udio separately we indicate the expected number of tags and the probability of seeing more than one in a string according to a fitted Poisson distribution. UNDEFINED refers to tags that appear in a string but don’t match with our vocabulary.
| Category | n. of tags | ||||
|---|---|---|---|---|---|
| GENRE/STYLE | 657 | 1.15e + 00 | 3.90e + 00 | 6.84e‑01 | 9.80e‑01 |
| QUALIFIER | 324 | 8.38e‑01 | 3.56e+00 | 5.67e‑01 | 9.72e‑01 |
| INSTRUMENT | 108 | 2.54e‑01 | 2.58e‑01 | 2.24e‑01 | 2.28e‑01 |
| STRUCTURE | 68 | 1.34e‑01 | 2.96e‑01 | 1.26e‑01 | 2.56e‑01 |
| VOICE | 51 | 1.27e‑01 | 6.08e‑01 | 1.19e‑01 | 4.55e‑01 |
| YEAR | 22 | 2.98e‑02 | 5.39e‑02 | 2.93e‑02 | 5.25e‑02 |
| KEY | 10 | 3.65e‑03 | 3.53e‑03 | 3.64e‑03 | 3.53e‑03 |
| BPM | 6 | 1.63e‑03 | 3.93e‑04 | 1.63e‑03 | 3.93e‑04 |
| UNDEFINED | ‑ | −1.26e+00 | 1.15e+00 | 7.17e‑01 | 6.84e‑01 |
Figure 6
Clusters of the most common tags (combined ranking from both services). Colors correspond to macro‑categories defined manually. Text corresponds to the most prevalent tag in each cluster of the clusters we find with HDBSCAN. Grey circles indicate outliers.
Table 5
The 10 most replaced artists found in Udio’s metadata under replaced_tags. The full list contains 703 artists.
| Artist | # | Replaced Tags |
|---|---|---|
| XXXTentacion | 26 | emo rap, alternative r&b, hip hop, contemporary r&b, r&b, pop rap, aggressive, self‑hatred, boastful, depressive |
| Drake | 19 | male vocalist, pop rap, contemporary r&b, hip hop, r&b, alternative r&b, atmospheric, introspective, apathetic, mellow, bittersweet |
| Taylor Swift | 18 | alt‑pop, singer–songwriter, synthpop, nocturnal, romantic, love, atmospheric, lonely, sentimental, longing, concept album, lethargic, passionate, 2020s |
| Foo Fighters | 18 | male vocalist, alternative rock, post‑grunge, acoustic rock, energetic, melodic |
| The Beatles | 17 | male vocalist, psychedelic pop, pop rock, psychedelia, sunshine pop, art pop, melodic, lush, love, fantasy, optimistic, dense, pastoral |
| Depeche Mode | 17 | male vocalist, synthpop, downtempo, ambient pop, electronic, melancholic, melodic, calm, soothing, lush, mellow, nocturnal |
| Adele | 17 | female vocalist, pop soul, adult contemporary, pop, blue‑eyed soul, passionate, sad, sentimental |
| J. S. Bach | 16 | classical music, baroque music |
| The Weeknd | 14 | male vocalist, alternative r&b, electropop, r&b, electronic, synthpop, nu‑disco, party, hedonistic |
| ABBA | 14 | female vocalist, europop, euro‑disco, dance, pop, disco, optimistic, energetic, uplifting, melodic, rhythmic, party, lush |
Table 6
Top most prevalent metatags. In cases where numbers appear, e.g., Chorus 2, they were stripped and merged into one category.
| Sequence | Suno | Udio | Total |
|---|---|---|---|
| verse | 73722 | 14548 | 88270 |
| chorus | 48670 | 16672 | 65342 |
| bridge | 17826 | 4665 | 22491 |
| outro | 6163 | 2386 | 8549 |
| pre‑chorus | 3725 | 2914 | 6639 |
| end | 3747 | 289 | 4036 |
| intro | 2436 | 1171 | 3607 |
| instrumental | 2682 | 710 | 3392 |
| drop | 662 | 1403 | 2065 |
| guitar solo | 1212 | 835 | 2047 |
| hook | 912 | 468 | 1380 |
| break | 943 | 212 | 1155 |
| interlude | 538 | 398 | 936 |
| fade out | 644 | 208 | 852 |
| instrumental break | 504 | 280 | 784 |
| solo | 537 | 236 | 773 |
| instrumental solo | 633 | 39 | 672 |
| instrumental intro | 596 | 64 | 660 |
| breakdown | 260 | 277 | 537 |
| refrain | 314 | 203 | 517 |
| instrumental interlude | 452 | 55 | 507 |
| yeah | 3 | 466 | 469 |
| pre‑hook | 426 | 15 | 441 |
| build | 163 | 267 | 430 |
| final chorus | 144 | 255 | 399 |