Separate a song in four steps

export DUETA_API_KEY="dueta_sk_..."

curl https://dueta.ai/v1/credits \
  -H "Authorization: Bearer $DUETA_API_KEY"
# -> {"balance_usd": 20.0, "ledger": [...]}

SIZE=$(wc -c < song.wav)
curl -X POST https://dueta.ai/v1/uploads \
  -H "Authorization: Bearer $DUETA_API_KEY" \
  -H "Content-Type: application/json" \
  -d "{\"filename\": \"song.wav\", \"size_bytes\": $SIZE}"
# -> 201 {"id": "upl_9f2c7a41d0e8", "state": "pending",
#         "content_url": "/v1/uploads/upl_9f2c7a41d0e8/content", ...}

# Raw body, not multipart. The response is the upload, now "ready".
curl -X PUT https://dueta.ai/v1/uploads/$UPLOAD_ID/content \
  -H "Authorization: Bearer $DUETA_API_KEY" \
  -H "Content-Type: application/octet-stream" \
  --data-binary @song.wav
# -> {"state": "ready", "duration_seconds": 612.4, "sample_rate": 48000, ...}

curl -X POST https://dueta.ai/v1/jobs/music-separation \
  -H "Authorization: Bearer $DUETA_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"inputs": ["upl_9f2c7a41d0e8"]}'
# -> 201, the job. result.stems lists the 14 stems once it succeeds.
# From a YouTube link instead of an upload:
#   -d '{"source_url": "https://www.youtube.com/watch?v=dQw4w9WgXcQ"}'

while :; do
  JSON=$(curl -sS --fail-with-body -H "Authorization: Bearer $DUETA_API_KEY" \
    https://dueta.ai/v1/jobs/$JOB_ID) || { echo "$JSON"; exit 1; }   # 4xx/5xx: the error body
  echo "$JSON" |
    jq -r '[.status, .stage, (.progress * 100 | floor | tostring) + "%"] | join("  ")'
  case $(echo "$JSON" | jq -r .status) in
    succeeded) break ;;
    queued|running) ;;
    failed|canceled) echo "$JSON" | jq -r .error; exit 1 ;;
    *) echo "$JSON"; exit 1 ;;   # not a job at all: an error body
  esac
  sleep 2
done

# WAV, byte for byte as rendered:
curl -fL -H "Authorization: Bearer $DUETA_API_KEY" -o stem.wav \
  "https://dueta.ai/v1/jobs/$JOB_ID/stems/$STEM_NAME"

# FLAC, the same samples losslessly at about half the size:
curl -fL -H "Authorization: Bearer $DUETA_API_KEY" -o stem.flac \
  "https://dueta.ai/v1/jobs/$JOB_ID/stems/$STEM_NAME?format=flac"