While full scores are often under copyright, several notable transcriptions and educational versions are available: Orchestration #12 – Density & Doublings C – Gil Evans
It’s corrupting. The file is breaking up.
Use software like or Transcribe! to slow down the recording. Start with the bass part (Paul Chambers), then add the tuba (Bill Barber), then add the horns. You will internalize Evans’ process in a way no PDF ever could teach you.