To speed up video in Media Player Classic - Home Cinema (MPC-HC) while keeping the audio pitch natural (avoiding the "chipmunk" effect), you must ensure Internal Audio Renderer is active. How to Enable Speed Up Without Pitch Shift
Check File Compatibility: Some users report that pitch correction works more consistently with AAC audio than with MP3 or FLAC in older versions of the renderer. mpc hc speed up without pitch
MPC-HC has built-in shortcuts for speed adjustment that work out of the box in most standard configurations. To speed up video in Media Player Classic
5.2. High-quality / High-speed (1.5–3.0×, transcription or study) transcription or study)