Pemotong Audio

Audio digital mewakili suara sebagai urutan sampel diskrit -- nilai numerik yang menggambarkan tekanan udara pada titik waktu tertentu. Sample rate (misalnya, 44.100 Hz) menentukan berapa banyak sampel per detik. Bit depth (misalnya, 16-bit) menentukan rentang nilai yang mungkin untuk setiap sampel. Bersama-sama, sample rate dan bit depth menentukan kualitas audio.

The Web Audio API provides the AudioContext interface, which can decode audio files (MP3, WAV, OGG, M4A) into raw PCM (pulse-code modulation) sample data stored in an AudioBuffer. This buffer contains the sample data as Float32Array values (-1.0 to 1.0) for each channel. To clip the audio, the tool copies the samples between the start and end positions into a new AudioBuffer, which is then encoded back into a file format using a WAV encoder or an MP3 encoder (lame.js).

For sample-accurate editing, the start and end positions are specified in samples (or seconds, which are converted to samples by multiplying by the sample rate). This allows precise cuts at any point in the audio -- essential for music production where a cut even a few samples off the beat is noticeable. The Web Audio API also provides real-time playback via AudioBufferSourceNode, allowing you to preview the selection before exporting.

WAV is the best format for audio clips because it's lossless -- the clip is an exact copy of the original samples. WAV files are uncompressed, so they're large (about 10 MB per minute at 44.1 kHz, 16-bit, stereo). MP3 is a compressed format that uses psychoacoustic models to discard sounds humans can't hear, achieving 10:1 compression with minimal quality loss. For voice recordings and podcasts, MP3 at 128 kbps is sufficient. For music, use 192-320 kbps.

When clipping MP3 files, there's a technical consideration: MP3 encodes audio in frames of 1152 samples. Cutting at a frame boundary is fast and lossless (no re-encoding), but cutting between frame boundaries requires re-encoding, which introduces generational loss. Our tool re-encodes the clip for precise control, which is acceptable for most use cases. For professional audio editing where generational loss is unacceptable, use WAV source files and export to WAV.