#!/usr/bin/env python3
import subprocess, math, array

SRC="filename.flac"
OUT="silence-filename.flac"
SR=96000
CHUNK=0.1
STEP=int(SR*CHUNK)
THRESH=-32
SIL=bytearray()

pcm=subprocess.check_output([
    "ffmpeg","-i",SRC,"-vn","-f","f32le","-ac","1","-ar",str(SR),"-"
],stderr=subprocess.DEVNULL)

a=array.array('f'); a.frombytes(pcm)
N=len(a)

for i in range(0, N, STEP):
    seg=a[i:i+STEP]
    if not seg: break
    rms=math.sqrt(math.fsum(x*x for x in seg)/len(seg))
    peak=max(abs(x) for x in seg)
    db_r=20*math.log10(rms)  if rms>0  else -1000
    db_p=20*math.log10(peak) if peak>0 else -1000
    if db_r<THRESH and db_p<THRESH:
        SIL.extend(seg.tobytes())

if SIL:
    subprocess.run([
        "ffmpeg","-y","-f","f32le","-ac","1","-ar",str(SR),"-i","-",OUT
    ],input=SIL,stderr=subprocess.DEVNULL)