Firstly this questions is inferred from this answer answer .In that answer provides us a splitting a mp3 file with Python . That code is usefull , but for splitting two pieces . For instance if I want to split 30.00 th second to end of the audio , it is cool , but if I want to split from 30.00 to 35.00 it is useless for it . Below of that answer there is a comment about how to trim audio, like I said ,specific piece. When I imply that instructions to code it looked like that :
import struct
import sys
#MP3 frames are not independent because of the byte reservoir. This script does not account for
#that in determining where to do the split.
def SplitMp3(fi, firstSplit_sec,secondSplit_sec, out):
#Constants for MP3
bitrates = {0x0: "free", 0x1: 32, 0x2: 40, 0x3: 48, 0x4: 56, 0x5: 64, 0x6: 80, 0x7: 96, 0x8: 112,
0x9: 128, 0xa: 160, 0xb: 192, 0xc: 224, 0xd: 256, 0xe: 320, 0xf: "bad"}
freqrates = {0x0: 44100, 0x1: 48000, 0x2: 32000, 0x3: "reserved"}
countMpegFrames = 0
frameDuration = 0.026
unrecognizedBytes = 0
firstSplitFrame = int(round(firstSplit_sec / frameDuration))
secondSplitFrame = int(round(secondSplit_sec / frameDuration))
while True:
startPos = fi.tell()
#Check for 3 byte headers
id3Start = fi.read(3)
if len(id3Start) == 3:
if id3Start == b'TAG':
#print ("Found ID3 v1/1.1 header")
fi.seek(startPos + 256)
continue
if id3Start == b'ID3':
#Possibly a ID3v2 header
majorVer, minorVer, flags, encSize = struct.unpack(">BBBI", fi.read(7))
if majorVer != 0xFF and minorVer != 0xFF:
encSize1 = (encSize & 0x7f000000) >> 24
encSize2 = (encSize & 0x7f0000) >> 16
encSize3 = (encSize & 0x7f00) >> 8
encSize4 = (encSize & 0x7f)
if encSize1 < 0x80 and encSize2 < 0x80 and encSize3 < 0x80 and encSize4 < 0x80:
size = ((encSize & 0x7f000000) >> 3) + ((encSize & 0x7f0000) >> 2) + ((encSize & 0x7f00) >> 1) + (encSize & 0x7f)
unsync = (flags >> 7) & 0x1
extendedHeader = (flags >> 6) & 0x1
experimental = (flags >> 5) & 0x1
#print ("Found ID3v2 header")
#print ("version", majorVer, minorVer, unsync, extendedHeader, experimental)
#print ("size", size)
#TODO extendedHeader not supported yet
fi.seek(startPos + 10 + size)
continue
#Check for 4 byte headers
fi.seek(startPos)
headerRaw = fi.read(4)
if len(headerRaw) == 4:
headerWord = struct.unpack(">I", headerRaw)[0]
#Check for MPEG-1 audio frame
if headerWord & 0xfff00000 == 0xfff00000:
#print ("Possible MPEG-1 audio header", hex(headerWord))
countMpegFrames += 1
ver = (headerWord & 0xf0000) >> 16
bitrateEnc = (headerWord & 0xf000) >> 12
freqEnc = (headerWord & 0xf00) >> 8
mode = (headerWord & 0xf0) >> 4
cpy = (headerWord & 0xf)
if ver & 0xe == 0xa and freqEnc != 0xf:
#print ("Probably an MP3 frame")
bitrate = bitrates[bitrateEnc]
freq = freqrates[freqEnc >> 2]
padding = ((freqEnc >> 1) & 0x1) == 1
#print ("bitrate", bitrate, "kbps")
#print ("freq", freq, "Hz")
#print ("padding", padding)
frameLen = int((144 * bitrate * 1000 / freq ) + padding)
#Copy frame to output
fi.seek(startPos)
frameData = fi.read(frameLen)
if (secondSplitFrame >= countMpegFrames) and (countMpegFrames >= firstSplitFrame):
out.write(frameData)
fi.seek(startPos + frameLen)
continue
else:
raise RuntimeError("Unsupported format:", hex(ver), "header:", hex(headerWord))
#If no header can be detected, move on to the next byte
fi.seek(startPos)
nextByteRaw = fi.read(1)
if len(nextByteRaw) == 0:
break #End of file
unrecognizedBytes += 1
#print ("unrecognizedBytes", unrecognizedBytes)
#print ("countMpegFrames", countMpegFrames)
#print ("duration", countMpegFrames * frameDuration, "sec")
When I use this function it produces loosy output . For instance if I want to split 0.0 to 41.00 it gives me 0.00 to 37.00 , and this loosieness is increasing with amount of slice. I've struggled to understand some parts of code . So I am asking how can I solve that loosiness ? Am I missing something ?
Note : I already tried to pydub and similar modules . But they are useless . Always giving memory error and slow . This is really fast .
