我正在寻找一种快速、最好是标准库机制来确定 wav 文件的位深度,例如“16 位”或“24 位”。
我正在使用对 Sox 的子进程调用来获取过多的音频元数据,但是子进程调用非常慢,我目前只能从 Sox 可靠地获取的唯一信息是位深度。
内置的 wave 模块没有“getbitdepth()”之类的功能,并且也不兼容 24 位 wav 文件 - 我可以使用“尝试除外”来使用 wave 模块访问文件元数据(如果有效,请手动记录它是 16 位的)然后除了调用 sox 之外(其中 sox 将执行分析以准确记录其位深度)。我担心的是,这种方法感觉像是猜测工作。如果读取一个 8 位文件怎么办?如果不是,我会手动分配 16 位。
SciPy.io.wavefile 也与 24 位音频不兼容,因此会产生类似的问题。
本教程非常有趣,甚至包括一些非常低级(至少 Python 是低级)的脚本示例,用于从 wav 文件头中提取信息 - 不幸的是,这些脚本不适用于 16 位音频。
有什么方法可以简单地(并且不调用 sox)确定我正在检查的 wav 文件的位深度是多少?
我正在使用的波头解析器脚本如下:
import struct
import os
def print_wave_header(f):
'''
Function takes an audio file path as a parameter and
returns a dictionary of metadata parsed from the header
'''
r = {} #the results of the header parse
r['path'] = f
fin = open(f,"rb") # Read wav file, "r flag" - read, "b flag" - binary
ChunkID=fin.read(4) # First four bytes are ChunkID which must be "RIFF" in ASCII
r["ChunkID"]=ChunkID
ChunkSizeString=fin.read(4) # Total Size of File in Bytes - 8 Bytes
ChunkSize=struct.unpack('I',ChunkSizeString) # 'I' Format is to to treat the 4 bytes as unsigned 32-bit inter
TotalSize=ChunkSize[0]+8 # The subscript is used because struct unpack returns everything as tuple
r["TotalSize"]=TotalSize
DataSize=TotalSize-44 # This is the number of bytes of data
r["DataSize"]=DataSize
Format=fin.read(4) # "WAVE" in ASCII
r["Format"]=Format
SubChunk1ID=fin.read(4) # "fmt " in ASCII
r["SubChunk1ID"]=SubChunk1ID
SubChunk1SizeString=fin.read(4) # Should be 16 (PCM, Pulse Code Modulation)
SubChunk1Size=struct.unpack("I",SubChunk1SizeString) # 'I' format to treat as unsigned 32-bit integer
r["SubChunk1Size"]=SubChunk1Size
AudioFormatString=fin.read(2) # Should be 1 (PCM)
AudioFormat=struct.unpack("H",AudioFormatString) ## 'H' format to treat as unsigned 16-bit integer
r["AudioFormat"]=AudioFormat[0]
NumChannelsString=fin.read(2) # Should be 1 for mono, 2 for stereo
NumChannels=struct.unpack("H",NumChannelsString) # 'H' unsigned 16-bit integer
r["NumChannels"]=NumChannels[0]
SampleRateString=fin.read(4) # Should be 44100 (CD sampling rate)
SampleRate=struct.unpack("I",SampleRateString)
r["SampleRate"]=SampleRate[0]
ByteRateString=fin.read(4) # 44100*NumChan*2 (88200 - Mono, 176400 - Stereo)
ByteRate=struct.unpack("I",ByteRateString) # 'I' unsigned 32 bit integer
r["ByteRate"]=ByteRate[0]
BlockAlignString=fin.read(2) # NumChan*2 (2 - Mono, 4 - Stereo)
BlockAlign=struct.unpack("H",BlockAlignString) # 'H' unsigned 16-bit integer
r["BlockAlign"]=BlockAlign[0]
BitsPerSampleString=fin.read(2) # 16 (CD has 16-bits per sample for each channel)
BitsPerSample=struct.unpack("H",BitsPerSampleString) # 'H' unsigned 16-bit integer
r["BitsPerSample"]=BitsPerSample[0]
SubChunk2ID=fin.read(4) # "data" in ASCII
r["SubChunk2ID"]=SubChunk2ID
SubChunk2SizeString=fin.read(4) # Number of Data Bytes, Same as DataSize
SubChunk2Size=struct.unpack("I",SubChunk2SizeString)
r["SubChunk2Size"]=SubChunk2Size[0]
S1String=fin.read(2) # Read first data, number between -32768 and 32767
S1=struct.unpack("h",S1String)
r["S1"]=S1[0]
S2String=fin.read(2) # Read second data, number between -32768 and 32767
S2=struct.unpack("h",S2String)
r["S2"]=S2[0]
S3String=fin.read(2) # Read second data, number between -32768 and 32767
S3=struct.unpack("h",S3String)
r["S3"]=S3[0]
S4String=fin.read(2) # Read second data, number between -32768 and 32767
S4=struct.unpack("h",S4String)
r["S4"]=S4[0]
S5String=fin.read(2) # Read second data, number between -32768 and 32767
S5=struct.unpack("h",S5String)
r["S5"]=S5[0]
fin.close()
return r