mp3文件的时间长度

你可以用 pymad . 这是一个外部图书馆,但不要落入“不在这里发明”的陷阱。您不需要任何外部库的具体原因是什么?

import mad

mf = mad.MadFile("foo.mp3")
track_length_in_milliseconds = mf.total_time()    

斑点 here .

如果您确实不想使用外部库,请查看 here 看看他是怎么做到的。警告:这很复杂。

为了谷歌追随者的利益,这里还有一些外部LIB:

mpg321-t

midentify(基本上是mplayer)请参见 Using mplayer to determine length of audio/video file

mencoder(将无效参数传递给它,它会发出错误消息,但也会提供有关该文件的信息,例如$mencoder inputfile.mp3-o false)

http://mediainfo.sourceforge.net/en

出口工具

linux“file”命令

mp3info

短袜队

参考文献: https://superuser.com/questions/36871/linux-command-line-utility-to-determine-mp3-bitrate

http://www.ruby-forum.com/topic/139468

mp3 length in milliseconds

在Python中,解析MP3二进制blob以计算一些东西很简单

这听起来是个很高的要求。我不懂Python,但这里有一些代码是我从另一个我曾经试图编写的程序中重构出来的。

它是C++的(抱歉,这是我的)。同样,它只处理恒定比特率的MPEG 1音频层3文件。那个 应该

// determines the duration, in seconds, of an MP3;
// assumes MPEG 1 (not 2 or 2.5) Audio Layer 3 (not 1 or 2)
// constant bit rate (not variable)

#include <iostream>
#include <fstream>
#include <cstdlib>

using namespace std;

//Bitrates, assuming MPEG 1 Audio Layer 3
const int bitrates[16] = {
         0,  32000,  40000,  48000,  56000,  64000,  80000,   96000,
    112000, 128000, 160000, 192000, 224000, 256000, 320000,       0
  };


//Intel processors are little-endian;
//search Google or see: http://en.wikipedia.org/wiki/Endian
int reverse(int i)
{
    int toReturn = 0;
    toReturn |= ((i & 0x000000FF) << 24);
    toReturn |= ((i & 0x0000FF00) << 8);
    toReturn |= ((i & 0x00FF0000) >> 8);
    toReturn |= ((i & 0xFF000000) >> 24);
    return toReturn;
}

//In short, data in ID3v2 tags are stored as
//"syncsafe integers". This is so the tag info
//isn't mistaken for audio data, and attempted to
//be "played". For more info, have fun Googling it.
int syncsafe(int i)
{
 int toReturn = 0;
 toReturn |= ((i & 0x7F000000) >> 24);
 toReturn |= ((i & 0x007F0000) >>  9);
 toReturn |= ((i & 0x00007F00) <<  6);
 toReturn |= ((i & 0x0000007F) << 21);
 return toReturn;     
}

//How much room does ID3 version 1 tag info
//take up at the end of this file (if any)?
int id3v1size(ifstream& infile)
{
   streampos savePos = infile.tellg(); 

   //get to 128 bytes from file end
   infile.seekg(0, ios::end);
   streampos length = infile.tellg() - (streampos)128;
   infile.seekg(length);

   int size;
   char buffer[3] = {0};
   infile.read(buffer, 3);
   if( buffer[0] == 'T' && buffer[1] == 'A' && buffer[2] == 'G' )
     size = 128; //found tag data
   else
     size = 0; //nothing there

   infile.seekg(savePos);

   return size;

}

//how much room does ID3 version 2 tag info
//take up at the beginning of this file (if any)
int id3v2size(ifstream& infile)
{
   streampos savePos = infile.tellg(); 
   infile.seekg(0, ios::beg);

   char buffer[6] = {0};
   infile.read(buffer, 6);
   if( buffer[0] != 'I' || buffer[1] != 'D' || buffer[2] != '3' )
   {   
       //no tag data
       infile.seekg(savePos);
       return 0;
   }

   int size = 0;
   infile.read(reinterpret_cast<char*>(&size), sizeof(size));
   size = syncsafe(size);

   infile.seekg(savePos);
   //"size" doesn't include the 10 byte ID3v2 header
   return size + 10;
}

int main(int argCount, char* argValues[])
{
  //you'll have to change this
  ifstream infile("C:/Music/Bush - Comedown.mp3", ios::binary);

  if(!infile.is_open())
  {
   infile.close();
   cout << "Error opening file" << endl;
   system("PAUSE");
   return 0;
  }

  //determine beginning and end of primary frame data (not ID3 tags)
  infile.seekg(0, ios::end);
  streampos dataEnd = infile.tellg();

  infile.seekg(0, ios::beg);
  streampos dataBegin = 0;

  dataEnd -= id3v1size(infile);
  dataBegin += id3v2size(infile);

  infile.seekg(dataBegin,ios::beg);

  //determine bitrate based on header for first frame of audio data
  int headerBytes = 0;
  infile.read(reinterpret_cast<char*>(&headerBytes),sizeof(headerBytes));

  headerBytes = reverse(headerBytes);
  int bitrate = bitrates[(int)((headerBytes >> 12) & 0xF)];

  //calculate duration, in seconds
  int duration = (dataEnd - dataBegin)/(bitrate/8);

  infile.close();

  //print duration in minutes : seconds
  cout << duration/60 << ":" << duration%60 << endl;

  system("PAUSE");
  return 0;
}

简单使用 mutagen

$pip install mutagen

from mutagen.mp3 import MP3
audio = MP3(file_path)
print audio.info.length

https://github.com/sampsyo/audioread

audio = audioread.audio_open('/path/to/mp3')
print audio.channels, audio.samplerate, audio.duration

这种方法适用于CBR文件(恒定比特率),VBR文件的工作原理则完全不同。

对于第一层文件,请使用以下公式:

帧长字节=(12*比特率/采样器+填充)*4

FrameLengthInBytes=144*比特率/采样率+填充

Information about MPEG Audio Frame Header