mp3文件的时间长度

时间:2008-09-23 06:33:15

标签: python mp3 media

确定给定mp3文件的长度(以秒为单位)的最简单方法是什么,不使用外部库? (蟒蛇来源高度赞赏)

6 个答案:

答案 0 :(得分:25)

您可以使用pymad。它是一个外部库,但不适用于Not Invented Here陷阱。你不想要任何外部库的任何特殊原因吗?

import mad

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

发现here

-

如果您真的不想使用外部库,请查看here并查看他是如何完成的。警告:这很复杂。

答案 1 :(得分:9)

对于谷歌粉丝来说,这里还有一些外部库:

mpg321 -t

ffmpeg -i

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

mencoder(传递它无效的params,它会吐出一条错误信息,但也会提供有关文件的信息,ex $ mencoder inputfile.mp3 -o fake)

mediainfo program http://mediainfo.sourceforge.net/en

exiftool

linux“file”命令

mp3info

SOX

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

(将其作为其他人添加的维基。)

和libs:.net:naudio,java:jlayer,c:libmad

干杯!

答案 2 :(得分:7)

  
    

简单,用Python解析MP3二进制blob来计算某些内容

  

这听起来像是一个非常高的订单。我不知道Python,但这里有一些代码我已经从我曾经尝试过的另一个程序中重构过。

注意:它是用C ++编写的(抱歉,这就是我所拥有的)。此外,原样,它只处理恒定比特率MPEG 1音频第3层文件。那个应该涵盖最多,但我无法保证在所有情况下都能正常工作。希望这可以满足您的需求,并希望将其重构为Python比从头开始更容易。

// 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;
}

答案 3 :(得分:6)

只需使用mutagen

即可
$pip install mutagen

在python shell中使用它:

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

答案 4 :(得分:3)

另外看一下audioread(包括ubuntu在内的一些Linux发行版都有包),https://github.com/sampsyo/audioread

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

答案 5 :(得分:0)

您可以计算文件中的帧数。每个帧都有一个起始码,虽然我无法回想起起始码的确切值,但我没有MPEG规范。每帧具有一定的长度,对于MPEG1第二层约为40ms。

此方法适用于CBR文件(恒定比特率),VBR文件的工作方式完全不同。

从以下文件中:

对于第一层文件我们这个公式:

FrameLengthInBytes =(12 * BitRate / SampleRate + Padding)* 4

对于第二层和第二层III文件使用以下公式:

FrameLengthInBytes = 144 * BitRate / SampleRate + Padding

Information about MPEG Audio Frame Header