How do I find the length of an audio file?
Audio files come in many different formats like MP3, WAV, FLAC, and AAC. Some of the most commonly used formats today are MP3 for compressed audio and WAV for uncompressed CD-quality audio (Source). Audio files can vary greatly in length depending on factors like their bitrate, sampling rate, and duration of the recorded audio.
There are many reasons why someone may want to find the length of an audio file. Some common use cases include:
- Checking if an audio file will fit on a CD
- Verifying the length of audio used in video editing projects
- Organizing music tracks by length
- Estimating the size of audio files before downloading them
- Labeling audio files with their duration
Knowing the length of audio files allows better media management and ensures the right audio is selected for specific applications. This guide will cover multiple methods to check audio length on different platforms.
Check File Properties
The most straightforward way to check the length of an audio file is to view its file properties. Most operating systems show basic file information like name, date modified, and file size when you right-click on a file and select “Properties”.
On Windows, right-click on the audio file and choose Properties. In the Details tab, look for “Duration” to see the length in HH:MM:SS format.
On Mac, Control-click the file and select Get Info. Look under More Info for the audio length in seconds.
On Linux distributions like Ubuntu, right-click and go to Properties > Details to find audio length.
On iOS, tap and hold on the file, then tap the ‘i’ icon to see details including duration.
On Android, long press on the file and select Details. Scroll down to view the length.
Checking file properties is the easiest way to quickly get audio length information on any platform.
Use a Media Player
Many popular media players like VLC, iTunes, and Windows Media Player will display the length of audio files. This can be a quick and easy way to find the duration.
In VLC, the total duration of an audio playlist is shown at the top of the left menu when in Playlist view. You can also right-click on individual files and select “Information” to see the length of that file (Source). In newer versions of VLC the total playlist duration may be hidden, but can be revealed by resizing the menu (Source).
iTunes and Windows Media Player similarly display the length of the currently playing audio track. You can also right-click on a file and view the properties to find the exact duration.
So if you already use a media player to listen to your audio files, check there first as it likely provides an easy way to see the length.
Use Command Line Tools
For advanced users, command line tools like ffprobe or mediainfo can show length:
To get audio length with ffprobe, first install ffmpeg which includes ffprobe. Then run a command like:
ffprobe -i audiofile.mp3 -show_entries format=duration -v quiet -of csv="p=0"
This will output the duration in seconds. See this Stack Overflow post for more details.
Mediainfo is another command line tool to get metadata like duration. After installing, run:
mediainfo audiofile.mp3
And look for the duration value. See the Mediainfo documentation for more information.
These command line methods provide accurate length data and work for any audio format. However they do require some technical skill to install and use.
Use Audio Editing Software
Audio editing tools like Audacity and Garageband will display the length of audio files you open. This makes it easy to quickly check the duration.
For example, in Audacity you can open an audio file and look in the Track Control Panel. Enable the “Length” option to see the total duration of the track. You can also select a portion of the audio and Audacity will show the selection length.
Likewise, in Garageband on Mac, simply open an audio file and look at the timeline ruler at the top. This will show the total length in minutes and seconds. You can also select a section and see the selection length.
So audio editing applications provide a handy way to visually see the duration of an audio file without needing to play through the entire thing.
Online Audio Length Checkers
There are various websites that can check the length of audio files online. These sites allow you to easily upload an audio file and will analyze it to determine the duration.
Sites like Online-Convert and Convertio have free audio length checkers. To use them, go to the site and select the “Audio” or “Audio duration” tool. Then click upload and select the audio file from your computer. Once uploaded, the site will process the file and show the length in minutes and seconds.
Other sites like Audio Length Checker and Audio File Calculator are dedicated solely to checking audio length. These sites work similarly – simply upload your audio file and it will automatically analyze the length. Some also extract and display other metadata like bitrate.
Online audio length checkers provide a quick and easy way to get the duration of an audio file without needing to install any specialized software. They support common formats like MP3, WAV, FLAC, M4A and more. Just make sure your audio file is 10MB or less for the online checkers to process.
Extract Length Data Programmatically
Developers can programmatically extract length data using libraries like mutagen:
import mutagen
from mutagen.mp3 import MP3
audio = MP3("example.mp3")
print(audio.info.length)
This simple Python snippet uses mutagen to open the MP3 file and print its length in seconds. Similar libraries exist for other languages like Node.js.
Here is an example in JavaScript using the wavesurfer.js library:
var wavesurfer = WaveSurfer.create({
container: '#waveform'
});
wavesurfer.load('example.wav');
wavesurfer.on('ready', function() {
var duration = wavesurfer.getDuration();
console.log(duration);
});
This loads the audio file, then prints its duration in seconds once it’s finished loading. Programmatic access allows developers to easily integrate audio length data into applications.
Considerations for Length Data Accuracy
The displayed length of an audio file may differ slightly from the actual length due to a variety of factors. Sampling frequency, bit rate, encoder settings, and rounding can all impact the precision of length measurements.
For example, an MP3 file encoded at a constant bit rate of 128kbps will display a length rounded to the nearest second. However, the actual duration may be a fraction of a second longer or shorter. This rounding imprecision accumulates for long files. WAV and FLAC files often provide sample-accurate length data.
Additionally, some media players and command line tools rely on metadata tags for length, which could be incorrectly set or imprecise. Checking multiple sources can help identify any discrepancy between reported and actual duration.
For maximum accuracy, length should be extracted directly from the media data stream or calculated from the source parameters like sampling rate. Audio editing software can usually determine highly precise lengths.
Understanding these factors allows you to determine if a small deviation in reported duration is expected and reasonable. While length data may not be exact down to the millisecond, it still provides a good general indication of an audio file’s playtime.
Other Metadata Available
Along with length, other metadata like bitrate, channels can be viewed for audio files. This additional metadata provides more technical details about the audio file.
Metadata like bitrate (quality of audio encoding) and channels (mono, stereo etc) can typically be found in the same locations as the length data:
- File properties window in Windows Explorer or Mac Finder
- Media players like VLC and iTunes
- Audio editing software like Audacity
- Online audio metadata viewers
- Command line tools like ffprobe
Having access to full metadata provides a comprehensive technical profile of an audio file beyond just its length.
Conclusion
There are several methods available to find the length of an audio file. You can view the file properties in your operating system to see the reported duration. Media players like VLC can also display the length when you open the file. For batch operations, you can use command line tools like ffprobe or Sox to extract the duration. Audio editing software like Audacity reads audio metadata and can show you the length as well. Online audio length checkers provide a quick way to get the duration without downloading any software. And for developers, audio duration can be programmatically extracted by reading the metadata with libraries like Mutagen in Python.
When looking at audio length, it’s important to keep in mind factors that affect accuracy. The desired length is the actual duration of the audio content. However, the reported duration may differ slightly in some cases. Low sample rates can cause rounding errors in the length calculation. Variable bitrates may also lead to imprecise duration values. And lossy compression like MP3 encoding can alter the audio data in a way that changes the duration estimate. So when precision is important, use original high quality uncompressed audio files.