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iphonecocoa-touch
Ilya Suzdalnitski
Ilya Suzdalnitski

Reputation: 53540

iPhone: get duration of an audio file

What is the easiest way to get a duration of an audio file?

I could create an object of AVAudioPlayer, initialize it with URL and than get the duration, but this way is too long. Is there an easier way?

Thanks.

Upvotes: 9

Views: 8597

Answers (8)

Nazir
Nazir

Reputation: 1975

sample code from answer How to get the duration of an audio file in iOS?. This is the best answer.

AVURLAsset* audioAsset = [AVURLAsset URLAssetWithURL:audioFileURL options:nil]; 
CMTime audioDuration = audioAsset.duration; 
float audioDurationSeconds = CMTimeGetSeconds(audioDuration);

Upvotes: 1

pgb
pgb

Reputation: 25001

You can use the Audio File Services functions. There's one property to get that should give you the estimated duration. Code:

    NSURL *afUrl = [NSURL fileURLWithPath:soundPath];
    AudioFileID fileID;
    OSStatus result = AudioFileOpenURL((CFURLRef)afUrl, kAudioFileReadPermission, 0, &fileID);
    Float64 outDataSize = 0;
    UInt32 thePropSize = sizeof(Float64);
    result = AudioFileGetProperty(fileID, kAudioFilePropertyEstimatedDuration, &thePropSize, &outDataSize);
    AudioFileClose(fileID);

You can check the docs here

Upvotes: 10

Ishwar Hingu
Ishwar Hingu

Reputation: 560

 AVURLAsset* audioAsset = [AVURLAsset URLAssetWithURL:mp3_url options:nil];
                    [audioAsset loadValuesAsynchronouslyForKeys:@[@"duration"] completionHandler:^{
                        CMTime audioDuration = audioAsset.duration;
                        float audioDurationSeconds = CMTimeGetSeconds(audioDuration);

                        NSLog(@"duration:%f",audioDurationSeconds);
                    }];

Upvotes: 1

Mazyod
Mazyod

Reputation: 22559

Combining AVAudioPlayer with Swift becomes as easy as (I am migrating a Realm table below, but you get the idea):

import AVFoundation

let resource = old!["filename"] as? String
let afUrl = NSBundle.mainBundle().URLForResource(resource, withExtension: nil)
let player = try! AVAudioPlayer(contentsOfURL: afUrl!)

new!["duration"] = Double(player.duration)

Upvotes: 2

newenglander
newenglander

Reputation: 2049

In case anyone lands here looking for a way to get the duration for both audio and video files, have a look at this answer to another post, which instead uses AVAsset instead:

https://stackoverflow.com/a/7052147/381233

Using AudioFileGetProperty (like the other two main answers here) to get the duration of A/V files didn't work for a few .mov files on my device (result was always 0), while the solution using AVAsset got the duration for all audio and video files on my device.

(Interestingly enough, however, the duration from both solutions was sometimes 1 second more than that displayed in the UI of an actual AVAudioPlayer. Most likely the AVAudioPlayer uses a non-standard rounding routine for the displayed duration.)

Upvotes: 1

Farhad Malekpour
Farhad Malekpour

Reputation: 1394

Correct code is 

NSURL *afUrl = [NSURL fileURLWithPath:soundPath];
AudioFileID fileID;
OSStatus result = AudioFileOpenURL((CFURLRef)afUrl, kAudioFileReadPermission, 0, &fileID);
Float64 outDataSize = 0;
UInt32 thePropSize = sizeof(Float64);
result = AudioFileGetProperty(fileID, kAudioFilePropertyEstimatedDuration, &thePropSize, &outDataSize);
AudioFileClose(fileID);

outDataSize should be Float64 not UInt64.

Upvotes: 15

MusiGenesis
MusiGenesis

Reputation: 75296

It depends on the file type. If it's a WAV file you can locate the file's header and determine the playback duration that way. If it's a compressed format (*.mp3 etc.) you're better off sticking to the method you mentioned.

Upvotes: 2

Dave Gamble
Dave Gamble

Reputation: 4174

If you know anything about the audio file in question (samplerate, bitdepth, channel count), and it's an uncompressed format (WAV/AIFF), then you can calculate the /approximate/ duration from the filesize:

length_in_seconds = (file_length-guess_100_bytes_for_header) / (samplerate*(bitdepth*channel_count/8))

Upvotes: 2

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