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Updated on 2025-05-20

Code examples for intercepting and splitting audio and video in iOS

Code examples for intercepting and splitting audio and video in iOS

Updated: May 20, 2025 08:26:47 Author: Chenzai, born in the 1990s
In iOS development, intercepting or segmenting audio and video is a common requirement, suitable for short video editing, voice message cropping, media content editing and other scenarios. This function can be efficiently implemented using the AVFoundation framework. The following will introduce in detail how to intercept or segment audio and video in iOS, and provide complete code examples and usage methods. Friends who need it can refer to it.

Core idea

The core steps for intercepting or segmenting audio and video are as follows:

  • Load original audio and video files（AVURLAsset）
  • Set the time range（CMTimeRange) Specify the start time and duration to be intercepted
  • Create an export session（AVAssetExportSession）
  • Export the target file(support.mp4、.m4aetc.)
  • Handle asynchronous export completion callback

Video Intercept Example (Objective-C)

- (void)trimVideoFromURL:(NSURL *)inputURL startTime:(NSTimeInterval)startTime duration:(NSTimeInterval)duration completion:(void (^)(NSURL *outputURL, NSError *error))completion {
    AVURLAsset *asset = [AVURLAsset URLAssetWithURL:inputURL options:nil];
    
    // 1. Create an export session    AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:asset presetName:AVAssetExportPresetHighestQuality];
    
    // 2. Set the output path and file format    NSString *outputPath = [NSTemporaryDirectory() stringByAppendingPathComponent:@"trimmedVideo.mp4"];
     = [NSURL fileURLWithPath:outputPath];
     = AVFileTypeMPEG4;
    
    // 3. Set the time range (start ~ start + duration)    CMTime startCMTime = CMTimeMakeWithSeconds(startTime, 600);
    CMTime durationCMTime = CMTimeMakeWithSeconds(duration, 600);
    CMTimeRange timeRange = CMTimeRangeMake(startCMTime, durationCMTime);
     = timeRange;
    
    // 4. Asynchronous export    [exportSession exportAsynchronouslyWithCompletionHandler:^{
        if ( == AVAssetExportSessionStatusCompleted) {
            NSLog(@"Video intercepted successfully: %@", outputPath);
            if (completion) completion([NSURL fileURLWithPath:outputPath], nil);
        } else {
            NSError *error = ;
            NSLog(@"Video interception failed: %@", );
            if (completion) completion(nil, error);
        }
    }];
}

How to use

NSURL *videoURL = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"myVideo" ofType:@"mp4"]];
[self trimVideoFromURL:videoURL startTime:5.0 duration:10.0 completion:^(NSURL *outputURL, NSError *error) {
    if (outputURL) {
        NSLog(@"Intercepted video path: %@", );
    }
}];

Audio intercepting example (Objective-C)

- (void)trimAudioFromURL:(NSURL *)inputURL startTime:(NSTimeInterval)startTime duration:(NSTimeInterval)duration completion:(void (^)(NSURL *outputURL, NSError *error))completion {
    AVURLAsset *asset = [AVURLAsset URLAssetWithURL:inputURL options:nil];
    
    AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:asset presetName:AVAssetExportPresetAppleM4A];
    
    NSString *outputPath = [NSTemporaryDirectory() stringByAppendingPathComponent:@"trimmedAudio.m4a"];
     = [NSURL fileURLWithPath:outputPath];
     = AVFileTypeAppleM4A;
    
    CMTime startCMTime = CMTimeMakeWithSeconds(startTime, 600);
    CMTime durationCMTime = CMTimeMakeWithSeconds(duration, 600);
    CMTimeRange timeRange = CMTimeRangeMake(startCMTime, durationCMTime);
     = timeRange;
    
    [exportSession exportAsynchronouslyWithCompletionHandler:^{
        if ( == AVAssetExportSessionStatusCompleted) {
            NSLog(@"Audio interception successfully: %@", outputPath);
            if (completion) completion([NSURL fileURLWithPath:outputPath], nil);
        } else {
            NSError *error = ;
            NSLog(@"Audio interception failed: %@", );
            if (completion) completion(nil, error);
        }
    }];
}

How to use

NSURL *audioURL = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"myAudio" ofType:@"mp3"]];
[self trimAudioFromURL:audioURL startTime:3.0 duration:5.0 completion:^(NSURL *outputURL, NSError *error) {
    if (outputURL) {
        NSLog(@"Intercepted audio path: %@", );
    }
}];

Things to note

project illustrate
Time unit useCMTimeMakeWithSecondsConvert seconds toCMTime
Output path useNSTemporaryDirectory()Avoid storage problems
Output format Video recommendation.mp4, audio recommendation.m4aor.caf
Export performance useAVAssetExportPresetLowQualityCan improve processing speed
Error handling examineand

Extension suggestions

  • Multi-fragment splicing: Can be combinedAVMutableCompositionRealize multi-section cropped content splicing.
  • Background export: It is recommended to execute large files in the background thread to avoid blocking the main thread.
  • Third-party library: If you need more complex editing functions, you can useFFmpeg-iOSorGPUImage。

Summarize

passAVAssetExportSessionoftimeRangeProperties, you can easily intercept content from any time period from audio and video files. This method is suitable for both audio and video, with good compatibility and performance, and is one of the basic skills in iOS audio and video processing.

The above is the detailed content of the code example for intercepting and segmenting audio and video in iOS. For more information about intercepting and segmenting audio and video in iOS, please pay attention to my other related articles!

  • iOS
  • Intercept
  • segmentation
  • Audio and video

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