我搜索了很多，但找不到任何相关内容...我正在处理 iOS 音频文件，这就是我想要做的...
AVAudioRecorder 完成此操作）我有两个标记，即开始和结束偏移量，使用此信息我想修剪记录的文件并将其保存回来。我不想使用“搜索”，因为稍后我想同步播放所有录制的文件（就像时间轴中的 Flash 电影剪辑一样），最后我想导出为一个音频文件。
【问题讨论】：
这是我用来从预先存在的文件中修剪音频的代码。如果您已保存或正在保存为其他格式，则需要更改 M4A 相关常量。
- (BOOL)trimAudio
{
float vocalStartMarker = <starting time>;
float vocalEndMarker = <ending time>;
NSURL *audioFileInput = <your pre-existing file>;
NSURL *audioFileOutput = <the file you want to create>;
if (!audioFileInput || !audioFileOutput)
{
return NO;
}
[[NSFileManager defaultManager] removeItemAtURL:audioFileOutput error:NULL];
AVAsset *asset = [AVAsset assetWithURL:audioFileInput];
AVAssetExportSession *exportSession = [AVAssetExportSession exportSessionWithAsset:asset
presetName:AVAssetExportPresetAppleM4A];
if (exportSession == nil)
{
return NO;
}
CMTime startTime = CMTimeMake((int)(floor(vocalStartMarker * 100)), 100);
CMTime stopTime = CMTimeMake((int)(ceil(vocalEndMarker * 100)), 100);
CMTimeRange exportTimeRange = CMTimeRangeFromTimeToTime(startTime, stopTime);
exportSession.outputURL = audioFileOutput;
exportSession.outputFileType = AVFileTypeAppleM4A;
exportSession.timeRange = exportTimeRange;
[exportSession exportAsynchronouslyWithCompletionHandler:^
{
if (AVAssetExportSessionStatusCompleted == exportSession.status)
{
// It worked!
}
else if (AVAssetExportSessionStatusFailed == exportSession.status)
{
// It failed...
}
}];
return YES;
}
还有Technical Q&A 1730，它给出了一个更详细的方法。
【讨论】：
在 .m 中导入以下两个库
#import "BJRangeSliderWithProgress.h"
#import < AVFoundation/AVFoundation.h >
粘贴以下代码后，您将能够在两个拇指的帮助下修剪音频文件。
- (void) viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
mySlider = [[BJRangeSliderWithProgress alloc] initWithFrame:CGRectMake(20, 100, 300, 50)];
[mySlider setDisplayMode:BJRSWPAudioSetTrimMode];
[mySlider addTarget:self action:@selector(valueChanged) forControlEvents:UIControlEventValueChanged];
[mySlider setMinValue:0.0];
NSString *strInputFilePath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"saewill.mp3"];
NSURL *audioFileInput = [NSURL fileURLWithPath:strInputFilePath];
audioPlayer=[[AVAudioPlayer alloc]initWithContentsOfURL:audioFileInput error:nil];
[mySlider setMaxValue:audioPlayer.duration];
[self.view addSubview:mySlider];
}
-(void)valueChanged {
NSLog(@"%f %f", mySlider.leftValue, mySlider.rightValue);
}
-(IBAction)playTheSong
{
// Path of your source audio file
NSString *strInputFilePath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"saewill.mp3"];
NSURL *audioFileInput = [NSURL fileURLWithPath:strInputFilePath];
// Path of your destination save audio file
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES);
NSString *libraryCachesDirectory = [paths objectAtIndex:0];
//libraryCachesDirectory = [libraryCachesDirectory stringByAppendingPathComponent:@"Caches"];
NSString *strOutputFilePath = [libraryCachesDirectory stringByAppendingPathComponent:@"output.mov"];
NSString *requiredOutputPath = [libraryCachesDirectory stringByAppendingPathComponent:@"output.m4a"];
NSURL *audioFileOutput = [NSURL fileURLWithPath:requiredOutputPath];
[[NSFileManager defaultManager] removeItemAtURL:audioFileOutput error:NULL];
AVAsset *asset = [AVAsset assetWithURL:audioFileInput];
AVAssetExportSession *exportSession = [AVAssetExportSession exportSessionWithAsset:asset
presetName:AVAssetExportPresetAppleM4A];
float startTrimTime = mySlider.leftValue;
float endTrimTime = mySlider.rightValue;
CMTime startTime = CMTimeMake((int)(floor(startTrimTime * 100)), 100);
CMTime stopTime = CMTimeMake((int)(ceil(endTrimTime * 100)), 100);
CMTimeRange exportTimeRange = CMTimeRangeFromTimeToTime(startTime, stopTime);
exportSession.outputURL = audioFileOutput;
exportSession.outputFileType = AVFileTypeAppleM4A;
exportSession.timeRange = exportTimeRange;
[exportSession exportAsynchronouslyWithCompletionHandler:^
{
if (AVAssetExportSessionStatusCompleted == exportSession.status)
{
NSLog(@"Success!");
NSLog(@" OUtput path is \n %@", requiredOutputPath);
NSFileManager * fm = [[NSFileManager alloc] init];
[fm moveItemAtPath:strOutputFilePath toPath:requiredOutputPath error:nil];
//[[NSFileManager defaultManager] removeItemAtURL:audioFileOutput error:NULL];
NSURL *url=[NSURL fileURLWithPath:requiredOutputPath];
NSError *error;
audioPlayer=[[AVAudioPlayer alloc]initWithContentsOfURL:url error:&error];
audioPlayer.numberOfLoops=0;
[audioPlayer play];
}
else if (AVAssetExportSessionStatusFailed == exportSession.status)
{
NSLog(@"failed with error: %@", exportSession.error.localizedDescription);
}
}];
}
【讨论】：
这是一个示例代码，它从开始和结束偏移量修剪音频文件并将其保存回来。 请检查此iOS Audio Trimming。
// Path of your source audio file
NSString *strInputFilePath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"abc.mp3"];
NSURL *audioFileInput = [NSURL fileURLWithPath:strInputFilePath];
// Path of your destination save audio file
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES);
NSString *libraryCachesDirectory = [paths objectAtIndex:0];
libraryCachesDirectory = [libraryCachesDirectory stringByAppendingPathComponent:@"Caches"];
NSString *strOutputFilePath = [NSString stringWithFormat:@"%@%@",libraryCachesDirectory,@"/abc.mp4"];
NSURL *audioFileOutput = [NSURL fileURLWithPath:strOutputFilePath];
if (!audioFileInput || !audioFileOutput)
{
return NO;
}
[[NSFileManager defaultManager] removeItemAtURL:audioFileOutput error:NULL];
AVAsset *asset = [AVAsset assetWithURL:audioFileInput];
AVAssetExportSession *exportSession = [AVAssetExportSession exportSessionWithAsset:asset presetName:AVAssetExportPresetAppleM4A];
if (exportSession == nil)
{
return NO;
}
float startTrimTime = 0;
float endTrimTime = 5;
CMTime startTime = CMTimeMake((int)(floor(startTrimTime * 100)), 100);
CMTime stopTime = CMTimeMake((int)(ceil(endTrimTime * 100)), 100);
CMTimeRange exportTimeRange = CMTimeRangeFromTimeToTime(startTime, stopTime);
exportSession.outputURL = audioFileOutput;
exportSession.outputFileType = AVFileTypeAppleM4A;
exportSession.timeRange = exportTimeRange;
[exportSession exportAsynchronouslyWithCompletionHandler:^
{
if (AVAssetExportSessionStatusCompleted == exportSession.status)
{
NSLog(@"Success!");
}
else if (AVAssetExportSessionStatusFailed == exportSession.status)
{
NSLog(@"failed");
}
}];
【讨论】：
// 斯威夫特 4.2
如果有人仍然在此处快速寻找答案。
//音频修剪
func trimAudio(asset: AVAsset, startTime: Double, stopTime: Double, finished:@escaping (URL) -> ())
{
let compatiblePresets = AVAssetExportSession.exportPresets(compatibleWith:asset)
if compatiblePresets.contains(AVAssetExportPresetMediumQuality) {
guard let exportSession = AVAssetExportSession(asset: asset,
presetName: AVAssetExportPresetAppleM4A) else{return}
// Creating new output File url and removing it if already exists.
let furl = createUrlInAppDD("trimmedAudio.m4a") //Custom Function
removeFileIfExists(fileURL: furl) //Custom Function
exportSession.outputURL = furl
exportSession.outputFileType = AVFileType.m4a
let start: CMTime = CMTimeMakeWithSeconds(startTime, preferredTimescale: asset.duration.timescale)
let stop: CMTime = CMTimeMakeWithSeconds(stopTime, preferredTimescale: asset.duration.timescale)
let range: CMTimeRange = CMTimeRangeFromTimeToTime(start: start, end: stop)
exportSession.timeRange = range
exportSession.exportAsynchronously(completionHandler: {
switch exportSession.status {
case .failed:
print("Export failed: \(exportSession.error!.localizedDescription)")
case .cancelled:
print("Export canceled")
default:
print("Successfully trimmed audio")
DispatchQueue.main.async(execute: {
finished(furl)
})
}
})
}
}
您也可以将其用于视频剪辑。对于视频修剪，将导出会话的值替换为如下：
guard let exportSession = AVAssetExportSession(asset:asset, presetName: AVAssetExportPresetPassthrough) else{return}
文件类型为 mp4
exportSession.outputFileType = AVFileType.mp4
【讨论】：