我使用 AVAudioRecorder 录制并保存 caf 音频文件。当我将 (300 mb).caf 转换为 .wav 格式时,应用程序因错误而崩溃(收到内存警告。级别 = 1 和收到内存警告。级别 = 2)。如何使用 NSInputStream 读取音频文件和 NSOutputStream 写入音频文件。
-(void) convertToWav:(NSNumber *) numIndex
{
// set up an AVAssetReader to read from the iPod Library
int index = [numIndex integerValue];
NSString *strName;
NSString *strFilePath1 =[delegate.strCassettePathSide stringByAppendingPathComponent:@"audio_list.plist"];
bool bTapeInfoFileExists = [[NSFileManager defaultManager] fileExistsAtPath:strFilePath1];
if (bTapeInfoFileExists)
{
NSMutableDictionary *dictInfo = [[NSMutableDictionary alloc] initWithContentsOfFile:strFilePath1];
if ([dictInfo valueForKey:@"lastName"])
strName =[dictInfo valueForKey:@"lastName"];
else
strName= [delegate.arrNameList objectAtIndex:0];
}
else
{
strName = [delegate.arrNameList objectAtIndex:0];
}
NSString *cafFilePath =[[delegate.arrSessionList objectAtIndex:index] valueForKey:@"path"];
NSURL *assetURL = [NSURL fileURLWithPath:cafFilePath];
AVURLAsset *songAsset = [AVURLAsset URLAssetWithURL:assetURL options:nil];
NSError *assetError = nil;
AVAssetReader *assetReader = [AVAssetReader assetReaderWithAsset:songAsset
error:&assetError]
;
if (assetError) {
NSLog (@"error: %@", assetError);
return;
}
AVAssetReaderOutput *assetReaderOutput = [AVAssetReaderAudioMixOutput
assetReaderAudioMixOutputWithAudioTracks:songAsset.tracks
audioSettings: nil];
if (! [assetReader canAddOutput: assetReaderOutput]) {
NSLog (@"can't add reader output... die!");
return;
}
[assetReader addOutput: assetReaderOutput];
NSString *strWavFileName = [NSString stringWithFormat:@"%@.wav",[[cafFilePath lastPathComponent] stringByDeletingPathExtension]];
NSString *wavFilePath = [delegate.strCassettePathSide stringByAppendingPathComponent:strWavFileName];
if ([[NSFileManager defaultManager] fileExistsAtPath:wavFilePath])
{
[[NSFileManager defaultManager] removeItemAtPath:wavFilePath error:nil];
}
NSURL *exportURL = [NSURL fileURLWithPath:wavFilePath];
AVAssetWriter *assetWriter = [AVAssetWriter assetWriterWithURL:exportURL
fileType:AVFileTypeWAVE
error:&assetError];
if (assetError)
{
NSLog (@"error: %@", assetError);
return;
}
AppDelegate *appDelegate =[[UIApplication sharedApplication]delegate];
int nSampleRate=[[appDelegate.dictWAVQuality valueForKey:@"samplerate"] integerValue];
AudioChannelLayout channelLayout;
memset(&channelLayout, 0, sizeof(AudioChannelLayout));
channelLayout.mChannelLayoutTag = kAudioChannelLayoutTag_Stereo;
NSDictionary *outputSettings = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithInt:kAudioFormatLinearPCM], AVFormatIDKey,
[NSNumber numberWithFloat:nSampleRate], AVSampleRateKey,
[NSNumber numberWithInt:2], AVNumberOfChannelsKey,
[NSData dataWithBytes:&channelLayout length:sizeof(AudioChannelLayout)], AVChannelLayoutKey,
[NSNumber numberWithInt:16], AVLinearPCMBitDepthKey,
[NSNumber numberWithBool:NO], AVLinearPCMIsNonInterleaved,
[NSNumber numberWithBool:NO],AVLinearPCMIsFloatKey,
[NSNumber numberWithBool:NO], AVLinearPCMIsBigEndianKey,
nil];
AVAssetWriterInput *assetWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio
outputSettings:outputSettings];
if ([assetWriter canAddInput:assetWriterInput])
{
[assetWriter addInput:assetWriterInput];
}
else
{
NSLog(@"can't add asset writer input... die!");
return;
}
assetWriterInput.expectsMediaDataInRealTime = NO;
[assetWriter startWriting];
[assetReader startReading];
AVAssetTrack *soundTrack = [songAsset.tracks objectAtIndex:0];
CMTime startTime = CMTimeMake (0, soundTrack.naturalTimeScale);
[assetWriter startSessionAtSourceTime: startTime];
__block UInt64 convertedByteCount = 0;
dispatch_queue_t mediaInputQueue = dispatch_queue_create("mediaInputQueue", NULL);
[assetWriterInput requestMediaDataWhenReadyOnQueue:mediaInputQueue
usingBlock: ^
{
while (assetWriterInput.readyForMoreMediaData)
{
CMSampleBufferRef nextBuffer = [assetReaderOutput copyNextSampleBuffer];
if (nextBuffer)
{
// append buffer
[assetWriterInput appendSampleBuffer: nextBuffer];
convertedByteCount += CMSampleBufferGetTotalSampleSize (nextBuffer);
}
else
{
[assetWriterInput markAsFinished];
// [assetWriter finishWriting];
[assetReader cancelReading];
[dictTemp setValue:wavFilePath forKey:@"path"];
[dictTemp setValue:nil forKey:@"progress"];
[delegate.arrSessionList replaceObjectAtIndex:index withObject:dictTemp];
NSString *strListFilePath = [delegate.strCassettePathSide stringByAppendingPathComponent:@"audiolist.plist"];
[delegate.arrSessionList writeToFile:strListFilePath atomically:YES];
break;
}
}
}];}