IOS上的WaveForm
我正在寻找如何绘制声音的幅度。
我发现http://supermegaultragroovy.com/2009/10/06/drawing-waveforms/，但我有一些问题。 如何得到表示audio的浮点值列表？
谢谢大家。
我在这里find了这个例子： 使用AVAssetReader绘制波形 ，改变它并基于。开发一个新的类。
这个类返回UIImageView。
//.h file #import <UIKit/UIKit.h> @interface WaveformImageVew : UIImageView{ } -(id)initWithUrl:(NSURL*)url; - (NSData *) renderPNGAudioPictogramLogForAssett:(AVURLAsset *)songAsset; @end //.m file #import "WaveformImageVew.h" #define absX(x) (x<0?0-x:x) #define minMaxX(x,mn,mx) (x<=mn?mn:(x>=mx?mx:x)) #define noiseFloor (-50.0) #define decibel(amplitude) (20.0 * log10(absX(amplitude)/32767.0)) #define imgExt @"png" #define imageToData(x) UIImagePNGRepresentation(x) @implementation WaveformImageVew -(id)initWithUrl:(NSURL*)url{ if(self = [super init]){ AVURLAsset * urlA = [AVURLAsset URLAssetWithURL:url options:nil]; [self setImage:[UIImage imageWithData:[self renderPNGAudioPictogramLogForAssett:urlA]]]; } return self; } -(UIImage *) audioImageLogGraph:(Float32 *) samples normalizeMax:(Float32) normalizeMax sampleCount:(NSInteger) sampleCount channelCount:(NSInteger) channelCount imageHeight:(float) imageHeight { CGSize imageSize = CGSizeMake(sampleCount, imageHeight); UIGraphicsBeginImageContext(imageSize); CGContextRef context = UIGraphicsGetCurrentContext(); CGContextSetFillColorWithColor(context, [UIColor blackColor].CGColor); CGContextSetAlpha(context,1.0); CGRect rect; rect.size = imageSize; rect.origin.x = 0; rect.origin.y = 0; CGColorRef leftcolor = [[UIColor whiteColor] CGColor]; CGColorRef rightcolor = [[UIColor redColor] CGColor]; CGContextFillRect(context, rect); CGContextSetLineWidth(context, 1.0); float halfGraphHeight = (imageHeight / 2) / (float) channelCount ; float centerLeft = halfGraphHeight; float centerRight = (halfGraphHeight*3) ; float sampleAdjustmentFactor = (imageHeight/ (float) channelCount) / (normalizeMax - noiseFloor) / 2; for (NSInteger intSample = 0 ; intSample < sampleCount ; intSample ++ ) { Float32 left = *samples++; float pixels = (left - noiseFloor) * sampleAdjustmentFactor; CGContextMoveToPoint(context, intSample, centerLeft-pixels); CGContextAddLineToPoint(context, intSample, centerLeft+pixels); CGContextSetStrokeColorWithColor(context, leftcolor); CGContextStrokePath(context); if (channelCount==2) { Float32 right = *samples++; float pixels = (right - noiseFloor) * sampleAdjustmentFactor; CGContextMoveToPoint(context, intSample, centerRight - pixels); CGContextAddLineToPoint(context, intSample, centerRight + pixels); CGContextSetStrokeColorWithColor(context, rightcolor); CGContextStrokePath(context); } } // Create new image UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext(); // Tidy up UIGraphicsEndImageContext(); return newImage; } - (NSData *) renderPNGAudioPictogramLogForAssett:(AVURLAsset *)songAsset { NSError * error = nil; AVAssetReader * reader = [[AVAssetReader alloc] initWithAsset:songAsset error:&error]; AVAssetTrack * songTrack = [songAsset.tracks objectAtIndex:0]; NSDictionary* outputSettingsDict = [[NSDictionary alloc] initWithObjectsAndKeys: [NSNumber numberWithInt:kAudioFormatLinearPCM],AVFormatIDKey, // [NSNumber numberWithInt:44100.0],AVSampleRateKey, /*Not Supported*/ // [NSNumber numberWithInt: 2],AVNumberOfChannelsKey, /*Not Supported*/ [NSNumber numberWithInt:16],AVLinearPCMBitDepthKey, [NSNumber numberWithBool:NO],AVLinearPCMIsBigEndianKey, [NSNumber numberWithBool:NO],AVLinearPCMIsFloatKey, [NSNumber numberWithBool:NO],AVLinearPCMIsNonInterleaved, nil]; AVAssetReaderTrackOutput* output = [[AVAssetReaderTrackOutput alloc] initWithTrack:songTrack outputSettings:outputSettingsDict]; [reader addOutput:output]; [output release]; UInt32 sampleRate,channelCount; NSArray* formatDesc = songTrack.formatDescriptions; for(unsigned int i = 0; i < [formatDesc count]; ++i) { CMAudioFormatDescriptionRef item = (CMAudioFormatDescriptionRef)[formatDesc objectAtIndex:i]; const AudioStreamBasicDescription* fmtDesc = CMAudioFormatDescriptionGetStreamBasicDescription (item); if(fmtDesc ) { sampleRate = fmtDesc->mSampleRate; channelCount = fmtDesc->mChannelsPerFrame; // NSLog(@"channels:%u, bytes/packet: %u, sampleRate %f",fmtDesc->mChannelsPerFrame, fmtDesc->mBytesPerPacket,fmtDesc->mSampleRate); } } UInt32 bytesPerSample = 2 * channelCount; Float32 normalizeMax = noiseFloor; NSLog(@"normalizeMax = %f",normalizeMax); NSMutableData * fullSongData = [[NSMutableData alloc] init]; [reader startReading]; UInt64 totalBytes = 0; Float64 totalLeft = 0; Float64 totalRight = 0; Float32 sampleTally = 0; NSInteger samplesPerPixel = sampleRate / 50; while (reader.status == AVAssetReaderStatusReading){ AVAssetReaderTrackOutput * trackOutput = (AVAssetReaderTrackOutput *)[reader.outputs objectAtIndex:0]; CMSampleBufferRef sampleBufferRef = [trackOutput copyNextSampleBuffer]; if (sampleBufferRef){ CMBlockBufferRef blockBufferRef = CMSampleBufferGetDataBuffer(sampleBufferRef); size_t length = CMBlockBufferGetDataLength(blockBufferRef); totalBytes += length; NSAutoreleasePool *wader = [[NSAutoreleasePool alloc] init]; NSMutableData * data = [NSMutableData dataWithLength:length]; CMBlockBufferCopyDataBytes(blockBufferRef, 0, length, data.mutableBytes); SInt16 * samples = (SInt16 *) data.mutableBytes; int sampleCount = length / bytesPerSample; for (int i = 0; i < sampleCount ; i ++) { Float32 left = (Float32) *samples++; left = decibel(left); left = minMaxX(left,noiseFloor,0); totalLeft += left; Float32 right; if (channelCount==2) { right = (Float32) *samples++; right = decibel(right); right = minMaxX(right,noiseFloor,0); totalRight += right; } sampleTally++; if (sampleTally > samplesPerPixel) { left = totalLeft / sampleTally; if (left > normalizeMax) { normalizeMax = left; } // NSLog(@"left average = %f, normalizeMax = %f",left,normalizeMax); [fullSongData appendBytes:&left length:sizeof(left)]; if (channelCount==2) { right = totalRight / sampleTally; if (right > normalizeMax) { normalizeMax = right; } [fullSongData appendBytes:&right length:sizeof(right)]; } totalLeft = 0; totalRight = 0; sampleTally = 0; } } [wader drain]; CMSampleBufferInvalidate(sampleBufferRef); CFRelease(sampleBufferRef); } } NSData * finalData = nil; if (reader.status == AVAssetReaderStatusFailed || reader.status == AVAssetReaderStatusUnknown){ // Something went wrong. Handle it. } if (reader.status == AVAssetReaderStatusCompleted){ // You're done. It worked. NSLog(@"rendering output graphics using normalizeMax %f",normalizeMax); UIImage *test = [self audioImageLogGraph:(Float32 *) fullSongData.bytes normalizeMax:normalizeMax sampleCount:fullSongData.length / (sizeof(Float32) * 2) channelCount:2 imageHeight:100]; finalData = imageToData(test); } [fullSongData release]; [reader release]; return finalData; } @end 一直在阅读你的问题，并为此创build了一个控件。 看起来像这样：
代码在这里：
https://github.com/fulldecent/FDWaveformView
这里讨论：
https://www.cocoacontrols.com/controls/fdwaveformview
更新2015-01-29 ：这个项目变得强大并且使得一致的版本。 感谢所有曝光的SO！
我可以给你参考一下我在应用程序中实现的。 这是苹果的例子。 AurioTouch的例子分析了三种声音audio。 苹果还没有提供直接分析audio波…所以这个例子还使用麦克风来分析声音… …
其中3只用示波器分析幅度效应。 我必须彻底改变这个代码以符合我的要求，所以如果你打算使用，那么祝你好运…
你还可以看到另一个使用这种幅度的例子：苹果的说话
这是我用来将audio数据（audio文件）转换为浮点表示并保存到数组中的代码。
-(void) PrintFloatDataFromAudioFile { NSString * name = @"Filename"; //YOUR FILE NAME NSString * source = [[NSBundle mainBundle] pathForResource:name ofType:@"m4a"]; // SPECIFY YOUR FILE FORMAT const char *cString = [source cStringUsingEncoding:NSASCIIStringEncoding]; CFStringRef str = CFStringCreateWithCString( NULL, cString, kCFStringEncodingMacRoman ); CFURLRef inputFileURL = CFURLCreateWithFileSystemPath( kCFAllocatorDefault, str, kCFURLPOSIXPathStyle, false ); ExtAudioFileRef fileRef; ExtAudioFileOpenURL(inputFileURL, &fileRef); AudioStreamBasicDescription audioFormat; audioFormat.mSampleRate = 44100; // GIVE YOUR SAMPLING RATE audioFormat.mFormatID = kAudioFormatLinearPCM; audioFormat.mFormatFlags = kLinearPCMFormatFlagIsFloat; audioFormat.mBitsPerChannel = sizeof(Float32) * 8; audioFormat.mChannelsPerFrame = 1; // Mono audioFormat.mBytesPerFrame = audioFormat.mChannelsPerFrame * sizeof(Float32); // == sizeof(Float32) audioFormat.mFramesPerPacket = 1; audioFormat.mBytesPerPacket = audioFormat.mFramesPerPacket * audioFormat.mBytesPerFrame; // = sizeof(Float32) // 3) Apply audio format to the Extended Audio File ExtAudioFileSetProperty( fileRef, kExtAudioFileProperty_ClientDataFormat, sizeof (AudioStreamBasicDescription), //= audioFormat &audioFormat); int numSamples = 1024; //How many samples to read in at a time UInt32 sizePerPacket = audioFormat.mBytesPerPacket; // = sizeof(Float32) = 32bytes UInt32 packetsPerBuffer = numSamples; UInt32 outputBufferSize = packetsPerBuffer * sizePerPacket; // So the lvalue of outputBuffer is the memory location where we have reserved space UInt8 *outputBuffer = (UInt8 *)malloc(sizeof(UInt8 *) * outputBufferSize); AudioBufferList convertedData ;//= malloc(sizeof(convertedData)); convertedData.mNumberBuffers = 1; // Set this to 1 for mono convertedData.mBuffers[0].mNumberChannels = audioFormat.mChannelsPerFrame; //also = 1 convertedData.mBuffers[0].mDataByteSize = outputBufferSize; convertedData.mBuffers[0].mData = outputBuffer; // UInt32 frameCount = numSamples; float *samplesAsCArray; int j =0; double floatDataArray[882000] ; // SPECIFY YOUR DATA LIMIT MINE WAS 882000 , SHOULD BE EQUAL TO OR MORE THAN DATA LIMIT while (frameCount > 0) { ExtAudioFileRead( fileRef, &frameCount, &convertedData ); if (frameCount > 0) { AudioBuffer audioBuffer = convertedData.mBuffers[0]; samplesAsCArray = (float *)audioBuffer.mData; // CAST YOUR mData INTO FLOAT for (int i =0; i<1024 /*numSamples */; i++) { //YOU CAN PUT numSamples INTEAD OF 1024 floatDataArray[j] = (double)samplesAsCArray[i] ; //PUT YOUR DATA INTO FLOAT ARRAY printf("\n%f",floatDataArray[j]); //PRINT YOUR ARRAY'S DATA IN FLOAT FORM RANGING -1 TO +1 j++; } } }}
这是我的答案，thx所有的怪胎
obj-c
这里是代码：
-(void) listenerData:(NSNotification *) notify { int resnum=112222; unsigned int bitsum=0; for(int i=0;i<4;i++) { bitsum+=(resnum>>(i*8))&0xff; } bitsum=bitsum&0xff; NSString * check=[NSString stringWithFormat:@"%x %x",resnum,bitsum]; check=nil; self.drawData=notify.object;`` [self setNeedsDisplay]; } -(void)drawRect:(CGRect)rect { NSArray *data=self.drawData; NSData *tdata=[data objectAtIndex:0]; double *srcdata=(double*)tdata.bytes; int datacount=tdata.length/sizeof(double); tdata=[data objectAtIndex:1]; double *coveddata=(double*)tdata.bytes; CGContextRef context=UIGraphicsGetCurrentContext(); CGRect bounds=self.bounds; CGContextClearRect(context, bounds); CGFloat midpos=bounds.size.height/2; CGContextBeginPath(context); const double scale=1.0/100; CGFloat step=bounds.size.width/(datacount-1); CGContextMoveToPoint(context, 0, midpos); CGFloat xpos=0; for(int i=0;i<datacount;i++) { CGContextAddLineToPoint(context, xpos, midpos-srcdata[i]*scale); xpos+=step; } CGContextAddLineToPoint(context, bounds.size.width, midpos); CGContextClosePath(context); CGContextSetRGBFillColor(context, 1.0, 0.0, 0.0, 1.0); CGContextFillPath(context); CGContextBeginPath(context); const double scale2=1.0/100; CGContextMoveToPoint(context, 0, midpos); xpos=0; for(int i=0;i<datacount;i++) { CGContextAddLineToPoint(context, xpos, midpos+coveddata[i]*scale2); xpos+=step; } CGContextAddLineToPoint(context, bounds.size.width, midpos); CGContextClosePath(context); CGContextSetRGBFillColor(context, 1.0, 0.0, 1.0, 1.0); CGContextFillPath(context); }