注:

本人也是剛接觸直播參考網(wǎng)上的資料的學(xué)習(xí)一下客情，有很多不足之處敬請(qǐng)諒解臭脓！
附Demo地址:
https://github.com/yuhangjob/VideoAndAudioCapture

屏幕快照 2016-07-05 11.01.00.png

H264編碼.h

//
//  H264Encoder.h
//  AVCaptureSession
//
//  Created by 劉宇航 on 16/7/4.
//  Copyright ? 2016年 劉宇航. All rights reserved.
//

#import <Foundation/Foundation.h>
#import <AVFoundation/AVFoundation.h>
#import <VideoToolbox/VideoToolbox.h>

@protocol H264EncoderDelegate <NSObject>

- (void)gotSpsPps:(NSData*)sps pps:(NSData*)pps;
- (void)gotEncodedData:(NSData*)data isKeyFrame:(BOOL)isKeyFrame;

@end
@interface H264Encoder : NSObject

- (void) initWithConfiguration;
- (void) start:(int)width  height:(int)height;
- (void) initEncode:(int)width  height:(int)height;
- (void) encode:(CMSampleBufferRef )sampleBuffer;
- (void) End;

@property (weak, nonatomic) NSString *error;
@property (weak, nonatomic) id<H264EncoderDelegate> delegate;
@end

H264編碼.m

//
//  H264Encoder.m
//  AVCaptureSession
//
//  Created by 劉宇航 on 16/7/4.
//  Copyright ? 2016年 劉宇航. All rights reserved.
//

#import "H264Encoder.h"

@implementation H264Encoder

{
    NSString * yuvFile;
    VTCompressionSessionRef EncodingSession;
    dispatch_queue_t aQueue;
    CMFormatDescriptionRef  format;
    CMSampleTimingInfo * timingInfo;
    BOOL initialized;
    int  frameCount;
    NSData *sps;
    NSData *pps;
}
@synthesize error;

- (void) initWithConfiguration
{
    
    EncodingSession = nil;
    initialized = true;
    aQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
    frameCount = 0;
    sps = NULL;
    pps = NULL;
    
}

void didCompressH264(void *outputCallbackRefCon, void *sourceFrameRefCon, OSStatus status, VTEncodeInfoFlags infoFlags,
                     CMSampleBufferRef sampleBuffer )
{
    //    NSLog(@"didCompressH264 called with status %d infoFlags %d", (int)status, (int)infoFlags);
    if (status != 0) return;
    
    if (!CMSampleBufferDataIsReady(sampleBuffer))
    {
        NSLog(@"didCompressH264 data is not ready ");
        return;
    }
    H264Encoder* encoder = (__bridge H264Encoder*)outputCallbackRefCon;
    
    // Check if we have got a key frame first
    bool keyframe = !CFDictionaryContainsKey( (CFArrayGetValueAtIndex(CMSampleBufferGetSampleAttachmentsArray(sampleBuffer, true), 0)), kCMSampleAttachmentKey_NotSync);
    
    if (keyframe)
    {
        CMFormatDescriptionRef format = CMSampleBufferGetFormatDescription(sampleBuffer);
        // CFDictionaryRef extensionDict = CMFormatDescriptionGetExtensions(format);
        // Get the extensions
        // From the extensions get the dictionary with key "SampleDescriptionExtensionAtoms"
        // From the dict, get the value for the key "avcC"
        
        size_t sparameterSetSize, sparameterSetCount;
        const uint8_t *sparameterSet;
        OSStatus statusCode = CMVideoFormatDescriptionGetH264ParameterSetAtIndex(format, 0, &sparameterSet, &sparameterSetSize, &sparameterSetCount, 0 );
        if (statusCode == noErr)
        {
            // Found sps and now check for pps
            size_t pparameterSetSize, pparameterSetCount;
            const uint8_t *pparameterSet;
            OSStatus statusCode = CMVideoFormatDescriptionGetH264ParameterSetAtIndex(format, 1, &pparameterSet, &pparameterSetSize, &pparameterSetCount, 0 );
            if (statusCode == noErr)
            {
                // Found pps
                encoder->sps = [NSData dataWithBytes:sparameterSet length:sparameterSetSize];
                encoder->pps = [NSData dataWithBytes:pparameterSet length:pparameterSetSize];
                if (encoder->_delegate)
                {
                    [encoder->_delegate gotSpsPps:encoder->sps pps:encoder->pps];
                }
            }
        }
    }
    
    CMBlockBufferRef dataBuffer = CMSampleBufferGetDataBuffer(sampleBuffer);
    size_t length, totalLength;
    char *dataPointer;
    OSStatus statusCodeRet = CMBlockBufferGetDataPointer(dataBuffer, 0, &length, &totalLength, &dataPointer);
    if (statusCodeRet == noErr) {
        
        size_t bufferOffset = 0;
        static const int AVCCHeaderLength = 4;
        while (bufferOffset < totalLength - AVCCHeaderLength) {
            
            // Read the NAL unit length
            uint32_t NALUnitLength = 0;
            memcpy(&NALUnitLength, dataPointer + bufferOffset, AVCCHeaderLength);
            
            // Convert the length value from Big-endian to Little-endian
            NALUnitLength = CFSwapInt32BigToHost(NALUnitLength);
            
            NSData* data = [[NSData alloc] initWithBytes:(dataPointer + bufferOffset + AVCCHeaderLength) length:NALUnitLength];
            [encoder->_delegate gotEncodedData:data isKeyFrame:keyframe];
            
            // Move to the next NAL unit in the block buffer
            bufferOffset += AVCCHeaderLength + NALUnitLength;
        }
        
    }
    
}

- (void) start:(int)width  height:(int)height
{
    int frameSize = (width * height * 1.5);
    
    if (!initialized)
    {
        NSLog(@"H264: Not initialized");
        error = @"H264: Not initialized";
        return;
    }
    dispatch_sync(aQueue, ^{
        
        // For testing out the logic, lets read from a file and then send it to encoder to create h264 stream
        
        // Create the compression session
        OSStatus status = VTCompressionSessionCreate(NULL, width, height, kCMVideoCodecType_H264, NULL, NULL, NULL, didCompressH264, (__bridge void *)(self),  &EncodingSession);
        NSLog(@"H264: VTCompressionSessionCreate %d", (int)status);
        
        if (status != 0)
        {
            NSLog(@"H264: Unable to create a H264 session");
            error = @"H264: Unable to create a H264 session";
            
            return ;
            
        }
        
        // Set the properties
        VTSessionSetProperty(EncodingSession, kVTCompressionPropertyKey_RealTime, kCFBooleanTrue);
        VTSessionSetProperty(EncodingSession, kVTCompressionPropertyKey_AllowFrameReordering, kCFBooleanFalse);
        VTSessionSetProperty(EncodingSession, kVTCompressionPropertyKey_MaxKeyFrameInterval, 240);
        
        VTSessionSetProperty(EncodingSession, kVTCompressionPropertyKey_ProfileLevel, kVTProfileLevel_H264_High_AutoLevel);
        
        
        // Tell the encoder to start encoding
        VTCompressionSessionPrepareToEncodeFrames(EncodingSession);
        
        // Start reading from the file and copy it to the buffer
        
        // Open the file using POSIX as this is anyway a test application
        int fd = open([yuvFile UTF8String], O_RDONLY);
        if (fd == -1)
        {
            NSLog(@"H264: Unable to open the file");
            error = @"H264: Unable to open the file";
            
            return ;
        }
        
        NSMutableData* theData = [[NSMutableData alloc] initWithLength:frameSize] ;
        NSUInteger actualBytes = frameSize;
        while (actualBytes > 0)
        {
            void* buffer = [theData mutableBytes];
            NSUInteger bufferSize = [theData length];
            
            actualBytes = read(fd, buffer, bufferSize);
            if (actualBytes < frameSize)
                [theData setLength:actualBytes];
            
            frameCount++;
            // Create a CM Block buffer out of this data
            CMBlockBufferRef BlockBuffer = NULL;
            OSStatus status = CMBlockBufferCreateWithMemoryBlock(NULL, buffer, actualBytes,kCFAllocatorNull, NULL, 0, actualBytes, kCMBlockBufferAlwaysCopyDataFlag, &BlockBuffer);
            
            // Check for error
            if (status != noErr)
            {
                NSLog(@"H264: CMBlockBufferCreateWithMemoryBlock failed with %d", (int)status);
                error = @"H264: CMBlockBufferCreateWithMemoryBlock failed ";
                
                return ;
            }
            
            // Create a CM Sample Buffer
            CMSampleBufferRef sampleBuffer = NULL;
            CMFormatDescriptionRef formatDescription;
            CMFormatDescriptionCreate ( kCFAllocatorDefault, // Allocator
                                       kCMMediaType_Video,
                                       'I420',
                                       NULL,
                                       &formatDescription );
            CMSampleTimingInfo sampleTimingInfo = {CMTimeMake(1, 300)};
            
            OSStatus statusCode = CMSampleBufferCreate(kCFAllocatorDefault, BlockBuffer, YES, NULL, NULL, formatDescription, 1, 1, &sampleTimingInfo, 0, NULL, &sampleBuffer);
            
            // Check for error
            if (statusCode != noErr) {
                NSLog(@"H264: CMSampleBufferCreate failed with %d", (int)statusCode);
                error = @"H264: CMSampleBufferCreate failed ";
                
                return;
            }
            CFRelease(BlockBuffer);
            BlockBuffer = NULL;
            
            // Get the CV Image buffer
            CVImageBufferRef imageBuffer = (CVImageBufferRef)CMSampleBufferGetImageBuffer(sampleBuffer);
            
            // Create properties
            CMTime presentationTimeStamp = CMTimeMake(frameCount, 300);
            //CMTime duration = CMTimeMake(1, DURATION);
            VTEncodeInfoFlags flags;
            
            // Pass it to the encoder
            statusCode = VTCompressionSessionEncodeFrame(EncodingSession,
                                                         imageBuffer,
                                                         presentationTimeStamp,
                                                         kCMTimeInvalid,
                                                         NULL, NULL, &flags);
            // Check for error
            if (statusCode != noErr) {
                NSLog(@"H264: VTCompressionSessionEncodeFrame failed with %d", (int)statusCode);
                error = @"H264: VTCompressionSessionEncodeFrame failed ";
                
                // End the session
                VTCompressionSessionInvalidate(EncodingSession);
                CFRelease(EncodingSession);
                EncodingSession = NULL;
                error = NULL;
                return;
            }
            //            NSLog(@"H264: VTCompressionSessionEncodeFrame Success");
            
        }
        
        // Mark the completion
        VTCompressionSessionCompleteFrames(EncodingSession, kCMTimeInvalid);
        
        // End the session
        VTCompressionSessionInvalidate(EncodingSession);
        CFRelease(EncodingSession);
        EncodingSession = NULL;
        error = NULL;
        
        close(fd);
    });
    
    
}
- (void) initEncode:(int)width  height:(int)height
{
    dispatch_sync(aQueue, ^{
        
        // For testing out the logic, lets read from a file and then send it to encoder to create h264 stream
        
        // Create the compression session
        OSStatus status = VTCompressionSessionCreate(NULL, width, height, kCMVideoCodecType_H264, NULL, NULL, NULL, didCompressH264, (__bridge void *)(self),  &EncodingSession);
        NSLog(@"H264: VTCompressionSessionCreate %d", (int)status);
        
        if (status != 0)
        {
            NSLog(@"H264: Unable to create a H264 session");
            error = @"H264: Unable to create a H264 session";
            
            return ;
            
        }
        
        // Set the properties
        VTSessionSetProperty(EncodingSession, kVTCompressionPropertyKey_RealTime, kCFBooleanTrue);
        VTSessionSetProperty(EncodingSession, kVTCompressionPropertyKey_ProfileLevel, kVTProfileLevel_H264_Main_AutoLevel);
        
        
        // Tell the encoder to start encoding
        VTCompressionSessionPrepareToEncodeFrames(EncodingSession);
    });
}
- (void) encode:(CMSampleBufferRef )sampleBuffer
{
    dispatch_sync(aQueue, ^{
        
        frameCount++;
        // Get the CV Image buffer
        CVImageBufferRef imageBuffer = (CVImageBufferRef)CMSampleBufferGetImageBuffer(sampleBuffer);
        
        // Create properties
        CMTime presentationTimeStamp = CMTimeMake(frameCount, 1000);
        //CMTime duration = CMTimeMake(1, DURATION);
        VTEncodeInfoFlags flags;
        
        // Pass it to the encoder
        OSStatus statusCode = VTCompressionSessionEncodeFrame(EncodingSession,
                                                              imageBuffer,
                                                              presentationTimeStamp,
                                                              kCMTimeInvalid,
                                                              NULL, NULL, &flags);
        // Check for error
        if (statusCode != noErr) {
            NSLog(@"H264: VTCompressionSessionEncodeFrame failed with %d", (int)statusCode);
            error = @"H264: VTCompressionSessionEncodeFrame failed ";
            
            // End the session
            VTCompressionSessionInvalidate(EncodingSession);
            CFRelease(EncodingSession);
            EncodingSession = NULL;
            error = NULL;
            return;
        }
        //            NSLog(@"H264: VTCompressionSessionEncodeFrame Success");
    });
    
    
}

- (void) End
{
    // Mark the completion
    VTCompressionSessionCompleteFrames(EncodingSession, kCMTimeInvalid);
    
    // End the session
    VTCompressionSessionInvalidate(EncodingSession);
    CFRelease(EncodingSession);
    EncodingSession = NULL;
    error = NULL;
    
}

@end

AAC編碼.h

//
//  AACEncoder.h
//  AVCaptureSession
//
//  Created by 劉宇航 on 16/7/4.
//  Copyright ? 2016年 劉宇航. All rights reserved.
//

#import <Foundation/Foundation.h>
#import <AVFoundation/AVFoundation.h>
#import <AudioToolbox/AudioToolbox.h>

@interface AACEncoder : NSObject

@property (nonatomic) dispatch_queue_t encoderQueue;
@property (nonatomic) dispatch_queue_t callbackQueue;

- (void) encodeSampleBuffer:(CMSampleBufferRef)sampleBuffer completionBlock:(void (^)(NSData *encodedData, NSError* error))completionBlock;

@end

AAC編碼.m

//
//  AACEncoder.m
//  AVCaptureSession
//
//  Created by 劉宇航 on 16/7/4.
//  Copyright ? 2016年 劉宇航. All rights reserved.
//

#import "AACEncoder.h"

@interface AACEncoder()
@property (nonatomic) AudioConverterRef audioConverter;
@property (nonatomic) uint8_t *aacBuffer;
@property (nonatomic) NSUInteger aacBufferSize;
@property (nonatomic) char *pcmBuffer;
@property (nonatomic) size_t pcmBufferSize;

@end

@implementation AACEncoder

- (void) dealloc {
    AudioConverterDispose(_audioConverter);
    free(_aacBuffer);
}

- (id) init {
    if (self = [super init]) {
        _encoderQueue = dispatch_queue_create("AAC Encoder Queue", DISPATCH_QUEUE_SERIAL);
        _callbackQueue = dispatch_queue_create("AAC Encoder Callback Queue", DISPATCH_QUEUE_SERIAL);
        _audioConverter = NULL;
        _pcmBufferSize = 0;
        _pcmBuffer = NULL;
        _aacBufferSize = 1024;
        _aacBuffer = malloc(_aacBufferSize * sizeof(uint8_t));
        memset(_aacBuffer, 0, _aacBufferSize);
    }
    return self;
}

- (void) setupEncoderFromSampleBuffer:(CMSampleBufferRef)sampleBuffer {
    AudioStreamBasicDescription inAudioStreamBasicDescription = *CMAudioFormatDescriptionGetStreamBasicDescription((CMAudioFormatDescriptionRef)CMSampleBufferGetFormatDescription(sampleBuffer));
    
    AudioStreamBasicDescription outAudioStreamBasicDescription = {0}; // Always initialize the fields of a new audio stream basic description structure to zero, as shown here: ...
    outAudioStreamBasicDescription.mSampleRate = inAudioStreamBasicDescription.mSampleRate; // The number of frames per second of the data in the stream, when the stream is played at normal speed. For compressed formats, this field indicates the number of frames per second of equivalent decompressed data. The mSampleRate field must be nonzero, except when this structure is used in a listing of supported formats (see “kAudioStreamAnyRate”).
    outAudioStreamBasicDescription.mFormatID = kAudioFormatMPEG4AAC; // kAudioFormatMPEG4AAC_HE does not work. Can't find `AudioClassDescription`. `mFormatFlags` is set to 0.
    outAudioStreamBasicDescription.mFormatFlags = kMPEG4Object_AAC_LC; // Format-specific flags to specify details of the format. Set to 0 to indicate no format flags. See “Audio Data Format Identifiers” for the flags that apply to each format.
    outAudioStreamBasicDescription.mBytesPerPacket = 0; // The number of bytes in a packet of audio data. To indicate variable packet size, set this field to 0. For a format that uses variable packet size, specify the size of each packet using an AudioStreamPacketDescription structure.
    outAudioStreamBasicDescription.mFramesPerPacket = 1024; // The number of frames in a packet of audio data. For uncompressed audio, the value is 1. For variable bit-rate formats, the value is a larger fixed number, such as 1024 for AAC. For formats with a variable number of frames per packet, such as Ogg Vorbis, set this field to 0.
    outAudioStreamBasicDescription.mBytesPerFrame = 0; // The number of bytes from the start of one frame to the start of the next frame in an audio buffer. Set this field to 0 for compressed formats. ...
    outAudioStreamBasicDescription.mChannelsPerFrame = 1; // The number of channels in each frame of audio data. This value must be nonzero.
    outAudioStreamBasicDescription.mBitsPerChannel = 0; // ... Set this field to 0 for compressed formats.
    outAudioStreamBasicDescription.mReserved = 0; // Pads the structure out to force an even 8-byte alignment. Must be set to 0.
    AudioClassDescription *description = [self
                                          getAudioClassDescriptionWithType:kAudioFormatMPEG4AAC
                                          fromManufacturer:kAppleSoftwareAudioCodecManufacturer];
    
    OSStatus status = AudioConverterNewSpecific(&inAudioStreamBasicDescription, &outAudioStreamBasicDescription, 1, description, &_audioConverter);
    if (status != 0) {
        NSLog(@"setup converter: %d", (int)status);
    }
}

- (AudioClassDescription *)getAudioClassDescriptionWithType:(UInt32)type
                                           fromManufacturer:(UInt32)manufacturer
{
    static AudioClassDescription desc;
    
    UInt32 encoderSpecifier = type;
    OSStatus st;
    
    UInt32 size;
    st = AudioFormatGetPropertyInfo(kAudioFormatProperty_Encoders,
                                    sizeof(encoderSpecifier),
                                    &encoderSpecifier,
                                    &size);
    if (st) {
        NSLog(@"error getting audio format propery info: %d", (int)(st));
        return nil;
    }
    
    unsigned int count = size / sizeof(AudioClassDescription);
    AudioClassDescription descriptions[count];
    st = AudioFormatGetProperty(kAudioFormatProperty_Encoders,
                                sizeof(encoderSpecifier),
                                &encoderSpecifier,
                                &size,
                                descriptions);
    if (st) {
        NSLog(@"error getting audio format propery: %d", (int)(st));
        return nil;
    }
    
    for (unsigned int i = 0; i < count; i++) {
        if ((type == descriptions[i].mSubType) &&
            (manufacturer == descriptions[i].mManufacturer)) {
            memcpy(&desc, &(descriptions[i]), sizeof(desc));
            return &desc;
        }
    }
    
    return nil;
}

static OSStatus inInputDataProc(AudioConverterRef inAudioConverter, UInt32 *ioNumberDataPackets, AudioBufferList *ioData, AudioStreamPacketDescription **outDataPacketDescription, void *inUserData)
{
    AACEncoder *encoder = (__bridge AACEncoder *)(inUserData);
    UInt32 requestedPackets = *ioNumberDataPackets;
    //NSLog(@"Number of packets requested: %d", (unsigned int)requestedPackets);
    size_t copiedSamples = [encoder copyPCMSamplesIntoBuffer:ioData];
    if (copiedSamples < requestedPackets) {
        //NSLog(@"PCM buffer isn't full enough!");
        *ioNumberDataPackets = 0;
        return -1;
    }
    *ioNumberDataPackets = 1;
    //NSLog(@"Copied %zu samples into ioData", copiedSamples);
    return noErr;
}

- (size_t) copyPCMSamplesIntoBuffer:(AudioBufferList*)ioData {
    size_t originalBufferSize = _pcmBufferSize;
    if (!originalBufferSize) {
        return 0;
    }
    ioData->mBuffers[0].mData = _pcmBuffer;
    ioData->mBuffers[0].mDataByteSize = _pcmBufferSize;
    _pcmBuffer = NULL;
    _pcmBufferSize = 0;
    return originalBufferSize;
}

- (void) encodeSampleBuffer:(CMSampleBufferRef)sampleBuffer completionBlock:(void (^)(NSData * encodedData, NSError* error))completionBlock {
    CFRetain(sampleBuffer);
    dispatch_async(_encoderQueue, ^{
        if (!_audioConverter) {
            [self setupEncoderFromSampleBuffer:sampleBuffer];
        }
        CMBlockBufferRef blockBuffer = CMSampleBufferGetDataBuffer(sampleBuffer);
        CFRetain(blockBuffer);
        OSStatus status = CMBlockBufferGetDataPointer(blockBuffer, 0, NULL, &_pcmBufferSize, &_pcmBuffer);
        NSError *error = nil;
        if (status != kCMBlockBufferNoErr) {
            error = [NSError errorWithDomain:NSOSStatusErrorDomain code:status userInfo:nil];
        }
        //NSLog(@"PCM Buffer Size: %zu", _pcmBufferSize);
        
        memset(_aacBuffer, 0, _aacBufferSize);
        AudioBufferList outAudioBufferList = {0};
        outAudioBufferList.mNumberBuffers = 1;
        outAudioBufferList.mBuffers[0].mNumberChannels = 1;
        outAudioBufferList.mBuffers[0].mDataByteSize = _aacBufferSize;
        outAudioBufferList.mBuffers[0].mData = _aacBuffer;
        AudioStreamPacketDescription *outPacketDescription = NULL;
        UInt32 ioOutputDataPacketSize = 1;
        status = AudioConverterFillComplexBuffer(_audioConverter, inInputDataProc, (__bridge void *)(self), &ioOutputDataPacketSize, &outAudioBufferList, outPacketDescription);
        //NSLog(@"ioOutputDataPacketSize: %d", (unsigned int)ioOutputDataPacketSize);
        NSData *data = nil;
        if (status == 0) {
            NSData *rawAAC = [NSData dataWithBytes:outAudioBufferList.mBuffers[0].mData length:outAudioBufferList.mBuffers[0].mDataByteSize];
            NSData *adtsHeader = [self adtsDataForPacketLength:rawAAC.length];
            NSMutableData *fullData = [NSMutableData dataWithData:adtsHeader];
            [fullData appendData:rawAAC];
            data = fullData;
        } else {
            error = [NSError errorWithDomain:NSOSStatusErrorDomain code:status userInfo:nil];
        }
        if (completionBlock) {
            dispatch_async(_callbackQueue, ^{
                completionBlock(data, error);
            });
        }
        CFRelease(sampleBuffer);
        CFRelease(blockBuffer);
    });
}

/**
 *  Add ADTS header at the beginning of each and every AAC packet.
 *  This is needed as MediaCodec encoder generates a packet of raw
 *  AAC data.
 *
 *  Note the packetLen must count in the ADTS header itself.
 *  See: http://wiki.multimedia.cx/index.php?title=ADTS
 *  Also: http://wiki.multimedia.cx/index.php?title=MPEG-4_Audio#Channel_Configurations
 **/
- (NSData*) adtsDataForPacketLength:(NSUInteger)packetLength {
    int adtsLength = 7;
    char *packet = malloc(sizeof(char) * adtsLength);
    // Variables Recycled by addADTStoPacket
    int profile = 2;  //AAC LC
    //39=MediaCodecInfo.CodecProfileLevel.AACObjectELD;
    int freqIdx = 4;  //44.1KHz
    int chanCfg = 1;  //MPEG-4 Audio Channel Configuration. 1 Channel front-center
    NSUInteger fullLength = adtsLength + packetLength;
    // fill in ADTS data
    packet[0] = (char)0xFF; // 11111111     = syncword
    packet[1] = (char)0xF9; // 1111 1 00 1  = syncword MPEG-2 Layer CRC
    packet[2] = (char)(((profile-1)<<6) + (freqIdx<<2) +(chanCfg>>2));
    packet[3] = (char)(((chanCfg&3)<<6) + (fullLength>>11));
    packet[4] = (char)((fullLength&0x7FF) >> 3);
    packet[5] = (char)(((fullLength&7)<<5) + 0x1F);
    packet[6] = (char)0xFC;
    NSData *data = [NSData dataWithBytesNoCopy:packet length:adtsLength freeWhenDone:YES];
    return data;
}

@end

ViewController.m

//
//  ViewController.m
//  AVCaptureSession
//
//  Created by 劉宇航 on 16/7/1.
//  Copyright ? 2016年 劉宇航. All rights reserved.
//
#import "ViewController.h"
#import <AVFoundation/AVFoundation.h>
#import "AACEncoder.h"
#import "H264Encoder.h"
#import "avformat.h"
#define CAPTURE_FRAMES_PER_SECOND       20
#define SAMPLE_RATE                     44100
#define VideoWidth                      480
#define VideoHeight                     640
@interface ViewController ()<AVCaptureVideoDataOutputSampleBufferDelegate,AVCaptureAudioDataOutputSampleBufferDelegate,H264EncoderDelegate>
// 負(fù)責(zé)輸如何輸出設(shè)備之間的數(shù)據(jù)傳遞
@property (nonatomic, strong) AVCaptureSession           *session;
// 隊(duì)列
@property (nonatomic, strong) dispatch_queue_t           videoQueue;
@property (nonatomic, strong) dispatch_queue_t           AudioQueue;

// 負(fù)責(zé)從 AVCaptureDevice 獲得輸入數(shù)據(jù)
@property (nonatomic, strong) AVCaptureDeviceInput       *captureDeviceInput;
@property (nonatomic, strong) AVCaptureVideoDataOutput   *videoOutput;
@property (nonatomic, strong) AVCaptureConnection        *videoConnection;
@property (nonatomic, strong) AVCaptureConnection        *audioConnection;
// 拍攝預(yù)覽圖層
@property (nonatomic, strong) AVCaptureVideoPreviewLayer *previewLayer;
@property (nonatomic, strong) H264Encoder                *h264Encoder;
@property (nonatomic, strong) AACEncoder                 *aacEncoder;
@property (nonatomic, strong) NSMutableData              *data;
@property (nonatomic, copy  ) NSString                   *h264File;
@property (nonatomic, strong) NSFileHandle               *fileHandle;
@property (nonatomic, strong) UIButton                   *startBtn;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    _data = [NSMutableData new];
    //初始化AVCaptureSession
    _session = [AVCaptureSession new];
    
//    [self setupAudioCapture];
//    [self setupVideoCapture];
    [self initStartBtn];
}
#pragma mark - 設(shè)置音頻
- (void)setupAudioCapture {
    
    self.aacEncoder = [AACEncoder new];
    
    AVCaptureDevice *audioDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio];
    
    NSError *error = nil;
    
    AVCaptureDeviceInput *audioInput = [[AVCaptureDeviceInput alloc]initWithDevice:audioDevice error:&error];
    
    if (error) {
        
        NSLog(@"Error getting audio input device:%@",error.description);
    }
    
    if ([self.session canAddInput:audioInput]) {
        
        [self.session addInput:audioInput];
    }
    
    self.AudioQueue = dispatch_queue_create("Audio Capture Queue", DISPATCH_QUEUE_SERIAL);
    
    AVCaptureAudioDataOutput *audioOutput = [AVCaptureAudioDataOutput new];
    [audioOutput setSampleBufferDelegate:self queue:self.AudioQueue];
    
    if ([self.session canAddOutput:audioOutput]) {
        
        [self.session addOutput:audioOutput];
    }
    
    self.audioConnection = [audioOutput connectionWithMediaType:AVMediaTypeAudio];
    

}
- (AVCaptureDevice *)cameraWithPosition:(AVCaptureDevicePosition)position
{
    NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
    for ( AVCaptureDevice *device in devices )
        if ( device.position == position )
            return device;
    return nil;
}

#pragma mark - 設(shè)置視頻 capture
- (void)setupVideoCapture {
    
   
    self.h264Encoder = [H264Encoder new];
    [self.h264Encoder initWithConfiguration];
    [self.h264Encoder initEncode:480 height:640];
    self.h264Encoder.delegate = self;

    if ([_session canSetSessionPreset:AVCaptureSessionPreset1280x720]) {
        // 設(shè)置分辨率
        _session.sessionPreset = AVCaptureSessionPreset1280x720;
    }
//
    //設(shè)置采集的 Video 和 Audio 格式甘萧，這兩個(gè)是分開(kāi)設(shè)置的，也就是說(shuō)昆箕，你可以只采集視頻辕羽。
    //配置采集輸入源(攝像頭)
    
    NSError *error = nil;
    //獲得一個(gè)采集設(shè)備, 例如前置/后置攝像頭
    AVCaptureDevice *videoDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    
//    videoDevice = [self cameraWithPosition:AVCaptureDevicePositionBack];
 //   videoDevice.position = AVCaptureDevicePositionBack;
    //用設(shè)備初始化一個(gè)采集的輸入對(duì)象
    AVCaptureDeviceInput *videoInput = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:&error];
    if (error) {
        NSLog(@"Error getting video input device:%@",error.description);
        
    }
    if ([_session canAddInput:videoInput]) {
        [_session addInput:videoInput];
    }
    
    //配置采集輸出,即我們?nèi)〉靡曨l圖像的接口
    _videoQueue = dispatch_queue_create("Video Capture Queue", DISPATCH_QUEUE_SERIAL);
    _videoOutput = [AVCaptureVideoDataOutput new];
    [_videoOutput setSampleBufferDelegate:self queue:_videoQueue];
    
    // 配置輸出視頻圖像格式
    NSDictionary *captureSettings = @{(NSString*)kCVPixelBufferPixelFormatTypeKey: @(kCVPixelFormatType_32BGRA)};
    _videoOutput.videoSettings = captureSettings;
    _videoOutput.alwaysDiscardsLateVideoFrames = YES;
    
    if ([_session canAddOutput:_videoOutput]) {
        [_session addOutput:_videoOutput];
    }
    // 保存Connection,用于SampleBufferDelegate中判斷數(shù)據(jù)來(lái)源(video or audio?)
    _videoConnection = [_videoOutput connectionWithMediaType:AVMediaTypeVideo];
    
    // 啟動(dòng)session
    [_session startRunning];
    //將當(dāng)前硬件采集視頻圖像顯示到屏幕
    _previewLayer = [AVCaptureVideoPreviewLayer layerWithSession:_session];
    _previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill; // 設(shè)置預(yù)覽時(shí)的視頻縮放方式
    [[_previewLayer connection] setVideoOrientation:AVCaptureVideoOrientationPortrait]; // 設(shè)置視頻的朝向
    
    _previewLayer.frame = CGRectMake(0, 20, self.view.frame.size.height, self.view.frame.size.height - 80);
    [self.view.layer addSublayer:_previewLayer];
    
    
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths firstObject];
    
    self.h264File = [documentsDirectory stringByAppendingString:@"lyh.h264"];
    [fileManager removeItemAtPath:self.h264File error:nil];
    [fileManager createFileAtPath:self.h264File contents:nil attributes:nil];
    self.fileHandle = [NSFileHandle fileHandleForWritingAtPath:self.h264File];
    
   

}

#pragma mark - 實(shí)現(xiàn) AVCaptureOutputDelegate：
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection {
    
    CMTime pts = CMSampleBufferGetDuration(sampleBuffer);
    
    double dPTS = (double)(pts.value) / pts.timescale;
    NSLog(@"DPTS is %f",dPTS);
    
    // 這里的sampleBuffer就是采集到的數(shù)據(jù)了，但它是Video還是Audio的數(shù)據(jù)，得根據(jù)connection來(lái)判斷
    if (connection == _videoConnection) {  // Video
        //NSLog(@"在這里獲得video sampleBuffer搓谆，做進(jìn)一步處理（編碼H.264）");
   
         // 取得當(dāng)前視頻尺寸信息
         CVPixelBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
         NSInteger width = CVPixelBufferGetWidth(pixelBuffer);
         NSInteger height = CVPixelBufferGetHeight(pixelBuffer);
        [self.h264Encoder encode:sampleBuffer];
    
    } else if (connection == _audioConnection) {  // Audio
        
        //NSLog(@"這里獲得audio sampleBuffer炒辉，做進(jìn)一步處理（編碼AAC）");
        
        [self.aacEncoder encodeSampleBuffer:sampleBuffer completionBlock:^(NSData *encodedData, NSError *error) {
            
            if (encodedData) {
                
                NSLog(@"Audio data (%lu):%@", (unsigned long)encodedData.length,encodedData.description);
#pragma mark -  音頻數(shù)據(jù)(encodedData)
                [self.data appendData:encodedData];
            }else {
                
                NSLog(@"Error encoding AAC: %@", error);

            }

        }];
        
    }
    
}

- (void)gotSpsPps:(NSData*)sps pps:(NSData*)pps {
    
    const char bytes[] = "\x00\x00\x00\x01";
    size_t length = (sizeof bytes) - 1; //string literals have implicit trailing '\0'
    NSData *ByteHeader = [NSData dataWithBytes:bytes length:length];
    [_fileHandle writeData:ByteHeader];
    [_fileHandle writeData:sps];
    [_fileHandle writeData:ByteHeader];
    [_fileHandle writeData:pps];
    
//    avformat_alloc_output_context2(<#AVFormatContext **ctx#>, <#AVOutputFormat *oformat#>, <#const char *format_name#>, <#const char *filename#>)
    
}
- (void)gotEncodedData:(NSData*)data isKeyFrame:(BOOL)isKeyFrame {
    
    NSLog(@"Video data (%lu):%@", (unsigned long)data.length,data.description);
    
    if (_fileHandle != NULL)
    {
        const char bytes[] = "\x00\x00\x00\x01";
        size_t length = (sizeof bytes) - 1; //string literals have implicit trailing '\0'
        NSData *ByteHeader = [NSData dataWithBytes:bytes length:length];
        
#pragma mark
#pragma mark - 視頻數(shù)據(jù)(data)
        
        [_fileHandle writeData:ByteHeader];
        //[fileHandle writeData:UnitHeader];
        [_fileHandle writeData:data];
        
    }
    
}

#pragma mark - 錄制
- (void)startBtnClicked:(UIButton *)btn
{
    btn.selected = !btn.selected;
    
    if (btn.selected)
    {
        [self startCamera];
        [_startBtn setTitle:@"Stop" forState:UIControlStateNormal];
        
    }
    else
    {
        [_startBtn setTitle:@"Start" forState:UIControlStateNormal];
        [self stopCarmera];
    }
    
}

- (void) startCamera
{
    [self setupAudioCapture];
    [self setupVideoCapture];
    [self.session commitConfiguration];
    [self.session startRunning];
}

- (void) stopCarmera
{
//    [_h264Encoder End];
    [_session stopRunning];
//    //close(fd);
    [_fileHandle closeFile];
    _fileHandle = NULL;
//
    // 獲取程序Documents目錄路徑
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    
    NSMutableString * path = [[NSMutableString alloc]initWithString:documentsDirectory];
    [path appendString:@"/AACFile"];
    
    [_data writeToFile:path atomically:YES];
    
}

- (void)initStartBtn
{
    _startBtn = [UIButton buttonWithType:UIButtonTypeCustom];
    _startBtn.frame = CGRectMake(0, 0, 100, 40);
    _startBtn.backgroundColor = [UIColor lightGrayColor];
    _startBtn.center = CGPointMake([UIScreen mainScreen].bounds.size.width / 2, [UIScreen mainScreen].bounds.size.height - 30);
    [_startBtn addTarget:self action:@selector(startBtnClicked:) forControlEvents:UIControlEventTouchUpInside];
    [_startBtn setTitle:@"Start" forState:UIControlStateNormal];
    [_startBtn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [self.view addSubview:_startBtn];
}
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end