iOS 使用libx264编码视频

首先视频采集使用AVCaptureSession，输出参数设置如下

 AVCaptureVideoDataOutput *newVideoOutput = [[AVCaptureVideoDataOutput alloc] init];

    [newVideoOutput setAlwaysDiscardsLateVideoFrames:YES];

    NSDictionary *settings = [[NSDictionary alloc] initWithObjectsAndKeys:

                              [NSNumber numberWithUnsignedInt:kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange],

//                              [NSNumber numberWithInt:kCVPixelFormatType_32BGRA],

                              kCVPixelBufferPixelFormatTypeKey,

                              nil];

在代理里面取得视频的buffer，先把x264编译，我参照了http://blog.youkuaiyun.com/ixfly/article/details/7621258。

首先到http://www.videolan.org/developers/x264.html下载x264的库，然后解压，我解压出是x264-snapshot-20130604-2245文件夹

打开shell，进入x264的目录，执行如下语句

CC=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc ./configure --host=arm-apple-darwin --sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.1.sdk --prefix='dist' --extra-cflags='-arch armv7s' --extra-ldflags='-arch armv7s -L/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.1.sdk/usr/lib/system' --enable-pic

然后make&&make install，libx264.a就出来啦。

将libx264.a添加到工程

将x264目录手动拷贝到工程下面，方便以后跟着工程走

在xcode下面BuildSetting里面设置Header Search Paths，一相对路径的形式指向你刚才拷贝的目录

好啦，现在可以使用x264了

要包含下面三个.h文件

#include "x264.h"

#include "common/common.h"

#include "encoder/set.h"

我写了个x264管理的类

代码如下

头文件

#import <Foundation/Foundation.h>

#import <CoreMedia/CoreMedia.h>

#include "x264.h"

#include "common/common.h"

#include "encoder/set.h"

@interface x264Manager : NSObject{

    x264_param_t * p264Param;

    x264_picture_t * p264Pic;

    x264_t *p264Handle;

    x264_nal_t  *p264Nal;

    int previous_nal_size;

    unsigned  char * pNal;

    FILE *fp;

    unsigned char szBodyBuffer[1024*32];

}

- (void)initForX264; //初始化x264

- (void)initForFilePath; //初始化编码后文件的保存路径

- (void)encoderToH264:(CMSampleBufferRef )pixelBuffer; //将CMSampleBufferRef格式的数据编码成h264并写入文件

@end

//

//  x264Manager.m

//  IOSCamDemo

//

//  Created by huangyuling on 6/5/13.

//  Copyright (c) 2013 hyl. All rights reserved.

//

#import "x264Manager.h"

@implementation x264Manager

- (void)initForX264{

 

        p264Param = malloc(sizeof(x264_param_t));

        p264Pic  = malloc(sizeof(x264_picture_t));

        memset(p264Pic,0,sizeof(x264_picture_t));

        //x264_param_default(p264Param);  //set default param

        x264_param_default_preset(p264Param, "veryfast", "zerolatency");

        p264Param->i_threads = 1;

        p264Param->i_width   = 352;  //set frame width

        p264Param->i_height  = 288;  //set frame height

        p264Param->b_cabac =0;

        p264Param->i_bframe =0;

        p264Param->b_interlaced=0;

        p264Param->rc.i_rc_method=X264_RC_ABR;//X264_RC_CQP

        p264Param->i_level_idc=21;

        p264Param->rc.i_bitrate=128;

        p264Param->b_intra_refresh = 1;

        p264Param->b_annexb = 1;

        p264Param->i_keyint_max=25;

        p264Param->i_fps_num=15;

        p264Param->i_fps_den=1;

        p264Param->b_annexb = 1;

        //    p264Param->i_csp = X264_CSP_I420;

        x264_param_apply_profile(p264Param, "baseline");

        if((p264Handle = x264_encoder_open(p264Param)) == NULL)

        {

            fprintf( stderr, "x264_encoder_open failed/n" );

            return ;

        }

        x264_picture_alloc(p264Pic, X264_CSP_I420, p264Param->i_width, p264Param->i_height);

        p264Pic->i_type = X264_TYPE_AUTO;

  

}

- (void)initForFilePath{

    char *path = [self GetFilePathByfileName:"IOSCamDemo.h264"];

    NSLog(@"%s",path);

    fp = fopen(path,"wb");

}

- (char*)GetFilePathByfileName:(char*)filename

{

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES);

    NSString *documentsDirectory = [paths objectAtIndex:0];

    NSString *strName = [NSString stringWithFormat:@"%s",filename];

    

    NSString *writablePath = [documentsDirectory stringByAppendingPathComponent:strName];

    

    int len = [writablePath length];

    

    char *filepath = (char*)malloc(sizeof(char) * (len + 1));

    

    [writablePath getCString:filepath maxLength:len + 1 encoding:[NSString defaultCStringEncoding]];

    

    return filepath;

}

- (void)encoderToH264:(CMSampleBufferRef)sampleBuffer{

    

    CVImageBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);

    

    CVPixelBufferLockBaseAddress(pixelBuffer, 0);

   

    uint8_t  *baseAddress0 = (uint8_t *)CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 0);

    uint8_t  *baseAddress1 = (uint8_t *)CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 1);

    

    int         i264Nal;

    x264_picture_t pic_out;

    

    memcpy(p264Pic->img.plane[0], baseAddress0, 352*288);

    uint8_t * pDst1 = p264Pic->img.plane[1];

    uint8_t * pDst2 = p264Pic->img.plane[2];

    for( int i = 0; i < 352*288/4; i ++ )

    {

        *pDst1++ = *baseAddress1++;

        *pDst2++ = *baseAddress1++;

    }

    

    if( x264_encoder_encode( p264Handle, &p264Nal, &i264Nal, p264Pic ,&pic_out) < 0 )

    {

        fprintf( stderr, "x264_encoder_encode failed/n" );

    }

    NSLog(@"i264Nal======%d",i264Nal);

    

    if (i264Nal > 0) {

        

        int i_size;

        char * data=(char *)szBodyBuffer+100;

        for (int i=0 ; i<i264Nal; i++) {

            if (p264Handle->nal_buffer_size < p264Nal[i].i_payload*3/2+4) {

                p264Handle->nal_buffer_size = p264Nal[i].i_payload*2+4;

                x264_free( p264Handle->nal_buffer );

                p264Handle->nal_buffer = x264_malloc( p264Handle->nal_buffer_size );

            }

            i_size = p264Nal[i].i_payload;

            

            memcpy(data, p264Nal[i].p_payload, p264Nal[i].i_payload);

            fwrite(data, 1, i_size, fp);

        }

        

    }

    CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);

}

@end

注意到这里x264设置的时候也是352x288的，要与上面output里面设置的一致才好，你也选择其他宽高

然后先初始化保存路径，在哪里初始化自己选择，我的程序是

[self.manager264 initForFilePath];

在

AVCaptureVideoDataOutputSampleBufferDelegate代理的方法中我们会获得数据，在那里调用前面的方法编码，不过记得编码签要初始化x264，我实在一开始就初始化了

 x264Manager *m264 = [[x264Manager alloc]init];

        [m264 initForX264];

        self.manager264 = m264;

        [m264 release];

下面是代理的方法

#pragma - remark AVCaptureVideo(Audio)DataOutputSampleBufferDelegate method

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection{

    if (captureOutput == self.captureManager.videOutput) {

        [self.manager264 encoderToH264:sampleBuffer];

    }

}

感觉差不多结束了，以后发现漏了啥再补充吧