No.08 Xcode(5.1.x) 使用FFmpeg

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1.从 https://github.com/kewlbear/FFmpeg-iOS-build-script 获取到一套能运行于armv7, armv7s, arm64, i386的ffmpeg库;

2.在工程配置中, 加入libz.dylib, libbz2.dylib, libiconv.dylib这三个系统库;

3.在代码中加入avcodec.h, swscale.h, avformat.h等ffmpeg的库文件, 其中avcodec.h是必要的, 其他则根据需要添加;

4.在工程配置中, 加入搜索路径 "$(PROJECT_DIR)/工程名/ffmpeg/lib" 和 "$(PROJECT_DIR)/工程名/ffmpeg/include"

5.填写代码, 可以参考 http://blog.csdn.net/smking/article/details/7561688

6.已经编译好的库: http://download.csdn.net/download/huayu608/7671881

以下是调用ffmpeg接口时的demo代码

#include "avcodec.h"#include "swscale.h"#include "avformat.h"typedef struct SwsContext SwsContext;typedef struct structVideoDecode {    AVCodec*        mAVCodec;    AVCodecContext* mAVCodecContext;    AVFrame*        mAVFrame;    AVPicture       mAVPicture;    SwsContext*     mSwsContext;} VideoDecode;int videox_init(){    av_register_all();    avcodec_register_all();    return 0;}int videox_unit(){    return 0;}int videox_began(long video_format, long image_width, long image_height, long* out_vd_handle){    VideoDecode* vd = (VideoDecode*)malloc(sizeof(VideoDecode));    if (vd == 0)        return -1;    memset(vd, 0, sizeof(VideoDecode));    *out_vd_handle = (long)vd;        // VIDEO_FORMAT_H264等宏是公司私有的标识    enum AVCodecID codeId = CODEC_ID_NONE;    switch (video_format)    {        case VIDEO_FORMAT_H264:   {codeId = AV_CODEC_ID_H264;  break;}        case VIDEO_FORMAT_MJPEG4: {codeId = AV_CODEC_ID_MJPEG; break;}        default:                  {break;}    }        vd->mAVCodec = avcodec_find_decoder(codeId);    if (!vd->mAVCodec)    {        return -2;    }        vd->mAVCodecContext = avcodec_alloc_context3(vd->mAVCodec);    if(!vd->mAVCodecContext)    {        return -3;    }    vd->mAVCodecContext->width = image_width;    vd->mAVCodecContext->height = image_height;    vd->mAVCodecContext->pix_fmt = PIX_FMT_YUV420P;        if (avcodec_open2(vd->mAVCodecContext, vd->mAVCodec, 0) < 0) // 需要加锁    {        return -4;    }        vd->mAVFrame = av_frame_alloc();    if (!vd->mAVFrame)    {        return -5;    }    avpicture_alloc(&vd->mAVPicture, PIX_FMT_RGB24, vd->mAVCodecContext->width, vd->mAVCodecContext->height);        vd->mSwsContext = sws_getCachedContext(0,                                           vd->mAVCodecContext->width,                                           vd->mAVCodecContext->height,                                           vd->mAVCodecContext->pix_fmt,                                           vd->mAVCodecContext->width,          // 生成图像的宽度                                           vd->mAVCodecContext->height,         // 生成图像的高度                                           PIX_FMT_RGB24,                                           SWS_FAST_BILINEAR, NULL, NULL, NULL);    return 0;}int videox_ended(long vd_handle){    if (vd_handle == 0)        return -1;        VideoDecode* vd = (VideoDecode*)vd_handle;        if(vd->mAVCodecContext)    {        avcodec_close(vd->mAVCodecContext); // 需要加锁av_free(vd->mAVCodecContext);vd->mAVCodecContext = 0;    }        if(vd->mAVFrame)    {av_free(vd->mAVFrame);vd->mAVFrame = 0;    }        avpicture_free(&vd->mAVPicture);        if (vd->mSwsContext)    {        sws_freeContext(vd->mSwsContext);    }        free(vd);    vd = 0;        return 0;}int videox_decode(long vd_handle, uint8_t* in_264Buffer, int in_264BufferSize, uint8_t** out_RGBBuffer, int* out_RGBBufferSize, long* out_image_width, long* out_image_height){    if (vd_handle == 0 || in_264Buffer == 0 || in_264BufferSize == 0)        return -1;        VideoDecode* dv = (VideoDecode*)vd_handle;        AVPacket avpkt;    av_init_packet(&avpkt);    avpkt.data = in_264Buffer;    // packet data will be allocated by the encoder    avpkt.size = in_264BufferSize;        int got_picture;    int consumed_bytes = avcodec_decode_video2(dv->mAVCodecContext, dv->mAVFrame, &got_picture, &avpkt);    av_free_packet(&avpkt);if (consumed_bytes <= 0 || dv->mAVFrame->data[0] == 0)    {        return -2;    }        // 把数据从pFrame写到picture之中    sws_scale(dv->mSwsContext,              dv->mAVFrame->data,              dv->mAVFrame->linesize,              0,              dv->mAVCodecContext->height,              dv->mAVPicture.data,              dv->mAVPicture.linesize);        *out_RGBBuffer = dv->mAVPicture.data[0];    *out_RGBBufferSize = dv->mAVPicture.linesize[0] * dv->mAVCodecContext->height;    *out_image_width = dv->mAVCodecContext->width;    *out_image_height = dv->mAVCodecContext->height;        return 0;}

    if (mVideoDecode)        videox_ended(mVideoDecode);    videox_began(format, frame_head->width, frame_head->height, &mVideoDecode);    ... ...     long w = 0;    long h = 0;                    uint8_t* RGBBuffer = 0;    int RGBBufferSize = 0;    int ret = videox_decode(mVideoDecode, (uint8_t*)a264Buffer, a264Length, &RGBBuffer, &RGBBufferSize, &w, &h);    dispatch_async(dispatch_get_main_queue(), ^{                            if (self.stream && ret >= 0)        {            CFDataRef data = CFDataCreateWithBytesNoCopy(kCFAllocatorDefault, RGBBuffer, RGBBufferSize, kCFAllocatorNull);            CGDataProviderRef provider = CGDataProviderCreateWithCFData(data);            CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();            int bitsPerComponent = 8;                   // 8位存储一个Component            int bitsPerPixel =3* bitsPerComponent;    // RGB存储，只用三个字节，而不是像RGBA要用4个字节，所以这里一个像素点要3个8位来存储            int bytesPerRow =3* w;                    // 每行有width个象素点，每个点用3个字节，另外注意：pict.linesize[0]=bytesPerRow=1056            CGImageRef cgImage = CGImageCreate(w,                                               h,                                               bitsPerComponent,                                               bitsPerPixel,                                               bytesPerRow, // pict.linesize[0],等效                                               colorSpace,                                               kCGBitmapByteOrderDefault,                                               provider,                                               NULL,                                               NO,                                               kCGRenderingIntentDefault);            mImageView.image = [UIImage imageWithCGImage:cgImage];            CGColorSpaceRelease(colorSpace);            CGImageRelease(cgImage);            CGDataProviderRelease(provider);            CFRelease(data);        }    });

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