h.264 to avi

参考资料：

http://blog.csdn.net/sunnylion1982/article/details/38376453

http://blog.csdn.net/happydeer/article/details/8775

http://blog.csdn.net/zhujinghao_09/article/details/44458245

https://github.com/Sebmaster/avi.js

http://blog.csdn.net/yi7900/article/details/7481599

代码：

debugger;
var record=new Worker("/js/media/record.js")
record.onmessage=function (e) {
    if(e.data.type=="blob"){
        var blob=e.data.data
        var a=document.createElement("a")
        var url=URL.createObjectURL(blob)
        a.href=url
        document.documentElement.appendChild(a)
        a.download="guxi.avi"
        a.id="guxi"
        a.click()
    }
}

代码：

"use strict";

(function() {

    /**
     * @param {Uint8Array} buf
     * @param {number} idx
     * @param {Array.<number>} bytes
     */
    function writeBytes(buf, idx, bytes) {
        for (var i=0; i < bytes.length; ++i) {
            buf[idx + i] = bytes[i];
        }
    }

    /**
     * @param {Uint8Array} buf
     * @param {number} idx
     * @param {number} num
     */
    function writeShort(buf, idx, num) {
        buf[idx] = num & 255;
        buf[idx + 1] = (num >> 8) & 255;
    }

    /**
     * @param {Uint8Array} buf
     * @param {number} idx
     * @param {number} num
     */
    function writeInt(buf, idx, num) {
        buf[idx] = num & 255;
        buf[idx + 1] = (num >> 8) & 255;
        buf[idx + 2] = (num >> 16) & 255;
        buf[idx + 3] = (num >> 24) & 255;
    }

    /**
     * @param {number} idx
     * @param {string} str
     */
    function writeString(buf, idx, str) {
        for (var i=0; i < str.length; ++i) {
            buf[idx + i] = str.charCodeAt(i) & 255;
        }
    }


///////////////////////////////////////////////////////avi数据结构
    //12 "RIFF" SIZE(TYPE+DATA) "AVI "
    //12 "LIST" SIZE(TYPE+DATA) "hdrl"
    //64 AVIMAINHEADER数据结构--"avih" 56+8=64
    //12 "LIST" SIZE "strl"
    //"strh" AVISTREAMHEADER 数据结构 64=56+8
    //"strf" BITMAPINFO数据结构 或 WAVEFORMATEX数据结构 48=40+8 或 38=30+8
    //多个流 两个 视频+音频
    //12 LIST size MOVI
///////////////////////////////////////////////////////////////////

    /**
     * @constructor
     */
    function AVIJS(width,height,fps) {
        this.settings = {
            "width": width,
            "height": height,
            "fps":fps
        };
        /** @type {Array.<Object{"data","type"}>} */
        this.frames = [];
    };

    AVIJS.prototype.getBuffer = function() {
        var headerInfoNum=88+124;
        var frames=this.frames.length//所有帧
        var vframe=0;//视频帧
        var aframe=0;//音频帧
        var bytes=0;//所有帧的字节数
        for(var i=0;i<this.frames.length;i++){
            if(this.frames[i].type=="video"){
                vframe++
            }else{
                aframe++
            }
            bytes+=this.frames[i].data.length+(this.frames[i].data.length%2==0?0:1)
        }
        var dataNum=frames*8+12+bytes;//数据及其头的字节数


        var buffer = new Uint8Array(headerInfoNum + dataNum);

        //前88位
        writeString(buffer, 0, 'RIFF');
        writeInt(buffer, 4, headerInfoNum + dataNum-8);
        writeString(buffer, 8, 'AVI ');
        writeString(buffer, 12, 'LIST');
        writeInt(buffer, 16, headerInfoNum-20);//88+124+114
        writeString(buffer, 20, 'hdrl');
        //AVIMAINHEADER数据结构
        writeString(buffer, 24, 'avih');
        writeInt(buffer, 28, 56);
        writeInt(buffer, 32, 1000000/this.settings.fps);
        writeInt(buffer, 36, 0);
        writeInt(buffer, 40, 0);
        writeInt(buffer, 44, 0);
        writeInt(buffer, 48, 0);
        writeInt(buffer, 52, 0); //为交互格式指定初始帧数（非交互格式应该指定为0）
        writeInt(buffer, 56, 2);
        writeInt(buffer, 60, 0);
        writeInt(buffer, 64, this.settings.width);
        writeInt(buffer, 68, this.settings.height);
        writeInt(buffer, 72, 0);
        writeInt(buffer, 76, 0);
        writeInt(buffer, 80, 0);
        writeInt(buffer, 84, 0);

        //视频头信息 124
        var vbuf=new Uint8Array(124)
        writeString(vbuf, 0, 'LIST');
        writeInt(vbuf, 4, 116);
        writeString(vbuf, 8, 'strl');
        writeString(vbuf, 12, 'strh');
        writeInt(vbuf, 16, 56);
        writeString(vbuf, 20, 'vids'); //流的类型
        writeString(vbuf, 24, 'H264'); //解码器
        writeInt(vbuf, 28, 0); //标记：是否允许这个流输出？调色板是否变化？
        writeShort(vbuf, 32, 0); // Priority
        writeShort(vbuf, 34, 0); // Language
        writeInt(vbuf, 36, 0); // Initial frames
        writeInt(vbuf, 40, 1); // Scale
        writeInt(vbuf, 44, this.settings.fps*1); // Rate:fps*scale
        writeInt(vbuf, 48, 0); // Startdelay
        writeInt(vbuf, 52, 500); // Length
        writeInt(vbuf, 56, 0); // suggested buffer size
        writeInt(vbuf, 60, 0); // quality
        writeInt(vbuf, 64, 0); // sampleSize
        writeShort(vbuf, 68, 0); // Rect left
        writeShort(vbuf, 70, 0); // Rect top
        writeShort(vbuf, 72, this.settings.width); // Rect width
        writeShort(vbuf, 74, this.settings.height); // Rect height
        writeString(vbuf, 76, 'strf');
        writeInt(vbuf, 80, 40);
        writeInt(vbuf, 84, 40); // struct size
        writeInt(vbuf, 88, this.settings.width); // width
        writeInt(vbuf, 92, this.settings.height); // height
        writeShort(vbuf, 96, 1); // planes
        writeShort(vbuf, 98, 16); // bits per pixel
        writeString(vbuf, 100, "H264"); // compression
        writeInt(vbuf, 104, 0); // image size  是否乘以3????
        writeInt(vbuf, 108, 0); // x pixels per meter
        writeInt(vbuf, 112, 0); // y pixels per meter
        writeInt(vbuf, 116, 0); // colortable used
        writeInt(vbuf, 120, 0); // colortable important
        buffer.set(vbuf,88);

        // //音频头信息 114
        // var abuf=new Uint8Array(114);
        // writeString(abuf, 0, 'LIST');
        // writeInt(abuf, 4, 106);
        // writeString(abuf, 8, 'strl');
        // writeString(abuf, 12, 'strh');
        // writeInt(abuf, 16, 56);
        // writeString(abuf, 20, 'auds'); //流的类型
        // writeString(abuf, 24, 'PCM '); //解码器 0x55
        // writeInt(abuf, 28, 0); //标记
        // writeShort(abuf, 32, 0); // Priority
        // writeShort(abuf, 34, 0); // Language
        // writeInt(abuf, 36, 0); // Initial frames
        // writeInt(abuf, 40, 1); // Scale
        // writeInt(abuf, 44, 30); // Rate 0x5dc0
        // writeInt(abuf, 48, 0); // Startdelay
        // writeInt(abuf, 52, frames-500); // Length 0x1d19c0
        // writeInt(abuf, 56, 1024*1024); // suggested buffer size 0x240
        // writeInt(abuf, 60, 0xffffffff); // quality
        // writeInt(abuf, 64, 0);
        // writeShort(abuf, 68, 0);
        // writeShort(abuf, 70, 0);
        // writeShort(abuf, 72, 0);
        // writeShort(abuf, 74, 0);
        // //WAVEFORMATEX数据结构
        // writeString(abuf, 76, 'strf');
        // writeInt(abuf, 80, 30);
        // writeShort(abuf,84,1)//wFormatTag pcm
        // writeShort(abuf,86,1)//nChannels 通道
        // writeInt(abuf,88,8000)//nSamplesPerSec 采样率
        // writeInt(abuf,92,16000)//nAvgBytesPerSec 平均数据传输率
        // writeShort(abuf,96,2)//nBlockAlign 最小数据的原子大小
        // writeShort(abuf,98,0)//wBitsPerSample
        // writeShort(abuf,100,0)//cbSize
        // writeShort(abuf,102,1)
        // writeShort(abuf,104,2)
        // writeShort(abuf,106,0)
        // writeShort(abuf,108,32772)
        // writeShort(abuf,110,1)
        // writeShort(abuf,112,0)
        // buffer.set(abuf,212);


        writeString(buffer,headerInfoNum,"LIST")
        writeInt(buffer,headerInfoNum+4,dataNum-8)
        writeString(buffer,headerInfoNum+8,"movi")

        var offset=headerInfoNum+12;
        for(var i=0;i<this.frames.length;i++){
            var tmpnum=this.frames[i].data.length+8+(this.frames[i].data.length%2==0?0:1)
            var tmp=new Uint8Array(tmpnum)
            if(this.frames[i].type=="video"){
                writeString(tmp,0,"00dc")
            }else{
                writeString(tmp,0,"01wb")
            }
            writeInt(tmp,4,tmpnum-8)
            writeBytes(tmp,8,this.frames[i].data)
            buffer.set(tmp,offset)
            offset+=tmpnum
        }
        var blob;
        try {
            blob = new Blob([buffer.buffer], { 'type' : 'video/msvideo' });
        } catch (e) {
            var builder = new (typeof BlobBuilder !== 'undefined' ? BlobBuilder : WebKitBlobBuilder)();
            builder.append(buffer.buffer);
            blob = builder.getBlob('video/msvideo');
        }

        return blob;
    };
    var scope = new Function('return this')();
    scope['AVIJS'] = AVIJS;
})();