3gp文件格式研究 (转windcao的专栏） - 嵌入式 - it博客网.htm

研究3gp文件格式时总结的资料

            (red, green, blue)如果gmod不是copy的话会用到.<BR>SMHD包括两个字段 
            <BR>+--+--+<BR>|bl|rs|<BR>+--+--+<BR>&nbsp;<BR>bl:balance 是一个定点小数(精度 
            8.8) 前8bits是整数,后8bits是小数.如果值为0说明左右声道是相同的.全左的情况下值为-1.0 
            全右则为1.0.<BR>rs:reserved 
            保留字段.<BR>HMHD包括5个字段.如下:<BR>+--+--+[4]-+[4]-+[4]-+<BR>|mp|ap|mbrt|abrt|resv|<BR>+--+--+----+----+----+<BR>&nbsp;<BR>mp:maxPDUsize 
            最大PDU长度 <FONT color=#ff0000>-pdu是啥???????? 
            知道啥是pdu的朋友请告诉我.</FONT><BR>ap:avgPDUsize 平均PDU长度 <BR>mbrt:maxbitrate 
            最大比特率 <BR>abrt:avgbitrate 平均比特率 <BR>resv:reserved 保留字段 
            <BR><BR>NMHD是个空的fullbox 
            <BR><BR>DINF是一个普通的box,也是一个容器,它包括url,urn,dref三个fullbox<BR>url 
            内部是一个UTF-8编码的0结尾的字符串<BR>string location;<BR>url里面则是两个<BR>string 
            name;<BR>string 
            location;<BR>这两个都被称为DataEntryBox.<BR>dref里面是一个url或者urn的列表.首先它有一个字段<BR>unsigned 
            int(32) 
            entry_count;DataEntryBox的列表的个数.<BR>然后就是DataEntryBox的列表<BR><BR>STBL是一个普通的box,也是一个容器,里面包含了很多媒体采样信息.<BR><BR>STTS是一个fullbox里面包含了采样的时间长度信息<BR>内部的数据首先是列表长度<BR>unsigned 
            int(32) entry_count;<BR>然后就是采用时长列表.<BR>列表每一项都由两个字段组成.<BR>unsigned 
            int(32) sample_count;采样个数<BR>unsigned int(32) 
            sample_delta;每个采样的时间长度.<BR><BR>在认识stsd之前我们首先要了解一个数据结构SampleEntry和它的子类AudioSampleEntry,VisualSampleEntry和HintSampleEntry<BR></P>
            <P><IMG height=91 alt=sample_e 
            src="3gp文件格式研究 (转windcao的专栏） - 嵌入式 - IT博客网.files/sampleentry.gif" 
            width=372></P>SampleEntry 
            是一个继成box的抽象的数据结构模型.<BR>除了size,type外它包括两个字段,如下:<BR>+[4]-+[4]-+[6]---+--+<BR>|size|type|resved|di|<BR>+----+----+------+--+<BR>resved:reserved,保留字段<BR>di:data_reference_index,序号.<BR>从这个抽象数据结构继承下来的三个子类分别增加了几个独特的新字段.<BR><BR>HintSampleEntry<BR>+[4]-+[4]-+[6]---+--+[n]-+<BR>|size|type|resved|di|data|<BR>+----+----+------+--+----+<BR>resved:reserved,保留字段<BR>di:data_reference_index,序号.<BR>data:是一个0结尾的utf8编码的字符串.<BR><BR>VisualSampleEntry<BR>+[4]-+[4]-+[6]---+--+--+--+[12]---------+--+--+[4]-+[4]-+[4]-+--+[32]----...---+--+--+<BR>|size|type|resved|di|pd|rs|pre_defined 
            |wd|ht|hrsl|vrsl|resv|fc|compressorname|dp|pd|<BR>+----+----+------+--+--+--+-------------+--+--+----+----+----+--+--------...---+--+--+<BR>size:box长度<BR>type:box:类型<BR>resved:reserved,保留字段<BR>di:data_reference_index,序号.<BR>pd: 
            pre_defined 保留字段<BR>rs: reserved 保留字段<BR>pd: pre_defined 保留字段<BR>wd: 
            width 视频的宽<BR>ht: height 视频的高<BR>hrsl: horizresolution 
            水平分辨率如0x00480000; // 72 dpi<BR>vtsl: vertresolution 
            垂直分辨率如0x00480000; // 72 dpi<BR>rd: reserved 保留字段<BR>fc: frame_count 
            每个采样里面的贞数,一般是1;<BR>cmpn: compressorname 
            是一个数字开头的字符串.并且末尾有填料.对齐到32位.<BR>&nbsp;&nbsp;+-+[n]-+[x]-+<BR>&nbsp;&nbsp;|n|data|xpad|<BR>&nbsp;&nbsp;+-+----+----+<BR>n:number 
            of data.数据的长度,x+n+1=32<BR>dp: depth 视频的色深 0x18 表示24位色<BR>pd: 
            pre_defined 
            保留字段<BR><BR>AudioSampleEntry<BR>+[4]-+[4]-+[6]---+--+[8]-----+--+--+--+--+[4]-+<BR>|size|type|resved|di|reserved|cc|ss|pd|rs|sprt|<BR>+----+----+------+--+--------+--+--+--+--+----+<BR><BR>resved:reserved,保留字段<BR>di:data_reference_index,序号.<BR>reserved:保留字段<BR>cc: 
            channelcount 声道数1或者2;<BR>ss: samplesize 采样位数大小 8bit 8 ;16bit 
            16;<BR>pd: pre_defined 保留字段<BR>rs: reserved保留字段<BR>sprt:samplerate 
            采样率<BR><BR>stsd是一个采样包(SampleEntry)的列表,一般来讲同一个列表中只有一种SampleEntry.<BR>可以通过hdlr里面的handler_type来判断属于哪种SampleEntry.<BR>内部的数据首先是列表长度,一个32位无符号整数 
            entry_count;<BR>然后就是采样包列表.<BR>采样包有很多具体的实现.如下: 
            <DIV id=MP4VisualSampleEntry style="CURSOR: hand; COLOR: blue" 
            onclick="document.all.MP4VisualSampleEntryDisc.style.display=(document.all.MP4VisualSampleEntryDisc.style.display =='none')?'':'none'">+MP4VisualSampleEntry:MP4视频采样包. 
            </DIV>
            <DIV id=MP4VisualSampleEntryDisc 
            style="DISPLAY: none; MARGIN-LEFT: 20px">+[4]-+[4]-+[6]---+--+--+--+[12]---------+--+--+[4]-+[4]-+[4]-+--+[32]----...---+--+--+[n]-+<BR>|size|type|resved|di|pd|rs|pre_defined 
            |wd|ht|hrsl|vrsl|resv|fc|compressorname|dp|pd|esds|<BR>+----+----+------+--+--+--+-------------+--+--+----+----+----+--+--------...---+--+--+----+<BR>size:box长度<BR>type:box类型,内容'mp4v'<BR>resved:reserved,保留字段<BR>di:data_reference_index,序号.<BR>pd: 
            pre_defined 保留字段<BR>rs: reserved 保留字段<BR>pd: pre_defined 保留字段<BR>wd: 
            width 视频的宽<BR>ht: height 视频的高<BR>hrsl: horizresolution 
            水平分辨率如0x00480000; // 72 dpi<BR>vtsl: vertresolution 
            垂直分辨率如0x00480000; // 72 dpi<BR>rd: reserved 保留字段<BR>fc: frame_count 
            每个采样里面的贞数,一般是1;<BR>compressorname: 
            是一个数字开头的字符串.并且末尾有填料.对齐到32位.<BR>dp: depth 视频的色深 0x18 表示24位色<BR>pd: 
            pre_defined 保留字段<BR>
            <DIV id=esdsv style="CURSOR: hand; COLOR: blue" 
            onclick="document.all.esdsvDisc.style.display=(document.all.esdsvDisc.style.display =='none')?'':'none'">+esds:原子数据流描述包(Elementary 
            Stream Data Box). </DIV>
            <DIV id=esdsvDisc style="DISPLAY: none; MARGIN-LEFT: 20px">ES_ID — 
            set to 0 as stored; when built into a stream, the lower 16 bits of 
            the TrackID are used.<BR>streamDependenceFlag — set to 0 as stored; 
            if a dependency exists, it is indicated using a track reference of 
            type ‘dpnd’.<BR>URLflag — kept untouched, i.e. set to false, as the 
            stream is in the file, not remote.<BR>SLConfigDescriptor — is 
            predefined type 2.<BR>OCRStreamFlag — set to false in the file. 
            <BR></DIV></DIV>
            <DIV id=MP4AudioSampleEntry style="CURSOR: hand; COLOR: blue" 
            onclick="document.all.MP4AudioSampleEntryDisc.style.display=(document.all.MP4AudioSampleEntryDisc.style.display =='none')?'':'none'">+MP4AudioSampleEntry:Entry 
            type for audio samples defined in the MP4 specification. </DIV>
            <DIV id=MP4AudioSampleEntryDisc 
            style="DISPLAY: none; MARGIN-LEFT: 20px">+[4]-+[4]-+[6]---+--+[8]-----+--+--+--+--+[4]-+[n]-+<BR>|size|type|resved|di|reserved|cc|ss|pd|rs|sprt|esds|<BR>+----+----+------+--+--------+--+--+--+--+----+----+<BR>resved:reserved,保留字段<BR>di:data_reference_index,序号.<BR>reserved:保留字段<BR>cc: 
            channelcount 声道数1或者2;<BR>ss: samplesize 采样位数大小 8bit 8 ;16bit 
            16;<BR>pd: pre_defined 保留字段<BR>rs: reserved保留字段<BR>sprt:samplerate 
            采样率<BR>
            <DIV id=esdsa style="CURSOR: hand; COLOR: blue" 
            onclick="document.all.esdsaDisc.style.display=(document.all.esdsaDisc.style.display =='none')?'':'none'">+esds:Elementary 
            Stream Data Box.Box containing an elementary stream descriptor for 
            this stream. </DIV>
            <DIV id=esdsaDisc style="DISPLAY: none; MARGIN-LEFT: 20px">ES_ID — 
            set to 0 as stored; when built into a sntream, the lower 16 bits of 
            the TrackID are used.<BR>streamDependenceFlag — set to 0 as stored; 
            if a dependency exists, it is indicated using a track reference of 
            type ‘dpnd’.<BR>URLflag — kept untouched, i.e. set to false, as the 
            stream is in the file, not remote.<BR>SLConfigDescriptor — is 
            predefined type 2.<BR>OCRStreamFlag — set to false in the file. 
            <BR></DIV></DIV>
            <DIV id=AMRSampleEntry style="CURSOR: hand; COLOR: blue" 
            onclick="document.all.AMRSampleEntryDisc.style.display=(document.all.AMRSampleEntryDisc.style.display =='none')?'':'none'">+AMRSampleEntry:Entry 
            type for AMR and AMR-WB speech samples defined in clause 6.5 of the 
            present document. </DIV>
            <DIV id=AMRSampleEntryDisc 
            style="DISPLAY: none; MARGIN-LEFT: 20px">+[4]-+[4]-+[6]---+--+[8]-----+--+--+--+--+[4]-+[n]-+<BR>|size|type|resved|di|reserved|cc|ss|pd|rs|sprt|damr|<BR>+----+----+------+--+--------+--+--+--+--+----+----+<BR>type:'samr' 
            resved:reserved,保留字段<BR>di:data_reference_index,序号.<BR>reserved:保留字段<BR>cc: 
            channelcount 声道数1或者2;<BR>ss: samplesize 采样位数大小 8bit 8 ;16bit 
            16;<BR>pd: pre_defined 保留字段<BR>rs: reserved保留字段<BR>sprt:samplerate 
            采样率<BR>
            <DIV id=damr style="CURSOR: hand; COLOR: blue" 
            onclick="document.all.damrDisc.style.display=(document.all.damrDisc.style.display =='none')?'':'none'">+damr:AMRSpecificBox 
            </DIV>
            <DIV id=damrDisc 
            style="DISPLAY: none; MARGIN-LEFT: 20px">+[4]-+[4]-+[4]-+-+--+-+-+<BR>|size|type|vend|d|ms|m|f|<BR>+----+----+----+-+--+-+-+<BR>type:'damr' 
            vend:vendor<BR>d:decoder_version<BR>ms:mode_set<BR>m:mode_change_period<BR>f:frames_per_sample<BR></DIV></DIV>
            <DIV id=AMRWPSampleEntry style="CURSOR: hand; COLOR: blue" 
            onclick="document.all.AMRWPSampleEntryDisc.style.display=(document.all.AMRWPSampleEntryDisc.style.display =='none')?'':'none'">+AMRWPSampleEntry:Entry 
            type for AMR and AMR-WB speech samples defined in clause 6.5 of the 
            present document. </DIV>
            <DIV id=AMRWPSampleEntryDisc 
            style="DISPLAY: none; MARGIN-LEFT: 20px">+[4]-+[4]-+[6]---+--+[8]-----+--+--+--+--+[4]-+[n]-+<BR>|size|type|resved|di|reserved|cc|ss|pd|rs|sprt|dawp|<BR>+----+----+------+--+--------+--+--+--+--+----+----+<BR>type:'sawb' 
            resved:reserved,保留字段<BR>di:data_reference_index,序号.<BR>reserved:保留字段<BR>cc: 
            channelcount 声道数1或者2;<BR>ss: samplesize 采样位数大小 8bit 8 ;16bit 
            16;<BR>pd: pre_defined 保留字段<BR>rs: reserved保留字段<BR>sprt:samplerate 
            采样率<BR>
            <DIV id=dawp style="CURSOR: hand; COLOR: blue" 
            onclick="document.all.dawpDisc.style.display=(document.all.dawpDisc.style.display =='none')?'':'none'">+dawp:AMRWPDecSpecStruc 
            </DIV>
            <DIV id=dawpDisc style="DISPLAY: none; MARGIN-LEFT: 20px">The 
            AMRWPDecSpecStruc is defined as follows: 
            +[4]-+[4]-+[4]-+-+<BR>|size|type|vend|d|<BR>+----+----+----+-+<BR>type:'dawp'<BR>vend:vendor<BR>d:decoder_version<BR></DIV></DIV>
            <DIV id=H263SampleEntry style="CURSOR: hand; COLOR: blue" 
            onclick="document.all.H263SampleEntryDisc.style.display=(document.all.H263SampleEntryDisc.style.display =='none')?'':'none'">+H263SampleEntry:Entry 
            type for H.263 visual samples defined in clause 6.6 of the present 
            document. </DIV>
            <DIV id=H263SampleEntryDisc 
            style="DISPLAY: none; MARGIN-LEFT: 20px">+[4]-+[4]-+[6]---+--+--+--+[12]---------+--+--+[4]-+[4]-+[4]-+--+[32]----...---+--+--+[n]-+<BR>|size|type|resved|di|pd|rs|pre_defined 
            |wd|ht|hrsl|vrsl|resv|fc|compressorname|dp|pd|d263|<BR>+----+----+------+--+--+--+-------------+--+--+----+----+----+--+--------...---+--+--+----+<BR>size:box长度<BR>type:box类型,内容's263'<BR>resved:reserved,保留字段<BR>di:data_reference_index,序号.<BR>pd: 
            pre_defined 保留字段<BR>rs: reserved 保留字段<BR>pd: pre_defined 保留字段<BR>wd: 
            width 视频的宽<BR>ht: height 视频的高<BR>hrsl: horizresolution 
            水平分辨率如0x00480000; // 72 dpi<BR>vtsl: vertresolution 
            垂直分辨率如0x00480000; // 72 dpi<BR>resv: reserved 保留字段<BR>fc: 
            frame_count 每个采样里面的贞数,一般是1;<BR>compressorname: 
            是一个数字开头的字符串.并且末尾有填料.对齐到32位.<BR>dp: depth 视频的色深 0x18 表示24位色<BR>pd: 
            pre_defined 保留字段<BR>
            <DIV id=H263SpecificBox style="CURSOR: hand; COLOR: blue" 
            onclick="document.all.H263SpecificBoxDisc.style.display=(document.all.H263SpecificBoxDisc.style.display =='none')?'':'none'">+d263:H263SpecificBox 
            Information specific to the H.263 decoder. </DIV>
            <DIV id=H263SpecificBoxDisc 
            style="DISPLAY: none; MARGIN-LEFT: 20px">+[4]-+[4]-+[n]-------------+[m]-------+<BR>|size|type|H263DecSpecStruc|BitrateBox|<BR>+----+----+----------------+----------+<BR>type:内容'd263'<BR>
            <DIV id=H263DecSpecStruc style="CURSOR: hand; COLOR: blue" 
            onclick="document.all.H263DecSpecStrucDisc.style.display=(document.all.H263DecSpecStrucDisc.style.display =='none')?'':'none'"><BR>+H263DecSpecStruc: 
            H.263 信息包<BR></DIV>
            <DIV id=H263DecSpecStrucDisc 
            style="DISPLAY: none; MARGIN-LEFT: 20px">H263DecSpecStruc 
            注意这不是一个包而是个结构.<BR><BR>+[4]-+-+-+-+<BR>|vend|d|l|p|<BR>+----+-+-+-+<BR><BR>vend:vendor 
            销售商,4位的字符串例如 'VXYZ'<BR>d:decoder_version解码器版本<BR>l:H263_Level 
            h263版本<BR>p:H263_Profile h263特性<BR>l和p这两个定义是基于MIME media type 
            video/H263-2000标准的<BR>The profile and level specifications can be 
            found in [9].<BR>请参考ITU-T Recommendation H.263 (1998): "Video coding 
            for low bit rate communication".<BR>例 1: H.263 基本 = {H263_Level = 
            10, H263_Profile = 0}<BR>例 2: H.263 Profile 3 @ Level 10 = 
            {H263_Level = 10 , H263_Profile = 3}<BR>注意:hint轨迹也可能引用这个结构中的信息. 
            <BR></DIV>