ADTS.bt

//------------------------------------------------
//--- 010 Editor v2.0 Binary Template
//
//   File: ADTS.bt
//   Author: zhoubo
//   Version: 0.1
//   Purpose: Parse AAC ADTS audio files.
//   Category: Audio
//   File Mask: *.aac
//   ID Bytes: FF F? ?? ?? ?? ?? ?? //ADTS(Audio Data Transport Stream) Header, 7 or 9 bytes
//   History:
//   0.1 Initial release.
//   not ADIF：Audio Data Interchange Format
//
// More information available at:
//  https://en.wikipedia.org/wiki/AAC
//  https://juejin.cn/post/7032170229732442148
//------------------------------------------------

BigEndian();

// Forward declarations:

struct ADTS_HEADER;
struct ADTS_FRAME;

// Constants:

local int haveCRC = false;   // Record whether we have CRC chunk yet
local int64 last_frame_length = 0;

// Enums:

// Funtions:

// https://blog.csdn.net/C1033177205/article/details/107140640/
// https://www.jianshu.com/p/71d92c495ff9
string GetMPEGVersionComment(USHORT &id)
{
    local string comment = "";
    switch (id)
    {
    case 0:        comment = "MPEG-4"; break;
    case 1:        comment = "MPEG-2"; break;
    }
    return comment;
}

string GetProtectionAbsentComment(USHORT &protection_absent)
{
    local string comment = "";
    switch (protection_absent)
    {
    case 0:        comment = "ADTS has 9 bytes with CRC"; break;
    case 1:        comment = "ADTS has 7 bytes without CRC"; break;
    }
    return comment;
}

string GetProfileComment(INT64 &profile)
{
    local string comment = "";
    switch (profile)
    {
    case 0x00:        comment = "AAC Main"; break;
    case 0x01:        comment = "AAC LC(Low Complexity)"; break;
    case 0x10:        comment = "AAC SSR(Scalable Sample Rate)"; break;
    case 0x11:        comment = "AAC LTP(Long Term Prediction)"; break;
    }
    return comment;
}

string GetSamplingFrequencyIndexComment(INT64 &sampling_frequency_index)
{
    local string comment = "";
    switch (sampling_frequency_index)
    {
    case 0x0:        comment = "SampleRate 96000"; break;
    case 0x1:        comment = "SampleRate 88200"; break;
    case 0x2:        comment = "SampleRate 64000"; break;
    case 0x3:        comment = "SampleRate 48000"; break;
    case 0x4:        comment = "SampleRate 44100"; break;
    case 0x5:        comment = "SampleRate 32000"; break;
    case 0x6:        comment = "SampleRate 24000"; break;
    case 0x7:        comment = "SampleRate 22050"; break;
    case 0x8:        comment = "SampleRate 16000"; break;
    case 0x9:        comment = "SampleRate 12000"; break;
    case 0xa:        comment = "SampleRate 11025"; break;
    case 0xb:        comment = "SampleRate 8000"; break;
    case 0xc:        comment = "SampleRate 7350"; break;
    case 0xd:        comment = "SampleRate reserved"; break;
    case 0xe:        comment = "SampleRate reserved"; break;
    case 0xf:        comment = "SampleRate escape value"; break;
    }
    return comment;
}

string GetChannelComment(INT64 &channel_configuration)
{
    //0: Defined in AOT Specifc Config
    //1: 1 channel: front-center
    //2: 2 channels: front-left, front-right
    //3: 3 channels: front-center, front-left, front-right
    //4: 4 channels: front-center, front-left, front-right, back-center
    //5: 5 channels: front-center, front-left, front-right, back-left, back-right
    //6: 6 channels: front-center, front-left, front-right, back-left, back-right, LFE-channel
    //7: 8 channels: front-center, front-left, front-right, side-left, side-right, back-left, back-right, LFE-channel
    local string comment = "";
    switch (channel_configuration)
    {
    case 0:        comment = "Channel escape value"; break;
    case 1:        comment = "Channel 1"; break;
    case 2:        comment = "Channel 2"; break;
    case 3:        comment = "Channel 3"; break;
    case 4:        comment = "Channel 4"; break;
    case 5:        comment = "Channel 5"; break;
    case 6:        comment = "Channel 5.1"; break;
    case 7:        comment = "Channel 7.1"; break;
    }
    return comment;
}

string GetBitrateComment(INT64 &adts_buffer_fullness)
{
    local string comment = "";
    switch (adts_buffer_fullness)
    {
    case 0x7FF:        comment = "VBR"; break;
    default:        comment = "rate..??"; break;
    }
    return comment;
}

string GetRawDataBlockComment(INT64 &number_of_raw_data_blocks_in_frame)
{
    local string comment = "";
    switch (number_of_raw_data_blocks_in_frame)
    {
    case 0x0:       comment = "has 1 AAC data block"; break;
    default:        comment = "data block number + 1"; break;
    }
    return comment;
}


//-----------------------------------
// Define structures used in AAC files
//
// [1.adts_fixed_header information]
// syncword:                 占12bits。同步头，表示一个ADTS帧的开始，总是0xFFF。正是因为它的存在，才支持解码任意帧
// ID:                       占1bit。MPEG的版本，0为MPGE-4，1为MPGE-2
// layer:                    占2bits。总是”00”
// protection_absent:        占1bit。=0时，ADTS Header长度占9字节；=1时，ADTS Header占7字节
// profile:                  占2bit。使用哪个级别的AAC，值00、01、10分别对应Main、LC、SSR
// sampling_frequency_index: 占4bits。表示使用的采样率下标，通过这个下标在Sampling Frequencies[ ]数组中查找得知采样率的值
// private_bit:              占1bit。
// channel_configuration:    占3bit。表示声道数，如1-单声道，2-立体声
// original_copy:            占1bit。
// home:                     占1bit。
//
// [2.adts_variable_header information]
// copyright_identification_bit:       占1bit。
// copyright_identification_start:     占1bit。
// aac_frame_length:                   占13bits。表示一个ADTS帧的长度，即ADTS头（7或9字节）+sizeof(AAC Frame)；
// adts_buffer_fullness:               占11bits。值0x7FF，说明是码率可变的码流
// number_of_raw_data_blocks_in_frame: 占2bits。表示ADTS帧中有(number_of_raw_data_blocks_In_frame+1)个AAC原始帧
//
// [3.CRC information]
// crc_check:                占16bits。当protection_absent=0时

typedef struct 
{
    // ADTS_FIXED_HEADER
    USHORT syncword : 12;
    USHORT id : 1                           <comment = GetMPEGVersionComment>;
    USHORT layer : 2;
    USHORT protection_absent : 1            <comment = GetProtectionAbsentComment>;

    INT64 profile : 2                       <comment = GetProfileComment>;
    INT64 sampling_frequency_index : 4      <comment = GetSamplingFrequencyIndexComment>;
    INT64 private_bit : 1;
    INT64 channel_configuration : 3         <comment = GetChannelComment>;
    INT64 original_copy : 1;
    INT64 home : 1;

    // ADTS_VARIABLE_HEADER
    INT64 copyright_identification_bit : 1;
    INT64 copyright_identification_start : 1;
    INT64 aac_frame_length : 13;
    INT64 adts_buffer_fullness : 11               <comment = GetBitrateComment>;
    INT64 number_of_raw_data_blocks_in_frame : 2  <comment = GetRawDataBlockComment>;

    // ADTS_CRC_HEADER
    if (protection_absent == 0) // CRC if protection_absent = 0
    {
        //Printf( "Header has CRC.\n" );
        haveCRC = true;
        INT64 crc : 16;
        //INT64 data0 : 8;
    } else {
        //Printf( "Header has no CRC.\n" );
        //INT64 data0 : 8;
        //INT64 data1 : 8;
        //INT64 data2 : 8;
    }
}ADTS_HEADER;



typedef struct 
{
    SetBackColor( cLtBlue );
    ADTS_HEADER header;
    if (true != haveCRC)
    {
        FSeek(last_frame_length + 7);
        SetBackColor( cLtPurple );
        byte data[header.aac_frame_length - 7];
    } else {
        FSeek(last_frame_length + 9);
        SetBackColor( cLtPurple );
        byte data[header.aac_frame_length - 9];
    }
}ADTS_FRAME;

//---------------------------------------------


while (!FEof())
{
    ADTS_FRAME adtsFrame <name = "ADTS Frame">;
    if(adtsFrame.header.syncword != 0xFFF)
    {
        Warning( "File is not a valid ADTS AAC file. stop!!!" );
        return -1;
    }
    last_frame_length = last_frame_length + adtsFrame.header.aac_frame_length;
    FSeek(last_frame_length);
}