Aaru/DVD/MPEG.cs

// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : MPEG.cs
// Author(s)      : Rebecca Wallander <sakcheen+github@gmail.com>
//
// --[ Description ] ----------------------------------------------------------
//
//     Handles MPEG packets functionality.
//
// --[ License ] --------------------------------------------------------------
//
//     Permission is hereby granted, free of charge, to any person obtaining a
//     copy of this software and associated documentation files (the
//     "Software"), to deal in the Software without restriction, including
//     without limitation the rights to use, copy, modify, merge, publish,
//     distribute, sublicense, and/or sell copies of the Software, and to
//     permit persons to whom the Software is furnished to do so, subject to
//     the following conditions:
//
//     The above copyright notice and this permission notice shall be included
//     in all copies or substantial portions of the Software.
//
//     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
//     OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
//     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
//     IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
//     CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
//     TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
//     SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
// ----------------------------------------------------------------------------
// Copyright © 2023 Rebecca Wallander
// ****************************************************************************/

// http://www.mpucoder.com/DVD/vobov.html

using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;

namespace Aaru.Decryption.DVD;

public class MPEG
{
    static byte[] _mpeg2PackHeaderStartCode =
    {
        0x0, 0x0, 0x1
    };

    public enum Mpeg2StreamId : byte
    {
        ProgramEnd = 0xB9, PackHeader = 0xBA, SystemHeader = 0xBB,
        ProgramStreamMap = 0xBC, PrivateStream1 = 0xBD, PaddingStream = 0xBE,
        PrivateStream2 = 0xBF, EcmStream = 0xF0, EmmStream = 0xF1,
        ItuTRecH222_0_or_IsoIec13818_1AnnexA_or_IsoIec13818_6DsmccStream = 0xF2, IsoIec13522Stream = 0xF3,
        ItuTRecH222_1TypeA = 0xF4, ItuTRecH222_1TypeB = 0xF5, ItuTRecH222_1TypeC = 0xF6,
        ItuTRecH222_1TypeD = 0xF7, ItuTRecH222_1TypeE = 0xF8, AncillaryStream = 0xF9,
        Reserved1 = 0xFA, Reserved2 = 0xFB, Reserved3 = 0xFC,
        Reserved4 = 0xFD, Reserved5 = 0xFE, ProgramStreamDirectory = 0xFF,

        // DVD Video can only hold 8 audio streams
        MpegAudioStream1  = 0xC0, MpegAudioStream2  = 0xC1, MpegAudioStream3  = 0xC2,
        MpegAudioStream4  = 0xC3, MpegAudioStream5  = 0xC4, MpegAudioStream6  = 0xC5,
        MpegAudioStream7  = 0xC6, MpegAudioStream8  = 0xC7, MpegAudioStream9  = 0xC8,
        MpegAudioStream10 = 0xC9, MpegAudioStream11 = 0xCA, MpegAudioStream12 = 0xCB,
        MpegAudioStream13 = 0xCC, MpegAudioStream14 = 0xCD, MpegAudioStream15 = 0xCE,
        MpegAudioStream16 = 0xCF, MpegAudioStream17 = 0xD0, MpegAudioStream18 = 0xD1,
        MpegAudioStream19 = 0xD2, MpegAudioStream20 = 0xD3, MpegAudioStream21 = 0xD4,
        MpegAudioStream22 = 0xD5, MpegAudioStream23 = 0xD6, MpegAudioStream24 = 0xD7,
        MpegAudioStream25 = 0xD8, MpegAudioStream26 = 0xD9, MpegAudioStream27 = 0xDA,
        MpegAudioStream28 = 0xDB, MpegAudioStream29 = 0xDC, MpegAudioStream30 = 0xDD,
        MpegAudioStream31 = 0xDE, MpegAudioStream32 = 0xDF,

        // DVD Video can only hold 1 video stream
        MpegVideStream1  = 0xE0, MpegVideStream2  = 0xE1, MpegVideStream3  = 0xE2,
        MpegVideStream4  = 0xE3, MpegVideStream5  = 0xE4, MpegVideStream6  = 0xE5,
        MpegVideStream7  = 0xE6, MpegVideStream8  = 0xE7, MpegVideStream9  = 0xE8,
        MpegVideStream10 = 0xE9, MpegVideStream11 = 0xEA, MpegVideStream12 = 0xEB,
        MpegVideStream13 = 0xEC, MpegVideStream14 = 0xED, MpegVideStream15 = 0xEE,
        MpegVideStream16 = 0xEF
    }

    public struct MpegHeader
    {
        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 3)]
        public byte[] startCode;
        public byte packIdentifier;
        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 6)]
        public byte[] scrBlock;
        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 3)]
        public byte[] programMuxRateBlock;
        byte packStuffingLengthBlock;
    }

    public static bool ContainsMpegPackets(byte[] sectorData, uint blocks = 1, uint blockSize = 2048)
    {
        for(uint i = 0; i < blocks; i++)
            if(IsMpegPacket(sectorData.Skip((int)(i * blockSize))))
                return true;

        return false;
    }

    public static bool IsMpegPacket(IEnumerable<byte> sector) =>
        sector.Take(3).ToArray().SequenceEqual(_mpeg2PackHeaderStartCode);
}