using System.Text; namespace Nikse.SubtitleEdit.Core.SubtitleFormats { /// /// ARIB B24 decoding /// See https://github.com/johnoneil/arib/blob/master/analysis/analysis.txt + https://github.com/johnoneil/arib/blob/master/docs/arib_std_b-24_v5.2-E1_Data_Coding_for_Digital_Broadcast.pdf /// public static class AribB24Decoder { private static readonly Encoding EncodingKanji = Encoding.GetEncoding("ISO-2022-JP"); public static string AribToString(byte[] buffer, int index, int length) { int end = index + length; if (end > buffer.Length) end = buffer.Length; var sb = new StringBuilder(); int pos = index; while (pos < end) { var b = buffer[pos++]; if (b == 0x09) // Tab (09) { sb.Append("\t"); } else if (b == 0x0d && pos < end && buffer[pos] == 0x0a) // Carriage Return/Line Feed (0D0A) { sb.AppendLine(); pos++; } else if (b <= 0x1f) // C0 { ParseC0ControlSet(sb, b, ref pos, buffer); } else if (b == 0x20) // SP - Space character { sb.Append(" "); } else if (b >= 0x21 && b <= 0x7e) // GL - Graphic-set left { ParseGlArea(sb, b, ref pos, buffer); } else if (b == 0x7f) // DEL - Delete character { } else if (b >= 0x80 && b <= 0x9f) // C1 { ParseC1ControlSet(sb, b, ref pos, buffer); } else if (b >= 0xc0) // GR - Graphic-set right { ParseGrArea(sb, b, ref pos, buffer); } } return sb.ToString(); } private static void ParseC0ControlSet(StringBuilder sb, byte b, ref int pos, byte[] buffer) { switch (b) { case 0x07: // BEL - Bell break; case 0x08: // APB - Active position backward break; case 0x09: // APF - Active position forward break; case 0x0a: // APD - Active position down break; case 0x0b: // APU - Active position up break; case 0x0c: // CS - Clear screen break; case 0x0d: // APR - Active position return break; case 0x0e: // LS1 - Locking shift 1 break; case 0x0f: // LS0 - Locking shift 0 break; case 0x16: // PAPF - Parameterized active position forward break; case 0x18: // CAN - Cancel break; case 0x19: // SS2 - Single shift 2 break; case 0x1b: // ESC - Escape break; case 0x1c: // APS - Active position set break; case 0x1d: // SS3 - Single shift 3 break; case 0x1e: // RS - Record separator break; case 0x1f: // US - Unit separator break; } } private static void ParseC1ControlSet(StringBuilder sb, byte b, ref int pos, byte[] buffer) { switch (b) { case 0x80: // BKF - Black Foreground break; case 0x81: // RDF - Red Foreground break; case 0x82: // GRF - Green Foreground break; case 0x83: // YLF - Yellow Foreground break; case 0x84: // BLF - Blue Foreground break; case 0x85: // MGF - Magenta Foreground break; case 0x86: // CNF - Cyan Foreground break; case 0x87: // WHF - White Foreground break; case 0x88: // SSZ - Small Size break; case 0x89: // MSZ - Middle Size break; case 0x8a: // NSZ - Normal Size break; case 0x8b: // SZX - Character Size Controls b = buffer[pos++]; //SZX 06 / 0 : Tiny size (0x60) //SZX 04 / 1 : Double height (0x41) //SZX 04 / 4 : Double width (0x44) //SZX 04 / 5 : Double height and width (0x45) //SZX 06 / 11 : Special 1 (0x6b) //SZX 06 / 4 : Special 2 (0x64) break; case 0x90: // = COL - Colour Controls b = buffer[pos++]; if (b == 0x20) { pos++; } break; case 0x91: // LC - Flashing control break; case 0x92: // DC - Conceal Display Controls break; case 0x93: // OL - Pattern Polarity Controls break; case 0x94: // MM - Writing Mode Modification break; case 0x95: // MACRO - Macro Command break; case 0x97: // HLC - Highlight Character Block break; case 0x98: // RPC - Repeat Character break; case 0x99: // SPL - Stop Lining break; case 0x9a: // STL - Start Lining break; case 0x9b: // CSI - Control Sequence Introducer break; case 0x9d: // TIME - Time Controls break; } } private static void ParseGlArea(StringBuilder sb, byte b, ref int pos, byte[] buffer) { sb.Append(GetKanjiChar(b, buffer[pos++])); } private static void ParseGrArea(StringBuilder sb, byte b, ref int pos, byte[] buffer) { sb.Append(GetKanjiChar(b, buffer[pos++])); } private static string GetKanjiChar(byte b1, byte b2) { return EncodingKanji.GetString(new byte[] { 0x1B, 0x24, 0x40, b1, b2, 0x1B, 0x28, 0x4A }); } } }