public static int GetPageNumber(TeletextPacketPayload packet)
{
var address = (TeletextHamming.UnHamming84(packet.Address[1]) << 4) | TeletextHamming.UnHamming84(packet.Address[0]);
var m = address & 0x7;
if (m == 0)
{
m = 8;
}
var y = (address >> 3) & 0x1f;
if (y == 0)
{
var i = (TeletextHamming.UnHamming84(packet.Data[1]) << 4) | TeletextHamming.UnHamming84(packet.Data[0]);
var flagSubtitle = (TeletextHamming.UnHamming84(packet.Data[5]) & 0x08) >> 3;
if (flagSubtitle == 1 && i < 0xff)
{
var bcdPage = (m << 8) | (TeletextHamming.UnHamming84(packet.Data[1]) << 4) | TeletextHamming.UnHamming84(packet.Data[0]);
return(BcdToDec((ulong)bcdPage));
}
}
return(-1);
}
public static void ProcessTelxPacket(DataUnitT dataUnitId, TeletextPacketPayload packet, ulong timestamp, TeletextRunSettings teletextRunSettings, int targetPageNumberBcd, int targetPageNumberDec)
{
// variable names conform to ETS 300 706, chapter 7.1.2
var address = (TeletextHamming.UnHamming84(packet.Address[1]) << 4) | TeletextHamming.UnHamming84(packet.Address[0]);
var m = address & 0x7;
if (m == 0)
{
m = 8;
}
var y = (address >> 3) & 0x1f;
var designationCode = y > 25 ? TeletextHamming.UnHamming84(packet.Data[0]) : 0x00;
if (y == 0) // PAGE HEADER
{
// CC map
var i = (TeletextHamming.UnHamming84(packet.Data[1]) << 4) | TeletextHamming.UnHamming84(packet.Data[0]);
var flagSubtitle = (TeletextHamming.UnHamming84(packet.Data[5]) & 0x08) >> 3;
CcMap[i] |= (byte)(flagSubtitle << (m - 1));
// Page number and control bits
var pageNumber = (m << 8) | (TeletextHamming.UnHamming84(packet.Data[1]) << 4) | TeletextHamming.UnHamming84(packet.Data[0]);
var charset = ((TeletextHamming.UnHamming84(packet.Data[7]) & 0x08) | (TeletextHamming.UnHamming84(packet.Data[7]) & 0x04) | (TeletextHamming.UnHamming84(packet.Data[7]) & 0x02)) >> 1;
//uint8_t flag_suppress_header = unham_8_4(packet.data[6]) & 0x01;
//uint8_t flag_inhibit_display = (unham_8_4(packet.data[6]) & 0x08) >> 3;
// ETS 300 706, chapter 9.3.1.3:
// When set to '1' the service is designated to be in Serial mode and the transmission of a page is terminated
// by the next page header with a different page number.
// When set to '0' the service is designated to be in Parallel mode and the transmission of a page is terminated
// by the next page header with a different page number but the same magazine number.
// The same setting shall be used for all page headers in the service.
// ETS 300 706, chapter 7.2.1: Page is terminated by and excludes the next page header packet
// having the same magazine address in parallel transmission mode, or any magazine address in serial transmission mode.
_transmissionMode = (TransmissionMode)(TeletextHamming.UnHamming84(packet.Data[7]) & 0x01);
// FIXME: Well, this is not ETS 300 706 kosher, however we are interested in DATA_UNIT_EBU_TELETEXT_SUBTITLE only
if (_transmissionMode == TransmissionMode.TransmissionModeParallel && dataUnitId != DataUnitT.DataUnitEbuTeletextSubtitle)
{
return;
}
if (_receivingData &&
(_transmissionMode == TransmissionMode.TransmissionModeSerial && Page(pageNumber) != Page(targetPageNumberBcd) ||
_transmissionMode == TransmissionMode.TransmissionModeParallel && Page(pageNumber) != Page(targetPageNumberBcd) && m == Magazine(targetPageNumberBcd))
)
{
_receivingData = false;
return;
}
// Page transmission is terminated, however now we are waiting for our new page
if (targetPageNumberBcd != pageNumber)
{
return;
}
// Now we have the beginning of page transmission; if there is page_buffer pending, process it
if (_pageBuffer.Tainted)
{
// it would be nice, if subtitle hides on previous video frame, so we contract 40 ms (1 frame @25 fps)
_pageBuffer.HideTimestamp = timestamp - 40;
ProcessPage(_pageBuffer, teletextRunSettings, targetPageNumberDec);
}
_pageBuffer.ShowTimestamp = timestamp;
_pageBuffer.HideTimestamp = 0;
_pageBuffer.Text = new int[25, 40];
_pageBuffer.Tainted = false;
_receivingData = true;
_primaryCharset.G0X28 = (int)BoolT.Undef;
var c = _primaryCharset.G0M29 != (int)BoolT.Undef ? _primaryCharset.G0M29 : charset;
RemapG0Charset(c);
/*
* // I know -- not needed; in subtitles we will never need disturbing teletext page status bar
* // displaying tv station name, current time etc.
* if (flag_suppress_header == NO) {
* for (uint8_t i = 14; i < 40; i++) page_buffer.text[y,i] = telx_to_ucs2(packet.data[i]);
* //page_buffer.tainted = YES;
* }
*/
}
else if (m == Magazine(targetPageNumberBcd) && y >= 1 && y <= 23 && _receivingData)
{
// ETS 300 706, chapter 9.4.1: Packets X/26 at presentation Levels 1.5, 2.5, 3.5 are used for addressing
// a character location and overwriting the existing character defined on the Level 1 page
// ETS 300 706, annex B.2.2: Packets with Y = 26 shall be transmitted before any packets with Y = 1 to Y = 25;
// so page_buffer.text[y,i] may already contain any character received
// in frame number 26, skip original G0 character
for (var i = 0; i < 40; i++)
{
if (_pageBuffer.Text[y, i] == 0x00)
{
_pageBuffer.Text[y, i] = TelxToUcs2(packet.Data[i]);
}
}
_pageBuffer.Tainted = true;
}
else if (m == Magazine(targetPageNumberBcd) && y == 26 && _receivingData)
{
// ETS 300 706, chapter 12.3.2: X/26 definition
var x26Row = 0;
var triplets = new uint[13];
var j = 0;
for (var i = 1; i < 40; i += 3, j++)
{
triplets[j] = TeletextHamming.UnHamming2418((packet.Data[i + 2] << 16) | (packet.Data[i + 1] << 8) | packet.Data[i]);
}
for (var j2 = 0; j2 < 13; j2++)
{
if (triplets[j2] == 0xffffffff)
{
// invalid data (HAM24/18 uncorrectable error detected), skip group
_config.LogError($"! Unrecoverable data error; UNHAM24/18()={triplets[j2]}");
continue;
}
var data = (triplets[j2] & 0x3f800) >> 11;
var mode = (triplets[j2] & 0x7c0) >> 6;
var address2 = triplets[j2] & 0x3f;
var rowAddressGroup = address2 >= 40 && address2 <= 63;
// ETS 300 706, chapter 12.3.1, table 27: set active position
if (mode == 0x04 && rowAddressGroup)
{
x26Row = (int)(address2 - 40);
if (x26Row == 0)
{
x26Row = 24;
}
}
// ETS 300 706, chapter 12.3.1, table 27: termination marker
if (mode >= 0x11 && mode <= 0x1f && rowAddressGroup)
{
break;
}
// ETS 300 706, chapter 12.3.1, table 27: character from G2 set
int x26Col;
if (mode == 0x0f && !rowAddressGroup)
{
x26Col = (int)address2;
if (data > 31)
{
_pageBuffer.Text[x26Row, x26Col] = TeletextTables.G2[0, data - 0x20];
}
}
// ETS 300 706, chapter 12.3.1, table 27: G0 character with diacritical mark
if (mode >= 0x11 && mode <= 0x1f && !rowAddressGroup)
{
x26Col = (int)address2;
if (data >= 65 && data <= 90) // A-Z
{
_pageBuffer.Text[x26Row, x26Col] = TeletextTables.G2Accents[mode - 0x11, data - 65];
}
else if (data >= 97 && data <= 122) // a-z
{
_pageBuffer.Text[x26Row, x26Col] = TeletextTables.G2Accents[mode - 0x11, data - 71];
}
else // other
{
_pageBuffer.Text[x26Row, x26Col] = TelxToUcs2((byte)data);
}
}
}
}
else if (m == Magazine(targetPageNumberBcd) && y == 28 && _receivingData)
{
// TODO:
// ETS 300 706, chapter 9.4.7: Packet X/28/4
// Where packets 28/0 and 28/4 are both transmitted as part of a page, packet 28/0 takes precedence over 28/4 for all but the color map entry coding.
if (designationCode == 0 || designationCode == 4)
{
// ETS 300 706, chapter 9.4.2: Packet X/28/0 Format 1
// ETS 300 706, chapter 9.4.7: Packet X/28/4
uint triplet0 = TeletextHamming.UnHamming2418((packet.Data[3] << 16) | (packet.Data[2] << 8) | packet.Data[1]);
if (triplet0 == 0xffffffff)
{
// invalid data (HAM24/18 uncorrectable error detected), skip group
_config.LogError($"! Unrecoverable data error; UNHAM24/18()={triplet0}");
}
else
{
// ETS 300 706, chapter 9.4.2: Packet X/28/0 Format 1 only
if ((triplet0 & 0x0f) == 0x00)
{
_primaryCharset.G0X28 = (int)((triplet0 & 0x3f80) >> 7);
RemapG0Charset(_primaryCharset.G0X28);
}
}
}
}
else if (m == Magazine(targetPageNumberBcd) && y == 29)
{
// TODO:
// ETS 300 706, chapter 9.5.1 Packet M/29/0
// Where M/29/0 and M/29/4 are transmitted for the same magazine, M/29/0 takes precedence over M/29/4.
if (designationCode == 0 || designationCode == 4)
{
// ETS 300 706, chapter 9.5.1: Packet M/29/0
// ETS 300 706, chapter 9.5.3: Packet M/29/4
uint triplet0 = TeletextHamming.UnHamming2418((packet.Data[3] << 16) | (packet.Data[2] << 8) | packet.Data[1]);
if (triplet0 == 0xffffffff)
{
// invalid data (HAM24/18 uncorrectable error detected), skip group
_config.LogError($"! Unrecoverable data error; UNHAM24/18()={triplet0}");
}
else
{
// ETS 300 706, table 11: Coding of Packet M/29/0
// ETS 300 706, table 13: Coding of Packet M/29/4
if ((triplet0 & 0xff) == 0x00)
{
_primaryCharset.G0M29 = (int)((triplet0 & 0x3f80) >> 7);
// X/28 takes precedence over M/29
if (_primaryCharset.G0X28 == (int)BoolT.Undef)
{
RemapG0Charset(_primaryCharset.G0M29);
}
}
}
}
}
else if (m == 8 && y == 30)
{
// ETS 300 706, chapter 9.8: Broadcast Service Data Packets
if (!_states.ProgrammeInfoProcessed)
{
// ETS 300 706, chapter 9.8.1: Packet 8/30 Format 1
if (TeletextHamming.UnHamming84(packet.Data[0]) < 2)
{
_config.LogInfoNoNewLine("- Programme Identification Data = ");
for (var i = 20; i < 40; i++)
{
var c = TelxToUcs2(packet.Data[i]);
// strip any control codes from PID, eg. TVP station
if (c < 0x20)
{
continue;
}
_config.LogInfoNoNewLine(Ucs2ToUtf8(c));
}
_config.LogInfo(string.Empty);
// OMG! ETS 300 706 stores timestamp in 7 bytes in Modified Julian Day in BCD format + HH:MM:SS in BCD format
// + timezone as 5-bit count of half-hours from GMT with 1-bit sign
// In addition all decimals are incremented by 1 before transmission.
long t = 0;
// 1st step: BCD to Modified Julian Day
t += (packet.Data[10] & 0x0f) * 10000;
t += ((packet.Data[11] & 0xf0) >> 4) * 1000;
t += (packet.Data[11] & 0x0f) * 100;
t += ((packet.Data[12] & 0xf0) >> 4) * 10;
t += packet.Data[12] & 0x0f;
t -= 11111;
// 2nd step: conversion Modified Julian Day to unix timestamp
t = (t - 40587) * 86400;
// 3rd step: add time
t += 3600 * (((packet.Data[13] & 0xf0) >> 4) * 10 + (packet.Data[13] & 0x0f));
t += 60 * (((packet.Data[14] & 0xf0) >> 4) * 10 + (packet.Data[14] & 0x0f));
t += ((packet.Data[15] & 0xf0) >> 4) * 10 + (packet.Data[15] & 0x0f);
t -= 40271;
// 4th step: conversion to time_t
var span = TimeSpan.FromTicks(t * TimeSpan.TicksPerSecond);
var t2 = new DateTime(1970, 1, 1).Add(span);
var localTime = TimeZoneInfo.ConvertTimeFromUtc(t2, TimeZoneInfo.Local);
_config.LogInfo($"- Programme Timestamp (UTC) = {localTime.ToLongDateString()} {localTime.ToLongTimeString()}");
_config.LogInfo($"- Transmission mode = {(_transmissionMode == TransmissionMode.TransmissionModeSerial ? "serial" : "parallel")}");
_states.ProgrammeInfoProcessed = true;
}
}
}
}
