vdr/dvbsubtitle.c

/*
 * dvbsubtitle.c: DVB subtitles
 *
 * See the main source file 'vdr.c' for copyright information and
 * how to reach the author.
 *
 * Original author: Marco Schl<EFBFBD><EFBFBD>ler <marco@lordzodiac.de>
 * With some input from the "subtitle plugin" by Pekka Virtanen <pekka.virtanen@sci.fi>
 *
 * $Id: dvbsubtitle.c 2.19 2011/09/10 09:43:40 kls Exp $
 */


#include "dvbsubtitle.h"
#define __STDC_FORMAT_MACROS // Required for format specifiers
#include <inttypes.h>
#include "device.h"

#define PAGE_COMPOSITION_SEGMENT   0x10
#define REGION_COMPOSITION_SEGMENT 0x11
#define CLUT_DEFINITION_SEGMENT    0x12
#define OBJECT_DATA_SEGMENT        0x13
#define DISPLAY_DEFINITION_SEGMENT 0x14
#define END_OF_DISPLAY_SET_SEGMENT 0x80

// Set these to 'true' for debug output:
static bool DebugConverter = false;
static bool DebugSegments = false;
static bool DebugPages = false;
static bool DebugRegions = false;
static bool DebugObjects = false;
static bool DebugCluts = false;

#define dbgconverter(a...) if (DebugConverter) fprintf(stderr, a)
#define dbgsegments(a...) if (DebugSegments) fprintf(stderr, a)
#define dbgpages(a...) if (DebugPages) fprintf(stderr, a)
#define dbgregions(a...) if (DebugRegions) fprintf(stderr, a)
#define dbgobjects(a...) if (DebugObjects) fprintf(stderr, a)
#define dbgcluts(a...) if (DebugCluts) fprintf(stderr, a)

// --- cSubtitleClut ---------------------------------------------------------

class cSubtitleClut : public cListObject {
private:
  int clutId;
  int version;
  cPalette palette2;
  cPalette palette4;
  cPalette palette8;
public:
  cSubtitleClut(int ClutId);
  int ClutId(void) { return clutId; }
  int Version(void) { return version; }
  void SetVersion(int Version) { version = Version; }
  void SetColor(int Bpp, int Index, tColor Color);
  const cPalette *GetPalette(int Bpp);
  };

cSubtitleClut::cSubtitleClut(int ClutId)
:palette2(2)
,palette4(4)
,palette8(8)
{
  clutId = ClutId;
  version = -1;
}

void cSubtitleClut::SetColor(int Bpp, int Index, tColor Color)
{
  switch (Bpp) {
    case 2: palette2.SetColor(Index, Color); break;
    case 4: palette4.SetColor(Index, Color); break;
    case 8: palette8.SetColor(Index, Color); break;
    default: esyslog("ERROR: wrong Bpp in cSubtitleClut::SetColor(%d, %d, %08X)", Bpp, Index, Color);
    }
}

const cPalette *cSubtitleClut::GetPalette(int Bpp)
{
  switch (Bpp) {
    case 2: return &palette2;
    case 4: return &palette4;
    case 8: return &palette8;
    default: esyslog("ERROR: wrong Bpp in cSubtitleClut::GetPalette(%d)", Bpp);
    }
  return &palette8;
}

// --- cSubtitleObject -------------------------------------------------------

class cSubtitleObject : public cListObject {
private:
  int objectId;
  int version;
  int codingMethod;
  bool nonModifyingColorFlag;
  int nibblePos;
  uchar backgroundColor;
  uchar foregroundColor;
  int providerFlag;
  int px;
  int py;
  cBitmap *bitmap;
  void DrawLine(int x, int y, tIndex Index, int Length);
  uchar Get2Bits(const uchar *Data, int &Index);
  uchar Get4Bits(const uchar *Data, int &Index);
  bool Decode2BppCodeString(const uchar *Data, int &Index, int&x, int y);
  bool Decode4BppCodeString(const uchar *Data, int &Index, int&x, int y);
  bool Decode8BppCodeString(const uchar *Data, int &Index, int&x, int y);
public:
  cSubtitleObject(int ObjectId, cBitmap *Bitmap);
  int ObjectId(void) { return objectId; }
  int Version(void) { return version; }
  int CodingMethod(void) { return codingMethod; }
  bool NonModifyingColorFlag(void) { return nonModifyingColorFlag; }
  void DecodeSubBlock(const uchar *Data, int Length, bool Even);
  void SetVersion(int Version) { version = Version; }
  void SetBackgroundColor(uchar BackgroundColor) { backgroundColor = BackgroundColor; }
  void SetForegroundColor(uchar ForegroundColor) { foregroundColor = ForegroundColor; }
  void SetNonModifyingColorFlag(bool NonModifyingColorFlag) { nonModifyingColorFlag = NonModifyingColorFlag; }
  void SetCodingMethod(int CodingMethod) { codingMethod = CodingMethod; }
  void SetPosition(int x, int y) { px = x; py = y; }
  void SetProviderFlag(int ProviderFlag) { providerFlag = ProviderFlag; }
  };

cSubtitleObject::cSubtitleObject(int ObjectId, cBitmap *Bitmap)
{
  objectId = ObjectId;
  version = -1;
  codingMethod = -1;
  nonModifyingColorFlag = false;
  nibblePos = 0;
  backgroundColor = 0;
  foregroundColor = 0;
  providerFlag = -1;
  px = py = 0;
  bitmap = Bitmap;
}

void cSubtitleObject::DecodeSubBlock(const uchar *Data, int Length, bool Even)
{
  int x = 0;
  int y = Even ? 0 : 1;
  for (int index = 0; index < Length; ) {
      switch (Data[index++]) {
        case 0x10: {
             nibblePos = 8;
             while (Decode2BppCodeString(Data, index, x, y) && index < Length)
                   ;
             if (!nibblePos)
                index++;
             break;
             }
        case 0x11: {
             nibblePos = 4;
             while (Decode4BppCodeString(Data, index, x, y) && index < Length)
                   ;
             if (!nibblePos)
                index++;
             break;
             }
        case 0x12:
             while (Decode8BppCodeString(Data, index, x, y) && index < Length)
                   ;
             break;
        case 0x20: //TODO
             dbgobjects("sub block 2 to 4 map\n");
             index += 4;
             break;
        case 0x21: //TODO
             dbgobjects("sub block 2 to 8 map\n");
             index += 4;
             break;
        case 0x22: //TODO
             dbgobjects("sub block 4 to 8 map\n");
             index += 16;
             break;
        case 0xF0:
             x = 0;
             y += 2;
             break;
        default: dbgobjects("unknown sub block %s %d\n", __FUNCTION__, __LINE__);
        }
      }
}

void cSubtitleObject::DrawLine(int x, int y, tIndex Index, int Length)
{
  if (nonModifyingColorFlag && Index == 1)
     return;
  x += px;
  y += py;
  for (int pos = x; pos < x + Length; pos++)
      bitmap->SetIndex(pos, y, Index);
}

uchar cSubtitleObject::Get2Bits(const uchar *Data, int &Index)
{
  uchar result = Data[Index];
  if (!nibblePos) {
     Index++;
     nibblePos = 8;
     }
  nibblePos -= 2;
  return (result >> nibblePos) & 0x03;
}

uchar cSubtitleObject::Get4Bits(const uchar *Data, int &Index)
{
  uchar result = Data[Index];
  if (!nibblePos) {
     Index++;
     nibblePos = 4;
     }
  else {
     result >>= 4;
     nibblePos -= 4;
     }
  return result & 0x0F;
}

bool cSubtitleObject::Decode2BppCodeString(const uchar *Data, int &Index, int &x, int y)
{
  int rl = 0;
  int color = 0;
  uchar code = Get2Bits(Data, Index);
  if (code) {
     color = code;
     rl = 1;
     }
  else {
     code = Get2Bits(Data, Index);
     if (code & 2) { // switch_1
        rl = ((code & 1) << 2) + Get2Bits(Data, Index) + 3;
        color = Get2Bits(Data, Index);
        }
     else if (code & 1)
        rl = 1; //color 0
     else {
        code = Get2Bits(Data, Index);
        switch (code & 3) { //switch_3
          case 0:
               return false;
          case 1:
               rl = 2; //color 0
               break;
          case 2:
               rl = (Get2Bits(Data, Index) << 2) + Get2Bits(Data, Index) + 12;
               color = Get2Bits(Data, Index);
               break;
          case 3:
               rl = (Get2Bits(Data, Index) << 6) + (Get2Bits(Data, Index) << 4) + (Get2Bits(Data, Index) << 2) + Get2Bits(Data, Index) + 29;
               color = Get2Bits(Data, Index);
               break;
          default: ;
          }
        }
     }
  DrawLine(x, y, color, rl);
  x += rl;
  return true;
}

bool cSubtitleObject::Decode4BppCodeString(const uchar *Data, int &Index, int &x, int y)
{
  int rl = 0;
  int color = 0;
  uchar code = Get4Bits(Data, Index);
  if (code) {
     color = code;
     rl = 1;
     }
  else {
     code = Get4Bits(Data, Index);
     if (code & 8) { // switch_1
        if (code & 4) { //switch_2
           switch (code & 3) { //switch_3
             case 0: // color 0
                  rl = 1;
                  break;
             case 1: // color 0
                  rl = 2;
                  break;
             case 2:
                  rl = Get4Bits(Data, Index) + 9;
                  color = Get4Bits(Data, Index);
                  break;
             case 3:
                  rl = (Get4Bits(Data, Index) << 4) + Get4Bits(Data, Index) + 25;
                  color = Get4Bits(Data, Index);
                  break;
             default: ;
             }
           }
        else {
           rl = (code & 3) + 4;
           color = Get4Bits(Data, Index);
           }
        }
     else { // color 0
        if (!code)
           return false;
        rl = code + 2;
        }
     }
  DrawLine(x, y, color, rl);
  x += rl;
  return true;
}

bool cSubtitleObject::Decode8BppCodeString(const uchar *Data, int &Index, int &x, int y)
{
  int rl = 0;
  int color = 0;
  uchar code = Data[Index++];
  if (code) {
     color = code;
     rl = 1;
     }
  else {
     code = Data[Index++];
     rl = code & 0x63;
     if (code & 0x80)
        color = Data[Index++];
     else if (!rl)
        return false; //else color 0
     }
  DrawLine(x, y, color, rl);
  x += rl;
  return true;
}

// --- cSubtitleRegion -------------------------------------------------------

class cSubtitleRegion : public cListObject, public cBitmap {
private:
  int regionId;
  int version;
  int clutId;
  int horizontalAddress;
  int verticalAddress;
  int level;
  cList<cSubtitleObject> objects;
public:
  cSubtitleRegion(int RegionId);
  int RegionId(void) { return regionId; }
  int Version(void) { return version; }
  int ClutId(void) { return clutId; }
  int Level(void) { return level; }
  int Depth(void) { return Bpp(); }
  void FillRegion(tIndex Index);
  cSubtitleObject *GetObjectById(int ObjectId, bool New = false);
  int HorizontalAddress(void) { return horizontalAddress; }
  int VerticalAddress(void) { return verticalAddress; }
  void SetVersion(int Version) { version = Version; }
  void SetClutId(int ClutId) { clutId = ClutId; }
  void SetLevel(int Level);
  void SetDepth(int Depth);
  void SetHorizontalAddress(int HorizontalAddress) { horizontalAddress = HorizontalAddress; }
  void SetVerticalAddress(int VerticalAddress) { verticalAddress = VerticalAddress; }
  };

cSubtitleRegion::cSubtitleRegion(int RegionId)
:cBitmap(1, 1, 4)
{
  regionId = RegionId;
  version = -1;
  clutId = -1;
  horizontalAddress = 0;
  verticalAddress = 0;
  level = 0;
}

void cSubtitleRegion::FillRegion(tIndex Index)
{
  dbgregions("FillRegion %d\n", Index);
  for (int y = 0; y < Height(); y++) {
      for (int x = 0; x < Width(); x++)
          SetIndex(x, y, Index);
      }
}

cSubtitleObject *cSubtitleRegion::GetObjectById(int ObjectId, bool New)
{
  cSubtitleObject *result = NULL;
  for (cSubtitleObject *so = objects.First(); so; so = objects.Next(so)) {
      if (so->ObjectId() == ObjectId)
         result = so;
      }
  if (!result && New) {
     result = new cSubtitleObject(ObjectId, this);
     objects.Add(result);
     }
  return result;
}

void cSubtitleRegion::SetLevel(int Level)
{
  if (Level > 0 && Level < 4)
     level = 1 << Level;
}

void cSubtitleRegion::SetDepth(int Depth)
{
  if (Depth > 0 && Depth < 4)
     SetBpp(1 << Depth);
}

// --- cDvbSubtitlePage ------------------------------------------------------

class cDvbSubtitlePage : public cListObject {
private:
  int pageId;
  int version;
  int state;
  int64_t pts;
  int timeout;
  cList<cSubtitleClut> cluts;
public:
  cList<cSubtitleRegion> regions;
  cDvbSubtitlePage(int PageId);
  virtual ~cDvbSubtitlePage();
  int PageId(void) { return pageId; }
  int Version(void) { return version; }
  int State(void) { return state; }
  tArea *GetAreas(double FactorX, double FactorY);
  cSubtitleClut *GetClutById(int ClutId, bool New = false);
  cSubtitleObject *GetObjectById(int ObjectId);
  cSubtitleRegion *GetRegionById(int RegionId, bool New = false);
  int64_t Pts(void) const { return pts; }
  int Timeout(void) { return timeout; }
  void SetVersion(int Version) { version = Version; }
  void SetPts(int64_t Pts) { pts = Pts; }
  void SetState(int State);
  void SetTimeout(int Timeout) { timeout = Timeout; }
  void UpdateRegionPalette(cSubtitleClut *Clut);
  };

cDvbSubtitlePage::cDvbSubtitlePage(int PageId)
{
  pageId = PageId;
  version = -1;
  state = -1;
  pts = 0;
  timeout = 0;
}

cDvbSubtitlePage::~cDvbSubtitlePage()
{
}

tArea *cDvbSubtitlePage::GetAreas(double FactorX, double FactorY)
{
  if (regions.Count() > 0) {
     tArea *Areas = new tArea[regions.Count()];
     tArea *a = Areas;
     for (cSubtitleRegion *sr = regions.First(); sr; sr = regions.Next(sr)) {
         a->x1 = int(round(FactorX * sr->HorizontalAddress()));
         a->y1 = int(round(FactorY * sr->VerticalAddress()));
         a->x2 = int(round(FactorX * (sr->HorizontalAddress() + sr->Width() - 1)));
         a->y2 = int(round(FactorY * (sr->VerticalAddress() + sr->Height() - 1)));
         a->bpp = sr->Bpp();
         while ((a->Width() & 3) != 0)
               a->x2++; // aligns width to a multiple of 4, so 2, 4 and 8 bpp will work
         a++;
         }
     return Areas;
     }
  return NULL;
}

cSubtitleClut *cDvbSubtitlePage::GetClutById(int ClutId, bool New)
{
  cSubtitleClut *result = NULL;
  for (cSubtitleClut *sc = cluts.First(); sc; sc = cluts.Next(sc)) {
      if (sc->ClutId() == ClutId)
         result = sc;
      }
  if (!result && New) {
     result = new cSubtitleClut(ClutId);
     cluts.Add(result);
     }
  return result;
}

cSubtitleRegion *cDvbSubtitlePage::GetRegionById(int RegionId, bool New)
{
  cSubtitleRegion *result = NULL;
  for (cSubtitleRegion *sr = regions.First(); sr; sr = regions.Next(sr)) {
      if (sr->RegionId() == RegionId)
         result = sr;
      }
  if (!result && New) {
     result = new cSubtitleRegion(RegionId);
     regions.Add(result);
     }
  return result;
}

cSubtitleObject *cDvbSubtitlePage::GetObjectById(int ObjectId)
{
  cSubtitleObject *result = NULL;
  for (cSubtitleRegion *sr = regions.First(); sr && !result; sr = regions.Next(sr))
      result = sr->GetObjectById(ObjectId);
  return result;
}

void cDvbSubtitlePage::SetState(int State)
{
  state = State;
  switch (state) {
    case 0: // normal case - page update
         dbgpages("page update\n");
         break;
    case 1: // aquisition point - page refresh
         dbgpages("page refresh\n");
         regions.Clear();
         break;
    case 2: // mode change - new page
         dbgpages("new Page\n");
         regions.Clear();
         cluts.Clear();
         break;
    case 3: // reserved
         break;
    default: dbgpages("unknown page state (%s %d)\n", __FUNCTION__, __LINE__);
    }
}

void cDvbSubtitlePage::UpdateRegionPalette(cSubtitleClut *Clut)
{
  for (cSubtitleRegion *sr = regions.First(); sr; sr = regions.Next(sr)) {
      if (sr->ClutId() == Clut->ClutId())
         sr->Replace(*Clut->GetPalette(sr->Bpp()));
      }
}

// --- cDvbSubtitleAssembler -------------------------------------------------

class cDvbSubtitleAssembler {
private:
  uchar *data;
  int length;
  int pos;
  int size;
  bool Realloc(int Size);
public:
  cDvbSubtitleAssembler(void);
  virtual ~cDvbSubtitleAssembler();
  void Reset(void);
  unsigned char *Get(int &Length);
  void Put(const uchar *Data, int Length);
  };

cDvbSubtitleAssembler::cDvbSubtitleAssembler(void)
{
  data = NULL;
  size = 0;
  Reset();
}

cDvbSubtitleAssembler::~cDvbSubtitleAssembler()
{
  free(data);
}

void cDvbSubtitleAssembler::Reset(void)
{
  length = 0;
  pos = 0;
}

bool cDvbSubtitleAssembler::Realloc(int Size)
{
  if (Size > size) {
     Size = max(Size, 2048);
     if (uchar *NewBuffer = (uchar *)realloc(data, Size)) {
        size = Size;
        data = NewBuffer;
        }
     else {
        esyslog("ERROR: can't allocate memory for subtitle assembler");
        length = 0;
        size = 0;
        free(data);
        data = NULL;
        return false;
        }
     }
  return true;
}

unsigned char *cDvbSubtitleAssembler::Get(int &Length)
{
  if (length > pos + 5) {
     Length = (data[pos + 4] << 8) + data[pos + 5] + 6;
     if (length >= pos + Length) {
        unsigned char *result = data + pos;
        pos += Length;
        return result;
        }
     }
  return NULL;
}

void cDvbSubtitleAssembler::Put(const uchar *Data, int Length)
{
  if (Length && Realloc(length + Length)) {
     memcpy(data + length, Data, Length);
     length += Length;
     }
}

// --- cDvbSubtitleBitmaps ---------------------------------------------------

class cDvbSubtitleBitmaps : public cListObject {
private:
  int64_t pts;
  int timeout;
  tArea *areas;
  int numAreas;
  double osdFactorX;
  double osdFactorY;
  cVector<cBitmap *> bitmaps;
public:
  cDvbSubtitleBitmaps(int64_t Pts, int Timeout, tArea *Areas, int NumAreas, double OsdFactorX, double OsdFactorY);
  ~cDvbSubtitleBitmaps();
  int64_t Pts(void) { return pts; }
  int Timeout(void) { return timeout; }
  void AddBitmap(cBitmap *Bitmap);
  void Draw(cOsd *Osd);
  };

cDvbSubtitleBitmaps::cDvbSubtitleBitmaps(int64_t Pts, int Timeout, tArea *Areas, int NumAreas, double OsdFactorX, double OsdFactorY)
{
  pts = Pts;
  timeout = Timeout;
  areas = Areas;
  numAreas = NumAreas;
  osdFactorX = OsdFactorX;
  osdFactorY = OsdFactorY;
}

cDvbSubtitleBitmaps::~cDvbSubtitleBitmaps()
{
  delete[] areas;
  for (int i = 0; i < bitmaps.Size(); i++)
      delete bitmaps[i];
}

void cDvbSubtitleBitmaps::AddBitmap(cBitmap *Bitmap)
{
  bitmaps.Append(Bitmap);
}

void cDvbSubtitleBitmaps::Draw(cOsd *Osd)
{
  bool Scale = !(DoubleEqual(osdFactorX, 1.0) && DoubleEqual(osdFactorY, 1.0));
  bool AntiAlias = true;
  if (Scale && osdFactorX > 1.0 || osdFactorY > 1.0) {
     // Upscaling requires 8bpp:
     int Bpp[MAXOSDAREAS];
     for (int i = 0; i < numAreas; i++) {
         Bpp[i] = areas[i].bpp;
         areas[i].bpp = 8;
         }
     if (Osd->CanHandleAreas(areas, numAreas) != oeOk) {
        for (int i = 0; i < numAreas; i++)
            Bpp[i] = areas[i].bpp = Bpp[i];
        AntiAlias = false;
        }
     }
  if (Osd->SetAreas(areas, numAreas) == oeOk) {
     for (int i = 0; i < bitmaps.Size(); i++) {
         cBitmap *b = bitmaps[i];
         if (Scale)
            b = b->Scaled(osdFactorX, osdFactorY, AntiAlias);
         Osd->DrawBitmap(int(round(b->X0() * osdFactorX)), int(round(b->Y0() * osdFactorY)), *b);
         if (b != bitmaps[i])
            delete b;
         }
     Osd->Flush();
     }
}

// --- cDvbSubtitleConverter -------------------------------------------------

int cDvbSubtitleConverter::setupLevel = 0;

cDvbSubtitleConverter::cDvbSubtitleConverter(void)
:cThread("subtitleConverter")
{
  dvbSubtitleAssembler = new cDvbSubtitleAssembler;
  osd = NULL;
  frozen = false;
  ddsVersionNumber = -1;
  displayWidth = windowWidth = 720;
  displayHeight = windowHeight = 576;
  windowHorizontalOffset = 0;
  windowVerticalOffset = 0;
  SetOsdData();
  pages = new cList<cDvbSubtitlePage>;
  bitmaps = new cList<cDvbSubtitleBitmaps>;
  Start();
}

cDvbSubtitleConverter::~cDvbSubtitleConverter()
{
  Cancel(3);
  delete dvbSubtitleAssembler;
  delete osd;
  delete bitmaps;
  delete pages;
}

void cDvbSubtitleConverter::SetupChanged(void)
{
  setupLevel++;
}

void cDvbSubtitleConverter::Reset(void)
{
  dbgconverter("Converter reset -----------------------\n");
  dvbSubtitleAssembler->Reset();
  Lock();
  pages->Clear();
  bitmaps->Clear();
  DELETENULL(osd);
  frozen = false;
  ddsVersionNumber = -1;
  displayWidth = windowWidth = 720;
  displayHeight = windowHeight = 576;
  windowHorizontalOffset = 0;
  windowVerticalOffset = 0;
  SetOsdData();
  Unlock();
}

int cDvbSubtitleConverter::ConvertFragments(const uchar *Data, int Length)
{
  if (Data && Length > 8) {
     int PayloadOffset = PesPayloadOffset(Data);
     int SubstreamHeaderLength = 4;
     bool ResetSubtitleAssembler = Data[PayloadOffset + 3] == 0x00;

     // Compatibility mode for old subtitles plugin:
     if ((Data[7] & 0x01) && (Data[PayloadOffset - 3] & 0x81) == 0x01 && Data[PayloadOffset - 2] == 0x81) {
        PayloadOffset--;
        SubstreamHeaderLength = 1;
        ResetSubtitleAssembler = Data[8] >= 5;
        }

     if (Length > PayloadOffset + SubstreamHeaderLength) {
        int64_t pts = PesHasPts(Data) ? PesGetPts(Data) : 0;
        if (pts)
           dbgconverter("Converter PTS: %"PRId64"\n", pts);
        const uchar *data = Data + PayloadOffset + SubstreamHeaderLength; // skip substream header
        int length = Length - PayloadOffset - SubstreamHeaderLength; // skip substream header
        if (ResetSubtitleAssembler)
           dvbSubtitleAssembler->Reset();

        if (length > 3) {
           if (data[0] == 0x20 && data[1] == 0x00 && data[2] == 0x0F)
              dvbSubtitleAssembler->Put(data + 2, length - 2);
           else
              dvbSubtitleAssembler->Put(data, length);

           int Count;
           while (true) {
                 unsigned char *b = dvbSubtitleAssembler->Get(Count);
                 if (b && b[0] == 0x0F) {
                    if (ExtractSegment(b, Count, pts) == -1)
                       break;
                    }
                 else
                    break;
                 }
           }
        }
     return Length;
     }
  return 0;
}

int cDvbSubtitleConverter::Convert(const uchar *Data, int Length)
{
  if (Data && Length > 8) {
     int PayloadOffset = PesPayloadOffset(Data);
     if (Length > PayloadOffset) {
        int64_t pts = PesGetPts(Data);
        if (pts)
           dbgconverter("Converter PTS: %"PRId64"\n", pts);
        const uchar *data = Data + PayloadOffset;
        int length = Length - PayloadOffset;
        if (length > 3) {
           if (data[0] == 0x20 && data[1] == 0x00 && data[2] == 0x0F) {
              data += 2;
              length -= 2;
              }
           const uchar *b = data;
           while (length > 0) {
                 if (b[0] == 0x0F) {
                    int n = ExtractSegment(b, length, pts);
                    if (n < 0)
                       break;
                    b += n;
                    length -= n;
                    }
                 else
                    break;
                 }
           }
        }
     return Length;
     }
  return 0;
}

#define LimitTo32Bit(n) ((n) & 0x00000000FFFFFFFFL)
#define MAXDELTA 40000 // max. reasonable PTS/STC delta in ms

void cDvbSubtitleConverter::Action(void)
{
  int LastSetupLevel = setupLevel;
  cTimeMs Timeout;
  while (Running()) {
        int WaitMs = 100;
        if (!frozen) {
           LOCK_THREAD;
           if (osd) {
              int NewSetupLevel = setupLevel;
              if (Timeout.TimedOut() || LastSetupLevel != NewSetupLevel) {
                 DELETENULL(osd);
                 }
              LastSetupLevel = NewSetupLevel;
              }
           if (cDvbSubtitleBitmaps *sb = bitmaps->First()) {
              int64_t STC = cDevice::PrimaryDevice()->GetSTC();
              int64_t Delta = LimitTo32Bit(sb->Pts()) - LimitTo32Bit(STC); // some devices only deliver 32 bits
              if (Delta > (int64_t(1) << 31))
                 Delta -= (int64_t(1) << 32);
              else if (Delta < -((int64_t(1) << 31) - 1))
                 Delta += (int64_t(1) << 32);
              Delta /= 90; // STC and PTS are in 1/90000s
              if (Delta <= MAXDELTA) {
                 if (Delta <= 0) {
                    dbgconverter("Got %d bitmaps, showing #%d\n", bitmaps->Count(), sb->Index() + 1);
                    if (AssertOsd()) {
                       sb->Draw(osd);
                       Timeout.Set(sb->Timeout() * 1000);
                       dbgconverter("PTS: %"PRId64"  STC: %"PRId64" (%"PRId64") timeout: %d\n", sb->Pts(), cDevice::PrimaryDevice()->GetSTC(), Delta, sb->Timeout());
                       }
                    bitmaps->Del(sb);
                    }
                 else if (Delta < WaitMs)
                    WaitMs = Delta;
                 }
              else
                 bitmaps->Del(sb);
              }
           }
        cCondWait::SleepMs(WaitMs);
        }
}

tColor cDvbSubtitleConverter::yuv2rgb(int Y, int Cb, int Cr)
{
  int Ey, Epb, Epr;
  int Eg, Eb, Er;

  Ey = (Y - 16);
  Epb = (Cb - 128);
  Epr = (Cr - 128);
  /* ITU-R 709 */
  Er = max(min(((298 * Ey             + 460 * Epr) / 256), 255), 0);
  Eg = max(min(((298 * Ey -  55 * Epb - 137 * Epr) / 256), 255), 0);
  Eb = max(min(((298 * Ey + 543 * Epb            ) / 256), 255), 0);

  return (Er << 16) | (Eg << 8) | Eb;
}

void cDvbSubtitleConverter::SetOsdData(void)
{
  int OsdWidth, OsdHeight;
  double OsdAspect;
  int VideoWidth, VideoHeight;
  double VideoAspect;
  cDevice::PrimaryDevice()->GetOsdSize(OsdWidth, OsdHeight, OsdAspect);
  cDevice::PrimaryDevice()->GetVideoSize(VideoWidth, VideoHeight, VideoAspect);
  if (OsdWidth == displayWidth && OsdHeight == displayHeight || VideoWidth == 0) {
     osdFactorX = osdFactorY = 1.0;
     osdDeltaX = osdDeltaY = 0;
     }
  else {
     osdFactorX = VideoAspect * OsdHeight / displayWidth;
     osdFactorY = double(OsdHeight) / displayHeight;
     osdDeltaX = (OsdWidth - displayWidth * osdFactorX) / 2;
     osdDeltaY = (OsdHeight - displayHeight * osdFactorY) / 2;
     }
}

bool cDvbSubtitleConverter::AssertOsd(void)
{
  LOCK_THREAD;
  return osd || (osd = cOsdProvider::NewOsd(int(round(osdFactorX * windowHorizontalOffset + osdDeltaX)), int(round(osdFactorY * windowVerticalOffset + osdDeltaY)) + Setup.SubtitleOffset, OSD_LEVEL_SUBTITLES));
}

int cDvbSubtitleConverter::ExtractSegment(const uchar *Data, int Length, int64_t Pts)
{
  if (Length > 5 && Data[0] == 0x0F) {
     int segmentLength = (Data[4] << 8) + Data[5] + 6;
     if (segmentLength > Length)
        return -1;
     int segmentType = Data[1];
     int pageId = (Data[2] << 8) + Data[3];
     cDvbSubtitlePage *page = NULL;
     LOCK_THREAD;
     for (cDvbSubtitlePage *sp = pages->First(); sp; sp = pages->Next(sp)) {
         if (sp->PageId() == pageId) {
            page = sp;
            break;
            }
         }
     if (!page) {
        page = new cDvbSubtitlePage(pageId);
        pages->Add(page);
        dbgpages("Create SubtitlePage %d  (total pages = %d)\n", pageId, pages->Count());
        }
     if (Pts)
        page->SetPts(Pts);
     switch (segmentType) {
       case PAGE_COMPOSITION_SEGMENT: {
            dbgsegments("PAGE_COMPOSITION_SEGMENT\n");
            int pageVersion = (Data[6 + 1] & 0xF0) >> 4;
            if (pageVersion == page->Version())
               break; // no update
            page->SetVersion(pageVersion);
            page->SetTimeout(Data[6]);
            page->SetState((Data[6 + 1] & 0x0C) >> 2);
            page->regions.Clear();
            dbgpages("Update page id %d version %d pts %"PRId64" timeout %d state %d\n", pageId, page->Version(), page->Pts(), page->Timeout(), page->State());
            for (int i = 6 + 2; i < segmentLength; i += 6) {
                cSubtitleRegion *region = page->GetRegionById(Data[i], true);
                region->SetHorizontalAddress((Data[i + 2] << 8) + Data[i + 3]);
                region->SetVerticalAddress((Data[i + 4] << 8) + Data[i + 5]);
                }
            break;
            }
       case REGION_COMPOSITION_SEGMENT: {
            dbgsegments("REGION_COMPOSITION_SEGMENT\n");
            cSubtitleRegion *region = page->GetRegionById(Data[6]);
            if (!region)
               break;
            int regionVersion = (Data[6 + 1] & 0xF0) >> 4;
            if (regionVersion == region->Version())
               break; // no update
            region->SetVersion(regionVersion);
            bool regionFillFlag = (Data[6 + 1] & 0x08) >> 3;
            int regionWidth = (Data[6 + 2] << 8) | Data[6 + 3];
            if (regionWidth < 1)
               regionWidth = 1;
            int regionHeight = (Data[6 + 4] << 8) | Data[6 + 5];
            if (regionHeight < 1)
               regionHeight = 1;
            region->SetSize(regionWidth, regionHeight);
            region->SetLevel((Data[6 + 6] & 0xE0) >> 5);
            region->SetDepth((Data[6 + 6] & 0x1C) >> 2);
            region->SetClutId(Data[6 + 7]);
            dbgregions("Region pageId %d id %d version %d fill %d width %d height %d level %d depth %d clutId %d\n", pageId, region->RegionId(), region->Version(), regionFillFlag, regionWidth, regionHeight, region->Level(), region->Depth(), region->ClutId());
            if (regionFillFlag) {
               switch (region->Bpp()) {
                 case 2: region->FillRegion((Data[6 + 9] & 0x0C) >> 2); break;
                 case 4: region->FillRegion((Data[6 + 9] & 0xF0) >> 4); break;
                 case 8: region->FillRegion(Data[6 + 8]); break;
                 default: dbgregions("unknown bpp %d (%s %d)\n", region->Bpp(), __FUNCTION__, __LINE__);
                 }
               }
            for (int i = 6 + 10; i < segmentLength; i += 6) {
                cSubtitleObject *object = region->GetObjectById((Data[i] << 8) | Data[i + 1], true);
                int objectType = (Data[i + 2] & 0xC0) >> 6;
                object->SetCodingMethod(objectType);
                object->SetProviderFlag((Data[i + 2] & 0x30) >> 4);
                int objectHorizontalPosition = ((Data[i + 2] & 0x0F) << 8) | Data[i + 3];
                int objectVerticalPosition = ((Data[i + 4] & 0x0F) << 8) | Data[i + 5];
                object->SetPosition(objectHorizontalPosition, objectVerticalPosition);
                if (objectType == 0x01 || objectType == 0x02) {
                   object->SetForegroundColor(Data[i + 6]);
                   object->SetBackgroundColor(Data[i + 7]);
                   i += 2;
                   }
                }
            break;
            }
       case CLUT_DEFINITION_SEGMENT: {
            dbgsegments("CLUT_DEFINITION_SEGMENT\n");
            cSubtitleClut *clut =  page->GetClutById(Data[6], true);
            int clutVersion = (Data[6 + 1] & 0xF0) >> 4;
            if (clutVersion == clut->Version())
               break; // no update
            clut->SetVersion(clutVersion);
            dbgcluts("Clut pageId %d id %d version %d\n", pageId, clut->ClutId(), clut->Version());
            for (int i = 6 + 2; i < segmentLength; i += 2) {
                uchar clutEntryId = Data[i];
                bool fullRangeFlag = Data[i + 1] & 1;
                uchar yval;
                uchar crval;
                uchar cbval;
                uchar tval;
                if (fullRangeFlag) {
                   yval  = Data[i + 2];
                   crval = Data[i + 3];
                   cbval = Data[i + 4];
                   tval  = Data[i + 5];
                   }
                else {
                   yval   =   Data[i + 2] & 0xFC;
                   crval  =  (Data[i + 2] & 0x03) << 6;
                   crval |=  (Data[i + 3] & 0xC0) >> 2;
                   cbval  =  (Data[i + 3] & 0x3C) << 2;
                   tval   =  (Data[i + 3] & 0x03) << 6;
                   }
                tColor value = 0;
                if (yval) {
                   value = yuv2rgb(yval, cbval, crval);
                   value |= ((10 - (clutEntryId ? Setup.SubtitleFgTransparency : Setup.SubtitleBgTransparency)) * (255 - tval) / 10) << 24;
                   }
                int EntryFlags = Data[i + 1];
                dbgcluts("%2d %d %d %d %08X\n", clutEntryId, (EntryFlags & 0x80) ? 2 : 0, (EntryFlags & 0x40) ? 4 : 0, (EntryFlags & 0x20) ? 8 : 0, value);
                if ((EntryFlags & 0x80) != 0)
                   clut->SetColor(2, clutEntryId, value);
                if ((EntryFlags & 0x40) != 0)
                   clut->SetColor(4, clutEntryId, value);
                if ((EntryFlags & 0x20) != 0)
                   clut->SetColor(8, clutEntryId, value);
                i += fullRangeFlag ? 4 : 2;
                }
            dbgcluts("\n");
            page->UpdateRegionPalette(clut);
            break;
            }
       case OBJECT_DATA_SEGMENT: {
            dbgsegments("OBJECT_DATA_SEGMENT\n");
            cSubtitleObject *object = page->GetObjectById((Data[6] << 8) | Data[6 + 1]);
            if (!object)
               break;
            int objectVersion = (Data[6 + 2] & 0xF0) >> 4;
            if (objectVersion == object->Version())
               break; // no update
            object->SetVersion(objectVersion);
            int codingMethod = (Data[6 + 2] & 0x0C) >> 2;
            object->SetNonModifyingColorFlag(Data[6 + 2] & 0x01);
            dbgobjects("Object pageId %d id %d version %d method %d modify %d\n", pageId, object->ObjectId(), object->Version(), object->CodingMethod(), object->NonModifyingColorFlag());
            if (codingMethod == 0) { // coding of pixels
               int i = 6 + 3;
               int topFieldLength = (Data[i] << 8) | Data[i + 1];
               int bottomFieldLength = (Data[i + 2] << 8) | Data[i + 3];
               object->DecodeSubBlock(Data + i + 4, topFieldLength, true);
               if (bottomFieldLength)
                  object->DecodeSubBlock(Data + i + 4 + topFieldLength, bottomFieldLength, false);
               else
                  object->DecodeSubBlock(Data + i + 4, topFieldLength, false);
               }
            else if (codingMethod == 1) { // coded as a string of characters
               //TODO implement textual subtitles
               }
            break;
            }
       case DISPLAY_DEFINITION_SEGMENT: {
            dbgsegments("DISPLAY_DEFINITION_SEGMENT\n");
            int version = (Data[6] & 0xF0) >> 4;
            if (version != ddsVersionNumber) {
               int displayWindowFlag   = (Data[6] & 0x08) >> 3;
               windowHorizontalOffset = 0;
               windowVerticalOffset   = 0;
               displayWidth = windowWidth   = ((Data[7] << 8) | Data[8]) + 1;
               displayHeight = windowHeight = ((Data[9] << 8) | Data[10]) + 1;
               if (displayWindowFlag) { 
                  windowHorizontalOffset = (Data[11] << 8) | Data[12];                                // displayWindowHorizontalPositionMinimum
                  windowWidth            = ((Data[13] << 8) | Data[14]) - windowHorizontalOffset + 1; // displayWindowHorizontalPositionMaximum
                  windowVerticalOffset   = (Data[15] << 8) | Data[16];                                // displayWindowVerticalPositionMinimum
                  windowHeight           = ((Data[17] << 8) | Data[18]) - windowVerticalOffset + 1;   // displayWindowVerticalPositionMaximum
                  }
               SetOsdData();
               SetupChanged();
               ddsVersionNumber = version;
               }
            break;
            }
       case END_OF_DISPLAY_SET_SEGMENT: {
            dbgsegments("END_OF_DISPLAY_SET_SEGMENT\n");
            FinishPage(page);
            }
            break;
       default:
            dbgsegments("*** unknown segment type: %02X\n", segmentType);
       }
     return segmentLength;
     }
  return -1;
}

void cDvbSubtitleConverter::FinishPage(cDvbSubtitlePage *Page)
{
  if (!AssertOsd())
     return;
  tArea *Areas = Page->GetAreas(osdFactorX, osdFactorY);
  int NumAreas = Page->regions.Count();
  int Bpp = 8;
  bool Reduced = false;
  while (osd && osd->CanHandleAreas(Areas, NumAreas) != oeOk) {
        int HalfBpp = Bpp / 2;
        if (HalfBpp >= 2) {
           for (int i = 0; i < NumAreas; i++) {
               if (Areas[i].bpp >= Bpp) {
                  Areas[i].bpp = HalfBpp;
                  Reduced = true;
                  }
               }
           Bpp = HalfBpp;
           }
        else
           return; // unable to draw bitmaps
        }
  if (Reduced) {
     for (int i = 0; i < NumAreas; i++) {
         cSubtitleRegion *sr = Page->regions.Get(i);
         if (sr->Bpp() != Areas[i].bpp) {
            if (sr->Level() <= Areas[i].bpp) {
               //TODO this is untested - didn't have any such subtitle stream
               cSubtitleClut *Clut = Page->GetClutById(sr->ClutId());
               if (Clut) {
                  dbgregions("reduce region %d bpp %d level %d area bpp %d\n", sr->RegionId(), sr->Bpp(), sr->Level(), Areas[i].bpp);
                  sr->ReduceBpp(*Clut->GetPalette(sr->Bpp()));
                  }
               }
            else {
               dbgregions("condense region %d bpp %d level %d area bpp %d\n", sr->RegionId(), sr->Bpp(), sr->Level(), Areas[i].bpp);
               sr->ShrinkBpp(Areas[i].bpp);
               }
            }
         }
     }
  cDvbSubtitleBitmaps *Bitmaps = new cDvbSubtitleBitmaps(Page->Pts(), Page->Timeout(), Areas, NumAreas, osdFactorX, osdFactorY);
  bitmaps->Add(Bitmaps);
  for (cSubtitleRegion *sr = Page->regions.First(); sr; sr = Page->regions.Next(sr)) {
      int posX = sr->HorizontalAddress();
      int posY = sr->VerticalAddress();
      if (sr->Width() > 0 && sr->Height() > 0) {
         cBitmap *bm = new cBitmap(sr->Width(), sr->Height(), sr->Bpp(), posX, posY);
         bm->DrawBitmap(posX, posY, *sr);
         Bitmaps->AddBitmap(bm);
         }
      }
}