PVS-Studio warning V599 for ffdshow

class TsubtitleParser : public TsubtitleParserBase { .... }
class TsubtitleParserSubrip09 : public TsubtitleParser { .... }

// Factory Pattern
TsubtitleParserBase* TsubtitleParserBase::getParser(
  int format, double fps, const TsubtitlesSettings *cfg,
  const Tconfig *ffcfg, Tsubreader *subreader,
  bool utf8, bool isEmbedded)
{
  switch (format & Tsubreader::SUB_FORMATMASK) {
  case Tsubreader::SUB_MICRODVD  :
    return new TsubtitleParserMicrodvd(...);
  case Tsubreader::SUB_SUBRIP    :
    return new TsubtitleParserSubrip(...);
  case Tsubreader::SUB_SUBVIEWER :
    return new TsubtitleParserSubviewer(...);
  case Tsubreader::SUB_SAMI      :
    return new TsubtitleParserSami(...);
  case Tsubreader::SUB_VPLAYER   :
    return new TsubtitleParserVplayer(...);
  case Tsubreader::SUB_RT        :
    return new TsubtitleParserRt(...);
  case Tsubreader::SUB_SSA       :
    return new TsubtitleParserSSA(..., isEmbedded);
  case Tsubreader::SUB_DUNNOWHAT :
    return new TsubtitleParserDunnowhat(...);
  case Tsubreader::SUB_MPSUB     :
    return new TsubtitleParserMPsub(...);
  case Tsubreader::SUB_AQTITLE   :
    return new TsubtitleParserAqt(...);
  case Tsubreader::SUB_SUBVIEWER2:
    return new TsubtitleParserSubviewer2(...);
  case Tsubreader::SUB_SUBRIP09  :
    return new TsubtitleParserSubrip09(...);
  case Tsubreader::SUB_MPL2      :
    return new TsubtitleParserMPL2(...);
  default:
    return NULL;
  }
}

TsubtitleParserBase *parser;
parser = TsubtitleParserBase::getParser(
  type, fps1000 / 1000.0, cfg, ffcfg, subs, utf8, true);

TsubtitlesTextpinText::~TsubtitlesTextpinText()
{
  if (parser) {
    delete parser;
  }
}

A destructor is absent in TsubtitleParserBase. A virtual destructor is needed.

This suspicious code was found in ffdshow project by PVS-Studio static code analyzer.
Warning message is:
V599 The virtual destructor is not present, although the 'TsubtitleParserBase' class contains virtual functions. tsubtitlestextpintext.cpp 41

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/