class BWriter
{
public:
  BWriter(void);
  virtual ~BWriter(void);

  // implement per BFileInterface::GetRef
  virtual status_t GetStream(const BPositionIO * outStream, 
                             BMimeType * outMimeType) = 0;

  // implement per BFileInterface::SetRef
  virtual status_t SetStream(const BPositionIO & stream) = 0;

  // implement per BFileInterface::GetNextFileFormat
  virtual status_t GetNextFileFormat(int32 * cookie,
                                     media_file_format * outFormat) = 0;

  // implement per BFileInterface::DisposeFileFormatCookie
  virtual void DisposeFileFormatCookie(int32 cookie) = 0;

  // implement per BMediaFile::GetFileFormatInfo
  status_t GetFileFormatInfo(media_file_format *mfi) const;

  // The writer should do any cleanup required.  After
  // this function returns, the BPositionIO object will be
  // closed and deleted by the system (not you)
  virtual status_t Close(void);

  // the writer should provide several basic parameters
  // through this interface, such as B_TRACK_COUNT, and B_DURATION
  // note: these parameters are likely changing if the
  // file is still being actively written to
  // see also BMediaFile::GetParameterValue
  virtual status_t GetParameterValue(int32 id, const void * value, 
                                     size_t * size) = 0;
  // the writer supplies parameters for the
  // user to configure, such as bitrate, quantization, etc.
  // see also BMediaFile::SetParameterValue
  virtual status_t SetParameterValue(int32 id, const void * value,
                                     size_t size);
  // the writer may return a BParameterWeb for browsing
  // or configuring the file format's parameters. returns
  // NULL if the writer doesn't support this.
  // see also BMediaFile::Web
  virtual BParameterWeb * Web(void);

  ...
}