struct media_extract_info {
  bigtime_t time_to_extract;
  void * file_format_data;
  size_t file_format_data_size;
  int8   pad[??];

  media_extract_info();
}

class BMediaExtractor
{
public:
  BMediaExtractor();
  // start with a file or other source
  BMediaExtractor(const entry_ref * ref, int32 flags = 0);
  BMediaExtractor(BPositionIO * source, int32 flags = 0);

  // start with a file format specification
  BMediaExtractor(const media_file_format * inFormat,
                  const void * info = NULL, size_t infoSize = 0);
  BMediaExtractor(const media_file_format_info * info);
  virtual ~BMediaExtractor(void);
  status_t InitCheck() const;

  status_t SetSource(const entry_ref * ref, int32 flags = 0);
  status_t SetSource(BPositionIO * source, int32 flags = 0);

  status_t SetTo(const media_file_format * inFormat,
                 const void * info = NULL, size_t infoSize = 0);
  status_t SetTo(const media_file_format_info * info);
  status_t SetInputFormat(const media_file_format * inputFormat,
                          const void * inInfo = NULL, size_t inSize = 0);
  // for direct transcoding
  status_t SetOutputFormat(media_file_format * outputFormat);
  status_t SetDestination(const entry_ref * ref, int32 flags = 0);
  status_t SetDestination(BPositionIO * source, int32 flags = 0);

  status_t Extract(void * outBuffer, int64 * outCount, 
                   media_header * outHeader, 
                   media_extract_info * outInfo);

  status_t GetExtractorInfo(media_file_format_info * outInfo) const;

  // convenience methods, just call to GetParameterValue
  inline int32 GetDuration() const {
    int32 value;
    GetParameterValue(B_DURATION,&value),0);
    return value;
  }
  inline int32 GetTrackCount() const {
    int32 value;
    GetParameterValue(B_TRACK_COUNT,&value,0);
    return value;
  }

  // provides B_TRACK_COUNT, and B_DURATION
  // see also BMediaFile::GetParameterValue
  virtual status_t GetParameterValue(int32 id, const void * value, 
                                     size_t * size) = 0;
  // additional configuration parameters
  // see also BMediaFile::SetParameterValue
  virtual status_t SetParameterValue(int32 id, const void * value,
                                     size_t size);
  // the extractor may return a BParameterWeb for browsing
  // or configuring the file format's parameters. returns
  // NULL if the extractor doesn't support this.
  // see also BMediaFile::Web
  virtual BParameterWeb * Web(void);

  ...

protected:
  virtual status_t GetNextChunk(const void ** chunkData,
                                size_t * chunkLength,
                                media_header * header) = 0;  

private:
  // unimplemented
  BMediaExtractor(const BMediaExtractor &);
  BMediaExtractor & operator=(const BMediaExtractor &);

  static status_t next_chunk(void *classptr, void**chunkData, 
                             size_t *chunkLen, media_header *mh);
  void ReleaseDecoder();

  BAddonManager * fExtractorsManager;
  BExtractor * fExtractor;
  int32 fExtractorID;
  status_t fInitStatus;

  // gobble gobble
  uint32 _reservedBMediaExtractor_[32];

  virtual status_t _ReservedBMediaExtractor_0(int 32 arg, ...);
  virtual status_t _ReservedBMediaExtractor_1(int 32 arg, ...);
  // ....
}