# Dirac - A Video Codec

Created by the British Broadcasting Corporation.

# dirac::DownConverter Class Reference

A class for fast downconversion of picture data. More...

`#include <downconvert.h>`

List of all members.

## Public Member Functions

- DownConverter ()
    Constructor.
- ~DownConverter ()
    Destructor.
- void DoDownConvert (const PicArray &old_data, PicArray &new_data)
    A function to do the actual down-conversion.

## Private Member Functions

- DownConverter (const DownConverter &cpy)
- DownConverter & operator= (const DownConverter &rhs)
- void RowLoop (const int colpos, PicArray &new_data)

## Private Attributes

- ValueType * m_row_buffer

## Static Private Attributes

- static const int Stage_I_Size = 6
- static const int StageI_I = 86
- static const int StageI_II = 46
- static const int StageI_III = 4
- static const int StageI_IV = -8
- static const int StageI_V = -4
- static const int StageI_VI = 4
- static const int StageI_Shift = 8

## Detailed Description

A class for fast down-conversion of picture data. The picture data is downconverted by a factor of two in each dimension, using fast filtering techniques. The filter is a half-band filter designed to trade off frequency response, ringiness, and aliasing

## Constructor & Destructor Documentation

dirac::DownConverter::DownConverter | ( |  | ) |

dirac::DownConverter::~DownConverter | ( |  | ) | `[inline]`

dirac::DownConverter::DownConverter | ( | const DownConverter & | cpy | ) | `[private]`

## Member Function Documentation

void dirac::DownConverter::DoDownConvert | ( | const PicArray & | old_data,
|  | PicArray & | new_data |
| ) |  |  |

A function to do the actual downconversion.

Parameters:

  | old_data | the picture data to be downconverted
  | new_data | the resulting down-converted data. The array must be of the correct size.

DownConverter& dirac::DownConverter::operator= | ( | const DownConverter & | rhs | ) | `[private]`

void dirac::DownConverter::RowLoop | ( | const int | colpos,
|  | PicArray & | new_data |
| ) |  |  | `[private]`

## Member Data Documentation

ValueType* dirac::DownConverter::m_row_buffer`[private]`

const int dirac::DownConverter::Stage_I_Size = 6`[static, private]`

const int dirac::DownConverter::StageI_I = 86`[static, private]`

const int dirac::DownConverter::StageI_II = 46`[static, private]`

const int dirac::DownConverter::StageI_III = 4`[static, private]`

const int dirac::DownConverter::StageI_IV = -8`[static, private]`

const int dirac::DownConverter::StageI_Shift = 8`[static, private]`

const int dirac::DownConverter::StageI_V = -4`[static, private]`

const int dirac::DownConverter::StageI_VI = 4`[static, private]`

The documentation for this class was generated from the following file:

- downconvert.h

© 2004 British Broadcasting Corporation. Dirac code licensed under the Mozilla Public License (MPL) Version 1.1.
HTML documentation generated by Dimitri van Heesch's excellent Doxygen tool.