Dirac - A Video Codec

Created by the British Broadcasting Corporation.

dirac::FrameBuffer

dirac::FrameBuffer Class Reference

Holds frames both for reference and to overcome reordering delay. More...

#include <frame_buffer.h>

List of all members.

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

The buffer holds frames in a stack to overcome both reordering due to bi-directional prediction and use as references for subsequence motion estimation. Frames, and components of frames, can be accessed by their frame numbers. GOP parameters can be included in the constructors so that frames can be given types (I frame, L1 frame or L2 frame) on being pushed onto the stack; alternatively, these parameters can be overridden.

Constructor & Destructor Documentation

dirac::FrameBuffer::FrameBuffer (  ) 

dirac::FrameBuffer::FrameBuffer ( ChromaFormat  cf,
int  xlen,
int  ylen,
int  c_xlen,
int  c_ylen,
unsigned int  vd 
)

Creates a FrameBuffer using the chroma format. Suitable for compressing when there are no L2 frames, or when the temporal prediction structure is to be determined on the fly.

Parameters:
cf the Chroma format of frames in the buffer
xlen the luma width of frames in the buffer
ylen the luma height of frames in the buffer
c_xlen the chroma width of frames in the buffer
c_ylen the chroma height of frames in the buffer
vd the video depth of the data in the buffer

dirac::FrameBuffer::FrameBuffer ( ChromaFormat  cf,
int  numL1,
int  L1sep,
int  xlen,
int  ylen,
int  c_xlen,
int  c_ylen,
unsigned int  vd 
)

Creates a FrameBuffer using the chroma format, the number of L1 frames between I frames and the separation in frames between L1 frames. Suitable for compressing when there is a full GOP structure or when the temporal prediction structure is to be determined on the fly.

Parameters:
cf the Chroma format of frames in the buffer
numL1 the number of Layer 1 frames before the next I frame. 0 means that there is only one I frame.
L1sep the number of Layer 2 frames between Layer 1 frames
xlen the luma width of frames in the buffer
ylen the luma height of frames in the buffer
c_xlen the chroma width of frames in the buffer
c_ylen the chroma height of frames in the buffer
vd the video depth of the data in the buffer

dirac::FrameBuffer::FrameBuffer ( const FrameBuffer &  cpy  ) 

Copy constructor. Removes the current contents of the frame buffer and copies in the contents of the initialising buffer.

dirac::FrameBuffer::~FrameBuffer (  ) 

Member Function Documentation

void dirac::FrameBuffer::Clean ( int  fnum  ) 

Delete frame.

Parameters:
fnum frame number in display order to be deleted from frame buffer

void dirac::FrameBuffer::Clean ( int  show_fnum,
int  current_coded_fnum 
)

Delete frames which have been output and which are no longer required for reference. Expiry times are set in each frame's frame parameters.

Parameters:
show_fnum frame number in display order that can be output
current_coded_fnum frame number in display order of frame currently being coded

const PicArray& dirac::FrameBuffer::GetComponent ( unsigned int  frame_num,
CompSort  c 
) const

PicArray& dirac::FrameBuffer::GetComponent ( unsigned int  frame_num,
CompSort  c 
)

const FrameParams& dirac::FrameBuffer::GetFParams (  )  const [inline]

const Frame& dirac::FrameBuffer::GetFrame ( unsigned int  fnum  )  const

Frame& dirac::FrameBuffer::GetFrame ( unsigned int  fnum  ) 

const PicArray& dirac::FrameBuffer::GetUpComponent ( unsigned int  frame_num,
CompSort  c 
) const

PicArray& dirac::FrameBuffer::GetUpComponent ( unsigned int  frame_num,
CompSort  c 
)

FrameBuffer& dirac::FrameBuffer::operator= ( const FrameBuffer &  rhs  ) 

Operator=. Assigns all elements of the rhs to the lhs.

void dirac::FrameBuffer::PushFrame ( StreamPicInput *  picin,
unsigned int  fnum 
)

Read a new frame into the buffer. Frame parameters associated with the frame will be derived from the frame number and the internal GOP parameters in the frame buffer.

Parameters:
picin the picture input
fnum the frame number

void dirac::FrameBuffer::PushFrame ( StreamPicInput *  picin,
const FrameParams &  fp 
)

Read a new frame into the buffer. Frame parameters associated with the frame will be as given by the frame parameter object.

Parameters:
picin the picture input
fp the frame parameters to apply to the frame

void dirac::FrameBuffer::PushFrame ( const Frame &  frame  ) 

Put a copy of a new frame into the top of the buffer.

void dirac::FrameBuffer::PushFrame ( const FrameParams &  fp  ) 

Put a new frame into the top of the buffer. Frame parameters associated with the frame will be as given by the frame parameter object.

void dirac::FrameBuffer::PushFrame ( unsigned int  frame_num  ) 

Put a new frame into the top of the buffer. Frame parameters associated with the frame will be the built-in parameters for the buffer.

Parameters:
frame_num the number of the frame being inserted

void dirac::FrameBuffer::Remove ( unsigned int  fnum  )  [private]

Remove a frame with a given frame number (in display order) from the buffer. Searches through the buffer and removes frame(s) with that number.

void dirac::FrameBuffer::SetFrameParams ( unsigned int  fnum  )  [private]

size_t dirac::FrameBuffer::Size (  )  const [inline]

Member Data Documentation

std::map<unsigned int,unsigned int> dirac::FrameBuffer::m_fnum_map [private]

FrameParams dirac::FrameBuffer::m_fparams [private]

std::vector<Frame*> dirac::FrameBuffer::m_frame_data [private]

std::vector<bool> dirac::FrameBuffer::m_frame_in_use [private]

unsigned int dirac::FrameBuffer::m_gop_len [private]

unsigned int dirac::FrameBuffer::m_L1_sep [private]

unsigned int dirac::FrameBuffer::m_num_L1 [private]

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

© 2004 British Broadcasting Corporation. Dirac code licensed under the Mozilla Public License (MPL) Version 1.1.
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