MntMPEG1PicHdr Class Reference

The MpegPicHdr structure contains all the parameters contained in the picture header of a mpeg stream. More...

#include <mnt_mpeg1_pic.h>

List of all members.

Public Member Functions
int	parse (BitParser *bp)
	Assuming the BitParser bp is pointing to the beginning of a picture header in the bitstream, parse the header and initialized\ the structure pointed to by hdr.
int	find (BitParser *bp)
	Scan forward in the bitstream using BitParser bp, looking for the next picture header, and position bp's cursor at the beginning of the picture header.
int	dump (BitParser *inbp, BitParser *outbp)
	Assuming the BitParser inbp is pointing to the beginning of a picture header in the bitstream, dump the header (without parsing it) from the input bitstream to the output bitstream attached to BitParser outbp.
int	skip (BitParser *bp)
	Assuming that the bitstream position is at the beginning of a MPEG pic header, skip the bitstream using BitParser bp without parsing and return the number of bytes skipped.
int	encode (BitParser *bp)
	Encode the content of pic header hdr into bitstream using BitParser bp.
Public Attributes
short	temporal_reference_
	Frame number module 1024.
char	type_
	Indicates the type of encoding for this picture : could be I_FRAME, P_FRAME, B_FRAME or D_FRAME.
unsigned short	vbv_delay_
char	full_pel_forward_vector_
	For P/B frames, indicates if the forward motion vector is in full or half pixel units.
char	full_pel_backward_vector_
	For B frames, indicates if the backward motion vector is in full or half pixel units.
Motion Vector Scales
Use internally for decoding motion vectors from bitstream. See standard for details.
char	forward_r_size_
char	forward_f_
char	backward_r_size_
char	backward_f_

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Detailed Description

The MpegPicHdr structure contains all the parameters contained in the picture header of a mpeg stream.

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Member Function Documentation

int MntMPEG1PicHdr::dump (  BitParser *  inbp, BitParser *  outbp )

Assuming the BitParser inbp is pointing to the beginning of a picture header in the bitstream, dump the header (without parsing it) from the input bitstream to the output bitstream attached to BitParser outbp. After dumping, the current bitparser cursor position is at the end of the picture header and beginning of a slice header ("picture body"). Returns: Return the number of bytes dumped, or DVM_MPEG_INVALID_START_CODE if inbp is not pointing to a picture header.

int MntMPEG1PicHdr::encode (  BitParser *  bp  )

Encode the content of pic header hdr into bitstream using BitParser bp. Returns: Return the number of bytes encoded into the bitstream.

int MntMPEG1PicHdr::find (  BitParser *  bp  )

Scan forward in the bitstream using BitParser bp, looking for the next picture header, and position bp's cursor at the beginning of the picture header. Returns: Return the number of bytes skipped, or DVM_MPEG_NOT_FOUND if cannot find any header.

int MntMPEG1PicHdr::parse (  BitParser *  bp  )

Assuming the BitParser bp is pointing to the beginning of a picture header in the bitstream, parse the header and initialized\ the structure pointed to by hdr. After parsing bp's current bit position is at the end of the picture header and beginning of a slice header (picture body). Returns: Return the number of bytes parsed, or DVM_MPEG_INVALID_START_CODE if bp is not pointing to a picture header.

int MntMPEG1PicHdr::skip (  BitParser *  bp  )

Assuming that the bitstream position is at the beginning of a MPEG pic header, skip the bitstream using BitParser bp without parsing and return the number of bytes skipped. After skipping the current bitparser position is at the end of the picture header and beginning of a slice header. Returns: Return the number of bytes skipped, or Return DVM_MPEG_INVALID_START_CODE if bp is not pointing to a picture header.

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Member Data Documentation

char MntMPEG1PicHdr::full_pel_backward_vector_

For B frames, indicates if the backward motion vector is in full or half pixel units. If this slot is 1, the backward motion vectors are in full-pixel units. If this slot is 0, the backward motion vectors are in half-pixel units.

char MntMPEG1PicHdr::full_pel_forward_vector_

For P/B frames, indicates if the forward motion vector is in full or half pixel units. If this slot is 1, the forward motion vectors are in full-pixel units. If this slot is 0, the forward motion vectors are in half-pixel units.

short MntMPEG1PicHdr::temporal_reference_

Frame number module 1024. This integer is associated with each picture, start from 0 for first (in display order) picture of each GOP. It increases by one modulo 1024 for every picture (in display order).

unsigned short MntMPEG1PicHdr::vbv_delay_

see standard

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

• mnt_mpeg1_pic.h
• mnt_mpeg1_pic.cc

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