MntMPEGFrameDecoder Class Reference

This component receives an MntMPEGRTPReassemblerBuffer, which contains an array of RTP packets, and decode the packets into YUV data. More...

#include <mnt_mpeg_frame_decoder.h>

Inheritance diagram for MntMPEGFrameDecoder:

List of all members.

Public Member Functions
	MntMPEGFrameDecoder ()
	Initialize the decoder with empty headers (sequence, GOP, picture and slice), and other members.
virtual void	recv (MntData *)
	This method expects a reassemble buffer as input, containing a sequence of packets that made up a complete MPEG frame.
int	copy_next_slice_to_bs (MntMPEGRTPReassemblerBuffer *buf, BitStream *bs, int &i)
	Copy the next complete slice from buffer to bitstream.
void	init_frame (MntMPEGFrame *frame)
void	decode_i_slice (BitStream *bs)
void	decode_p_slice (BitStream *bs)
void	decode_b_slice (BitStream *bs)
void	dct_i_to_byte (MntYUVFrame *, MntMPEGFrame *, MntYUVFrame *)
void	dct_p_to_byte (MntYUVFrame *, MntMPEGFrame *, MntYUVFrame *, MntYUVFrame *)
void	dct_b_to_byte (MntYUVFrame *, MntMPEGFrame *, MntYUVFrame *, MntYUVFrame *, MntYUVFrame *)
void	sc_i_to_byte (MntDCTImage *sc, MntByteImage *byte, MntByteImage *last)
void	sc_p_to_y (MntDCTImage *sc, MntVectorImage *mv, MntByteImage *prev, MntByteImage *byte, MntByteImage *last)
void	sc_p_to_uv (MntDCTImage *sc, MntVectorImage *mv, MntByteImage *prev, MntByteImage *byte, MntByteImage *last)
void	sc_b_to_y (MntDCTImage *sc, MntVectorImage *fwdmv, MntVectorImage *bwdmv, MntByteImage *prev, MntByteImage *future, MntByteImage *byte, MntByteImage *last)
void	sc_b_to_uv (MntDCTImage *sc, MntVectorImage *fwdmv, MntVectorImage *bwdmv, MntByteImage *prev, MntByteImage *future, MntByteImage *byte, MntByteImage *last)
void	process_seq_hdr ()
void	skip_p_macroblocks (int prev_mb_addr, int curr_mb_addr)
void	skip_b_macroblocks (int prev_mb_addr, int curr_mb_addr, int, int, int, int, int, int)
void	skip_macroblock (int curr_mb_addr)
Private Attributes
MntMPEG1SeqHdr *	seq_hdr_
MntMPEG1GopHdr *	gop_hdr_
MntMPEG1PicHdr *	pic_hdr_
MntMPEG1SliceHdr *	slice_hdr_
MntMPEGFrame *	frame_
BitStream *	bs_
BitParser *	bp_
MntYUVFrame *	curr_
MntYUVFrame *	prev_
MntYUVFrame *	next_
MntYUVFrame *	last_decoded_
int	skip_check_addr_
int	prev_fwd_down_
int	prev_fwd_right_
int	prev_bwd_down_
int	prev_bwd_right_
int	prev_fwd_exists_
int	prev_bwd_exists_
int	gop_start_
int	gop_size_
int	curr_frame_no_

---

Detailed Description

This component receives an MntMPEGRTPReassemblerBuffer, which contains an array of RTP packets, and decode the packets into YUV data.

---

Member Function Documentation

int MntMPEGFrameDecoder::copy_next_slice_to_bs (  MntMPEGRTPReassemblerBuffer *  buf, BitStream *  bs, int &  i )

Copy the next complete slice from buffer to bitstream. Update i to the last copied packet. Return 1 if successful, 0 if not (no more packets in buffer or no complete slices can be found due to loss packet). Important: Note that after copying the slices, the end of bitstream is padded with 4 bytes of 0x000001ff. This is necessary so that the slice decoder knows when to stop decoding.

void MntMPEGFrameDecoder::recv (  MntData *  data  )  [virtual]

This method expects a reassemble buffer as input, containing a sequence of packets that made up a complete MPEG frame. (No packet loss is assumed). It performs decoding in three main steps: (i) copy payload into bistream. (ii) decode slices into DCT blocks (iii) decode DCT blocks into uncompressed YUV data. The decoded data is then push to the next components. Reimplemented from MntComponent.

---

Member Data Documentation

BitParser* MntMPEGFrameDecoder::bp_ [private]

BitParser for the BitStream above

BitStream* MntMPEGFrameDecoder::bs_ [private]

BitStream to store payloads from RTP packets before decoding

MntYUVFrame* MntMPEGFrameDecoder::curr_ [private]

Current decoded frame

int MntMPEGFrameDecoder::curr_frame_no_ [private]

frame number (in display order) of the current frame being decoded

MntMPEGFrame* MntMPEGFrameDecoder::frame_ [private]

Pointer to an internal storage of partially decoded frame

MntMPEG1GopHdr* MntMPEGFrameDecoder::gop_hdr_ [private]

GOP header of the GOP being decoded

int MntMPEGFrameDecoder::gop_size_ [private]

the number of frames encountered in the current GOP

int MntMPEGFrameDecoder::gop_start_ [private]

frame number (in display order) of the first frame in the current GOP

MntYUVFrame* MntMPEGFrameDecoder::last_decoded_ [private]

The previous decoded frame for error concealment if some blocks are not decoded

MntYUVFrame* MntMPEGFrameDecoder::next_ [private]

Future reference frame to decode B-frames. Reimplemented from MntComponent.

MntMPEG1PicHdr* MntMPEGFrameDecoder::pic_hdr_ [private]

Picture header of the MPEG frame being decoded

MntYUVFrame* MntMPEGFrameDecoder::prev_ [private]

Previous reference frame to decode P or B-frames.

MntMPEG1SeqHdr* MntMPEGFrameDecoder::seq_hdr_ [private]

Sequence header of the MPEG video being decoded

int MntMPEGFrameDecoder::skip_check_addr_ [private]

last macroblock addr to check for skipping.

MntMPEG1SliceHdr* MntMPEGFrameDecoder::slice_hdr_ [private]

Slice header of the slice being decoded

---

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

• mnt_mpeg_frame_decoder.h
• mnt_mpeg_frame_decoder.cc

---