UnpackSideInfo _MP3

Unpacks side information from input bitstream for use during decoding of associated frame.

Syntax

IppStatus ippsUnpackSideInfo_MP3(Ipp8u** ppBitStream, IppMP3SideInfo* pDstSideInfo, int* pDstMainDataBegin, int* pDstPrivateBits, int* pDstScfsi, IppMP3FrameHeader* pFrameHeader);

Parameters

ppBitStream

Pointer to the pointer to the first byte of the side information associated with the current frame in the bit stream buffer. The function updates this parameter.

pFrameHeader

Pointer to the structure that contains the unpacked MP3 frame header. The header structure provides format information about the input bitstream. Both single- and dual-channel MPEG-1 and MPEG-2 modes are supported.

pDstSideInfo

Pointer to the MP3 side information structure. The structure contains side information that applies to all granules and all channels for the current frame. One or more of the structures are placed contiguously in the buffer pointed to by pDstSideInfo in the following order: {granule 0 (channel 0, channel 1), granule 1 (channel 0, channel 1)}.

pDstMainDataBegin

Pointer to the main_data_begin field.

pDstPrivateBits

Pointer to the private bits field.

pDstScfsi

Pointer to the buffer containing the scale factor selection information associated with the current frame. The data is organized contiguously in the buffer in the following order: {channel 0 (scfsi_band 0, scfsi_band 1, ..., scfsi_band 3), channel 1 (scfsi_band 0, scfsi_band 1, ..., scfsi_band 3)}.

Description

The function ippsUnpackSideInfo_MP3is declared in the ippac.h file. This function unpacks the side information from the input bitstream. Before calling the function ippsUnpackSideInfo_MP3, make sure that the pointer ppBitStream points to the first byte of the bit stream that contains the side information associated with the current frame. Before returning to the caller, the function updates the pointer ppBitStream so that it references the next byte after the side information.

Return Values

ippStsNoErr

Indicates no error.

ippStsNullPtrErr

Indicates an error when at least one of the pointers ppBitStream, pDstSideInfo, pDstMainDataBegin, pDstPrivateBits, pDstScfsi, pFrameHeader, or ppBitStream is NULL.

ippStsMP3FrameHeaderErr

Indicates an error when some elements in the MP3 frame header structure are invalid: pFrameHeader->id != IPP_MP3_ID_MPEG1 pFrameHeader->id != IPP_MP3_ID_MPEG2 pFrameHeader->layer != 1 pFrameHeader->mode exceeds [0..3].

ippStsMP3SideInfoErr

Indicates an error when the value of block_type is zero when window_switching_flag is set.

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