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Diffstat (limited to 'media/libstagefright/codecs/aacdec/get_pulse_data.cpp')
-rw-r--r-- | media/libstagefright/codecs/aacdec/get_pulse_data.cpp | 286 |
1 files changed, 286 insertions, 0 deletions
diff --git a/media/libstagefright/codecs/aacdec/get_pulse_data.cpp b/media/libstagefright/codecs/aacdec/get_pulse_data.cpp new file mode 100644 index 0000000..f9c24f4 --- /dev/null +++ b/media/libstagefright/codecs/aacdec/get_pulse_data.cpp @@ -0,0 +1,286 @@ +/* ------------------------------------------------------------------ + * Copyright (C) 1998-2009 PacketVideo + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either + * express or implied. + * See the License for the specific language governing permissions + * and limitations under the License. + * ------------------------------------------------------------------- + */ +/* + + Pathname: get_pulse_data.c + +------------------------------------------------------------------------------ + REVISION HISTORY + + Description: Modified from original shareware code + + Description: Modified to pass variables by reference to eliminate use + of global variables. + + Description: Put into PV format + + Description: 1) Change loop to use pointers. + 2) Rename to from get_nec_nc to get_pulse_data + + Description: Changes per code review + 1) Fix pathname + 2) Read in two fields to save call to getbits + 3) Change how pPulseInfo->number_pulse is stored. + + Description: Placed typecast to Int in places where UInt->Int + + Description: Replace some instances of getbits to get9_n_lessbits + when the number of bits read is 9. + + Who: Date: + Description: +------------------------------------------------------------------------------ + INPUT AND OUTPUT DEFINITIONS + + Inputs: + pInputStream = pointer to a BITS structure, used by the function getbits + to provide data. Data type pointer to BITS structure + + pPulseInfo = pointer to pulse data structure to be filled with data + concerning pulses in the frequency domain. + Data type pointer to PulseInfo + + Local Stores/Buffers/Pointers Needed: None + + Global Stores/Buffers/Pointers Needed: None + + Outputs: + status = return value, zero signifies success, non-zero otherwise. + Presently this function only returns a success, error + checking may be added later. + Data type Int. + + Pointers and Buffers Modified: + + pPulseInfo contents are updated with pulse information. Specifically, + pPulseInfo->number_pulse with the number of pulses found, and + pPulseInfo->pulse_start_sfb is set to the first scale factor band. + Then pPulseInfo->pulse_offset and pPulseInfo->pulse_amp are filled + with data. For these array, only the number of pulses defined will be + set, those values beyond the number of pulses will retain their previous + value and should not be read from. + Note: The value in pPulseInfo->number_pulse is different by a value of + one from the original ISO code. + + pInputBuffer contents are updated to the next location to be read from + the input stream. + + Local Stores Modified: None + + Global Stores Modified: None + +------------------------------------------------------------------------------ + FUNCTION DESCRIPTION + + This function fills in the pulse data structure with information to be used + later for restoring pulses in the spectrum. + +------------------------------------------------------------------------------ + REQUIREMENTS + + This function shall not use global or static variables. + +------------------------------------------------------------------------------ + REFERENCES + + (1) ISO/IEC 13818-7:1997 Titled "Information technology - Generic coding + of moving pictures and associated audio information - Part 7: Advanced + Audio Coding (AAC)", Table 6.17 - Syntax of pulse_data(), + page 15, and section 9.3 "Decoding process", starting on page 41. + + + (2) MPEG-2 NBC Audio Decoder + "This software module was originally developed by AT&T, Dolby + Laboratories, Fraunhofer Gesellschaft IIS in the course of development + of the MPEG-2 NBC/MPEG-4 Audio standard ISO/IEC 13818-7, 14496-1,2 and + 3. This software module is an implementation of a part of one or more + MPEG-2 NBC/MPEG-4 Audio tools as specified by the MPEG-2 NBC/MPEG-4 + Audio standard. ISO/IEC gives users of the MPEG-2 NBC/MPEG-4 Audio + standards free license to this software module or modifications thereof + for use in hardware or software products claiming conformance to the + MPEG-2 NBC/MPEG-4 Audio standards. Those intending to use this software + module in hardware or software products are advised that this use may + infringe existing patents. The original developer of this software + module and his/her company, the subsequent editors and their companies, + and ISO/IEC have no liability for use of this software module or + modifications thereof in an implementation. Copyright is not released + for non MPEG-2 NBC/MPEG-4 Audio conforming products.The original + developer retains full right to use the code for his/her own purpose, + assign or donate the code to a third party and to inhibit third party + from using the code for non MPEG-2 NBC/MPEG-4 Audio conforming products. + This copyright notice must be included in all copies or derivative + works." + Copyright(c)1996. + +------------------------------------------------------------------------------ + PSEUDO-CODE + + status = SUCCESS; + + CALL getbits(neededBits = LEN_PULSE_NPULSE + LEN_PULSE_ST_SFB, + pInputStream = pInputStream) + MODIFYING(*pInputStream) + RETURNING(temp) + + pPulseInfo->number_pulse = 1 + (temp >> LEN_PULSE_ST_SFB); + pPulseInfo->pulse_start_sfb = temp & ((1 << LEN_PULSE_ST_SFB) - 1); + + pPulseOffset = &pPulseInfo->pulse_offset[0]; + pPulseAmp = &pPulseInfo->pulse_amp[0]; + + FOR (i = PulseInfo->number_pulse; i > 0; i--) + CALL getbits(neededBits = LEN_PULSE_POFF + LEN_PULSE_PAMP, + pInputStream = pInputStream) + MODIFYING(*pInputStream) + RETURNING(temp) + + *pPulseOffset++ = temp >> LEN_PULSE_PAMP; + *pPulseAmp++ = temp & ((1 << LEN_PULSE_PAMP) - 1); + END FOR + + MODIFYING (*pInputStream) + MODIFYING (*pPulseInfo) + + RETURN status + +------------------------------------------------------------------------------ + RESOURCES USED + When the code is written for a specific target processor the + the resources used should be documented below. + + STACK USAGE: [stack count for this module] + [variable to represent + stack usage for each subroutine called] + + where: [stack usage variable] = stack usage for [subroutine + name] (see [filename].ext) + + DATA MEMORY USED: x words + + PROGRAM MEMORY USED: x words + + CLOCK CYCLES: [cycle count equation for this module] + [variable + used to represent cycle count for each subroutine + called] + + where: [cycle count variable] = cycle count for [subroutine + name] (see [filename].ext) + +------------------------------------------------------------------------------ +*/ + + +/*---------------------------------------------------------------------------- +; INCLUDES +----------------------------------------------------------------------------*/ + +#include "pv_audio_type_defs.h" +#include "ibstream.h" +#include "s_pulseinfo.h" +#include "s_bits.h" +#include "e_rawbitstreamconst.h" +#include "get_pulse_data.h" + + +/*---------------------------------------------------------------------------- +; MACROS +; Define module specific macros here +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; DEFINES +; Include all pre-processor statements here. Include conditional +; compile variables also. +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; LOCAL FUNCTION DEFINITIONS +; Function Prototype declaration +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; LOCAL VARIABLE DEFINITIONS +; Variable declaration - defined here and used outside this module +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; EXTERNAL FUNCTION REFERENCES +; Declare functions defined elsewhere and referenced in this module +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; EXTERNAL VARIABLES REFERENCES +; Declare variables used in this module but defined elsewhere +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; FUNCTION CODE +----------------------------------------------------------------------------*/ +Int get_pulse_data( + PulseInfo *pPulseInfo, + BITS *pInputStream) +{ + Int i; + Int *pPulseOffset; + Int *pPulseAmp; + Int status = SUCCESS; + UInt temp; + + /* + * Read in both field fields at once to save cycles. These are the + * original lines of code: + * pPulseInfo->number_pulse = getbits(LEN_PULSE_NPULSE, pInputStream); + * pPulseInfo->pulse_start_sfb = getbits(LEN_PULSE_ST_SFB, pInputStream); + */ + + temp = + get9_n_lessbits( + LEN_PULSE_NPULSE + LEN_PULSE_ST_SFB, + pInputStream); + + pPulseInfo->number_pulse = (Int)(1 + (temp >> LEN_PULSE_ST_SFB)); + pPulseInfo->pulse_start_sfb = (Int)(temp & ((1 << LEN_PULSE_ST_SFB) - 1)); + + pPulseOffset = &pPulseInfo->pulse_offset[0]; + pPulseAmp = &pPulseInfo->pulse_amp[0]; + + /* + * This loop needs to count one more than the number read in from + * the bitstream - look at reference [1]. + */ + + for (i = pPulseInfo->number_pulse; i > 0; i--) + { + /* + * Read in both fields. Original lines: + * *pPulseOffset++ = getbits(LEN_PULSE_POFF, pInputStream); + * *pPulseAmp++ = getbits(LEN_PULSE_PAMP, pInputStream); + */ + + temp = + get9_n_lessbits( + LEN_PULSE_POFF + LEN_PULSE_PAMP, + pInputStream); + + *pPulseOffset++ = (Int)(temp >> LEN_PULSE_PAMP); + + *pPulseAmp++ = (Int)(temp & ((1 << LEN_PULSE_PAMP) - 1)); + } + + return (status); +} + |