| /* ------------------------------------------------------------------ |
| * 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); |
| } |
| |
