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394 lines
11 KiB
394 lines
11 KiB
/******************************************************************************
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*
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* Copyright (C) 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*****************************************************************************
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* Originally developed and contributed by Ittiam Systems Pvt. Ltd, Bangalore
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*/
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/*!
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**************************************************************************
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* \file ih264d_nal.c
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*
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* \brief NAL parsing routines
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*
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* Detailed_description
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*
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* \author
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* - AI 19 11 2002 Creation
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**************************************************************************
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*/
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#include "ih264d_bitstrm.h"
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#include "ih264d_defs.h"
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#include "ih264_typedefs.h"
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#include "ih264_macros.h"
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#include "ih264_platform_macros.h"
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#include "ih264d_defs.h"
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#define NUM_OF_ZERO_BYTES_BEFORE_START_CODE 2
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#define EMULATION_PREVENTION_BYTE 0x03
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#define NAL_FIRST_BYTE_SIZE 1
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/*!
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**************************************************************************
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* \if Function name : ih264d_find_start_code \endif
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*
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* \brief
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* This function searches for the Start Code Prefix.
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*
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* \param pu1_buf : Pointer to char buffer which contains bitstream.
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* \param u4_cur_pos : Current position in the buffer.
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* \param u4_max_ofst : Number of bytes in Buffer.
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* \param pu4_length_of_start_code : Poiter to length of Start Code.
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*
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* \return
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* Returns 0 on success and -1 on error.
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*
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**************************************************************************
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*/
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#define START_CODE_NOT_FOUND -1
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#define END_OF_STREAM_BUFFER -2
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#define END_OF_STREAM -1
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void ih264d_check_if_aud(UWORD8 *pu1_buf,
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UWORD32 u4_cur_pos,
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UWORD32 u4_max_ofst,
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UWORD32 *pu4_next_is_aud)
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{
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UWORD8 u1_first_byte, u1_nal_unit_type;
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if(u4_cur_pos + 1 < u4_max_ofst)
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{
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u1_first_byte = pu1_buf[u4_cur_pos + 1];
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u1_nal_unit_type = NAL_UNIT_TYPE(u1_first_byte);
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if(u1_nal_unit_type == ACCESS_UNIT_DELIMITER_RBSP)
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{
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*pu4_next_is_aud = 1;
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}
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}
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}
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WORD32 ih264d_find_start_code(UWORD8 *pu1_buf,
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UWORD32 u4_cur_pos,
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UWORD32 u4_max_ofst,
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UWORD32 *pu4_length_of_start_code,
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UWORD32 *pu4_next_is_aud)
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{
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WORD32 zero_byte_cnt = 0;
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UWORD32 ui_curPosTemp;
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*pu4_length_of_start_code = 0;
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/*Find first start code */
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while(u4_cur_pos < u4_max_ofst)
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{
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if(pu1_buf[u4_cur_pos] == 0)
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zero_byte_cnt++;
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else if(pu1_buf[u4_cur_pos]
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== 0x01 && zero_byte_cnt >= NUM_OF_ZERO_BYTES_BEFORE_START_CODE)
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{
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/* Found the start code */
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u4_cur_pos++;
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break;
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}
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else
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{
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zero_byte_cnt = 0;
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}
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u4_cur_pos++;
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}
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/*Find Next Start Code */
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*pu4_length_of_start_code = u4_cur_pos;
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zero_byte_cnt = 0;
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ui_curPosTemp = u4_cur_pos;
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while(u4_cur_pos < u4_max_ofst)
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{
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if(pu1_buf[u4_cur_pos] == 0)
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zero_byte_cnt++;
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else if(pu1_buf[u4_cur_pos]
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== 0x01 && zero_byte_cnt >= NUM_OF_ZERO_BYTES_BEFORE_START_CODE)
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{
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/* Found the start code */
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ih264d_check_if_aud(pu1_buf, u4_cur_pos, u4_max_ofst,
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pu4_next_is_aud);
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return (u4_cur_pos - zero_byte_cnt - ui_curPosTemp);
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}
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else
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{
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zero_byte_cnt = 0;
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}
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u4_cur_pos++;
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}
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return (u4_cur_pos - zero_byte_cnt - ui_curPosTemp); //(START_CODE_NOT_FOUND);
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}
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/*!
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**************************************************************************
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* \if Function name : ih264d_get_next_nal_unit \endif
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*
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* \brief
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* This function reads one NAl unit.
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*
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* \param ps_nalStream : Poiter to NalUnitStream structure.
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* \param ps_nalUnit : Pointer to NalUnit.
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*
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* \return
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* Returns 0 on success and -1 on error.
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*
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**************************************************************************
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*/
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WORD32 ih264d_get_next_nal_unit(UWORD8 *pu1_buf,
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UWORD32 u4_cur_pos,
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UWORD32 u4_max_ofst,
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UWORD32 *pu4_length_of_start_code)
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{
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WORD32 i_length_of_nal_unit = 0;
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UWORD32 u4_next_is_aud;
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/* NAL Thread starts */
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ih264d_find_start_code(pu1_buf, u4_cur_pos, u4_max_ofst,
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pu4_length_of_start_code, &u4_next_is_aud);
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return (i_length_of_nal_unit);
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}
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/*!
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**************************************************************************
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* \if Function name : ih264d_process_nal_unit \endif
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*
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* \brief
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* This function removes emulation byte "0x03" from bitstream (EBSP to RBSP).
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* It also converts bytestream format into 32 bit little-endian format.
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*
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* \param ps_bitstrm : Poiter to dec_bit_stream_t structure.
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* \param pu1_nal_unit : Pointer to char buffer of NalUnit.
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* \param u4_numbytes_in_nal_unit : Number bytes in NalUnit buffer.
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*
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* \return
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* Returns number of bytes in RBSP ps_bitstrm.
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*
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* \note
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* This function is same as nal_unit() of 7.3.1. Apart from nal_unit()
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* implementation it converts char buffer into 32 bit Buffer. This
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* facilitates efficient access of bitstream. This has been done taking
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* into account present processor architectures.
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*
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**************************************************************************
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*/
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WORD32 ih264d_process_nal_unit(dec_bit_stream_t *ps_bitstrm,
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UWORD8 *pu1_nal_unit,
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UWORD32 u4_numbytes_in_nal_unit)
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{
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UWORD32 u4_num_bytes_in_rbsp;
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UWORD8 u1_cur_byte;
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WORD32 i = 0;
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WORD8 c_count;
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UWORD32 ui_word;
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UWORD32 *puc_bitstream_buffer = (UWORD32*)pu1_nal_unit;
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ps_bitstrm->pu4_buffer = puc_bitstream_buffer;
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/*--------------------------------------------------------------------*/
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/* First Byte of the NAL Unit */
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/*--------------------------------------------------------------------*/
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ui_word = *pu1_nal_unit++;
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/*--------------------------------------------------------------------*/
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/* Convertion of the EBSP to RBSP */
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/* ie Remove the emulation_prevention_byte [equal to 0x03] */
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/*--------------------------------------------------------------------*/
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u4_num_bytes_in_rbsp = 0;
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c_count = 0;
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//first iteration
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u1_cur_byte = *pu1_nal_unit++;
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ui_word = ((ui_word << 8) | u1_cur_byte);
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c_count++;
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if(u1_cur_byte != 0x00)
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c_count = 0;
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//second iteration
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u1_cur_byte = *pu1_nal_unit++;
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ui_word = ((ui_word << 8) | u1_cur_byte);
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u4_num_bytes_in_rbsp = 2;
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c_count++;
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if(u1_cur_byte != 0x00)
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c_count = 0;
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if(u4_numbytes_in_nal_unit > 2)
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{
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i = ((u4_numbytes_in_nal_unit - 3));
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}
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for(; i > 8; i -= 4)
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{
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// loop 0
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u1_cur_byte = *pu1_nal_unit++;
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if(c_count == NUM_OF_ZERO_BYTES_BEFORE_START_CODE
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&& u1_cur_byte == EMULATION_PREVENTION_BYTE)
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{
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c_count = 0;
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u1_cur_byte = *pu1_nal_unit++;
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i--;
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}
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ui_word = ((ui_word << 8) | u1_cur_byte);
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*puc_bitstream_buffer = ui_word;
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puc_bitstream_buffer++;
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c_count++;
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if(u1_cur_byte != 0x00)
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c_count = 0;
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// loop 1
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u1_cur_byte = *pu1_nal_unit++;
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if(c_count == NUM_OF_ZERO_BYTES_BEFORE_START_CODE
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&& u1_cur_byte == EMULATION_PREVENTION_BYTE)
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{
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c_count = 0;
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u1_cur_byte = *pu1_nal_unit++;
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i--;
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}
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ui_word = ((ui_word << 8) | u1_cur_byte);
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c_count++;
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if(u1_cur_byte != 0x00)
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c_count = 0;
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// loop 2
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u1_cur_byte = *pu1_nal_unit++;
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if(c_count == NUM_OF_ZERO_BYTES_BEFORE_START_CODE
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&& u1_cur_byte == EMULATION_PREVENTION_BYTE)
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{
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c_count = 0;
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u1_cur_byte = *pu1_nal_unit++;
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i--;
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}
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ui_word = ((ui_word << 8) | u1_cur_byte);
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c_count++;
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if(u1_cur_byte != 0x00)
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c_count = 0;
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// loop 3
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u1_cur_byte = *pu1_nal_unit++;
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if(c_count == NUM_OF_ZERO_BYTES_BEFORE_START_CODE
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&& u1_cur_byte == EMULATION_PREVENTION_BYTE)
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{
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c_count = 0;
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u1_cur_byte = *pu1_nal_unit++;
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i--;
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}
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ui_word = ((ui_word << 8) | u1_cur_byte);
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c_count++;
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if(u1_cur_byte != 0x00)
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c_count = 0;
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u4_num_bytes_in_rbsp += 4;
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}
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for(; i > 0; i--)
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{
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u1_cur_byte = *pu1_nal_unit++;
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if(c_count == NUM_OF_ZERO_BYTES_BEFORE_START_CODE
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&& u1_cur_byte == EMULATION_PREVENTION_BYTE)
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{
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c_count = 0;
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i--;
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u1_cur_byte = *pu1_nal_unit++;
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}
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ui_word = ((ui_word << 8) | u1_cur_byte);
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u4_num_bytes_in_rbsp++;
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if((u4_num_bytes_in_rbsp & 0x03) == 0x03)
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{
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*puc_bitstream_buffer = ui_word;
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puc_bitstream_buffer++;
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}
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c_count++;
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if(u1_cur_byte != 0x00)
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c_count = 0;
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}
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*puc_bitstream_buffer = (ui_word
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<< ((3 - (((u4_num_bytes_in_rbsp << 30) >> 30))) << 3));
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ps_bitstrm->u4_ofst = 0;
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ps_bitstrm->u4_max_ofst = ((u4_num_bytes_in_rbsp + NAL_FIRST_BYTE_SIZE) << 3);
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return (u4_num_bytes_in_rbsp);
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}
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/*!
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**************************************************************************
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* \if Function name : ih264d_rbsp_to_sodb \endif
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*
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* \brief
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* This function converts RBSP to SODB.
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*
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* \param ps_bitstrm : Poiter to dec_bit_stream_t structure.
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*
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* \return
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* None.
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*
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**************************************************************************
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*/
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void ih264d_rbsp_to_sodb(dec_bit_stream_t *ps_bitstrm)
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{
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UWORD32 ui_lastWord;
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UWORD32 ui_word;
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UWORD8 uc_lastByte;
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WORD8 i;
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ui_lastWord = (ps_bitstrm->u4_max_ofst >> 5);
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i = (ps_bitstrm->u4_max_ofst >> 3) & 0x03;
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if(i)
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{
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ui_word = ps_bitstrm->pu4_buffer[ui_lastWord];
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uc_lastByte = ((ui_word << ((i - 1) << 3)) >> 24);
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}
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else
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{
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ui_word = ps_bitstrm->pu4_buffer[ui_lastWord - 1];
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uc_lastByte = ((ui_word << 24) >> 24);
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}
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/*--------------------------------------------------------------------*/
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/* Find out the rbsp_stop_bit position in the last byte of rbsp */
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/*--------------------------------------------------------------------*/
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for(i = 0; (i < 8) && !CHECKBIT(uc_lastByte, i); ++i)
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;
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ps_bitstrm->u4_max_ofst = ps_bitstrm->u4_max_ofst - (i + 1);
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}
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