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/******************************************************************************
*
* Copyright (C) 2015 The Android Open Source Project
*
* 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.
*
*****************************************************************************
* Originally developed and contributed by Ittiam Systems Pvt. Ltd, Bangalore
*/
/**
******************************************************************************
* @file
* ih264e_bitstream.c
*
* @brief
* This file contains function definitions related to bitstream generation
*
* @author
* ittiam
*
* @par List of Functions:
* - ih264e_bitstrm_init()
* - ih264e_put_bits()
* - ih264e_put_bit()
* - ih264e_put_rbsp_trailing_bits()
* - ih264e_put_uev()
* - ih264e_put_sev()
* - ih264e_put_nal_start_code_prefix()
*
******************************************************************************
*/
/*****************************************************************************/
/* File Includes */
/*****************************************************************************/
/* System include files */
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <stdarg.h>
#include <math.h>
/* User include files */
#include "ih264e_config.h"
#include "ih264_typedefs.h"
#include "ih264_platform_macros.h"
#include "ih264_debug.h"
#include "ih264e_error.h"
#include "ih264e_bitstream.h"
#include "ih264_defs.h"
#include "ih264_macros.h"
/*****************************************************************************/
/* Function Definitions */
/*****************************************************************************/
/**
******************************************************************************
*
* @brief Initializes the encoder bitstream engine
*
* @par Description
* This routine needs to be called at start of slice/frame encode
*
* @param[in] ps_bitstrm
* pointer to bitstream context (handle)
*
* @param[in] p1_bitstrm_buf
* bitstream buffer pointer where the encoded stream is generated in byte order
*
* @param[in] u4_max_bitstrm_size
* indicates maximum bitstream buffer size. (in bytes)
* If actual stream size exceeds the maximum size, encoder should
* 1. Not corrupt data beyond u4_max_bitstrm_size bytes
* 2. Report an error back to application indicating overflow
*
* @return success or failure error code
*
******************************************************************************
*/
IH264E_ERROR_T ih264e_bitstrm_init(bitstrm_t *ps_bitstrm,
UWORD8 *pu1_bitstrm_buf,
UWORD32 u4_max_bitstrm_size)
{
ps_bitstrm->pu1_strm_buffer = pu1_bitstrm_buf;
ps_bitstrm->u4_max_strm_size = u4_max_bitstrm_size;
/* Default init values for other members of bitstream context */
ps_bitstrm->u4_strm_buf_offset = 0;
ps_bitstrm->u4_cur_word = 0;
ps_bitstrm->i4_bits_left_in_cw = WORD_SIZE;
ps_bitstrm->i4_zero_bytes_run = 0;
return(IH264E_SUCCESS);
}
/**
******************************************************************************
*
* @brief puts a code with specified number of bits into the bitstream
*
* @par Description
* inserts code_len number of bits from lsb of code_val into the
* bitstream. updates context members like u4_cur_word, u4_strm_buf_offset and
* i4_bits_left_in_cw. If the total words (u4_strm_buf_offset) exceeds max
* available size (u4_max_strm_size), returns error without corrupting data
* beyond it
*
* @param[in] ps_bitstrm
* pointer to bitstream context (handle)
*
* @param[in] u4_code_val
* code value that needs to be inserted in the stream.
*
* @param[in] code_len
* indicates code length (in bits) of code_val that would be inserted in
* bitstream buffer size. Range of length[1:WORD_SIZE]
*
* @remarks Assumptions: all bits from bit position code_len to msb of
* code_val shall be zero
*
* @return success or failure error code
*
******************************************************************************
*/
IH264E_ERROR_T ih264e_put_bits(bitstrm_t *ps_bitstrm,
UWORD32 u4_code_val,
WORD32 code_len)
{
UWORD32 u4_cur_word = ps_bitstrm->u4_cur_word;
WORD32 bits_left_in_cw = ps_bitstrm->i4_bits_left_in_cw;
/* check assumptions made in the module */
ASSERT(code_len > 0 && code_len <= WORD_SIZE);
if(code_len < WORD_SIZE)
ASSERT((u4_code_val >> code_len) == 0);
/* sanity check on the bitstream engine state */
ASSERT(bits_left_in_cw > 0 && bits_left_in_cw <= WORD_SIZE);
ASSERT(ps_bitstrm->i4_zero_bytes_run <= EPB_ZERO_BYTES);
ASSERT(ps_bitstrm->pu1_strm_buffer != NULL);
if(bits_left_in_cw > code_len)
{
/*******************************************************************/
/* insert the code in local bitstream word and return */
/* code is inserted in position of bits left (post decrement) */
/*******************************************************************/
bits_left_in_cw -= code_len;
u4_cur_word |= (u4_code_val << bits_left_in_cw);
ps_bitstrm->u4_cur_word = u4_cur_word;
ps_bitstrm->i4_bits_left_in_cw = bits_left_in_cw;
return(IH264E_SUCCESS);
}
else
{
/********************************************************************/
/* 1. insert partial code corresponding to bits left in cur word */
/* 2. flush all the bits of cur word to bitstream */
/* 3. insert emulation prevention bytes while flushing the bits */
/* 4. insert remaining bits of code starting from msb of cur word */
/* 5. update bitsleft in current word and stream buffer offset */
/********************************************************************/
IH264E_ERROR_T status = IH264E_SUCCESS;
WORD32 i, rem_bits = (code_len - bits_left_in_cw);
/* insert parital code corresponding to bits left in cur word */
u4_cur_word |= u4_code_val >> rem_bits;
for(i = WORD_SIZE; i > 0; i -= 8)
{
/* flush the bits in cur word byte by byte and copy to stream */
UWORD8 u1_next_byte = (u4_cur_word >> (i-8)) & 0xFF;
status |= ih264e_put_byte_epb(ps_bitstrm, u1_next_byte);
}
/* insert the remaining bits from code val into current word */
u4_cur_word = rem_bits ? (u4_code_val << (WORD_SIZE - rem_bits)) : 0;
/* update the state variables and return success */
ps_bitstrm->u4_cur_word = u4_cur_word;
ps_bitstrm->i4_bits_left_in_cw = WORD_SIZE - rem_bits;
return (status);
}
}
/**
******************************************************************************
*
* @brief inserts a 1-bit code into the bitstream
*
* @par Description
* inserts 1bit lsb of code_val into the bitstream
* updates context members like u4_cur_word, u4_strm_buf_offset and
* i4_bits_left_in_cw. If the total words (u4_strm_buf_offset) exceeds max
* available size (u4_max_strm_size), returns error without corrupting data
* beyond it
*
* @param[in] ps_bitstrm
* pointer to bitstream context (handle)
*
* @param[in] u4_code_val
* code value that needs to be inserted in the stream.
*
* @remarks Assumptions: all bits from bit position 1 to msb of code_val
* shall be zero
*
* @return success or failure error code
*
******************************************************************************
*/
IH264E_ERROR_T ih264e_put_bit(bitstrm_t *ps_bitstrm, UWORD32 u4_code_val)
{
/* call the put bits function for 1 bit and return */
return(ih264e_put_bits(ps_bitstrm, u4_code_val, 1));
}
/**
******************************************************************************
*
* @brief inserts rbsp trailing bits at the end of stream buffer (NAL)
*
* @par Description
* inserts rbsp trailing bits, updates context members like u4_cur_word and
* i4_bits_left_in_cw and flushes the same in the bitstream buffer. If the
* total words (u4_strm_buf_offset) exceeds max available size
* (u4_max_strm_size), returns error without corrupting data beyond it
*
* @param[in] ps_bitstrm
* pointer to bitstream context (handle)
*
* @return success or failure error code
*
******************************************************************************
*/
IH264E_ERROR_T ih264e_put_rbsp_trailing_bits(bitstrm_t *ps_bitstrm)
{
WORD32 i;
UWORD32 u4_cur_word = ps_bitstrm->u4_cur_word;
WORD32 bits_left_in_cw = ps_bitstrm->i4_bits_left_in_cw;
WORD32 bytes_left_in_cw = (bits_left_in_cw - 1) >> 3;
IH264E_ERROR_T status = IH264E_SUCCESS;
/* insert a 1 at the end of current word and flush all the bits */
u4_cur_word |= (1 << (bits_left_in_cw - 1));
/* get the bits to be inserted in msbdb of the word */
//u4_cur_word <<= (WORD_SIZE - bytes_left_in_cw + 1);
for(i = WORD_SIZE; i > (bytes_left_in_cw*8); i -= 8)
{
/* flush the bits in cur word byte by byte and copy to stream */
UWORD8 u1_next_byte = (u4_cur_word >> (i-8)) & 0xFF;
status |= ih264e_put_byte_epb(ps_bitstrm, u1_next_byte);
}
/* Default init values for scratch variables of bitstream context */
ps_bitstrm->u4_cur_word = 0;
ps_bitstrm->i4_bits_left_in_cw = WORD_SIZE;
ps_bitstrm->i4_zero_bytes_run = 0;
return (status);
}
/**
******************************************************************************
*
* @brief puts exponential golomb code of a unsigned integer into bitstream
*
* @par Description
* computes uev code for given syntax element and inserts the same into
* bitstream by calling ih264e_put_bits() interface.
*
* @param[in] ps_bitstrm
* pointer to bitstream context (handle)
*
* @param[in] u4_code_num
* unsigned integer input whose golomb code is written in stream
*
* @remarks Assumptions: code value can be represented in less than 16bits
*
* @return success or failure error code
*
******************************************************************************
*/
IH264E_ERROR_T ih264e_put_uev(bitstrm_t *ps_bitstrm, UWORD32 u4_code_num)
{
UWORD32 u4_bit_str, u4_range;
IH264E_ERROR_T e_error;
/* convert the codenum to exp-golomb bit code: Table 9-2 JCTVC-J1003_d7 */
u4_bit_str = u4_code_num + 1;
/* get range of the bit string and put using put_bits() */
GETRANGE(u4_range, u4_bit_str);
e_error = ih264e_put_bits(ps_bitstrm, u4_bit_str, (2 * u4_range - 1));
return(e_error);
}
/**
******************************************************************************
*
* @brief puts exponential golomb code of a signed integer into bitstream
*
* @par Description
* computes sev code for given syntax element and inserts the same into
* bitstream by calling ih264e_put_bits() interface.
*
* @param[in] ps_bitstrm
* pointer to bitstream context (handle)
*
* @param[in] syntax_elem
* signed integer input whose golomb code is written in stream
*
* @remarks Assumptions: code value can be represented in less than 16bits
*
* @return success or failure error code
*
******************************************************************************
*/
IH264E_ERROR_T ih264e_put_sev(bitstrm_t *ps_bitstrm, WORD32 syntax_elem)
{
UWORD32 u4_code_num, u4_bit_str, u4_range;
IH264E_ERROR_T e_error;
/************************************************************************/
/* convert the codenum to exp-golomb bit code for signed syntax element */
/* See Table9-2 and Table 9-3 of standard JCTVC-J1003_d7 */
/************************************************************************/
if(syntax_elem <= 0)
{
/* codeNum for non-positive integer = 2*abs(x) : Table9-3 */
u4_code_num = ((-syntax_elem) << 1);
}
else
{
/* codeNum for positive integer = 2x-1 : Table9-3 */
u4_code_num = (syntax_elem << 1) - 1;
}
/* convert the codenum to exp-golomb bit code: Table 9-2 JCTVC-J1003_d7 */
u4_bit_str = u4_code_num + 1;
/* get range of the bit string and put using put_bits() */
GETRANGE(u4_range, u4_bit_str);
e_error = ih264e_put_bits(ps_bitstrm, u4_bit_str, (2 * u4_range - 1));
return(e_error);
}
/**
******************************************************************************
*
* @brief insert NAL start code prefix (0x000001) into bitstream with an option
* of inserting leading_zero_8bits (which makes startcode prefix as 0x00000001)
*
* @par Description
* Although start code prefix could have been put by calling ih264e_put_bits(),
* ih264e_put_nal_start_code_prefix() is specially added to make sure emulation
* prevention insertion is not done for the NAL start code prefix which will
* surely happen otherwise by calling ih264e_put_bits() interface.
*
* @param[in] ps_bitstrm
* pointer to bitstream context (handle)
*
* @param[in] insert_leading_zero_8bits
* flag indicating if one more zero bytes needs to prefixed before start code
*
* @return success or failure error code
*
******************************************************************************
*/
IH264E_ERROR_T ih264e_put_nal_start_code_prefix(bitstrm_t *ps_bitstrm,
WORD32 insert_leading_zero_8bits)
{
UWORD32 u4_strm_buf_offset = ps_bitstrm->u4_strm_buf_offset;
UWORD8* pu1_strm_buf = ps_bitstrm->pu1_strm_buffer;
/* Bitstream buffer overflow check assuming worst case of 4 bytes */
if((u4_strm_buf_offset + 4) >= ps_bitstrm->u4_max_strm_size)
{
return(IH264E_BITSTREAM_BUFFER_OVERFLOW);
}
/* Insert leading zero 8 bits conditionally */
if(insert_leading_zero_8bits)
{
pu1_strm_buf[u4_strm_buf_offset] = 0x00;
u4_strm_buf_offset++;
}
/* Insert NAL start code prefix 0x00 00 01 */
pu1_strm_buf[u4_strm_buf_offset] = 0x00;
u4_strm_buf_offset++;
pu1_strm_buf[u4_strm_buf_offset] = 0x00;
u4_strm_buf_offset++;
pu1_strm_buf[u4_strm_buf_offset] = 0x01;
u4_strm_buf_offset++;
/* update the stream offset */
ps_bitstrm->u4_strm_buf_offset = u4_strm_buf_offset;
return (IH264E_SUCCESS);
}