/******************************************************************************
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*
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* Copyright (C) 2018 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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*
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* @file
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* ihevce_bitstream.h
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*
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* @brief
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* This file contains encoder bitstream engine related structures and
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* interface prototypes
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*
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* @author
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* ittiam
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*
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******************************************************************************
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*/
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#ifndef _IHEVCE_BITSTREAM_H_
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#define _IHEVCE_BITSTREAM_H_
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/*****************************************************************************/
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/* Constant Macros */
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/*****************************************************************************/
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/**
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******************************************************************************
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* @brief defines the maximum number of bits in a bitstream word
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******************************************************************************
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*/
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#define WORD_SIZE 32
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/**
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******************************************************************************
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* @brief The number of consecutive zero bytes for emulation prevention check
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******************************************************************************
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*/
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#define EPB_ZERO_BYTES 2
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/**
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******************************************************************************
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* @brief Emulation prevention insertion byte
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******************************************************************************
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*/
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#define EPB_BYTE 0x03
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/**
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******************************************************************************
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* @brief Maximum number of NALs in a frame
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******************************************************************************
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*/
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#define MAX_NALS_IN_AU 256
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/*****************************************************************************/
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/* Function Macros */
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/*****************************************************************************/
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/**
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******************************************************************************
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* @brief Macro to check if emulation prevention byte insertion is required
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******************************************************************************
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*/
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#define INSERT_EPB(zero_run, next_byte) ((zero_run) == EPB_ZERO_BYTES) && (0 == ((next_byte)&0xFC))
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/**
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******************************************************************************
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* @brief returns bits required to code a value
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******************************************************************************
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*/
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#define UE_LENGTH(bits, x) \
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{ \
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UWORD32 r_bit; \
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GETRANGE(r_bit, x + 1) \
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bits = (((r_bit - 1) << 1) + 1); \
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}
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/**
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******************************************************************************
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* @brief Inserts 1 byte and Emulation Prevention Byte(if any) into bitstream
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* Increments the stream offset and zero run correspondingly
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******************************************************************************
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*/
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#define PUTBYTE_EPB(ptr, off, byte, zero_run) \
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{ \
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if(INSERT_EPB(zero_run, byte)) \
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{ \
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ptr[off] = EPB_BYTE; \
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off++; \
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zero_run = 0; \
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} \
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\
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ptr[off] = byte; \
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off++; \
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zero_run = byte ? 0 : zero_run + 1; \
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}
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/**
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******************************************************************************
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* @brief Ensures Byte alignment of the slice header
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******************************************************************************
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*/
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#define BYTE_ALIGNMENT(ps_bitstrm) ihevce_put_rbsp_trailing_bits(ps_bitstrm)
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/*****************************************************************************/
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/* Structures */
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/*****************************************************************************/
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/**
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******************************************************************************
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* @brief Bitstream context for encoder
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******************************************************************************
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*/
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typedef struct bitstrm
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{
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/** points to start of stream buffer. */
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UWORD8 *pu1_strm_buffer;
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/**
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* max bitstream size (in bytes).
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* Encoded stream shall not exceed this size.
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*/
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UWORD32 u4_max_strm_size;
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/**
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`* byte offset (w.r.t pu1_strm_buffer) where next byte would be written
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* Bitstream engine makes sure it would not corrupt data beyond
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* u4_max_strm_size bytes
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*/
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UWORD32 u4_strm_buf_offset;
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/**
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* current bitstream word; It is a scratch word containing max of
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* WORD_SIZE bits. Will be copied to stream buffer when the word is
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* full
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*/
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UWORD32 u4_cur_word;
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/**
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* signifies number of bits available in u4_cur_word
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* bits from msb to i4_bits_left_in_cw of u4_cur_word have already been
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* inserted next bits would be inserted from pos [i4_bits_left_in_cw-1]
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* Range of this variable [1 : WORD_SIZE]
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*/
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WORD32 i4_bits_left_in_cw;
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/**
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* signifies the number of consecutive zero bytes propogated from previous
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* word. It is used for emulation prevention byte insertion in the stream
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*/
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WORD32 i4_zero_bytes_run;
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/** Total number of NAL units in the output buffer; Shall not exceed
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* MAX_NALS_IN_AU */
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WORD32 i4_num_nal;
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/** Pointer to start of each NAL unit in the output buffer */
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UWORD8 *apu1_nal_start[MAX_NALS_IN_AU];
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} bitstrm_t;
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/*****************************************************************************/
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/* Extern Function Declarations */
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/*****************************************************************************/
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IHEVCE_ERROR_T
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ihevce_bitstrm_init(bitstrm_t *ps_bitstrm, UWORD8 *pu1_bitstrm_buf, UWORD32 u4_max_bitstrm_size);
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IHEVCE_ERROR_T ihevce_put_bits(bitstrm_t *ps_bitstrm, UWORD32 u4_code_val, WORD32 code_len);
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IHEVCE_ERROR_T ihevce_put_bit(bitstrm_t *ps_bitstrm, UWORD32 u4_code_val);
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IHEVCE_ERROR_T ihevce_put_rbsp_trailing_bits(bitstrm_t *ps_bitstrm);
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IHEVCE_ERROR_T ihevce_put_uev(bitstrm_t *ps_bitstrm, UWORD32 u4_code_num);
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IHEVCE_ERROR_T ihevce_put_sev(bitstrm_t *ps_bitstrm, WORD32 syntax_elem);
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IHEVCE_ERROR_T
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ihevce_put_nal_start_code_prefix(bitstrm_t *ps_bitstrm, WORD32 insert_leading_zero_8bits);
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#endif /* _IHEVCE_BITSTREAM_H_ */
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