/*
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*
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* Copyright 2015 Rockchip Electronics Co. LTD
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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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#include <stdlib.h>
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#include <string.h>
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#include "rk_type.h"
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#include "mpp_mem.h"
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#include "mpp_bitread.h"
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static MPP_RET update_curbyte(BitReadCtx_t *bitctx)
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{
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if (bitctx->bytes_left_ < 1)
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return MPP_ERR_READ_BIT;
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// Emulation prevention three-byte detection.
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// If a sequence of 0x000003 is found, skip (ignore) the last byte (0x03).
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if (bitctx->need_prevention_detection
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&& (*bitctx->data_ == 0x03)
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&& ((bitctx->prev_two_bytes_ & 0xffff) == 0)) {
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// Detected 0x000003, skip last byte.
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++bitctx->data_;
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--bitctx->bytes_left_;
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++bitctx->emulation_prevention_bytes_;
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bitctx->used_bits += 8;
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// Need another full three bytes before we can detect the sequence again.
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bitctx->prev_two_bytes_ = 0xffff;
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if (bitctx->bytes_left_ < 1)
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return MPP_ERR_READ_BIT;
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}
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// Load a new byte and advance pointers.
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bitctx->curr_byte_ = *bitctx->data_++ & 0xff;
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--bitctx->bytes_left_;
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bitctx->num_remaining_bits_in_curr_byte_ = 8;
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bitctx->prev_two_bytes_ = (bitctx->prev_two_bytes_ << 8) | bitctx->curr_byte_;
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return MPP_OK;
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}
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/*!
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***********************************************************************
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* \brief
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* Read |num_bits| (1 to 31 inclusive) from the stream and return them
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* in |out|, with first bit in the stream as MSB in |out| at position
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* (|num_bits| - 1)
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***********************************************************************
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*/
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MPP_RET mpp_read_bits(BitReadCtx_t *bitctx, RK_S32 num_bits, RK_S32 *out)
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{
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RK_S32 bits_left = num_bits;
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*out = 0;
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if (num_bits > 31) {
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return MPP_ERR_READ_BIT;
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}
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while (bitctx->num_remaining_bits_in_curr_byte_ < bits_left) {
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// Take all that's left in current byte, shift to make space for the rest.
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*out |= (bitctx->curr_byte_ << (bits_left - bitctx->num_remaining_bits_in_curr_byte_));
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bits_left -= bitctx->num_remaining_bits_in_curr_byte_;
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if (update_curbyte(bitctx)) {
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return MPP_ERR_READ_BIT;
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}
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}
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*out |= (bitctx->curr_byte_ >> (bitctx->num_remaining_bits_in_curr_byte_ - bits_left));
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*out &= ((1 << num_bits) - 1);
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bitctx->num_remaining_bits_in_curr_byte_ -= bits_left;
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bitctx->used_bits += num_bits;
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return MPP_OK;
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}
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/*!
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***********************************************************************
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* \brief
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* read more than 32 bits data
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***********************************************************************
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*/
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MPP_RET mpp_read_longbits(BitReadCtx_t *bitctx, RK_S32 num_bits, RK_U32 *out)
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{
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RK_S32 val = 0, val1 = 0;
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if (num_bits < 32)
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return mpp_read_bits(bitctx, num_bits, (RK_S32 *)out);
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if (mpp_read_bits(bitctx, 16, &val)) {
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return MPP_ERR_READ_BIT;
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}
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if (mpp_read_bits(bitctx, (num_bits - 16), &val1)) {
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return MPP_ERR_READ_BIT;
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}
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*out = (RK_U32)((val << 16) | val1);
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return MPP_OK;
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}
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/*!
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***********************************************************************
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* \brief
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* skip bits (0 - 31)
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***********************************************************************
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*/
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MPP_RET mpp_skip_bits(BitReadCtx_t *bitctx, RK_S32 num_bits)
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{
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RK_S32 bits_left = num_bits;
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while (bitctx->num_remaining_bits_in_curr_byte_ < bits_left) {
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// Take all that's left in current byte, shift to make space for the rest.
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bits_left -= bitctx->num_remaining_bits_in_curr_byte_;
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if (update_curbyte(bitctx)) {
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return MPP_ERR_READ_BIT;
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}
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}
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bitctx->num_remaining_bits_in_curr_byte_ -= bits_left;
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bitctx->used_bits += num_bits;
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return MPP_OK;
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}
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/*!
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***********************************************************************
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* \brief
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* skip bits long (0 - 32)
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***********************************************************************
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*/
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MPP_RET mpp_skip_longbits(BitReadCtx_t *bitctx, RK_S32 num_bits)
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{
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if (mpp_skip_bits(bitctx, 16)) {
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return MPP_ERR_READ_BIT;
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}
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if (mpp_skip_bits(bitctx, (num_bits - 16))) {
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return MPP_ERR_READ_BIT;
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}
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return MPP_OK;
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}
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/*!
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***********************************************************************
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* \brief
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* show bits (0 - 31)
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***********************************************************************
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*/
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MPP_RET mpp_show_bits(BitReadCtx_t *bitctx, RK_S32 num_bits, RK_S32 *out)
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{
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MPP_RET ret = MPP_ERR_UNKNOW;
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BitReadCtx_t tmp_ctx = *bitctx;
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if (num_bits < 32)
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ret = mpp_read_bits(&tmp_ctx, num_bits, out);
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else
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ret = mpp_read_longbits(&tmp_ctx, num_bits, (RK_U32 *)out);
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return ret;
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}
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/*!
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***********************************************************************
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* \brief
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* show long bits (0 - 32)
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***********************************************************************
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*/
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MPP_RET mpp_show_longbits(BitReadCtx_t *bitctx, RK_S32 num_bits, RK_U32 *out)
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{
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MPP_RET ret = MPP_ERR_UNKNOW;
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BitReadCtx_t tmp_ctx = *bitctx;
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ret = mpp_read_longbits(&tmp_ctx, num_bits, out);
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return ret;
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}
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/*!
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***********************************************************************
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* \brief
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* read unsigned data
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***********************************************************************
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*/
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MPP_RET mpp_read_ue(BitReadCtx_t *bitctx, RK_U32 *val)
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{
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RK_S32 num_bits = -1;
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RK_S32 bit;
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RK_S32 rest;
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// Count the number of contiguous zero bits.
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do {
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if (mpp_read_bits(bitctx, 1, &bit)) {
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return MPP_ERR_READ_BIT;
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}
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num_bits++;
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} while (bit == 0);
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if (num_bits > 31) {
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return MPP_ERR_READ_BIT;
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}
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// Calculate exp-Golomb code value of size num_bits.
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*val = (1 << num_bits) - 1;
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if (num_bits > 0) {
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if (mpp_read_bits(bitctx, num_bits, &rest)) {
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return MPP_ERR_READ_BIT;
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}
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*val += rest;
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}
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return MPP_OK;
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}
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/*!
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***********************************************************************
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* \brief
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* read signed data
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***********************************************************************
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*/
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MPP_RET mpp_read_se(BitReadCtx_t *bitctx, RK_S32 *val)
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{
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RK_U32 ue;
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if (mpp_read_ue(bitctx, &ue)) {
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return MPP_ERR_READ_BIT;
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}
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if (ue % 2 == 0) { // odd
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*val = -(RK_S32)(ue >> 1);
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} else {
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*val = (RK_S32)((ue >> 1) + 1);
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}
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return MPP_OK;
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}
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/*!
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***********************************************************************
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* \brief
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* check whether has more rbsp data
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***********************************************************************
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*/
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RK_U32 mpp_has_more_rbsp_data(BitReadCtx_t *bitctx)
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{
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// remove tail byte which equal zero
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while (bitctx->bytes_left_ &&
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bitctx->data_[bitctx->bytes_left_ - 1] == 0)
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bitctx->bytes_left_--;
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// Make sure we have more bits, if we are at 0 bits in current byte
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// and updating current byte fails, we don't have more data anyway.
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if (bitctx->num_remaining_bits_in_curr_byte_ == 0 && update_curbyte(bitctx))
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return 0;
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// On last byte?
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if (bitctx->bytes_left_)
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return 1;
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// Last byte, look for stop bit;
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// We have more RBSP data if the last non-zero bit we find is not the
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// first available bit.
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return (bitctx->curr_byte_ &
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((1 << (bitctx->num_remaining_bits_in_curr_byte_ - 1)) - 1)) != 0;
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}
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/*!
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***********************************************************************
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* \brief
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* initialize bit read context
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***********************************************************************
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*/
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void mpp_set_bitread_ctx(BitReadCtx_t *bitctx, RK_U8 *data, RK_S32 size)
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{
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memset(bitctx, 0, sizeof(BitReadCtx_t));
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bitctx->data_ = data;
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bitctx->bytes_left_ = size;
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bitctx->num_remaining_bits_in_curr_byte_ = 0;
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// Initially set to 0xffff to accept all initial two-byte sequences.
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bitctx->prev_two_bytes_ = 0xffff;
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bitctx->emulation_prevention_bytes_ = 0;
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// add
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bitctx->buf = data;
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bitctx->buf_len = size;
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bitctx->used_bits = 0;
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bitctx->need_prevention_detection = 0;
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}
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/*!
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***********************************************************************
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* \brief
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* set whether detect 0x03 for h264 and h265
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***********************************************************************
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*/
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void mpp_set_pre_detection(BitReadCtx_t *bitctx)
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{
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bitctx->need_prevention_detection = 1;
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}
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/*!
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***********************************************************************
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* \brief
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* align data and get current point
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***********************************************************************
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*/
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RK_U8 *mpp_align_get_bits(BitReadCtx_t *bitctx)
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{
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int n = bitctx->num_remaining_bits_in_curr_byte_;
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if (n)
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mpp_skip_bits(bitctx, n);
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return bitctx->data_;
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}
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RK_S32 mpp_get_bits_left(BitReadCtx_t *bitctx)
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{
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return bitctx->bytes_left_ * 8 + bitctx->num_remaining_bits_in_curr_byte_;
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}
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RK_S32 mpp_get_bits_count(BitReadCtx_t *bitctx)
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{
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return bitctx->used_bits;
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}
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