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125 lines
4.8 KiB
125 lines
4.8 KiB
/******************************************************************************
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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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* \file vbr_storage_vbv.h
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*
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* \brief
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* This file contains all the necessary declarations for
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* vbr buffer control functions
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*
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* \date
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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 _VBR_STORAGE_VBV_H_
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#define _VBR_STORAGE_VBV_H_
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/******************************************************************************
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VBR STORAGE (VBV):
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Max. buffer filling rate: Rmax
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Max. buffer size: Bmax (as specified by level and profile)
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Current Buffer Level: Bcur
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Frame Rate: F
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For a storage scenario, the initial buffer size is assumed to be max. For every
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frame the Maximum bits filled in to the buffer is given by Rmaxfrm = Rmax/F. If
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the buffer overflows then the buffer is thresholded to the max buffer size.
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(overflow)
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B(0) /|
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---|--------------/-|------------------------------ Bmax
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| / |
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| /|/ |
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| /| / |
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| / | /|/ |
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|/ | / | /|
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|/ |/ |
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-----------------------|---------------------------
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|<->| |
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(1/F)=>1/frame_rate (underflow)
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B"(i) - Bits in buffer just before decoding a frame.
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B'(i) - Bits in buffer just after decoding a frame.
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B(0) (initBuffer size) = Bmax.
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B'(i) = B"(i) - bits_decoded
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B"(i) = Min( Bmax, B'(i-1) + Rmaxfrm)
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Overflow Scenario: In VBR case, since we have only a max filling rate (or input bit rate)
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buffer overflow is not a issue (since the buffer filling rate can be reduced to any value
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below this rate)
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Underflow Scenario: B'(i) should always be > 0. If not then, the buffer underflows. To
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prevent this condition the number bits that needs to be decoded must be equal to B"(i)
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which is equal to Min( Bmax, B'(i-1) + Rmaxfrm)
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****************************************************************************************/
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/*****************************************************************************/
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/* Function Declarations */
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/*****************************************************************************/
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typedef struct vbr_storage_vbv_t *vbr_storage_vbv_handle;
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WORD32 vbr_vbv_num_fill_use_free_memtab(
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vbr_storage_vbv_handle *pps_vbr_storage_vbv,
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itt_memtab_t *ps_memtab,
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ITT_FUNC_TYPE_E e_func_type);
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/* Initalises the vbv buffer status */
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void init_vbr_vbv(
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vbr_storage_vbv_handle ps_vbr_storage_vbv,
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WORD32 max_bit_rate, /* In bits/sec*/
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WORD32 max_frm_rate, /* In frames/1000 sec*/
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WORD32 i4_max_vbv_buff_size); /* in bits*/
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/* Updates the buffer after decoding a frame */
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void update_vbr_vbv(vbr_storage_vbv_handle ps_vbr_storage_vbv, WORD32 i4_total_bits_decoded);
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/* gets the max_number of bits that can be decoded out of the VBV without underflow */
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WORD32 get_max_target_bits(vbr_storage_vbv_handle ps_vbr_storage_vbv);
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WORD32 get_max_bits_inflow_per_frm_periode(vbr_storage_vbv_handle ps_vbr_storage_vbv);
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WORD32 get_cur_vbv_buf_size(vbr_storage_vbv_handle ps_vbr_storage_vbv);
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/* Queries the VBV buffer for the buffer status */
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vbv_buf_status_e get_vbv_buffer_status(
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vbr_storage_vbv_handle ps_vbr_storage_vbv,
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WORD32 i4_total_frame_bits, /* Total frame bits consumed */
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WORD32 *
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pi4_num_bits_to_prevent_vbv_underflow); /* num bits to prevent from underflow after update */
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WORD32 get_max_vbv_buf_size(vbr_storage_vbv_handle ps_vbr_storage_vbv);
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WORD32 get_vbv_buf_fullness(vbr_storage_vbv_handle ps_vbr_storage_vbv, UWORD32 u4_bits);
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WORD32 get_max_tgt_bits_dvd_comp(
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vbr_storage_vbv_handle ps_vbr_storage_vbv,
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WORD32 i4_rem_bits_in_gop,
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WORD32 i4_rem_frms_in_gop,
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picture_type_e e_pic_type);
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/* Changing input values at run time */
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void change_vbr_vbv_bit_rate(vbr_storage_vbv_handle ps_vbr_storage_vbv, WORD32 i4_max_bit_rate);
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void change_vbr_vbv_frame_rate(vbr_storage_vbv_handle ps_vbr_storage_vbv, WORD32 i4_frm_rate);
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#endif
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