blob: c53c66dd407a32afd0784f893edf03dba4cfd4b2 [file] [log] [blame]
* 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:
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License.
* Originally developed and contributed by Ittiam Systems Pvt. Ltd, Bangalore
Max. buffer filling rate: Rmax
Max. buffer size: Bmax (as specified by level and profile)
Current Buffer Level: Bcur
Frame Rate: F
For a storage scenario, the initial buffer size is assumed to be max. For every
frame the Maximum bits filled in to the buffer is given by Rmaxfrm = Rmax/F. If
the buffer overflows then the buffer is thresholded to the max buffer size.
B(0) /|
---|--------------/-|------------------------------ Bmax
| / |
| /|/ |
| /| / |
| / | /|/ |
|/ | / | /|
|/ |/ |
|<->| |
(1/F)=>1/frame_rate (underflow)
B"(i) - Bits in buffer just before decoding a frame.
B'(i) - Bits in buffer just after decoding a frame.
B(0) (initBuffer size) = Bmax.
B'(i) = B"(i) - bits_decoded
B"(i) = Min( Bmax, B'(i-1) + Rmaxfrm)
Overflow Scenario: In VBR case, since we have only a max filling rate (or input bit rate)
buffer overflow is not a issue (since the buffer filling rate can be reduced to any value
below this rate)
Underflow Scenario: B'(i) should always be > 0. If not then, the buffer underflows. To
prevent this condition the number bits that needs to be decoded must be equal to B"(i)
which is equal to Min( Bmax, B'(i-1) + Rmaxfrm)
typedef struct vbr_storage_vbv_t* vbr_storage_vbv_handle;
WORD32 irc_vbr_vbv_num_fill_use_free_memtab(vbr_storage_vbv_handle *pps_vbr_storage_vbv,
itt_memtab_t *ps_memtab,
ITT_FUNC_TYPE_E e_func_type);
/* Initalises the vbv buffer status */
void irc_init_vbr_vbv(vbr_storage_vbv_handle ps_vbr_storage_vbv,
WORD32 max_bit_rate, /* In bits/sec*/
WORD32 max_frm_rate, /* In frames/1000 sec*/
WORD32 i4_max_vbv_buff_size); /* in bits*/
/* Updates the buffer after decoding a frame */
void irc_update_vbr_vbv(vbr_storage_vbv_handle ps_vbr_storage_vbv,
WORD32 i4_total_bits_decoded);
/* gets the max_number of bits that can be decoded out of the VBV without underflow */
WORD32 irc_get_max_target_bits(vbr_storage_vbv_handle ps_vbr_storage_vbv);
WORD32 irc_get_max_bits_inflow_per_frm_periode(vbr_storage_vbv_handle ps_vbr_storage_vbv);
WORD32 irc_get_max_bits_per_tgt_frm(vbr_storage_vbv_handle ps_vbr_storage_vbv);
WORD32 irc_get_cur_vbv_buf_size(vbr_storage_vbv_handle ps_vbr_storage_vbv);
/* Queries the VBV buffer for the buffer status */
vbv_buf_status_e irc_get_vbv_buffer_status(vbr_storage_vbv_handle ps_vbr_storage_vbv,
WORD32 i4_total_frame_bits,
WORD32 *pi4_num_bits_to_prevent_vbv_underflow);
UWORD8 irc_restrict_swing_dvd_comp(vbr_storage_vbv_handle ps_vbr_storage_vbv);
WORD32 irc_get_max_vbv_buf_size(vbr_storage_vbv_handle ps_vbr_storage_vbv);
WORD32 irc_vbv_get_vbv_buf_fullness(vbr_storage_vbv_handle ps_vbr_storage_vbv,
UWORD32 u4_bits);
WORD32 irc_get_max_tgt_bits_dvd_comp(vbr_storage_vbv_handle ps_vbr_storage_vbv,
WORD32 i4_rem_bits_in_gop,
WORD32 i4_rem_frms_in_gop,
picture_type_e e_pic_type);
/* Changing input values at run time */
void irc_change_vbr_vbv_bit_rate(vbr_storage_vbv_handle ps_vbr_storage_vbv,
WORD32 i4_max_bit_rate);
void irc_change_vbr_vbv_frame_rate(vbr_storage_vbv_handle ps_vbr_storage_vbv,
WORD32 i4_frm_rate);
void irc_change_vbr_max_bits_per_tgt_frm(vbr_storage_vbv_handle ps_vbr_storage_vbv,
WORD32 i4_tgt_frm_rate);