| /****************************************************************************** |
| * |
| * 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 |
| */ |
| |
| #ifndef _VBR_STORAGE_VBV_H_ |
| #define _VBR_STORAGE_VBV_H_ |
| /****************************************************************************** |
| VBR STORAGE (VBV): |
| 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. |
| |
| (overflow) |
| 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); |
| #endif |
| |