Hamsalekha S | 8d3d303 | 2015-03-13 21:24:58 +0530 | [diff] [blame] | 1 | /****************************************************************************** |
| 2 | * |
| 3 | * Copyright (C) 2015 The Android Open Source Project |
| 4 | * |
| 5 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 6 | * you may not use this file except in compliance with the License. |
| 7 | * You may obtain a copy of the License at: |
| 8 | * |
| 9 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 10 | * |
| 11 | * Unless required by applicable law or agreed to in writing, software |
| 12 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 14 | * See the License for the specific language governing permissions and |
| 15 | * limitations under the License. |
| 16 | * |
| 17 | ***************************************************************************** |
| 18 | * Originally developed and contributed by Ittiam Systems Pvt. Ltd, Bangalore |
| 19 | */ |
| 20 | |
| 21 | #ifndef _VBR_STORAGE_VBV_H_ |
| 22 | #define _VBR_STORAGE_VBV_H_ |
| 23 | /****************************************************************************** |
| 24 | VBR STORAGE (VBV): |
| 25 | Max. buffer filling rate: Rmax |
| 26 | Max. buffer size: Bmax (as specified by level and profile) |
| 27 | Current Buffer Level: Bcur |
| 28 | Frame Rate: F |
| 29 | |
| 30 | For a storage scenario, the initial buffer size is assumed to be max. For every |
| 31 | frame the Maximum bits filled in to the buffer is given by Rmaxfrm = Rmax/F. If |
| 32 | the buffer overflows then the buffer is thresholded to the max buffer size. |
| 33 | |
| 34 | (overflow) |
| 35 | B(0) /| |
| 36 | ---|--------------/-|------------------------------ Bmax |
| 37 | | / | |
| 38 | | /|/ | |
| 39 | | /| / | |
| 40 | | / | /|/ | |
| 41 | |/ | / | /| |
| 42 | |/ |/ | |
| 43 | | |
| 44 | | |
| 45 | -----------------------|--------------------------- |
| 46 | |<->| | |
| 47 | (1/F)=>1/frame_rate (underflow) |
| 48 | |
| 49 | |
| 50 | B"(i) - Bits in buffer just before decoding a frame. |
| 51 | B'(i) - Bits in buffer just after decoding a frame. |
| 52 | |
| 53 | |
| 54 | B(0) (initBuffer size) = Bmax. |
| 55 | B'(i) = B"(i) - bits_decoded |
| 56 | B"(i) = Min( Bmax, B'(i-1) + Rmaxfrm) |
| 57 | |
| 58 | Overflow Scenario: In VBR case, since we have only a max filling rate (or input bit rate) |
| 59 | buffer overflow is not a issue (since the buffer filling rate can be reduced to any value |
| 60 | below this rate) |
| 61 | |
| 62 | Underflow Scenario: B'(i) should always be > 0. If not then, the buffer underflows. To |
| 63 | prevent this condition the number bits that needs to be decoded must be equal to B"(i) |
| 64 | which is equal to Min( Bmax, B'(i-1) + Rmaxfrm) |
| 65 | ****************************************************************************************/ |
| 66 | |
| 67 | typedef struct vbr_storage_vbv_t* vbr_storage_vbv_handle; |
| 68 | |
| 69 | WORD32 irc_vbr_vbv_num_fill_use_free_memtab(vbr_storage_vbv_handle *pps_vbr_storage_vbv, |
| 70 | itt_memtab_t *ps_memtab, |
| 71 | ITT_FUNC_TYPE_E e_func_type); |
| 72 | |
| 73 | /* Initalises the vbv buffer status */ |
| 74 | void irc_init_vbr_vbv(vbr_storage_vbv_handle ps_vbr_storage_vbv, |
| 75 | WORD32 max_bit_rate, /* In bits/sec*/ |
| 76 | WORD32 max_frm_rate, /* In frames/1000 sec*/ |
| 77 | WORD32 i4_max_vbv_buff_size); /* in bits*/ |
| 78 | |
| 79 | /* Updates the buffer after decoding a frame */ |
| 80 | void irc_update_vbr_vbv(vbr_storage_vbv_handle ps_vbr_storage_vbv, |
| 81 | WORD32 i4_total_bits_decoded); |
| 82 | |
| 83 | /* gets the max_number of bits that can be decoded out of the VBV without underflow */ |
| 84 | WORD32 irc_get_max_target_bits(vbr_storage_vbv_handle ps_vbr_storage_vbv); |
| 85 | |
| 86 | WORD32 irc_get_max_bits_inflow_per_frm_periode(vbr_storage_vbv_handle ps_vbr_storage_vbv); |
| 87 | |
| 88 | WORD32 irc_get_max_bits_per_tgt_frm(vbr_storage_vbv_handle ps_vbr_storage_vbv); |
| 89 | |
| 90 | WORD32 irc_get_cur_vbv_buf_size(vbr_storage_vbv_handle ps_vbr_storage_vbv); |
| 91 | |
| 92 | /* Queries the VBV buffer for the buffer status */ |
| 93 | vbv_buf_status_e irc_get_vbv_buffer_status(vbr_storage_vbv_handle ps_vbr_storage_vbv, |
| 94 | WORD32 i4_total_frame_bits, |
| 95 | WORD32 *pi4_num_bits_to_prevent_vbv_underflow); |
| 96 | |
| 97 | UWORD8 irc_restrict_swing_dvd_comp(vbr_storage_vbv_handle ps_vbr_storage_vbv); |
| 98 | |
| 99 | WORD32 irc_get_max_vbv_buf_size(vbr_storage_vbv_handle ps_vbr_storage_vbv); |
| 100 | |
| 101 | WORD32 irc_vbv_get_vbv_buf_fullness(vbr_storage_vbv_handle ps_vbr_storage_vbv, |
| 102 | UWORD32 u4_bits); |
| 103 | |
| 104 | WORD32 irc_get_max_tgt_bits_dvd_comp(vbr_storage_vbv_handle ps_vbr_storage_vbv, |
| 105 | WORD32 i4_rem_bits_in_gop, |
| 106 | WORD32 i4_rem_frms_in_gop, |
| 107 | picture_type_e e_pic_type); |
| 108 | |
| 109 | /* Changing input values at run time */ |
| 110 | void irc_change_vbr_vbv_bit_rate(vbr_storage_vbv_handle ps_vbr_storage_vbv, |
| 111 | WORD32 i4_max_bit_rate); |
| 112 | |
| 113 | void irc_change_vbr_vbv_frame_rate(vbr_storage_vbv_handle ps_vbr_storage_vbv, |
| 114 | WORD32 i4_frm_rate); |
| 115 | |
| 116 | void irc_change_vbr_max_bits_per_tgt_frm(vbr_storage_vbv_handle ps_vbr_storage_vbv, |
| 117 | WORD32 i4_tgt_frm_rate); |
| 118 | #endif |
| 119 | |