1/* ------------------------------------------------------------------
2 * Copyright (C) 1998-2009 PacketVideo
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
13 * express or implied.
14 * See the License for the specific language governing permissions
15 * and limitations under the License.
16 * -------------------------------------------------------------------
17 */
18/*
19------------------------------------------------------------------------------
20 INPUT AND OUTPUT DEFINITIONS
21
22 Inputs:
23    [input_variable_name] = [description of the input to module, its type
24                 definition, and length (when applicable)]
25
26 Local Stores/Buffers/Pointers Needed:
27    [local_store_name] = [description of the local store, its type
28                  definition, and length (when applicable)]
29    [local_buffer_name] = [description of the local buffer, its type
30                   definition, and length (when applicable)]
31    [local_ptr_name] = [description of the local pointer, its type
32                definition, and length (when applicable)]
33
34 Global Stores/Buffers/Pointers Needed:
35    [global_store_name] = [description of the global store, its type
36                   definition, and length (when applicable)]
37    [global_buffer_name] = [description of the global buffer, its type
38                definition, and length (when applicable)]
39    [global_ptr_name] = [description of the global pointer, its type
40                 definition, and length (when applicable)]
41
42 Outputs:
43    [return_variable_name] = [description of data/pointer returned
44                  by module, its type definition, and length
45                  (when applicable)]
46
47 Pointers and Buffers Modified:
48    [variable_bfr_ptr] points to the [describe where the
49      variable_bfr_ptr points to, its type definition, and length
50      (when applicable)]
51    [variable_bfr] contents are [describe the new contents of
52      variable_bfr]
53
54 Local Stores Modified:
55    [local_store_name] = [describe new contents, its type
56                  definition, and length (when applicable)]
57
58 Global Stores Modified:
59    [global_store_name] = [describe new contents, its type
60                   definition, and length (when applicable)]
61
62------------------------------------------------------------------------------
63 FUNCTION DESCRIPTION
64
65 This module calculates the DC quantization scale according
66 to the incoming Q and type.
67
68------------------------------------------------------------------------------
69 REQUIREMENTS
70
71 [List requirements to be satisfied by this module.]
72
73------------------------------------------------------------------------------
74 REFERENCES
75
76 [List all references used in designing this module.]
77
78------------------------------------------------------------------------------
79 PSEUDO-CODE
80
81------------------------------------------------------------------------------
82 RESOURCES USED
83   When the code is written for a specific target processor the
84     the resources used should be documented below.
85
86 STACK USAGE: [stack count for this module] + [variable to represent
87          stack usage for each subroutine called]
88
89     where: [stack usage variable] = stack usage for [subroutine
90         name] (see [filename].ext)
91
92 DATA MEMORY USED: x words
93
94 PROGRAM MEMORY USED: x words
95
96 CLOCK CYCLES: [cycle count equation for this module] + [variable
97           used to represent cycle count for each subroutine
98           called]
99
100     where: [cycle count variable] = cycle count for [subroutine
101        name] (see [filename].ext)
102
103------------------------------------------------------------------------------
104*/
105
106
107/*----------------------------------------------------------------------------
108; INCLUDES
109----------------------------------------------------------------------------*/
110#include    "mp4dec_lib.h"
111#include    "vlc_decode.h"
112#include    "bitstream.h"
113#include    "zigzag.h"
114
115/*----------------------------------------------------------------------------
116; MACROS
117; Define module specific macros here
118----------------------------------------------------------------------------*/
119
120
121/*----------------------------------------------------------------------------
122; DEFINES
123; Include all pre-processor statements here. Include conditional
124; compile variables also.
125----------------------------------------------------------------------------*/
126
127/*----------------------------------------------------------------------------
128; LOCAL FUNCTION DEFINITIONS
129; Function Prototype declaration
130----------------------------------------------------------------------------*/
131
132/*----------------------------------------------------------------------------
133; LOCAL STORE/BUFFER/POINTER DEFINITIONS
134; Variable declaration - defined here and used outside this module
135----------------------------------------------------------------------------*/
136
137/*----------------------------------------------------------------------------
138; EXTERNAL FUNCTION REFERENCES
139; Declare functions defined elsewhere and referenced in this module
140----------------------------------------------------------------------------*/
141
142/*----------------------------------------------------------------------------
143; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
144; Declare variables used in this module but defined elsewhere
145----------------------------------------------------------------------------*/
146
147/*----------------------------------------------------------------------------
148; FUNCTION CODE
149----------------------------------------------------------------------------*/
150int cal_dc_scaler(
151    int QP,
152    int type)
153{
154
155    /*----------------------------------------------------------------------------
156    ; Define all local variables
157    ----------------------------------------------------------------------------*/
158    int dc_scaler;
159
160    /*----------------------------------------------------------------------------
161    ; Function body here
162    ----------------------------------------------------------------------------*/
163    if (type == LUMINANCE_DC_TYPE)
164    {
165        if (QP > 0 && QP < 5) dc_scaler = 8;
166        else if (QP > 4 && QP < 9) dc_scaler = 2 * QP;
167        else if (QP > 8 && QP < 25) dc_scaler = QP + 8;
168        else dc_scaler = 2 * QP - 16;
169    }
170    else /* if (type == CHROMINANCE_DC_TYPE), there is no other types.  */
171    {
172        if (QP > 0 && QP < 5) dc_scaler = 8;
173        else if (QP > 4 && QP < 25) dc_scaler = (QP + 13) >> 1;
174        else dc_scaler = QP - 6;
175    }
176
177    /*----------------------------------------------------------------------------
178    ; Return nothing or data or data pointer
179    ----------------------------------------------------------------------------*/
180    return dc_scaler;
181}
182
183