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path: root/audio_codec/libraac/ga_config.c (plain)
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1/* ***** BEGIN LICENSE BLOCK *****
2 * Source last modified: $Id: ga_config.c,v 1.1.1.1.2.1 2005/05/04 18:21:58 hubbe Exp $
3 *
4 * REALNETWORKS CONFIDENTIAL--NOT FOR DISTRIBUTION IN SOURCE CODE FORM
5 * Portions Copyright (c) 1995-2005 RealNetworks, Inc.
6 * All Rights Reserved.
7 *
8 * The contents of this file, and the files included with this file,
9 * are subject to the current version of the Real Format Source Code
10 * Porting and Optimization License, available at
11 * https://helixcommunity.org/2005/license/realformatsource (unless
12 * RealNetworks otherwise expressly agrees in writing that you are
13 * subject to a different license). You may also obtain the license
14 * terms directly from RealNetworks. You may not use this file except
15 * in compliance with the Real Format Source Code Porting and
16 * Optimization License. There are no redistribution rights for the
17 * source code of this file. Please see the Real Format Source Code
18 * Porting and Optimization License for the rights, obligations and
19 * limitations governing use of the contents of the file.
20 *
21 * RealNetworks is the developer of the Original Code and owns the
22 * copyrights in the portions it created.
23 *
24 * This file, and the files included with this file, is distributed and
25 * made available on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND,
26 * EITHER EXPRESS OR IMPLIED, AND REALNETWORKS HEREBY DISCLAIMS ALL
27 * SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF
28 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT
29 * OR NON-INFRINGEMENT.
30 *
31 * Technology Compatibility Kit Test Suite(s) Location:
32 * https://rarvcode-tck.helixcommunity.org
33 *
34 * Contributor(s):
35 *
36 * ***** END LICENSE BLOCK ***** */
37
38/* parse an MPEG-4 general audio specific config structure from a bitstream */
39
40#include "ga_config.h"
41#include "aac_bitstream.h"
42
43const UINT32 aSampleRate[13] = {
44 96000, 88200, 64000, 48000, 44100, 32000, 24000, 22050, 16000, 12000,
45 11025, 8000, 7350
46};
47
48const UINT32 channelMapping[][4] = {
49 {0, 0, 0, 0},
50 {1, 0, 0, 0}, /* center */
51 {2, 0, 0, 0}, /* left, right */
52 {3, 0, 0, 0}, /* center, left, right */
53 {3, 0, 1, 0}, /* center, left, right, rear surround */
54 {3, 0, 2, 0}, /* center, left, right, left surround, right surround */
55 {3, 0, 2, 1}, /* center, left, right, left surround, right surround, lfe */
56 {5, 0, 2, 1}, /* center, left, right, left outside, right outside, left surround, right surround, lfe */
57};
58
59UINT32 ga_config_get_data(struct BITSTREAM *bs, ga_config_data *data)
60{
61 UINT32 i;
62 UINT32 index = 0;
63 UINT32 flag = 0;
64 UINT32 skip = 0;
65 UINT32 channelConfig = 0;
66
67 /* audio object type */
68 data->audioObjectType = readBits(bs, 5);
69
70 /* sampling frequency */
71 index = readBits(bs, 4);
72 if (index == 0xF) {
73 data->samplingFrequency = readBits(bs, 24);
74 } else {
75 data->samplingFrequency = aSampleRate[index];
76 }
77
78 /* channel configuration */
79 channelConfig = readBits(bs, 4);
80
81 /* sbr parameters */
82 if (data->audioObjectType == AACSBR) {
83 data->bSBR = TRUE;
84 index = readBits(bs, 4);
85 if (index == 0xF) {
86 data->extensionSamplingFrequency = readBits(bs, 24);
87 } else {
88 data->extensionSamplingFrequency = readBits(bs, 24);
89 }
90
91 data->audioObjectType = readBits(bs, 5);
92 } else {
93 data->extensionSamplingFrequency = data->samplingFrequency;
94 data->bSBR = FALSE;
95 }
96
97 /* make sure format is supported */
98 if (data->audioObjectType == AACMAIN ||
99 data->audioObjectType == AACLC ||
100 data->audioObjectType == AACLTP) {
101 flag = readBits(bs, 1);
102 data->frameLength = flag ? 960 : 1024;
103
104 flag = readBits(bs, 1);
105 if (flag) {
106 data->coreCoderDelay = readBits(bs, 14);
107 }
108
109 flag = readBits(bs, 1); /* extension flag - not defined */
110
111 if (channelConfig == 0) {
112 skip = readBits(bs, 4); /* ignore element instance tag */
113 skip = readBits(bs, 2); /* ignore object type */
114 skip = readBits(bs, 4); /* ignore sampling frequency index */
115
116 data->numFrontElements = readBits(bs, 4);
117 data->numSideElements = readBits(bs, 4);
118 data->numBackElements = readBits(bs, 4);
119 data->numLfeElements = readBits(bs, 2);
120 data->numAssocElements = readBits(bs, 3);
121 data->numValidCCElements = readBits(bs, 4);
122
123 if (readBits(bs, 1)) { /* mono mixdown present */
124 skip = readBits(bs, 4); /* ignore mixdown element */
125 }
126
127 if (readBits(bs, 1)) { /* stereo mixdown present */
128 skip = readBits(bs, 4); /* ignore mixdown element */
129 }
130
131 if (readBits(bs, 1)) { /* matrix mixdown present */
132 skip = readBits(bs, 2); /* ignore mixdown index */
133 skip = readBits(bs, 1); /* ignore surround enable */
134 }
135
136 for (i = 0; i < data->numFrontElements; i++) {
137 data->numFrontChannels += (1 + readBits(bs, 1));
138 skip = readBits(bs, 4); /* ignore tag select */
139 }
140 for (i = 0; i < data->numSideElements; i++) {
141 data->numSideChannels += (1 + readBits(bs, 1));
142 skip = readBits(bs, 4); /* ignore tag select */
143 }
144 for (i = 0; i < data->numBackElements; i++) {
145 data->numBackChannels += (1 + readBits(bs, 1));
146 skip = readBits(bs, 4); /* ignore tag select */
147 }
148 for (i = 0; i < data->numLfeElements; i++) {
149 skip = readBits(bs, 4); /* ignore tag select */
150 }
151 for (i = 0; i < data->numAssocElements; i++) {
152 skip = readBits(bs, 4); /* ignore tag select */
153 }
154 for (i = 0; i < data->numValidCCElements; i++) {
155 skip = readBits(bs, 1); /* ignore 'is_ind_sw' */
156 skip = readBits(bs, 4); /* ignore tag select */
157 }
158
159 byteAlign(bs);
160
161 /* ignore comment field data */
162 index = readBits(bs, 8);
163 for (i = 0; i < index; i++) {
164 skip = readBits(bs, 8);
165 }
166 } else {
167 if (channelConfig >= 8) {
168 return HXR_FAIL;
169 }
170
171 data->numFrontChannels = channelMapping[channelConfig][0];
172 data->numSideChannels = channelMapping[channelConfig][1];
173 data->numBackChannels = channelMapping[channelConfig][2];
174 data->numLfeElements = channelMapping[channelConfig][3];
175
176 data->numFrontElements = (data->numFrontChannels + 1) >> 1;
177 data->numSideElements = (data->numSideChannels + 1) >> 1;
178 data->numBackElements = (data->numBackChannels + 1) >> 1;
179 }
180
181 data->numChannels = data->numFrontChannels +
182 data->numSideChannels +
183 data->numBackChannels +
184 data->numLfeElements;
185
186 } else { /* format not supported */
187 return HXR_FAIL;
188 }
189
190 /* check for SBR info if there is enough data left in the bitstream */
191 if (!data->bSBR && bitsLeftInBitstream(bs) >= 16) {
192 if (readBits(bs, 11) == 0x2b7) {
193 if (readBits(bs, 5) == 5) {
194 data->bSBR = readBits(bs, 1);
195
196 if (data->bSBR) {
197 index = readBits(bs, 4);
198 if (index == 0xF) {
199 data->extensionSamplingFrequency = readBits(bs, 24);
200 } else {
201 data->extensionSamplingFrequency = aSampleRate[index];
202 }
203 }
204 }
205 }
206 }
207
208 return HXR_OK;
209}
210
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