FFmpeg: libavcodec/vorbis.c Source File

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libavcodec

vorbis.c

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1 /**

2 * @file

3 * Common code for Vorbis I encoder and decoder

4 * @author Denes Balatoni ( dbalatoni programozo hu )

5 *

6 * This file is part of FFmpeg.

7 *

8 * FFmpeg is free software; you can redistribute it and/or

9 * modify it under the terms of the GNU Lesser General Public

10 * License as published by the Free Software Foundation; either

11 * version 2.1 of the License, or (at your option) any later version.

12 *

13 * FFmpeg is distributed in the hope that it will be useful,

14 * but WITHOUT ANY WARRANTY; without even the implied warranty of

15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

16 * Lesser General Public License for more details.

17 *

18 * You should have received a copy of the GNU Lesser General Public

19 * License along with FFmpeg; if not, write to the Free Software

20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

21 */

23 /**

24 * @file

25 * Common code for Vorbis I encoder and decoder

26 * @author Denes Balatoni ( dbalatoni programozo hu )

27 */

29 #define BITSTREAM_READER_LE

30 #include "avcodec.h"

31 #include "get_bits.h"

33 #include "vorbis.h"

36 /* Helper functions */

38 // x^(1/n)

39 unsigned int ff_vorbis_nth_root(unsigned int x, unsigned int n)

40 {

41 unsigned int ret = 0, i, j;

43 do {

44 ++ret;

45 for (i = 0, j = ret; i < n - 1; i++)

46 j *= ret;

47 } while (j <= x);

49 return ret - 1;

50 }

52 // Generate vlc codes from vorbis huffman code lengths

54 // the two bits[p] > 32 checks should be redundant, all calling code should

55 // already ensure that, but since it allows overwriting the stack it seems

56 // reasonable to check redundantly.

57 int ff_vorbis_len2vlc(uint8_t *bits, uint32_t *codes, unsigned num)

58 {

59 uint32_t exit_at_level[33] = { 404 };

61 unsigned i, j, p, code;

63 #ifdef DEBUG

64 GetBitContext gb;

65 #endif

67 for (p = 0; (bits[p] == 0) && (p < num); ++p)

68 ;

69 if (p == num)

70 return 0;

72 codes[p] = 0;

73 if (bits[p] > 32)

74 return 1;

75 for (i = 0; i < bits[p]; ++i)

76 exit_at_level[i+1] = 1 << i;

78 #ifdef DEBUG

79 av_log(NULL, AV_LOG_INFO, " %u. of %u code len %d code %d - ", p, num, bits[p], codes[p]);

80 init_get_bits(&gb, (uint8_t *)&codes[p], bits[p]);

81 for (i = 0; i < bits[p]; ++i)

82 av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");

83 av_log(NULL, AV_LOG_INFO, "\n");

84 #endif

86 ++p;

88 for (; p < num; ++p) {

89 if (bits[p] > 32)

90 return 1;

91 if (bits[p] == 0)

92 continue;

93 // find corresponding exit(node which the tree can grow further from)

94 for (i = bits[p]; i > 0; --i)

95 if (exit_at_level[i])

96 break;

97 if (!i) // overspecified tree

98 return 1;

99 code = exit_at_level[i];

100 exit_at_level[i] = 0;

101 // construct code (append 0s to end) and introduce new exits

102 for (j = i + 1 ;j <= bits[p]; ++j)

103 exit_at_level[j] = code + (1 << (j - 1));

104 codes[p] = code;

105

106 #ifdef DEBUG

107 av_log(NULL, AV_LOG_INFO, " %d. code len %d code %d - ", p, bits[p], codes[p]);

108 init_get_bits(&gb, (uint8_t *)&codes[p], bits[p]);

109 for (i = 0; i < bits[p]; ++i)

110 av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");

111 av_log(NULL, AV_LOG_INFO, "\n");

112 #endif

113

114 }

115

116 //no exits should be left (underspecified tree - ie. unused valid vlcs - not allowed by SPEC)

117 for (p = 1; p < 33; p++)

118 if (exit_at_level[p])

119 return 1;

120

121 return 0;

122 }

123

124 int ff_vorbis_ready_floor1_list(AVCodecContext *avctx,

125 vorbis_floor1_entry *list, int values)

126 {

127 int i;

128 list[0].sort = 0;

129 list[1].sort = 1;

130 for (i = 2; i < values; i++) {

131 int j;

132 list[i].low = 0;

133 list[i].high = 1;

134 list[i].sort = i;

135 for (j = 2; j < i; j++) {

136 int tmp = list[j].x;

137 if (tmp < list[i].x) {

138 if (tmp > list[list[i].low].x)

139 list[i].low = j;

140 } else {

141 if (tmp < list[list[i].high].x)

142 list[i].high = j;

143 }

144 }

145 }

146 for (i = 0; i < values - 1; i++) {

147 int j;

148 for (j = i + 1; j < values; j++) {

149 if (list[i].x == list[j].x) {

150 av_log(avctx, AV_LOG_ERROR,

151 "Duplicate value found in floor 1 X coordinates\n");

152 return AVERROR_INVALIDDATA;

153 }

154 if (list[list[i].sort].x > list[list[j].sort].x) {

155 int tmp = list[i].sort;

156 list[i].sort = list[j].sort;

157 list[j].sort = tmp;

158 }

159 }

160 }

161 return 0;

162 }

163

164 static inline void render_line_unrolled(intptr_t x, int y, int x1,

165 intptr_t sy, int ady, int adx,

166 float *buf)

167 {

168 int err = -adx;

169 x -= x1 - 1;

170 buf += x1 - 1;

171 while (++x < 0) {

172 err += ady;

173 if (err >= 0) {

174 err += ady - adx;

175 y += sy;

176 buf[x++] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];

177 }

178 buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];

179 }

180 if (x <= 0) {

181 if (err + ady >= 0)

182 y += sy;

183 buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];

184 }

185 }

186

187 static void render_line(int x0, int y0, int x1, int y1, float *buf)

188 {

189 int dy = y1 - y0;

190 int adx = x1 - x0;

191 int ady = FFABS(dy);

192 int sy = dy < 0 ? -1 : 1;

193 buf[x0] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y0)];

194 if (ady*2 <= adx) { // optimized common case

195 render_line_unrolled(x0, y0, x1, sy, ady, adx, buf);

196 } else {

197 int base = dy / adx;

198 int x = x0;

199 int y = y0;

200 int err = -adx;

201 ady -= FFABS(base) * adx;

202 while (++x < x1) {

203 y += base;

204 err += ady;

205 if (err >= 0) {

206 err -= adx;

207 y += sy;

208 }

209 buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];

210 }

211 }

212 }

213

214 void ff_vorbis_floor1_render_list(vorbis_floor1_entry * list, int values,

215 uint16_t *y_list, int *flag,

216 int multiplier, float *out, int samples)

217 {

218 int lx, ly, i;

219 lx = 0;

220 ly = y_list[0] * multiplier;

221 for (i = 1; i < values; i++) {

222 int pos = list[i].sort;

223 if (flag[pos]) {

224 int x1 = list[pos].x;

225 int y1 = y_list[pos] * multiplier;

226 if (lx < samples)

227 render_line(lx, ly, FFMIN(x1,samples), y1, out);

228 lx = x1;

229 ly = y1;

230 }

231 if (lx >= samples)

232 break;

233 }

234 if (lx < samples)

235 render_line(lx, ly, samples, ly, out);

236 }

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