FFmpeg: libavcodec/dsicinaudio.c Source File

FFmpeg

[フレーム]

libavcodec

dsicinaudio.c

Go to the documentation of this file.

1 /*

2 * Delphine Software International CIN audio decoder

4 *

5 * This file is part of FFmpeg.

6 *

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

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

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

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

11 *

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

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

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

15 * Lesser General Public License for more details.

16 *

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

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

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

20 */

22 /**

23 * @file

24 * Delphine Software International CIN audio decoder

25 */

27 #include "libavutil/channel_layout.h"

29 #include "avcodec.h"

30 #include "bytestream.h"

31 #include "internal.h"

32 #include "mathops.h"

34 typedef struct CinAudioContext {

35 int initial_decode_frame;

36 int delta;

37 } CinAudioContext;

40 /* table defining a geometric sequence with multiplier = 32767 ^ (1 / 128) */

41 static const int16_t cinaudio_delta16_table[256] = {

42 0, 0, 0, 0, 0, 0, 0, 0,

43 0, 0, 0, 0, 0, 0, 0, 0,

44 0, 0, 0, -30210, -27853, -25680, -23677, -21829,

45 -20126, -18556, -17108, -15774, -14543, -13408, -12362, -11398,

46 -10508, -9689, -8933, -8236, -7593, -7001, -6455, -5951,

47 -5487, -5059, -4664, -4300, -3964, -3655, -3370, -3107,

48 -2865, -2641, -2435, -2245, -2070, -1908, -1759, -1622,

49 -1495, -1379, -1271, -1172, -1080, -996, -918, -847,

50 -781, -720, -663, -612, -564, -520, -479, -442,

51 -407, -376, -346, -319, -294, -271, -250, -230,

52 -212, -196, -181, -166, -153, -141, -130, -120,

53 -111, -102, -94, -87, -80, -74, -68, -62,

54 -58, -53, -49, -45, -41, -38, -35, -32,

55 -30, -27, -25, -23, -21, -20, -18, -17,

56 -15, -14, -13, -12, -11, -10, -9, -8,

57 -7, -6, -5, -4, -3, -2, -1, 0,

58 0, 1, 2, 3, 4, 5, 6, 7,

59 8, 9, 10, 11, 12, 13, 14, 15,

60 17, 18, 20, 21, 23, 25, 27, 30,

61 32, 35, 38, 41, 45, 49, 53, 58,

62 62, 68, 74, 80, 87, 94, 102, 111,

63 120, 130, 141, 153, 166, 181, 196, 212,

64 230, 250, 271, 294, 319, 346, 376, 407,

65 442, 479, 520, 564, 612, 663, 720, 781,

66 847, 918, 996, 1080, 1172, 1271, 1379, 1495,

67 1622, 1759, 1908, 2070, 2245, 2435, 2641, 2865,

68 3107, 3370, 3655, 3964, 4300, 4664, 5059, 5487,

69 5951, 6455, 7001, 7593, 8236, 8933, 9689, 10508,

70 11398, 12362, 13408, 14543, 15774, 17108, 18556, 20126,

71 21829, 23677, 25680, 27853, 30210, 0, 0, 0,

72 0, 0, 0, 0, 0, 0, 0, 0,

73 0, 0, 0, 0, 0, 0, 0, 0

74 };

76 static av_cold int cinaudio_decode_init(AVCodecContext *avctx)

77 {

78 CinAudioContext *cin = avctx->priv_data;

80 cin->initial_decode_frame = 1;

81 cin->delta = 0;

82 avctx->sample_fmt = AV_SAMPLE_FMT_S16;

83 avctx->channels = 1;

84 avctx->channel_layout = AV_CH_LAYOUT_MONO;

86 return 0;

87 }

89 static int cinaudio_decode_frame(AVCodecContext *avctx, void *data,

90 int *got_frame_ptr, AVPacket *avpkt)

91 {

92 AVFrame *frame = data;

93 const uint8_t *buf = avpkt->data;

94 CinAudioContext *cin = avctx->priv_data;

95 const uint8_t *buf_end = buf + avpkt->size;

96 int16_t *samples;

97 int delta, ret;

99 /* get output buffer */

100 frame->nb_samples = avpkt->size - cin->initial_decode_frame;

101 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)

102 return ret;

103 samples = (int16_t *)frame->data[0];

104

105 delta = cin->delta;

106 if (cin->initial_decode_frame) {

107 cin->initial_decode_frame = 0;

108 delta = sign_extend(AV_RL16(buf), 16);

109 buf += 2;

110 *samples++ = delta;

111 }

112 while (buf < buf_end) {

113 delta += cinaudio_delta16_table[*buf++];

114 delta = av_clip_int16(delta);

115 *samples++ = delta;

116 }

117 cin->delta = delta;

118

119 *got_frame_ptr = 1;

120

121 return avpkt->size;

122 }

123

124 AVCodec ff_dsicinaudio_decoder = {

125 .name = "dsicinaudio",

126 .long_name = NULL_IF_CONFIG_SMALL("Delphine Software International CIN audio"),

127 .type = AVMEDIA_TYPE_AUDIO,

128 .id = AV_CODEC_ID_DSICINAUDIO,

129 .priv_data_size = sizeof(CinAudioContext),

130 .init = cinaudio_decode_init,

131 .decode = cinaudio_decode_frame,

132 .capabilities = CODEC_CAP_DR1,

133 };

Generated on Sun Mar 8 2015 02:34:50 for FFmpeg by doxygen 1.8.2