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1 | /* |
2 | * Westwood SNDx codecs | |
3 | * Copyright (c) 2005 Konstantin Shishkov | |
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 | */ | |
21 | ||
22 | #include <stdint.h> | |
23 | ||
24 | #include "libavutil/channel_layout.h" | |
25 | #include "libavutil/common.h" | |
26 | #include "libavutil/intreadwrite.h" | |
27 | #include "avcodec.h" | |
28 | #include "internal.h" | |
29 | ||
30 | /** | |
31 | * @file | |
32 | * Westwood SNDx codecs | |
33 | * | |
34 | * Reference documents about VQA format and its audio codecs | |
35 | * can be found here: | |
36 | * http://www.multimedia.cx | |
37 | */ | |
38 | ||
39 | static const int8_t ws_adpcm_4bit[] = { | |
40 | -9, -8, -6, -5, -4, -3, -2, -1, | |
41 | 0, 1, 2, 3, 4, 5, 6, 8 | |
42 | }; | |
43 | ||
44 | static av_cold int ws_snd_decode_init(AVCodecContext *avctx) | |
45 | { | |
46 | avctx->channels = 1; | |
47 | avctx->channel_layout = AV_CH_LAYOUT_MONO; | |
48 | avctx->sample_fmt = AV_SAMPLE_FMT_U8; | |
49 | ||
50 | return 0; | |
51 | } | |
52 | ||
53 | static int ws_snd_decode_frame(AVCodecContext *avctx, void *data, | |
54 | int *got_frame_ptr, AVPacket *avpkt) | |
55 | { | |
56 | AVFrame *frame = data; | |
57 | const uint8_t *buf = avpkt->data; | |
58 | int buf_size = avpkt->size; | |
59 | ||
60 | int in_size, out_size, ret; | |
61 | int sample = 128; | |
62 | uint8_t *samples; | |
63 | uint8_t *samples_end; | |
64 | ||
65 | if (!buf_size) | |
66 | return 0; | |
67 | ||
68 | if (buf_size < 4) { | |
69 | av_log(avctx, AV_LOG_ERROR, "packet is too small\n"); | |
70 | return AVERROR(EINVAL); | |
71 | } | |
72 | ||
73 | out_size = AV_RL16(&buf[0]); | |
74 | in_size = AV_RL16(&buf[2]); | |
75 | buf += 4; | |
76 | ||
77 | if (in_size > buf_size) { | |
78 | av_log(avctx, AV_LOG_ERROR, "Frame data is larger than input buffer\n"); | |
79 | return AVERROR_INVALIDDATA; | |
80 | } | |
81 | ||
82 | /* get output buffer */ | |
83 | frame->nb_samples = out_size; | |
84 | if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) | |
85 | return ret; | |
86 | samples = frame->data[0]; | |
87 | samples_end = samples + out_size; | |
88 | ||
89 | if (in_size == out_size) { | |
90 | memcpy(samples, buf, out_size); | |
91 | *got_frame_ptr = 1; | |
92 | return buf_size; | |
93 | } | |
94 | ||
95 | while (samples < samples_end && buf - avpkt->data < buf_size) { | |
96 | int code, smp, size; | |
97 | uint8_t count; | |
98 | code = *buf >> 6; | |
99 | count = *buf & 0x3F; | |
100 | buf++; | |
101 | ||
102 | /* make sure we don't write past the output buffer */ | |
103 | switch (code) { | |
104 | case 0: smp = 4 * (count + 1); break; | |
105 | case 1: smp = 2 * (count + 1); break; | |
106 | case 2: smp = (count & 0x20) ? 1 : count + 1; break; | |
107 | default: smp = count + 1; break; | |
108 | } | |
109 | if (samples_end - samples < smp) | |
110 | break; | |
111 | ||
112 | /* make sure we don't read past the input buffer */ | |
113 | size = ((code == 2 && (count & 0x20)) || code == 3) ? 0 : count + 1; | |
114 | if ((buf - avpkt->data) + size > buf_size) | |
115 | break; | |
116 | ||
117 | switch (code) { | |
118 | case 0: /* ADPCM 2-bit */ | |
119 | for (count++; count > 0; count--) { | |
120 | code = *buf++; | |
121 | sample += ( code & 0x3) - 2; | |
122 | sample = av_clip_uint8(sample); | |
123 | *samples++ = sample; | |
124 | sample += ((code >> 2) & 0x3) - 2; | |
125 | sample = av_clip_uint8(sample); | |
126 | *samples++ = sample; | |
127 | sample += ((code >> 4) & 0x3) - 2; | |
128 | sample = av_clip_uint8(sample); | |
129 | *samples++ = sample; | |
130 | sample += (code >> 6) - 2; | |
131 | sample = av_clip_uint8(sample); | |
132 | *samples++ = sample; | |
133 | } | |
134 | break; | |
135 | case 1: /* ADPCM 4-bit */ | |
136 | for (count++; count > 0; count--) { | |
137 | code = *buf++; | |
138 | sample += ws_adpcm_4bit[code & 0xF]; | |
139 | sample = av_clip_uint8(sample); | |
140 | *samples++ = sample; | |
141 | sample += ws_adpcm_4bit[code >> 4]; | |
142 | sample = av_clip_uint8(sample); | |
143 | *samples++ = sample; | |
144 | } | |
145 | break; | |
146 | case 2: /* no compression */ | |
147 | if (count & 0x20) { /* big delta */ | |
148 | int8_t t; | |
149 | t = count; | |
150 | t <<= 3; | |
151 | sample += t >> 3; | |
152 | sample = av_clip_uint8(sample); | |
153 | *samples++ = sample; | |
154 | } else { /* copy */ | |
155 | memcpy(samples, buf, smp); | |
156 | samples += smp; | |
157 | buf += smp; | |
158 | sample = buf[-1]; | |
159 | } | |
160 | break; | |
161 | default: /* run */ | |
162 | memset(samples, sample, smp); | |
163 | samples += smp; | |
164 | } | |
165 | } | |
166 | ||
167 | frame->nb_samples = samples - frame->data[0]; | |
168 | *got_frame_ptr = 1; | |
169 | ||
170 | return buf_size; | |
171 | } | |
172 | ||
173 | AVCodec ff_ws_snd1_decoder = { | |
174 | .name = "ws_snd1", | |
175 | .long_name = NULL_IF_CONFIG_SMALL("Westwood Audio (SND1)"), | |
176 | .type = AVMEDIA_TYPE_AUDIO, | |
177 | .id = AV_CODEC_ID_WESTWOOD_SND1, | |
178 | .init = ws_snd_decode_init, | |
179 | .decode = ws_snd_decode_frame, | |
180 | .capabilities = CODEC_CAP_DR1, | |
181 | }; |