blob: 0f005807ae826612bca9b7963c63529fa9f6e1b5
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 = AV_CODEC_CAP_DR1, |
181 | }; |
182 |