3 * Copyright (c) 2005 Konstantin Shishkov
5 * This file is part of Libav.
7 * Libav 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.
12 * Libav 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.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 #include "libavutil/channel_layout.h"
25 #include "libavutil/common.h"
26 #include "libavutil/intreadwrite.h"
32 * Westwood SNDx codecs
34 * Reference documents about VQA format and its audio codecs
36 * http://www.multimedia.cx
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
44 typedef struct WSSndContext {
48 static av_cold int ws_snd_decode_init(AVCodecContext *avctx)
50 WSSndContext *s = avctx->priv_data;
53 avctx->channel_layout = AV_CH_LAYOUT_MONO;
54 avctx->sample_fmt = AV_SAMPLE_FMT_U8;
56 avcodec_get_frame_defaults(&s->frame);
57 avctx->coded_frame = &s->frame;
62 static int ws_snd_decode_frame(AVCodecContext *avctx, void *data,
63 int *got_frame_ptr, AVPacket *avpkt)
65 WSSndContext *s = avctx->priv_data;
66 const uint8_t *buf = avpkt->data;
67 int buf_size = avpkt->size;
69 int in_size, out_size, ret;
78 av_log(avctx, AV_LOG_ERROR, "packet is too small\n");
79 return AVERROR(EINVAL);
82 out_size = AV_RL16(&buf[0]);
83 in_size = AV_RL16(&buf[2]);
86 if (in_size > buf_size) {
87 av_log(avctx, AV_LOG_ERROR, "Frame data is larger than input buffer\n");
91 /* get output buffer */
92 s->frame.nb_samples = out_size;
93 if ((ret = ff_get_buffer(avctx, &s->frame)) < 0) {
94 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
97 samples = s->frame.data[0];
98 samples_end = samples + out_size;
100 if (in_size == out_size) {
101 memcpy(samples, buf, out_size);
103 *(AVFrame *)data = s->frame;
107 while (samples < samples_end && buf - avpkt->data < buf_size) {
114 /* make sure we don't write past the output buffer */
116 case 0: smp = 4 * (count + 1); break;
117 case 1: smp = 2 * (count + 1); break;
118 case 2: smp = (count & 0x20) ? 1 : count + 1; break;
119 default: smp = count + 1; break;
121 if (samples_end - samples < smp)
124 /* make sure we don't read past the input buffer */
125 size = ((code == 2 && (count & 0x20)) || code == 3) ? 0 : count + 1;
126 if ((buf - avpkt->data) + size > buf_size)
130 case 0: /* ADPCM 2-bit */
131 for (count++; count > 0; count--) {
133 sample += ( code & 0x3) - 2;
134 sample = av_clip_uint8(sample);
136 sample += ((code >> 2) & 0x3) - 2;
137 sample = av_clip_uint8(sample);
139 sample += ((code >> 4) & 0x3) - 2;
140 sample = av_clip_uint8(sample);
142 sample += (code >> 6) - 2;
143 sample = av_clip_uint8(sample);
147 case 1: /* ADPCM 4-bit */
148 for (count++; count > 0; count--) {
150 sample += ws_adpcm_4bit[code & 0xF];
151 sample = av_clip_uint8(sample);
153 sample += ws_adpcm_4bit[code >> 4];
154 sample = av_clip_uint8(sample);
158 case 2: /* no compression */
159 if (count & 0x20) { /* big delta */
164 sample = av_clip_uint8(sample);
167 memcpy(samples, buf, smp);
174 memset(samples, sample, smp);
179 s->frame.nb_samples = samples - s->frame.data[0];
181 *(AVFrame *)data = s->frame;
186 AVCodec ff_ws_snd1_decoder = {
188 .type = AVMEDIA_TYPE_AUDIO,
189 .id = AV_CODEC_ID_WESTWOOD_SND1,
190 .priv_data_size = sizeof(WSSndContext),
191 .init = ws_snd_decode_init,
192 .decode = ws_snd_decode_frame,
193 .capabilities = CODEC_CAP_DR1,
194 .long_name = NULL_IF_CONFIG_SMALL("Westwood Audio (SND1)"),