1/*
2 * 8SVX audio decoder
3 * Copyright (C) 2008 Jaikrishnan Menon
4 *
5 * This file is part of Libav.
6 *
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.
11 *
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.
16 *
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
20 */
21
22/**
23 * @file
24 * 8svx audio decoder
25 * @author Jaikrishnan Menon
26 *
27 * supports: fibonacci delta encoding
28 *         : exponential encoding
29 */
30
31#include "avcodec.h"
32
33/** decoder context */
34typedef struct EightSvxContext {
35    AVFrame frame;
36    uint8_t fib_acc[2];
37    const int8_t *table;
38
39    /* buffer used to store the whole first packet.
40       data is only sent as one large packet */
41    uint8_t *data[2];
42    int data_size;
43    int data_idx;
44} EightSvxContext;
45
46static const int8_t fibonacci[16]   = { -34, -21, -13,  -8, -5, -3, -2, -1,
47                                          0,   1,   2,   3,  5,  8, 13, 21 };
48static const int8_t exponential[16] = { -128, -64, -32, -16, -8, -4, -2, -1,
49                                           0,   1,   2,   4,  8, 16, 32, 64 };
50
51#define MAX_FRAME_SIZE 32768
52
53/**
54 * Delta decode the compressed values in src, and put the resulting
55 * decoded samples in dst.
56 *
57 * @param[in,out] state starting value. it is saved for use in the next call.
58 */
59static void delta_decode(uint8_t *dst, const uint8_t *src, int src_size,
60                         uint8_t *state, const int8_t *table, int channels)
61{
62    uint8_t val = *state;
63
64    while (src_size--) {
65        uint8_t d = *src++;
66        val = av_clip_uint8(val + table[d & 0xF]);
67        *dst = val;
68        dst += channels;
69        val = av_clip_uint8(val + table[d >> 4]);
70        *dst = val;
71        dst += channels;
72    }
73
74    *state = val;
75}
76
77static void raw_decode(uint8_t *dst, const int8_t *src, int src_size,
78                       int channels)
79{
80    while (src_size--) {
81        *dst = *src++ + 128;
82        dst += channels;
83    }
84}
85
86/** decode a frame */
87static int eightsvx_decode_frame(AVCodecContext *avctx, void *data,
88                                 int *got_frame_ptr, AVPacket *avpkt)
89{
90    EightSvxContext *esc = avctx->priv_data;
91    int buf_size;
92    uint8_t *out_data;
93    int ret;
94    int is_compr = (avctx->codec_id != CODEC_ID_PCM_S8_PLANAR);
95
96    /* for the first packet, copy data to buffer */
97    if (avpkt->data) {
98        int hdr_size  = is_compr ? 2 : 0;
99        int chan_size = (avpkt->size - hdr_size * avctx->channels) / avctx->channels;
100
101        if (avpkt->size < hdr_size * avctx->channels) {
102            av_log(avctx, AV_LOG_ERROR, "packet size is too small\n");
103            return AVERROR(EINVAL);
104        }
105        if (esc->data[0]) {
106            av_log(avctx, AV_LOG_ERROR, "unexpected data after first packet\n");
107            return AVERROR(EINVAL);
108        }
109
110        if (is_compr) {
111        esc->fib_acc[0] = avpkt->data[1] + 128;
112        if (avctx->channels == 2)
113            esc->fib_acc[1] = avpkt->data[2+chan_size+1] + 128;
114        }
115
116        esc->data_idx  = 0;
117        esc->data_size = chan_size;
118        if (!(esc->data[0] = av_malloc(chan_size)))
119            return AVERROR(ENOMEM);
120        if (avctx->channels == 2) {
121            if (!(esc->data[1] = av_malloc(chan_size))) {
122                av_freep(&esc->data[0]);
123                return AVERROR(ENOMEM);
124            }
125        }
126        memcpy(esc->data[0], &avpkt->data[hdr_size], chan_size);
127        if (avctx->channels == 2)
128            memcpy(esc->data[1], &avpkt->data[2*hdr_size+chan_size], chan_size);
129    }
130    if (!esc->data[0]) {
131        av_log(avctx, AV_LOG_ERROR, "unexpected empty packet\n");
132        return AVERROR(EINVAL);
133    }
134
135    /* decode next piece of data from the buffer */
136    buf_size = FFMIN(MAX_FRAME_SIZE, esc->data_size - esc->data_idx);
137    if (buf_size <= 0) {
138        *got_frame_ptr = 0;
139        return avpkt->size;
140    }
141
142    /* get output buffer */
143    esc->frame.nb_samples = buf_size * (is_compr + 1);
144    if ((ret = avctx->get_buffer(avctx, &esc->frame)) < 0) {
145        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
146        return ret;
147    }
148    out_data = esc->frame.data[0];
149
150    if (is_compr) {
151    delta_decode(out_data, &esc->data[0][esc->data_idx], buf_size,
152                 &esc->fib_acc[0], esc->table, avctx->channels);
153    if (avctx->channels == 2) {
154        delta_decode(&out_data[1], &esc->data[1][esc->data_idx], buf_size,
155                    &esc->fib_acc[1], esc->table, avctx->channels);
156    }
157    } else {
158        int ch;
159        for (ch = 0; ch < avctx->channels; ch++) {
160            raw_decode((int8_t *)&out_data[ch], &esc->data[ch][esc->data_idx],
161                       buf_size, avctx->channels);
162        }
163    }
164    esc->data_idx += buf_size;
165
166    *got_frame_ptr   = 1;
167    *(AVFrame *)data = esc->frame;
168
169    return avpkt->size;
170}
171
172/** initialize 8svx decoder */
173static av_cold int eightsvx_decode_init(AVCodecContext *avctx)
174{
175    EightSvxContext *esc = avctx->priv_data;
176
177    if (avctx->channels < 1 || avctx->channels > 2) {
178        av_log(avctx, AV_LOG_ERROR, "8SVX does not support more than 2 channels\n");
179        return AVERROR(EINVAL);
180    }
181
182    switch(avctx->codec->id) {
183        case CODEC_ID_8SVX_FIB:
184          esc->table = fibonacci;
185          break;
186        case CODEC_ID_8SVX_EXP:
187          esc->table = exponential;
188          break;
189        case CODEC_ID_PCM_S8_PLANAR:
190            break;
191        default:
192          return -1;
193    }
194    avctx->sample_fmt = AV_SAMPLE_FMT_U8;
195
196    avcodec_get_frame_defaults(&esc->frame);
197    avctx->coded_frame = &esc->frame;
198
199    return 0;
200}
201
202static av_cold int eightsvx_decode_close(AVCodecContext *avctx)
203{
204    EightSvxContext *esc = avctx->priv_data;
205
206    av_freep(&esc->data[0]);
207    av_freep(&esc->data[1]);
208
209    return 0;
210}
211
212AVCodec ff_eightsvx_fib_decoder = {
213  .name           = "8svx_fib",
214  .type           = AVMEDIA_TYPE_AUDIO,
215  .id             = CODEC_ID_8SVX_FIB,
216  .priv_data_size = sizeof (EightSvxContext),
217  .init           = eightsvx_decode_init,
218  .close          = eightsvx_decode_close,
219  .decode         = eightsvx_decode_frame,
220  .capabilities   = CODEC_CAP_DELAY | CODEC_CAP_DR1,
221  .long_name      = NULL_IF_CONFIG_SMALL("8SVX fibonacci"),
222};
223
224AVCodec ff_eightsvx_exp_decoder = {
225  .name           = "8svx_exp",
226  .type           = AVMEDIA_TYPE_AUDIO,
227  .id             = CODEC_ID_8SVX_EXP,
228  .priv_data_size = sizeof (EightSvxContext),
229  .init           = eightsvx_decode_init,
230  .close          = eightsvx_decode_close,
231  .decode         = eightsvx_decode_frame,
232  .capabilities   = CODEC_CAP_DELAY | CODEC_CAP_DR1,
233  .long_name      = NULL_IF_CONFIG_SMALL("8SVX exponential"),
234};
235
236AVCodec ff_pcm_s8_planar_decoder = {
237    .name           = "pcm_s8_planar",
238    .type           = AVMEDIA_TYPE_AUDIO,
239    .id             = CODEC_ID_PCM_S8_PLANAR,
240    .priv_data_size = sizeof(EightSvxContext),
241    .init           = eightsvx_decode_init,
242    .close          = eightsvx_decode_close,
243    .decode         = eightsvx_decode_frame,
244    .capabilities   = CODEC_CAP_DELAY | CODEC_CAP_DR1,
245    .long_name      = NULL_IF_CONFIG_SMALL("PCM signed 8-bit planar"),
246};
247