1/*
2 * Copyright (C) 2008 Jaikrishnan Menon
3 * Copyright (C) 2011 Stefano Sabatini
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/**
23 * @file
24 * 8svx audio decoder
25 * @author Jaikrishnan Menon
26 *
27 * supports: fibonacci delta encoding
28 *         : exponential encoding
29 *
30 * For more information about the 8SVX format:
31 * http://netghost.narod.ru/gff/vendspec/iff/iff.txt
32 * http://sox.sourceforge.net/AudioFormats-11.html
33 * http://aminet.net/package/mus/misc/wavepak
34 * http://amigan.1emu.net/reg/8SVX.txt
35 *
36 * Samples can be found here:
37 * http://aminet.net/mods/smpl/
38 */
39
40#include "libavutil/avassert.h"
41#include "avcodec.h"
42#include "internal.h"
43#include "libavutil/common.h"
44
45/** decoder context */
46typedef struct EightSvxContext {
47    uint8_t fib_acc[2];
48    const int8_t *table;
49
50    /* buffer used to store the whole first packet.
51       data is only sent as one large packet */
52    uint8_t *data[2];
53    int data_size;
54    int data_idx;
55} EightSvxContext;
56
57static const int8_t fibonacci[16]   = { -34,  -21, -13,  -8, -5, -3, -2, -1, 0, 1, 2, 3, 5, 8,  13, 21 };
58static const int8_t exponential[16] = { -128, -64, -32, -16, -8, -4, -2, -1, 0, 1, 2, 4, 8, 16, 32, 64 };
59
60#define MAX_FRAME_SIZE 2048
61
62/**
63 * Delta decode the compressed values in src, and put the resulting
64 * decoded samples in dst.
65 *
66 * @param[in,out] state starting value. it is saved for use in the next call.
67 * @param table delta sequence table
68 */
69static void delta_decode(uint8_t *dst, const uint8_t *src, int src_size,
70                         uint8_t *state, const int8_t *table)
71{
72    uint8_t val = *state;
73
74    while (src_size--) {
75        uint8_t d = *src++;
76        val = av_clip_uint8(val + table[d & 0xF]);
77        *dst++ = val;
78        val = av_clip_uint8(val + table[d >> 4]);
79        *dst++ = val;
80    }
81
82    *state = val;
83}
84
85/** decode a frame */
86static int eightsvx_decode_frame(AVCodecContext *avctx, void *data,
87                                 int *got_frame_ptr, AVPacket *avpkt)
88{
89    EightSvxContext *esc = avctx->priv_data;
90    AVFrame *frame       = data;
91    int buf_size;
92    int ch, ret;
93    int hdr_size = 2;
94
95    /* decode and interleave the first packet */
96    if (!esc->data[0] && avpkt) {
97        int chan_size = avpkt->size / avctx->channels - hdr_size;
98
99        if (avpkt->size % avctx->channels) {
100            av_log(avctx, AV_LOG_WARNING, "Packet with odd size, ignoring last byte\n");
101        }
102        if (avpkt->size < (hdr_size + 1) * avctx->channels) {
103            av_log(avctx, AV_LOG_ERROR, "packet size is too small\n");
104            return AVERROR(EINVAL);
105        }
106
107        esc->fib_acc[0] = avpkt->data[1] + 128;
108        if (avctx->channels == 2)
109            esc->fib_acc[1] = avpkt->data[2+chan_size+1] + 128;
110
111        esc->data_idx  = 0;
112        esc->data_size = chan_size;
113        if (!(esc->data[0] = av_malloc(chan_size)))
114            return AVERROR(ENOMEM);
115        if (avctx->channels == 2) {
116            if (!(esc->data[1] = av_malloc(chan_size))) {
117                av_freep(&esc->data[0]);
118                return AVERROR(ENOMEM);
119            }
120        }
121        memcpy(esc->data[0], &avpkt->data[hdr_size], chan_size);
122        if (avctx->channels == 2)
123            memcpy(esc->data[1], &avpkt->data[2*hdr_size+chan_size], chan_size);
124    }
125    if (!esc->data[0]) {
126        av_log(avctx, AV_LOG_ERROR, "unexpected empty packet\n");
127        return AVERROR(EINVAL);
128    }
129
130    /* decode next piece of data from the buffer */
131    buf_size = FFMIN(MAX_FRAME_SIZE, esc->data_size - esc->data_idx);
132    if (buf_size <= 0) {
133        *got_frame_ptr = 0;
134        return avpkt->size;
135    }
136
137    /* get output buffer */
138    frame->nb_samples = buf_size * 2;
139    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
140        return ret;
141
142    for (ch = 0; ch < avctx->channels; ch++) {
143        delta_decode(frame->data[ch], &esc->data[ch][esc->data_idx],
144                     buf_size, &esc->fib_acc[ch], esc->table);
145    }
146
147    esc->data_idx += buf_size;
148
149    *got_frame_ptr = 1;
150
151    return ((avctx->frame_number == 0)*hdr_size + buf_size)*avctx->channels;
152}
153
154static av_cold int eightsvx_decode_init(AVCodecContext *avctx)
155{
156    EightSvxContext *esc = avctx->priv_data;
157
158    if (avctx->channels < 1 || avctx->channels > 2) {
159        av_log(avctx, AV_LOG_ERROR, "8SVX does not support more than 2 channels\n");
160        return AVERROR_INVALIDDATA;
161    }
162
163    switch (avctx->codec->id) {
164    case AV_CODEC_ID_8SVX_FIB: esc->table = fibonacci;    break;
165    case AV_CODEC_ID_8SVX_EXP: esc->table = exponential;  break;
166    default:
167        av_log(avctx, AV_LOG_ERROR, "Invalid codec id %d.\n", avctx->codec->id);
168        return AVERROR_INVALIDDATA;
169    }
170    avctx->sample_fmt = AV_SAMPLE_FMT_U8P;
171
172    return 0;
173}
174
175static av_cold int eightsvx_decode_close(AVCodecContext *avctx)
176{
177    EightSvxContext *esc = avctx->priv_data;
178
179    av_freep(&esc->data[0]);
180    av_freep(&esc->data[1]);
181    esc->data_size = 0;
182    esc->data_idx = 0;
183
184    return 0;
185}
186
187#if CONFIG_EIGHTSVX_FIB_DECODER
188AVCodec ff_eightsvx_fib_decoder = {
189  .name           = "8svx_fib",
190  .long_name      = NULL_IF_CONFIG_SMALL("8SVX fibonacci"),
191  .type           = AVMEDIA_TYPE_AUDIO,
192  .id             = AV_CODEC_ID_8SVX_FIB,
193  .priv_data_size = sizeof (EightSvxContext),
194  .init           = eightsvx_decode_init,
195  .decode         = eightsvx_decode_frame,
196  .close          = eightsvx_decode_close,
197  .capabilities   = CODEC_CAP_DR1,
198  .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_U8P,
199                                                    AV_SAMPLE_FMT_NONE },
200};
201#endif
202#if CONFIG_EIGHTSVX_EXP_DECODER
203AVCodec ff_eightsvx_exp_decoder = {
204  .name           = "8svx_exp",
205  .long_name      = NULL_IF_CONFIG_SMALL("8SVX exponential"),
206  .type           = AVMEDIA_TYPE_AUDIO,
207  .id             = AV_CODEC_ID_8SVX_EXP,
208  .priv_data_size = sizeof (EightSvxContext),
209  .init           = eightsvx_decode_init,
210  .decode         = eightsvx_decode_frame,
211  .close          = eightsvx_decode_close,
212  .capabilities   = CODEC_CAP_DR1,
213  .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_U8P,
214                                                    AV_SAMPLE_FMT_NONE },
215};
216#endif
217