1/*
2 * NellyMoser audio decoder
3 * Copyright (c) 2007 a840bda5870ba11f19698ff6eb9581dfb0f95fa5,
4 *                    539459aeb7d425140b62a3ec7dbf6dc8e408a306, and
5 *                    520e17cd55896441042b14df2566a6eb610ed444
6 * Copyright (c) 2007 Loic Minier <lool at dooz.org>
7 *                    Benjamin Larsson
8 *
9 * Permission is hereby granted, free of charge, to any person obtaining a
10 * copy of this software and associated documentation files (the "Software"),
11 * to deal in the Software without restriction, including without limitation
12 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
13 * and/or sell copies of the Software, and to permit persons to whom the
14 * Software is furnished to do so, subject to the following conditions:
15 *
16 * The above copyright notice and this permission notice shall be included in
17 * all copies or substantial portions of the Software.
18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
22 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
24 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
25 * DEALINGS IN THE SOFTWARE.
26 */
27
28/**
29 * @file
30 * The 3 alphanumeric copyright notices are md5summed they are from the original
31 * implementors. The original code is available from http://code.google.com/p/nelly2pcm/
32 */
33
34#include "nellymoser.h"
35#include "libavutil/lfg.h"
36#include "libavutil/random_seed.h"
37#include "avcodec.h"
38#include "dsputil.h"
39#include "fft.h"
40
41#define ALT_BITSTREAM_READER_LE
42#include "get_bits.h"
43
44
45typedef struct NellyMoserDecodeContext {
46    AVCodecContext* avctx;
47    DECLARE_ALIGNED(16, float,float_buf)[NELLY_SAMPLES];
48    float           state[128];
49    AVLFG           random_state;
50    GetBitContext   gb;
51    int             add_bias;
52    float           scale_bias;
53    DSPContext      dsp;
54    FFTContext      imdct_ctx;
55    DECLARE_ALIGNED(16, float,imdct_out)[NELLY_BUF_LEN * 2];
56} NellyMoserDecodeContext;
57
58static void overlap_and_window(NellyMoserDecodeContext *s, float *state, float *audio, float *a_in)
59{
60    int bot, top;
61
62    bot = 0;
63    top = NELLY_BUF_LEN-1;
64
65    while (bot < NELLY_BUF_LEN) {
66        audio[bot] = a_in [bot]*ff_sine_128[bot]
67                    +state[bot]*ff_sine_128[top] + s->add_bias;
68
69        bot++;
70        top--;
71    }
72    memcpy(state, a_in + NELLY_BUF_LEN, sizeof(float)*NELLY_BUF_LEN);
73}
74
75static void nelly_decode_block(NellyMoserDecodeContext *s,
76                               const unsigned char block[NELLY_BLOCK_LEN],
77                               float audio[NELLY_SAMPLES])
78{
79    int i,j;
80    float buf[NELLY_FILL_LEN], pows[NELLY_FILL_LEN];
81    float *aptr, *bptr, *pptr, val, pval;
82    int bits[NELLY_BUF_LEN];
83    unsigned char v;
84
85    init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);
86
87    bptr = buf;
88    pptr = pows;
89    val = ff_nelly_init_table[get_bits(&s->gb, 6)];
90    for (i=0 ; i<NELLY_BANDS ; i++) {
91        if (i > 0)
92            val += ff_nelly_delta_table[get_bits(&s->gb, 5)];
93        pval = -pow(2, val/2048) * s->scale_bias;
94        for (j = 0; j < ff_nelly_band_sizes_table[i]; j++) {
95            *bptr++ = val;
96            *pptr++ = pval;
97        }
98
99    }
100
101    ff_nelly_get_sample_bits(buf, bits);
102
103    for (i = 0; i < 2; i++) {
104        aptr = audio + i * NELLY_BUF_LEN;
105
106        init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);
107        skip_bits_long(&s->gb, NELLY_HEADER_BITS + i*NELLY_DETAIL_BITS);
108
109        for (j = 0; j < NELLY_FILL_LEN; j++) {
110            if (bits[j] <= 0) {
111                aptr[j] = M_SQRT1_2*pows[j];
112                if (av_lfg_get(&s->random_state) & 1)
113                    aptr[j] *= -1.0;
114            } else {
115                v = get_bits(&s->gb, bits[j]);
116                aptr[j] = ff_nelly_dequantization_table[(1<<bits[j])-1+v]*pows[j];
117            }
118        }
119        memset(&aptr[NELLY_FILL_LEN], 0,
120               (NELLY_BUF_LEN - NELLY_FILL_LEN) * sizeof(float));
121
122        ff_imdct_calc(&s->imdct_ctx, s->imdct_out, aptr);
123        /* XXX: overlapping and windowing should be part of a more
124           generic imdct function */
125        overlap_and_window(s, s->state, aptr, s->imdct_out);
126    }
127}
128
129static av_cold int decode_init(AVCodecContext * avctx) {
130    NellyMoserDecodeContext *s = avctx->priv_data;
131
132    s->avctx = avctx;
133    av_lfg_init(&s->random_state, 0);
134    ff_mdct_init(&s->imdct_ctx, 8, 1, 1.0);
135
136    dsputil_init(&s->dsp, avctx);
137
138    if(s->dsp.float_to_int16 == ff_float_to_int16_c) {
139        s->add_bias = 385;
140        s->scale_bias = 1.0/(8*32768);
141    } else {
142        s->add_bias = 0;
143        s->scale_bias = 1.0/(1*8);
144    }
145
146    /* Generate overlap window */
147    if (!ff_sine_128[127])
148        ff_init_ff_sine_windows(7);
149
150    avctx->sample_fmt = SAMPLE_FMT_S16;
151    avctx->channel_layout = CH_LAYOUT_MONO;
152    return 0;
153}
154
155static int decode_tag(AVCodecContext * avctx,
156                      void *data, int *data_size,
157                      AVPacket *avpkt) {
158    const uint8_t *buf = avpkt->data;
159    int buf_size = avpkt->size;
160    NellyMoserDecodeContext *s = avctx->priv_data;
161    int blocks, i;
162    int16_t* samples;
163    *data_size = 0;
164    samples = (int16_t*)data;
165
166    if (buf_size < avctx->block_align)
167        return buf_size;
168
169    switch (buf_size) {
170        case 64:    // 8000Hz
171            blocks = 1; break;
172        case 128:   // 11025Hz
173            blocks = 2; break;
174        case 192:   // 16000Hz
175            blocks = 3; break;
176        case 256:   // 22050Hz
177            blocks = 4; break;
178        case 512:   // 44100Hz
179            blocks = 8; break;
180        default:
181            av_log(avctx, AV_LOG_DEBUG, "Tag size %d.\n", buf_size);
182            return buf_size;
183    }
184
185    for (i=0 ; i<blocks ; i++) {
186        nelly_decode_block(s, &buf[i*NELLY_BLOCK_LEN], s->float_buf);
187        s->dsp.float_to_int16(&samples[i*NELLY_SAMPLES], s->float_buf, NELLY_SAMPLES);
188        *data_size += NELLY_SAMPLES*sizeof(int16_t);
189    }
190
191    return buf_size;
192}
193
194static av_cold int decode_end(AVCodecContext * avctx) {
195    NellyMoserDecodeContext *s = avctx->priv_data;
196
197    ff_mdct_end(&s->imdct_ctx);
198    return 0;
199}
200
201AVCodec nellymoser_decoder = {
202    "nellymoser",
203    AVMEDIA_TYPE_AUDIO,
204    CODEC_ID_NELLYMOSER,
205    sizeof(NellyMoserDecodeContext),
206    decode_init,
207    NULL,
208    decode_end,
209    decode_tag,
210    .long_name = NULL_IF_CONFIG_SMALL("Nellymoser Asao"),
211};
212
213