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 "libavutil/channel_layout.h"
35 #include "libavutil/float_dsp.h"
36 #include "libavutil/lfg.h"
37 #include "libavutil/mem_internal.h"
38 #include "libavutil/random_seed.h"
39 
40 #define BITSTREAM_READER_LE
41 #include "avcodec.h"
42 #include "codec_internal.h"
43 #include "fft.h"
44 #include "get_bits.h"
45 #include "internal.h"
46 #include "nellymoser.h"
47 #include "sinewin.h"
48 
49 
50 typedef struct NellyMoserDecodeContext {
51     AVCodecContext* avctx;
52     AVLFG           random_state;
53     GetBitContext   gb;
54     float           scale_bias;
55     AVFloatDSPContext *fdsp;
56     FFTContext      imdct_ctx;
57     DECLARE_ALIGNED(32, float, imdct_buf)[2][NELLY_BUF_LEN];
58     float          *imdct_out;
59     float          *imdct_prev;
60 } NellyMoserDecodeContext;
61 
nelly_decode_block(NellyMoserDecodeContext *s, const unsigned char block[NELLY_BLOCK_LEN], float audio[NELLY_SAMPLES])62 static void nelly_decode_block(NellyMoserDecodeContext *s,
63                                const unsigned char block[NELLY_BLOCK_LEN],
64                                float audio[NELLY_SAMPLES])
65 {
66     int i,j;
67     float buf[NELLY_FILL_LEN], pows[NELLY_FILL_LEN];
68     float *aptr, *bptr, *pptr, val, pval;
69     int bits[NELLY_BUF_LEN];
70     unsigned char v;
71 
72     init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);
73 
74     bptr = buf;
75     pptr = pows;
76     val = ff_nelly_init_table[get_bits(&s->gb, 6)];
77     for (i=0 ; i<NELLY_BANDS ; i++) {
78         if (i > 0)
79             val += ff_nelly_delta_table[get_bits(&s->gb, 5)];
80         pval = -exp2(val/2048) * s->scale_bias;
81         for (j = 0; j < ff_nelly_band_sizes_table[i]; j++) {
82             *bptr++ = val;
83             *pptr++ = pval;
84         }
85 
86     }
87 
88     ff_nelly_get_sample_bits(buf, bits);
89 
90     for (i = 0; i < 2; i++) {
91         aptr = audio + i * NELLY_BUF_LEN;
92 
93         init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);
94         skip_bits_long(&s->gb, NELLY_HEADER_BITS + i*NELLY_DETAIL_BITS);
95 
96         for (j = 0; j < NELLY_FILL_LEN; j++) {
97             if (bits[j] <= 0) {
98                 aptr[j] = M_SQRT1_2*pows[j];
99                 if (av_lfg_get(&s->random_state) & 1)
100                     aptr[j] *= -1.0;
101             } else {
102                 v = get_bits(&s->gb, bits[j]);
103                 aptr[j] = ff_nelly_dequantization_table[(1<<bits[j])-1+v]*pows[j];
104             }
105         }
106         memset(&aptr[NELLY_FILL_LEN], 0,
107                (NELLY_BUF_LEN - NELLY_FILL_LEN) * sizeof(float));
108 
109         s->imdct_ctx.imdct_half(&s->imdct_ctx, s->imdct_out, aptr);
110         s->fdsp->vector_fmul_window(aptr, s->imdct_prev + NELLY_BUF_LEN / 2,
111                                    s->imdct_out, ff_sine_128,
112                                    NELLY_BUF_LEN / 2);
113         FFSWAP(float *, s->imdct_out, s->imdct_prev);
114     }
115 }
116 
decode_init(AVCodecContext * avctx)117 static av_cold int decode_init(AVCodecContext * avctx) {
118     NellyMoserDecodeContext *s = avctx->priv_data;
119 
120     s->avctx = avctx;
121     s->imdct_out = s->imdct_buf[0];
122     s->imdct_prev = s->imdct_buf[1];
123     av_lfg_init(&s->random_state, 0);
124     ff_mdct_init(&s->imdct_ctx, 8, 1, 1.0);
125 
126     s->fdsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT);
127     if (!s->fdsp)
128         return AVERROR(ENOMEM);
129 
130     s->scale_bias = 1.0/(32768*8);
131     avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
132 
133     av_channel_layout_uninit(&avctx->ch_layout);
134     avctx->ch_layout      = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;
135 
136     /* Generate overlap window */
137     ff_init_ff_sine_windows(7);
138 
139     return 0;
140 }
141 
decode_tag(AVCodecContext *avctx, AVFrame *frame, int *got_frame_ptr, AVPacket *avpkt)142 static int decode_tag(AVCodecContext *avctx, AVFrame *frame,
143                       int *got_frame_ptr, AVPacket *avpkt)
144 {
145     const uint8_t *buf = avpkt->data;
146     int buf_size = avpkt->size;
147     NellyMoserDecodeContext *s = avctx->priv_data;
148     int blocks, i, ret;
149     float   *samples_flt;
150 
151     blocks     = buf_size / NELLY_BLOCK_LEN;
152 
153     if (blocks <= 0) {
154         av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
155         return AVERROR_INVALIDDATA;
156     }
157 
158     if (buf_size % NELLY_BLOCK_LEN) {
159         av_log(avctx, AV_LOG_WARNING, "Leftover bytes: %d.\n",
160                buf_size % NELLY_BLOCK_LEN);
161     }
162 
163     /* get output buffer */
164     frame->nb_samples = NELLY_SAMPLES * blocks;
165     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
166         return ret;
167     samples_flt = (float *)frame->data[0];
168 
169     for (i=0 ; i<blocks ; i++) {
170         nelly_decode_block(s, buf, samples_flt);
171         samples_flt += NELLY_SAMPLES;
172         buf += NELLY_BLOCK_LEN;
173     }
174 
175     *got_frame_ptr = 1;
176 
177     return buf_size;
178 }
179 
decode_end(AVCodecContext * avctx)180 static av_cold int decode_end(AVCodecContext * avctx) {
181     NellyMoserDecodeContext *s = avctx->priv_data;
182 
183     ff_mdct_end(&s->imdct_ctx);
184     av_freep(&s->fdsp);
185 
186     return 0;
187 }
188 
189 const FFCodec ff_nellymoser_decoder = {
190     .p.name         = "nellymoser",
191     .p.long_name    = NULL_IF_CONFIG_SMALL("Nellymoser Asao"),
192     .p.type         = AVMEDIA_TYPE_AUDIO,
193     .p.id           = AV_CODEC_ID_NELLYMOSER,
194     .priv_data_size = sizeof(NellyMoserDecodeContext),
195     .init           = decode_init,
196     .close          = decode_end,
197     FF_CODEC_DECODE_CB(decode_tag),
198     .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_PARAM_CHANGE | AV_CODEC_CAP_CHANNEL_CONF,
199     .p.sample_fmts  = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLT,
200                                                       AV_SAMPLE_FMT_NONE },
201     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
202 };
203