libavcodec/nellymoserdec.c
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00001 /*
00002  * NellyMoser audio decoder
00003  * Copyright (c) 2007 a840bda5870ba11f19698ff6eb9581dfb0f95fa5,
00004  *                    539459aeb7d425140b62a3ec7dbf6dc8e408a306, and
00005  *                    520e17cd55896441042b14df2566a6eb610ed444
00006  * Copyright (c) 2007 Loic Minier <lool at dooz.org>
00007  *                    Benjamin Larsson
00008  *
00009  * Permission is hereby granted, free of charge, to any person obtaining a
00010  * copy of this software and associated documentation files (the "Software"),
00011  * to deal in the Software without restriction, including without limitation
00012  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
00013  * and/or sell copies of the Software, and to permit persons to whom the
00014  * Software is furnished to do so, subject to the following conditions:
00015  *
00016  * The above copyright notice and this permission notice shall be included in
00017  * all copies or substantial portions of the Software.
00018  *
00019  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00020  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00021  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
00022  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00023  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
00024  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
00025  * DEALINGS IN THE SOFTWARE.
00026  */
00027 
00034 #include "nellymoser.h"
00035 #include "libavutil/lfg.h"
00036 #include "libavutil/random_seed.h"
00037 #include "libavutil/audioconvert.h"
00038 #include "avcodec.h"
00039 #include "internal.h"
00040 #include "dsputil.h"
00041 #include "fft.h"
00042 #include "fmtconvert.h"
00043 #include "sinewin.h"
00044 
00045 #define BITSTREAM_READER_LE
00046 #include "get_bits.h"
00047 
00048 
00049 typedef struct NellyMoserDecodeContext {
00050     AVCodecContext* avctx;
00051     AVFrame         frame;
00052     float          *float_buf;
00053     DECLARE_ALIGNED(16, float, state)[NELLY_BUF_LEN];
00054     AVLFG           random_state;
00055     GetBitContext   gb;
00056     float           scale_bias;
00057     DSPContext      dsp;
00058     FFTContext      imdct_ctx;
00059     FmtConvertContext fmt_conv;
00060     DECLARE_ALIGNED(32, float, imdct_out)[NELLY_BUF_LEN * 2];
00061 } NellyMoserDecodeContext;
00062 
00063 static void nelly_decode_block(NellyMoserDecodeContext *s,
00064                                const unsigned char block[NELLY_BLOCK_LEN],
00065                                float audio[NELLY_SAMPLES])
00066 {
00067     int i,j;
00068     float buf[NELLY_FILL_LEN], pows[NELLY_FILL_LEN];
00069     float *aptr, *bptr, *pptr, val, pval;
00070     int bits[NELLY_BUF_LEN];
00071     unsigned char v;
00072 
00073     init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);
00074 
00075     bptr = buf;
00076     pptr = pows;
00077     val = ff_nelly_init_table[get_bits(&s->gb, 6)];
00078     for (i=0 ; i<NELLY_BANDS ; i++) {
00079         if (i > 0)
00080             val += ff_nelly_delta_table[get_bits(&s->gb, 5)];
00081         pval = -pow(2, val/2048) * s->scale_bias;
00082         for (j = 0; j < ff_nelly_band_sizes_table[i]; j++) {
00083             *bptr++ = val;
00084             *pptr++ = pval;
00085         }
00086 
00087     }
00088 
00089     ff_nelly_get_sample_bits(buf, bits);
00090 
00091     for (i = 0; i < 2; i++) {
00092         aptr = audio + i * NELLY_BUF_LEN;
00093 
00094         init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);
00095         skip_bits_long(&s->gb, NELLY_HEADER_BITS + i*NELLY_DETAIL_BITS);
00096 
00097         for (j = 0; j < NELLY_FILL_LEN; j++) {
00098             if (bits[j] <= 0) {
00099                 aptr[j] = M_SQRT1_2*pows[j];
00100                 if (av_lfg_get(&s->random_state) & 1)
00101                     aptr[j] *= -1.0;
00102             } else {
00103                 v = get_bits(&s->gb, bits[j]);
00104                 aptr[j] = ff_nelly_dequantization_table[(1<<bits[j])-1+v]*pows[j];
00105             }
00106         }
00107         memset(&aptr[NELLY_FILL_LEN], 0,
00108                (NELLY_BUF_LEN - NELLY_FILL_LEN) * sizeof(float));
00109 
00110         s->imdct_ctx.imdct_calc(&s->imdct_ctx, s->imdct_out, aptr);
00111         /* XXX: overlapping and windowing should be part of a more
00112            generic imdct function */
00113         s->dsp.vector_fmul_reverse(s->state, s->state, ff_sine_128, NELLY_BUF_LEN);
00114         s->dsp.vector_fmul_add(aptr, s->imdct_out, ff_sine_128, s->state, NELLY_BUF_LEN);
00115         memcpy(s->state, s->imdct_out + NELLY_BUF_LEN, sizeof(float)*NELLY_BUF_LEN);
00116     }
00117 }
00118 
00119 static av_cold int decode_init(AVCodecContext * avctx) {
00120     NellyMoserDecodeContext *s = avctx->priv_data;
00121 
00122     s->avctx = avctx;
00123     av_lfg_init(&s->random_state, 0);
00124     ff_mdct_init(&s->imdct_ctx, 8, 1, 1.0);
00125 
00126     dsputil_init(&s->dsp, avctx);
00127 
00128     if (avctx->request_sample_fmt == AV_SAMPLE_FMT_FLT) {
00129         s->scale_bias = 1.0/(32768*8);
00130         avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
00131     } else {
00132         s->scale_bias = 1.0/(1*8);
00133         avctx->sample_fmt = AV_SAMPLE_FMT_S16;
00134         ff_fmt_convert_init(&s->fmt_conv, avctx);
00135         s->float_buf = av_mallocz(NELLY_SAMPLES * sizeof(*s->float_buf));
00136         if (!s->float_buf) {
00137             av_log(avctx, AV_LOG_ERROR, "error allocating float buffer\n");
00138             return AVERROR(ENOMEM);
00139         }
00140     }
00141 
00142     /* Generate overlap window */
00143     if (!ff_sine_128[127])
00144         ff_init_ff_sine_windows(7);
00145 
00146     avctx->channel_layout = AV_CH_LAYOUT_MONO;
00147 
00148     avcodec_get_frame_defaults(&s->frame);
00149     avctx->coded_frame = &s->frame;
00150 
00151     return 0;
00152 }
00153 
00154 static int decode_tag(AVCodecContext *avctx, void *data,
00155                       int *got_frame_ptr, AVPacket *avpkt)
00156 {
00157     const uint8_t *buf = avpkt->data;
00158     int buf_size = avpkt->size;
00159     NellyMoserDecodeContext *s = avctx->priv_data;
00160     int blocks, i, ret;
00161     int16_t *samples_s16;
00162     float   *samples_flt;
00163 
00164     blocks     = buf_size / NELLY_BLOCK_LEN;
00165     if (blocks <= 0) {
00166         av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
00167         return AVERROR_INVALIDDATA;
00168     }
00169     if (buf_size % NELLY_BLOCK_LEN) {
00170         av_log(avctx, AV_LOG_WARNING, "Leftover bytes: %d.\n",
00171                buf_size % NELLY_BLOCK_LEN);
00172     }
00173     /* Normal numbers of blocks for sample rates:
00174      *  8000 Hz - 1
00175      * 11025 Hz - 2
00176      * 16000 Hz - 3
00177      * 22050 Hz - 4
00178      * 44100 Hz - 8
00179      */
00180 
00181     /* get output buffer */
00182     s->frame.nb_samples = NELLY_SAMPLES * blocks;
00183     if ((ret = ff_get_buffer(avctx, &s->frame)) < 0) {
00184         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00185         return ret;
00186     }
00187     samples_s16 = (int16_t *)s->frame.data[0];
00188     samples_flt = (float   *)s->frame.data[0];
00189 
00190     for (i=0 ; i<blocks ; i++) {
00191         if (avctx->sample_fmt == AV_SAMPLE_FMT_FLT) {
00192             nelly_decode_block(s, buf, samples_flt);
00193             samples_flt += NELLY_SAMPLES;
00194         } else {
00195             nelly_decode_block(s, buf, s->float_buf);
00196             s->fmt_conv.float_to_int16(samples_s16, s->float_buf, NELLY_SAMPLES);
00197             samples_s16 += NELLY_SAMPLES;
00198         }
00199         buf += NELLY_BLOCK_LEN;
00200     }
00201 
00202     *got_frame_ptr   = 1;
00203     *(AVFrame *)data = s->frame;
00204 
00205     return buf_size;
00206 }
00207 
00208 static av_cold int decode_end(AVCodecContext * avctx) {
00209     NellyMoserDecodeContext *s = avctx->priv_data;
00210 
00211     av_freep(&s->float_buf);
00212     ff_mdct_end(&s->imdct_ctx);
00213 
00214     return 0;
00215 }
00216 
00217 AVCodec ff_nellymoser_decoder = {
00218     .name           = "nellymoser",
00219     .type           = AVMEDIA_TYPE_AUDIO,
00220     .id             = CODEC_ID_NELLYMOSER,
00221     .priv_data_size = sizeof(NellyMoserDecodeContext),
00222     .init           = decode_init,
00223     .close          = decode_end,
00224     .decode         = decode_tag,
00225     .capabilities   = CODEC_CAP_DR1 | CODEC_CAP_PARAM_CHANGE,
00226     .long_name = NULL_IF_CONFIG_SMALL("Nellymoser Asao"),
00227     .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLT,
00228                                                       AV_SAMPLE_FMT_S16,
00229                                                       AV_SAMPLE_FMT_NONE },
00230 };
00231