PeerStreamer

/*

 * NellyMoser audio decoder

 * Copyright (c) 2007 a840bda5870ba11f19698ff6eb9581dfb0f95fa5,

 *                    539459aeb7d425140b62a3ec7dbf6dc8e408a306, and

 *                    520e17cd55896441042b14df2566a6eb610ed444

 * Copyright (c) 2007 Loic Minier <lool at dooz.org>

 *                    Benjamin Larsson

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the "Software"),

 * to deal in the Software without restriction, including without limitation

 * the rights to use, copy, modify, merge, publish, distribute, sublicense,

 * and/or sell copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

 * DEALINGS IN THE SOFTWARE.

 */

/**

 * @file

 * The 3 alphanumeric copyright notices are md5summed they are from the original

 * implementors. The original code is available from http://code.google.com/p/nelly2pcm/

 */

#include "nellymoser.h"

#include "libavutil/lfg.h"

#include "libavutil/random_seed.h"

#include "libavcore/audioconvert.h"

#include "avcodec.h"

#include "dsputil.h"

#include "fft.h"

#define ALT_BITSTREAM_READER_LE

#include "get_bits.h"

typedef struct NellyMoserDecodeContext {

    AVCodecContext* avctx;

    DECLARE_ALIGNED(16, float,float_buf)[NELLY_SAMPLES];

    float           state[128];

    AVLFG           random_state;

    GetBitContext   gb;

    float           scale_bias;

    DSPContext      dsp;

    FFTContext      imdct_ctx;

    DECLARE_ALIGNED(16, float,imdct_out)[NELLY_BUF_LEN * 2];

} NellyMoserDecodeContext;

static void overlap_and_window(NellyMoserDecodeContext *s, float *state, float *audio, float *a_in)

{

    int bot, top;

    bot = 0;

    top = NELLY_BUF_LEN-1;

    while (bot < NELLY_BUF_LEN) {

        audio[bot] = a_in [bot]*ff_sine_128[bot]

                    +state[bot]*ff_sine_128[top];

        bot++;

        top--;

    }

    memcpy(state, a_in + NELLY_BUF_LEN, sizeof(float)*NELLY_BUF_LEN);

}

static void nelly_decode_block(NellyMoserDecodeContext *s,

                               const unsigned char block[NELLY_BLOCK_LEN],

                               float audio[NELLY_SAMPLES])

{

    int i,j;

    float buf[NELLY_FILL_LEN], pows[NELLY_FILL_LEN];

    float *aptr, *bptr, *pptr, val, pval;

    int bits[NELLY_BUF_LEN];

    unsigned char v;

    init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);

    bptr = buf;

    pptr = pows;

    val = ff_nelly_init_table[get_bits(&s->gb, 6)];

    for (i=0 ; i<NELLY_BANDS ; i++) {

        if (i > 0)

            val += ff_nelly_delta_table[get_bits(&s->gb, 5)];

        pval = -pow(2, val/2048) * s->scale_bias;

        for (j = 0; j < ff_nelly_band_sizes_table[i]; j++) {

            *bptr++ = val;

            *pptr++ = pval;

        }

    }

    ff_nelly_get_sample_bits(buf, bits);

    for (i = 0; i < 2; i++) {

        aptr = audio + i * NELLY_BUF_LEN;

        init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);

        skip_bits_long(&s->gb, NELLY_HEADER_BITS + i*NELLY_DETAIL_BITS);

        for (j = 0; j < NELLY_FILL_LEN; j++) {

            if (bits[j] <= 0) {

                aptr[j] = M_SQRT1_2*pows[j];

                if (av_lfg_get(&s->random_state) & 1)

                    aptr[j] *= -1.0;

            } else {

                v = get_bits(&s->gb, bits[j]);

                aptr[j] = ff_nelly_dequantization_table[(1<<bits[j])-1+v]*pows[j];

            }

        }

        memset(&aptr[NELLY_FILL_LEN], 0,

               (NELLY_BUF_LEN - NELLY_FILL_LEN) * sizeof(float));

        ff_imdct_calc(&s->imdct_ctx, s->imdct_out, aptr);

        /* XXX: overlapping and windowing should be part of a more

           generic imdct function */

        overlap_and_window(s, s->state, aptr, s->imdct_out);

    }

}

static av_cold int decode_init(AVCodecContext * avctx) {

    NellyMoserDecodeContext *s = avctx->priv_data;

    s->avctx = avctx;

    av_lfg_init(&s->random_state, 0);

    ff_mdct_init(&s->imdct_ctx, 8, 1, 1.0);

    dsputil_init(&s->dsp, avctx);

    s->scale_bias = 1.0/(1*8);

    /* Generate overlap window */

    if (!ff_sine_128[127])

        ff_init_ff_sine_windows(7);

    avctx->sample_fmt = AV_SAMPLE_FMT_S16;

    avctx->channel_layout = AV_CH_LAYOUT_MONO;

    return 0;

}

static int decode_tag(AVCodecContext * avctx,

                      void *data, int *data_size,

                      AVPacket *avpkt) {

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    NellyMoserDecodeContext *s = avctx->priv_data;

    int blocks, i;

    int16_t* samples;

    *data_size = 0;

    samples = (int16_t*)data;

    if (buf_size < avctx->block_align)

        return buf_size;

    if (buf_size % 64) {

        av_log(avctx, AV_LOG_ERROR, "Tag size %d.\n", buf_size);

        return buf_size;

    }

    blocks = buf_size / 64;

    /* Normal numbers of blocks for sample rates:

     *  8000 Hz - 1

     * 11025 Hz - 2

     * 16000 Hz - 3

     * 22050 Hz - 4

     * 44100 Hz - 8

     */

    for (i=0 ; i<blocks ; i++) {

        nelly_decode_block(s, &buf[i*NELLY_BLOCK_LEN], s->float_buf);

        s->dsp.float_to_int16(&samples[i*NELLY_SAMPLES], s->float_buf, NELLY_SAMPLES);

        *data_size += NELLY_SAMPLES*sizeof(int16_t);

    }

    return buf_size;

}

static av_cold int decode_end(AVCodecContext * avctx) {

    NellyMoserDecodeContext *s = avctx->priv_data;

    ff_mdct_end(&s->imdct_ctx);

    return 0;

}

AVCodec ff_nellymoser_decoder = {

    "nellymoser",

    AVMEDIA_TYPE_AUDIO,

    CODEC_ID_NELLYMOSER,

    sizeof(NellyMoserDecodeContext),

    decode_init,

    NULL,

    decode_end,

    decode_tag,

    .long_name = NULL_IF_CONFIG_SMALL("Nellymoser Asao"),

};