PeerStreamer

/*

 * TTA (The Lossless True Audio) decoder

 * Copyright (c) 2006 Alex Beregszaszi

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file

 * TTA (The Lossless True Audio) decoder

 * (www.true-audio.com or tta.corecodec.org)

 * @author Alex Beregszaszi

 *

 */

#define ALT_BITSTREAM_READER_LE

//#define DEBUG

#include <limits.h>

#include "avcodec.h"

#include "get_bits.h"

#define FORMAT_INT 1

#define FORMAT_FLOAT 3

#define MAX_ORDER 16

typedef struct TTAFilter {

    int32_t shift, round, error, mode;

    int32_t qm[MAX_ORDER];

    int32_t dx[MAX_ORDER];

    int32_t dl[MAX_ORDER];

} TTAFilter;

typedef struct TTARice {

    uint32_t k0, k1, sum0, sum1;

} TTARice;

typedef struct TTAChannel {

    int32_t predictor;

    TTAFilter filter;

    TTARice rice;

} TTAChannel;

typedef struct TTAContext {

    AVCodecContext *avctx;

    GetBitContext gb;

    int flags, channels, bps, is_float, data_length;

    int frame_length, last_frame_length, total_frames;

    int32_t *decode_buffer;

    TTAChannel *ch_ctx;

} TTAContext;

#if 0

static inline int shift_1(int i)

{

    if (i < 32)

        return 1 << i;

    else

        return 0x80000000; // 16 << 31

}

static inline int shift_16(int i)

{

    if (i < 28)

        return 16 << i;

    else

        return 0x80000000; // 16 << 27

}

#else

static const uint32_t shift_1[] = {

    0x00000001, 0x00000002, 0x00000004, 0x00000008,

    0x00000010, 0x00000020, 0x00000040, 0x00000080,

    0x00000100, 0x00000200, 0x00000400, 0x00000800,

    0x00001000, 0x00002000, 0x00004000, 0x00008000,

    0x00010000, 0x00020000, 0x00040000, 0x00080000,

    0x00100000, 0x00200000, 0x00400000, 0x00800000,

    0x01000000, 0x02000000, 0x04000000, 0x08000000,

    0x10000000, 0x20000000, 0x40000000, 0x80000000,

    0x80000000, 0x80000000, 0x80000000, 0x80000000,

    0x80000000, 0x80000000, 0x80000000, 0x80000000

};

static const uint32_t * const shift_16 = shift_1 + 4;

#endif

static const int32_t ttafilter_configs[4][2] = {

    {10, 1},

    {9, 1},

    {10, 1},

    {12, 0}

};

static void ttafilter_init(TTAFilter *c, int32_t shift, int32_t mode) {

    memset(c, 0, sizeof(TTAFilter));

    c->shift = shift;

   c->round = shift_1[shift-1];

//    c->round = 1 << (shift - 1);

    c->mode = mode;

}

// FIXME: copy paste from original

static inline void memshl(register int32_t *a, register int32_t *b) {

    *a++ = *b++;

    *a++ = *b++;

    *a++ = *b++;

    *a++ = *b++;

    *a++ = *b++;

    *a++ = *b++;

    *a++ = *b++;

    *a = *b;

}

// FIXME: copy paste from original

// mode=1 encoder, mode=0 decoder

static inline void ttafilter_process(TTAFilter *c, int32_t *in, int32_t mode) {

    register int32_t *dl = c->dl, *qm = c->qm, *dx = c->dx, sum = c->round;

    if (!c->error) {

        sum += *dl++ * *qm, qm++;

        sum += *dl++ * *qm, qm++;

        sum += *dl++ * *qm, qm++;

        sum += *dl++ * *qm, qm++;

        sum += *dl++ * *qm, qm++;

        sum += *dl++ * *qm, qm++;

        sum += *dl++ * *qm, qm++;

        sum += *dl++ * *qm, qm++;

        dx += 8;

    } else if(c->error < 0) {

        sum += *dl++ * (*qm -= *dx++), qm++;

        sum += *dl++ * (*qm -= *dx++), qm++;

        sum += *dl++ * (*qm -= *dx++), qm++;

        sum += *dl++ * (*qm -= *dx++), qm++;

        sum += *dl++ * (*qm -= *dx++), qm++;

        sum += *dl++ * (*qm -= *dx++), qm++;

        sum += *dl++ * (*qm -= *dx++), qm++;

        sum += *dl++ * (*qm -= *dx++), qm++;

    } else {

        sum += *dl++ * (*qm += *dx++), qm++;

        sum += *dl++ * (*qm += *dx++), qm++;

        sum += *dl++ * (*qm += *dx++), qm++;

        sum += *dl++ * (*qm += *dx++), qm++;

        sum += *dl++ * (*qm += *dx++), qm++;

        sum += *dl++ * (*qm += *dx++), qm++;

        sum += *dl++ * (*qm += *dx++), qm++;

        sum += *dl++ * (*qm += *dx++), qm++;

    }

    *(dx-0) = ((*(dl-1) >> 30) | 1) << 2;

    *(dx-1) = ((*(dl-2) >> 30) | 1) << 1;

    *(dx-2) = ((*(dl-3) >> 30) | 1) << 1;

    *(dx-3) = ((*(dl-4) >> 30) | 1);

    // compress

    if (mode) {

        *dl = *in;

        *in -= (sum >> c->shift);

        c->error = *in;

    } else {

        c->error = *in;

        *in += (sum >> c->shift);

        *dl = *in;

    }

    if (c->mode) {

        *(dl-1) = *dl - *(dl-1);

        *(dl-2) = *(dl-1) - *(dl-2);

        *(dl-3) = *(dl-2) - *(dl-3);

    }

    memshl(c->dl, c->dl + 1);

    memshl(c->dx, c->dx + 1);

}

static void rice_init(TTARice *c, uint32_t k0, uint32_t k1)

{

    c->k0 = k0;

    c->k1 = k1;

    c->sum0 = shift_16[k0];

    c->sum1 = shift_16[k1];

}

static int tta_get_unary(GetBitContext *gb)

{

    int ret = 0;

    // count ones

    while(get_bits1(gb))

        ret++;

    return ret;

}

static const int64_t tta_channel_layouts[7] = {

    AV_CH_LAYOUT_STEREO,

    AV_CH_LAYOUT_STEREO|AV_CH_LOW_FREQUENCY,

    AV_CH_LAYOUT_QUAD,

    0,

    AV_CH_LAYOUT_5POINT1_BACK,

    AV_CH_LAYOUT_5POINT1_BACK|AV_CH_BACK_CENTER,

    AV_CH_LAYOUT_7POINT1_WIDE

};

static av_cold int tta_decode_init(AVCodecContext * avctx)

{

    TTAContext *s = avctx->priv_data;

    int i;

    s->avctx = avctx;

    // 30bytes includes a seektable with one frame

    if (avctx->extradata_size < 30)

        return -1;

    init_get_bits(&s->gb, avctx->extradata, avctx->extradata_size);

    if (show_bits_long(&s->gb, 32) == AV_RL32("TTA1"))

    {

        /* signature */

        skip_bits(&s->gb, 32);

//        if (get_bits_long(&s->gb, 32) != av_bswap32(AV_RL32("TTA1"))) {

//            av_log(s->avctx, AV_LOG_ERROR, "Missing magic\n");

//            return -1;

//        }

        s->flags = get_bits(&s->gb, 16);

        if (s->flags != 1 && s->flags != 3)

        {

            av_log(s->avctx, AV_LOG_ERROR, "Invalid flags\n");

            return -1;

        }

        s->is_float = (s->flags == FORMAT_FLOAT);

        avctx->channels = s->channels = get_bits(&s->gb, 16);

        if (s->channels > 1 && s->channels < 9)

            avctx->channel_layout = tta_channel_layouts[s->channels-2];

        avctx->bits_per_coded_sample = get_bits(&s->gb, 16);

        s->bps = (avctx->bits_per_coded_sample + 7) / 8;

        avctx->sample_rate = get_bits_long(&s->gb, 32);

        if(avctx->sample_rate > 1000000){ //prevent FRAME_TIME * avctx->sample_rate from overflowing and sanity check

            av_log(avctx, AV_LOG_ERROR, "sample_rate too large\n");

            return -1;

        }

        s->data_length = get_bits_long(&s->gb, 32);

        skip_bits(&s->gb, 32); // CRC32 of header

        if (s->is_float)

        {

            avctx->sample_fmt = AV_SAMPLE_FMT_FLT;

            av_log_ask_for_sample(s->avctx, "Unsupported sample format.\n");

            return -1;

        }

        else switch(s->bps) {

            case 1: avctx->sample_fmt = AV_SAMPLE_FMT_U8; break;

            case 2: avctx->sample_fmt = AV_SAMPLE_FMT_S16; break;

//            case 3: avctx->sample_fmt = AV_SAMPLE_FMT_S24; break;

            case 4: avctx->sample_fmt = AV_SAMPLE_FMT_S32; break;

            default:

                av_log_ask_for_sample(s->avctx,

                                      "Invalid/unsupported sample format.\n");

                return -1;

        }

        // FIXME: horribly broken, but directly from reference source

#define FRAME_TIME 1.04489795918367346939

        s->frame_length = (int)(FRAME_TIME * avctx->sample_rate);

        s->last_frame_length = s->data_length % s->frame_length;

        s->total_frames = s->data_length / s->frame_length +

                        (s->last_frame_length ? 1 : 0);

        av_log(s->avctx, AV_LOG_DEBUG, "flags: %x chans: %d bps: %d rate: %d block: %d\n",

            s->flags, avctx->channels, avctx->bits_per_coded_sample, avctx->sample_rate,

            avctx->block_align);

        av_log(s->avctx, AV_LOG_DEBUG, "data_length: %d frame_length: %d last: %d total: %d\n",

            s->data_length, s->frame_length, s->last_frame_length, s->total_frames);

        // FIXME: seek table

        for (i = 0; i < s->total_frames; i++)

            skip_bits(&s->gb, 32);

        skip_bits(&s->gb, 32); // CRC32 of seektable

        if(s->frame_length >= UINT_MAX / (s->channels * sizeof(int32_t))){

            av_log(avctx, AV_LOG_ERROR, "frame_length too large\n");

            return -1;

        }

        s->decode_buffer = av_mallocz(sizeof(int32_t)*s->frame_length*s->channels);

        if (!s->decode_buffer)

            return AVERROR(ENOMEM);

        s->ch_ctx = av_malloc(avctx->channels * sizeof(*s->ch_ctx));

        if (!s->ch_ctx)

            return AVERROR(ENOMEM);

    } else {

        av_log(avctx, AV_LOG_ERROR, "Wrong extradata present\n");

        return -1;

    }

    return 0;

}

static int tta_decode_frame(AVCodecContext *avctx,

        void *data, int *data_size,

        AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    TTAContext *s = avctx->priv_data;

    int i;

    init_get_bits(&s->gb, buf, buf_size*8);

    {

        int cur_chan = 0, framelen = s->frame_length;

        int32_t *p;

        if (*data_size < (framelen * s->channels * av_get_bits_per_sample_fmt(avctx->sample_fmt) / 8)) {

            av_log(avctx, AV_LOG_ERROR, "Output buffer size is too small.\n");

            return -1;

        }

        // FIXME: seeking

        s->total_frames--;

        if (!s->total_frames && s->last_frame_length)

            framelen = s->last_frame_length;

        // init per channel states

        for (i = 0; i < s->channels; i++) {

            s->ch_ctx[i].predictor = 0;

            ttafilter_init(&s->ch_ctx[i].filter, ttafilter_configs[s->bps-1][0], ttafilter_configs[s->bps-1][1]);

            rice_init(&s->ch_ctx[i].rice, 10, 10);

        }

        for (p = s->decode_buffer; p < s->decode_buffer + (framelen * s->channels); p++) {

            int32_t *predictor = &s->ch_ctx[cur_chan].predictor;

            TTAFilter *filter = &s->ch_ctx[cur_chan].filter;

            TTARice *rice = &s->ch_ctx[cur_chan].rice;

            uint32_t unary, depth, k;

            int32_t value;

            unary = tta_get_unary(&s->gb);

            if (unary == 0) {

                depth = 0;

                k = rice->k0;

            } else {

                depth = 1;

                k = rice->k1;

                unary--;

            }

            if (get_bits_left(&s->gb) < k)

                return -1;

            if (k) {

                if (k > MIN_CACHE_BITS)

                    return -1;

                value = (unary << k) + get_bits(&s->gb, k);

            } else

                value = unary;

            // FIXME: copy paste from original

            switch (depth) {

            case 1:

                rice->sum1 += value - (rice->sum1 >> 4);

                if (rice->k1 > 0 && rice->sum1 < shift_16[rice->k1])

                    rice->k1--;

                else if(rice->sum1 > shift_16[rice->k1 + 1])

                    rice->k1++;

                value += shift_1[rice->k0];

            default:

                rice->sum0 += value - (rice->sum0 >> 4);

                if (rice->k0 > 0 && rice->sum0 < shift_16[rice->k0])

                    rice->k0--;

                else if(rice->sum0 > shift_16[rice->k0 + 1])

                    rice->k0++;

            }

            // extract coded value

#define UNFOLD(x) (((x)&1) ? (++(x)>>1) : (-(x)>>1))

            *p = UNFOLD(value);

            // run hybrid filter

            ttafilter_process(filter, p, 0);

            // fixed order prediction

#define PRED(x, k) (int32_t)((((uint64_t)x << k) - x) >> k)

            switch (s->bps) {

                case 1: *p += PRED(*predictor, 4); break;

                case 2:

                case 3: *p += PRED(*predictor, 5); break;

                case 4: *p += *predictor; break;

            }

            *predictor = *p;

#if 0

            // extract 32bit float from last two int samples

            if (s->is_float && ((p - data) & 1)) {

                uint32_t neg = *p & 0x80000000;

                uint32_t hi = *(p - 1);

                uint32_t lo = abs(*p) - 1;

                hi += (hi || lo) ? 0x3f80 : 0;

                // SWAP16: swap all the 16 bits

                *(p - 1) = (hi << 16) | SWAP16(lo) | neg;

            }

#endif

            /*if ((get_bits_count(&s->gb)+7)/8 > buf_size)

            {

                av_log(NULL, AV_LOG_INFO, "overread!!\n");

                break;

            }*/

            // flip channels

            if (cur_chan < (s->channels-1))

                cur_chan++;

            else {

                // decorrelate in case of stereo integer

                if (!s->is_float && (s->channels > 1)) {

                    int32_t *r = p - 1;

                    for (*p += *r / 2; r > p - s->channels; r--)

                        *r = *(r + 1) - *r;

                }

                cur_chan = 0;

            }

        }

        if (get_bits_left(&s->gb) < 32)

            return -1;

        skip_bits(&s->gb, 32); // frame crc

        // convert to output buffer

        switch(s->bps) {

            case 1: {

                uint8_t *samples = data;

                for (p = s->decode_buffer; p < s->decode_buffer + (framelen * s->channels); p++)

                    *samples++ = *p + 0x80;

                *data_size = samples - (uint8_t *)data;

                break;

            }

            case 2: {

                uint16_t *samples = data;

                for (p = s->decode_buffer; p < s->decode_buffer + (framelen * s->channels); p++) {

//                    *samples++ = (unsigned char)*p;

//                    *samples++ = (unsigned char)(*p >> 8);

                    *samples++ = *p;

                }

                *data_size = (uint8_t *)samples - (uint8_t *)data;

                break;

            }

            default:

                av_log(s->avctx, AV_LOG_ERROR, "Error, only 16bit samples supported!\n");

        }

    }

//    return get_bits_count(&s->gb)+7)/8;

    return buf_size;

}

static av_cold int tta_decode_close(AVCodecContext *avctx) {

    TTAContext *s = avctx->priv_data;

    av_free(s->decode_buffer);

    av_freep(&s->ch_ctx);

    return 0;

}

AVCodec ff_tta_decoder = {

    "tta",

    AVMEDIA_TYPE_AUDIO,

    CODEC_ID_TTA,

    sizeof(TTAContext),

    tta_decode_init,

    NULL,

    tta_decode_close,

    tta_decode_frame,

    .long_name = NULL_IF_CONFIG_SMALL("True Audio (TTA)"),

};