/* * Bonk audio decoder * * 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 */ #include "libavutil/intreadwrite.h"#include "libavutil/mem.h"#include "avcodec.h"#include "codec_internal.h"#include "decode.h"#define BITSTREAM_READER_LE#include "get_bits.h" typedef struct BitCount {    uint8_t bit;    unsigned count;} BitCount; typedef struct BonkContext {    GetBitContext gb;    int skip;     uint8_t *bitstream;    int64_t max_framesize;    int bitstream_size;    int bitstream_index;     uint64_t nb_samples;    int lossless;    int mid_side;    int n_taps;    int down_sampling;    int samples_per_packet;     int state[2][2048], k[2048];    int *samples[2];    int *input_samples;    uint8_t quant[2048];    BitCount *bits;} BonkContext; static av_cold int bonk_close(AVCodecContext *avctx){    BonkContext *s = avctx->priv_data;     av_freep(&s->bitstream);    av_freep(&s->input_samples);    av_freep(&s->samples[0]);    av_freep(&s->samples[1]);    av_freep(&s->bits);    s->bitstream_size = 0;     return 0;} static av_cold int bonk_init(AVCodecContext *avctx){    BonkContext *s = avctx->priv_data;     avctx->sample_fmt = AV_SAMPLE_FMT_S16P;    if (avctx->extradata_size < 17)        return AVERROR(EINVAL);     if (avctx->extradata[0]) {        av_log(avctx, AV_LOG_ERROR, "Unsupported version.\n");        return AVERROR_INVALIDDATA;    }     if (avctx->ch_layout.nb_channels < 1 || avctx->ch_layout.nb_channels > 2)        return AVERROR_INVALIDDATA;     s->nb_samples = AV_RL32(avctx->extradata + 1) / avctx->ch_layout.nb_channels;    if (!s->nb_samples)        s->nb_samples = UINT64_MAX;    s->lossless = avctx->extradata[10] != 0;    s->mid_side = avctx->extradata[11] != 0;    s->n_taps = AV_RL16(avctx->extradata + 12);    if (!s->n_taps || s->n_taps > 2048)        return AVERROR(EINVAL);     s->down_sampling = avctx->extradata[14];    if (!s->down_sampling)        return AVERROR(EINVAL);     s->samples_per_packet = AV_RL16(avctx->extradata + 15);    if (!s->samples_per_packet)        return AVERROR(EINVAL);     if (s->down_sampling * s->samples_per_packet < s->n_taps)        return AVERROR_INVALIDDATA;     s->max_framesize = s->samples_per_packet * avctx->ch_layout.nb_channels * s->down_sampling * 16LL;    if (s->max_framesize > (INT32_MAX - AV_INPUT_BUFFER_PADDING_SIZE) / 8)        return AVERROR_INVALIDDATA;     s->bitstream = av_calloc(s->max_framesize + AV_INPUT_BUFFER_PADDING_SIZE, sizeof(*s->bitstream));    if (!s->bitstream)        return AVERROR(ENOMEM);     s->input_samples = av_calloc(s->samples_per_packet, sizeof(*s->input_samples));    if (!s->input_samples)        return AVERROR(ENOMEM);     s->samples[0] = av_calloc(s->samples_per_packet * s->down_sampling, sizeof(*s->samples[0]));    s->samples[1] = av_calloc(s->samples_per_packet * s->down_sampling, sizeof(*s->samples[0]));    if (!s->samples[0] || !s->samples[1])        return AVERROR(ENOMEM);     s->bits = av_calloc(s->max_framesize * 8, sizeof(*s->bits));    if (!s->bits)        return AVERROR(ENOMEM);     for (int i = 0; i < 512; i++) {        s->quant[i] = sqrt(i + 1);    }     return 0;} static unsigned read_uint_max(BonkContext *s, uint32_t max){    unsigned value = 0;     if (max == 0)        return 0;     av_assert0(max >> 31 == 0);     for (unsigned i = 1; i <= max - value; i+=i)        if (get_bits1(&s->gb))            value += i;     return value;} static int intlist_read(BonkContext *s, int *buf, int entries, int base_2_part){    int i, low_bits = 0, x = 0, max_x;    int n_zeros = 0, step = 256, dominant = 0;    int pos = 0, level = 0;    BitCount *bits = s->bits;    int passes = 1;     memset(buf, 0, entries * sizeof(*buf));    if (base_2_part) {        low_bits = get_bits(&s->gb, 4);         if (low_bits)            for (i = 0; i < entries; i++)                buf[i] = get_bits(&s->gb, low_bits);    }     while (n_zeros < entries) {        int steplet = step >> 8;         if (get_bits_left(&s->gb) <= 0)            return AVERROR_INVALIDDATA;         if (!get_bits1(&s->gb)) {            av_assert0(steplet >= 0);             if (steplet > 0) {                bits[x  ].bit   = dominant;                bits[x++].count = steplet;            }             if (!dominant)                n_zeros += steplet;             if (step > INT32_MAX*8LL/9 + 1)                return AVERROR_INVALIDDATA;            step += step / 8;        } else if (steplet > 0) {            int actual_run = read_uint_max(s, steplet - 1);             av_assert0(actual_run >= 0);             if (actual_run > 0) {                bits[x  ].bit   = dominant;                bits[x++].count = actual_run;            }             bits[x  ].bit   = !dominant;            bits[x++].count = 1;             if (!dominant)                n_zeros += actual_run;            else                n_zeros++;             step -= step / 8;        }         if (step < 256) {            step = 65536 / step;            dominant = !dominant;        }    }     max_x = x;    x = 0;    n_zeros = 0;    for (i = 0; n_zeros < entries; i++) {        if (x >= max_x)            return AVERROR_INVALIDDATA;         if (pos >= entries) {            pos = 0;            level += passes << low_bits;            passes = 1;            if (bits[x].bit && bits[x].count > entries - n_zeros)                passes =  bits[x].count / (entries - n_zeros);        }         if (level > 1 << 16)            return AVERROR_INVALIDDATA;         if (buf[pos] >= level) {            if (bits[x].bit)                buf[pos] += passes << low_bits;            else                n_zeros++;             av_assert1(bits[x].count >= passes);            bits[x].count -= passes;            x += bits[x].count == 0;        }         pos++;    }     for (i = 0; i < entries; i++) {        if (buf[i] && get_bits1(&s->gb)) {            buf[i] = -buf[i];        }    }     return 0;} static inline int shift_down(int a, int b){    return (a >> b) + (a < 0);} static inline int shift(int a, int b){    return a + (1 << b - 1) >> b;} #define LATTICE_SHIFT 10#define SAMPLE_SHIFT   4#define SAMPLE_FACTOR (1 << SAMPLE_SHIFT) static int predictor_calc_error(int *k, int *state, int order, int error){    int i, x = error - (unsigned)shift_down(k[order-1] * (unsigned)state[order-1], LATTICE_SHIFT);    int *k_ptr = &(k[order-2]),        *state_ptr = &(state[order-2]);     for (i = order-2; i >= 0; i--, k_ptr--, state_ptr--) {        unsigned k_value = *k_ptr, state_value = *state_ptr;         x -= (unsigned) shift_down(k_value * (unsigned)state_value, LATTICE_SHIFT);        state_ptr[1] = state_value + shift_down(k_value * x, LATTICE_SHIFT);    }     // don't drift too far, to avoid overflows    x = av_clip(x, -(SAMPLE_FACTOR << 16), SAMPLE_FACTOR << 16);     state[0] = x;     return x;} static void predictor_init_state(int *k, unsigned *state, int order){    for (int i = order - 2; i >= 0; i--) {        unsigned x = state[i];         for (int j = 0, p = i + 1; p < order; j++, p++) {            int tmp = x + shift_down(k[j] * state[p], LATTICE_SHIFT);             state[p] += shift_down(k[j] * x, LATTICE_SHIFT);            x = tmp;        }    }} static int bonk_decode(AVCodecContext *avctx, AVFrame *frame,                       int *got_frame_ptr, AVPacket *pkt){    BonkContext *s = avctx->priv_data;    GetBitContext *gb = &s->gb;    const uint8_t *buf;    int quant, n, buf_size, input_buf_size;    int ret = AVERROR_INVALIDDATA;     if ((!pkt->size && !s->bitstream_size) || s->nb_samples == 0) {        *got_frame_ptr = 0;        return pkt->size;    }     buf_size = FFMIN(pkt->size, s->max_framesize - s->bitstream_size);    input_buf_size = buf_size;    if (s->bitstream_index + s->bitstream_size + buf_size + AV_INPUT_BUFFER_PADDING_SIZE > s->max_framesize) {        memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);        s->bitstream_index = 0;    }    if (pkt->data)        memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], pkt->data, buf_size);    buf                = &s->bitstream[s->bitstream_index];    buf_size          += s->bitstream_size;    s->bitstream_size  = buf_size;    if (buf_size < s->max_framesize && pkt->data) {        *got_frame_ptr = 0;        return input_buf_size;    }     frame->nb_samples = FFMIN(s->samples_per_packet * s->down_sampling, s->nb_samples);    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)        goto fail;     if ((ret = init_get_bits8(gb, buf, buf_size)) < 0)        goto fail;     skip_bits(gb, s->skip);    if ((ret = intlist_read(s, s->k, s->n_taps, 0)) < 0)        goto fail;     for (int i = 0; i < s->n_taps; i++)        s->k[i] *= s->quant[i];    quant = s->lossless ? 1 : get_bits(&s->gb, 16) * SAMPLE_FACTOR;     for (int ch = 0; ch < avctx->ch_layout.nb_channels; ch++) {        const int samples_per_packet = s->samples_per_packet;        const int down_sampling = s->down_sampling;        const int offset = samples_per_packet * down_sampling - 1;        int *state = s->state[ch];        int *sample = s->samples[ch];         predictor_init_state(s->k, state, s->n_taps);        if ((ret = intlist_read(s, s->input_samples, samples_per_packet, 1)) < 0)            goto fail;         for (int i = 0; i < samples_per_packet; i++) {            for (int j = 0; j < s->down_sampling - 1; j++) {                sample[0] = predictor_calc_error(s->k, state, s->n_taps, 0);                sample++;            }             sample[0] = predictor_calc_error(s->k, state, s->n_taps, s->input_samples[i] * (unsigned)quant);            sample++;        }         sample = s->samples[ch];        for (int i = 0; i < s->n_taps; i++)            state[i] = sample[offset - i];    }     if (s->mid_side && avctx->ch_layout.nb_channels == 2) {        for (int i = 0; i < frame->nb_samples; i++) {            s->samples[1][i] += shift(s->samples[0][i], 1);            s->samples[0][i] -= s->samples[1][i];        }    }     if (!s->lossless) {        for (int ch = 0; ch < avctx->ch_layout.nb_channels; ch++) {            int *samples = s->samples[ch];            for (int i = 0; i < frame->nb_samples; i++)                samples[i] = shift(samples[i], 4);        }    }     for (int ch = 0; ch < avctx->ch_layout.nb_channels; ch++) {        int16_t *osamples = (int16_t *)frame->extended_data[ch];        int *samples = s->samples[ch];        for (int i = 0; i < frame->nb_samples; i++)            osamples[i] = av_clip_int16(samples[i]);    }     s->nb_samples -= frame->nb_samples;     s->skip = get_bits_count(gb) - 8 * (get_bits_count(gb) / 8);    n = get_bits_count(gb) / 8;     if (n > buf_size) {fail:        s->bitstream_size = 0;        s->bitstream_index = 0;        return AVERROR_INVALIDDATA;    }     *got_frame_ptr = 1;     if (s->bitstream_size) {        s->bitstream_index += n;        s->bitstream_size  -= n;        return input_buf_size;    }    return n;} const FFCodec ff_bonk_decoder = {    .p.name           = "bonk",    CODEC_LONG_NAME("Bonk audio"),    .p.type           = AVMEDIA_TYPE_AUDIO,    .p.id             = AV_CODEC_ID_BONK,    .priv_data_size   = sizeof(BonkContext),    .init             = bonk_init,    FF_CODEC_DECODE_CB(bonk_decode),    .close            = bonk_close,    .p.capabilities   = AV_CODEC_CAP_DELAY |#if FF_API_SUBFRAMES                        AV_CODEC_CAP_SUBFRAMES |#endif                        AV_CODEC_CAP_DR1,    .caps_internal    = FF_CODEC_CAP_INIT_CLEANUP,    .p.sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,                                                        AV_SAMPLE_FMT_NONE },};