/* * Audio Processing Technology codec for Bluetooth (aptX) * * Copyright (C) 2017  Aurelien Jacobs <aurel@gnuage.org> * * 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 "config_components.h" #include "libavutil/channel_layout.h"#include "aptx.h"#include "audio_frame_queue.h"#include "codec_internal.h"#include "encode.h"#include "internal.h" typedef struct AptXEncContext {    AptXContext common;    AudioFrameQueue afq;} AptXEncContext; /* * Half-band QMF analysis filter realized with a polyphase FIR filter. * Split into 2 subbands and downsample by 2. * So for each pair of samples that goes in, one sample goes out, * split into 2 separate subbands. */av_always_inlinestatic void aptx_qmf_polyphase_analysis(FilterSignal signal[NB_FILTERS],                                        const int32_t coeffs[NB_FILTERS][FILTER_TAPS],                                        int shift,                                        int32_t samples[NB_FILTERS],                                        int32_t *low_subband_output,                                        int32_t *high_subband_output){    int32_t subbands[NB_FILTERS];    int i;     for (i = 0; i < NB_FILTERS; i++) {        aptx_qmf_filter_signal_push(&signal[i], samples[NB_FILTERS-1-i]);        subbands[i] = aptx_qmf_convolution(&signal[i], coeffs[i], shift);    }     *low_subband_output  = av_clip_intp2(subbands[0] + subbands[1], 23);    *high_subband_output = av_clip_intp2(subbands[0] - subbands[1], 23);} /* * Two stage QMF analysis tree. * Split 4 input samples into 4 subbands and downsample by 4. * So for each group of 4 samples that goes in, one sample goes out, * split into 4 separate subbands. */static void aptx_qmf_tree_analysis(QMFAnalysis *qmf,                                   int32_t samples[4],                                   int32_t subband_samples[4]){    int32_t intermediate_samples[4];    int i;     /* Split 4 input samples into 2 intermediate subbands downsampled to 2 samples */    for (i = 0; i < 2; i++)        aptx_qmf_polyphase_analysis(qmf->outer_filter_signal,                                    aptx_qmf_outer_coeffs, 23,                                    &samples[2*i],                                    &intermediate_samples[0+i],                                    &intermediate_samples[2+i]);     /* Split 2 intermediate subband samples into 4 final subbands downsampled to 1 sample */    for (i = 0; i < 2; i++)        aptx_qmf_polyphase_analysis(qmf->inner_filter_signal[i],                                    aptx_qmf_inner_coeffs, 23,                                    &intermediate_samples[2*i],                                    &subband_samples[2*i+0],                                    &subband_samples[2*i+1]);} av_always_inlinestatic int32_t aptx_bin_search(int32_t value, int32_t factor,                               const int32_t *intervals, int32_t nb_intervals){    int32_t idx = 0;    int i;     for (i = nb_intervals >> 1; i > 0; i >>= 1)        if (MUL64(factor, intervals[idx + i]) <= ((int64_t)value << 24))            idx += i;     return idx;} static void aptx_quantize_difference(Quantize *quantize,                                     int32_t sample_difference,                                     int32_t dither,                                     int32_t quantization_factor,                                     ConstTables *tables){    const int32_t *intervals = tables->quantize_intervals;    int32_t quantized_sample, dithered_sample, parity_change;    int32_t d, mean, interval, inv, sample_difference_abs;    int64_t error;     sample_difference_abs = FFABS(sample_difference);    sample_difference_abs = FFMIN(sample_difference_abs, (1 << 23) - 1);     quantized_sample = aptx_bin_search(sample_difference_abs >> 4,                                       quantization_factor,                                       intervals, tables->tables_size);     d = rshift32_clip24(MULH(dither, dither), 7) - (1 << 23);    d = rshift64(MUL64(d, tables->quantize_dither_factors[quantized_sample]), 23);     intervals += quantized_sample;    mean = (intervals[1] + intervals[0]) / 2;    interval = (intervals[1] - intervals[0]) * (-(sample_difference < 0) | 1);     dithered_sample = rshift64_clip24(MUL64(dither, interval) + ((int64_t)av_clip_intp2(mean + d, 23) << 32), 32);    error = ((int64_t)sample_difference_abs << 20) - MUL64(dithered_sample, quantization_factor);    quantize->error = FFABS(rshift64(error, 23));     parity_change = quantized_sample;    if (error < 0)        quantized_sample--;    else        parity_change--;     inv = -(sample_difference < 0);    quantize->quantized_sample               = quantized_sample ^ inv;    quantize->quantized_sample_parity_change = parity_change    ^ inv;} static void aptx_encode_channel(Channel *channel, int32_t samples[4], int hd){    int32_t subband_samples[4];    int subband;    aptx_qmf_tree_analysis(&channel->qmf, samples, subband_samples);    ff_aptx_generate_dither(channel);    for (subband = 0; subband < NB_SUBBANDS; subband++) {        int32_t diff = av_clip_intp2(subband_samples[subband] - channel->prediction[subband].predicted_sample, 23);        aptx_quantize_difference(&channel->quantize[subband], diff,                                 channel->dither[subband],                                 channel->invert_quantize[subband].quantization_factor,                                 &ff_aptx_quant_tables[hd][subband]);    }} static void aptx_insert_sync(Channel channels[NB_CHANNELS], int32_t *idx){    if (aptx_check_parity(channels, idx)) {        int i;        Channel *c;        static const int map[] = { 1, 2, 0, 3 };        Quantize *min = &channels[NB_CHANNELS-1].quantize[map[0]];        for (c = &channels[NB_CHANNELS-1]; c >= channels; c--)            for (i = 0; i < NB_SUBBANDS; i++)                if (c->quantize[map[i]].error < min->error)                    min = &c->quantize[map[i]];         /* Forcing the desired parity is done by offsetting by 1 the quantized         * sample from the subband featuring the smallest quantization error. */        min->quantized_sample = min->quantized_sample_parity_change;    }} static uint16_t aptx_pack_codeword(Channel *channel){    int32_t parity = aptx_quantized_parity(channel);    return (((channel->quantize[3].quantized_sample & 0x06) | parity) << 13)         | (((channel->quantize[2].quantized_sample & 0x03)         ) << 11)         | (((channel->quantize[1].quantized_sample & 0x0F)         ) <<  7)         | (((channel->quantize[0].quantized_sample & 0x7F)         ) <<  0);} static uint32_t aptxhd_pack_codeword(Channel *channel){    int32_t parity = aptx_quantized_parity(channel);    return (((channel->quantize[3].quantized_sample & 0x01E) | parity) << 19)         | (((channel->quantize[2].quantized_sample & 0x00F)         ) << 15)         | (((channel->quantize[1].quantized_sample & 0x03F)         ) <<  9)         | (((channel->quantize[0].quantized_sample & 0x1FF)         ) <<  0);} static void aptx_encode_samples(AptXContext *ctx,                                int32_t samples[NB_CHANNELS][4],                                uint8_t *output){    int channel;    for (channel = 0; channel < NB_CHANNELS; channel++)        aptx_encode_channel(&ctx->channels[channel], samples[channel], ctx->hd);     aptx_insert_sync(ctx->channels, &ctx->sync_idx);     for (channel = 0; channel < NB_CHANNELS; channel++) {        ff_aptx_invert_quantize_and_prediction(&ctx->channels[channel], ctx->hd);        if (ctx->hd)            AV_WB24(output + 3*channel,                    aptxhd_pack_codeword(&ctx->channels[channel]));        else            AV_WB16(output + 2*channel,                    aptx_pack_codeword(&ctx->channels[channel]));    }} static int aptx_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,                             const AVFrame *frame, int *got_packet_ptr){    AptXEncContext *const s0 = avctx->priv_data;    AptXContext *const s = &s0->common;    int pos, ipos, channel, sample, output_size, ret;     if ((ret = ff_af_queue_add(&s0->afq, frame)) < 0)        return ret;     output_size = s->block_size * frame->nb_samples/4;    if ((ret = ff_get_encode_buffer(avctx, avpkt, output_size, 0)) < 0)        return ret;     for (pos = 0, ipos = 0; pos < output_size; pos += s->block_size, ipos += 4) {        int32_t samples[NB_CHANNELS][4];         for (channel = 0; channel < NB_CHANNELS; channel++)            for (sample = 0; sample < 4; sample++)                samples[channel][sample] = (int32_t)AV_RN32A(&frame->data[channel][4*(ipos+sample)]) >> 8;         aptx_encode_samples(s, samples, avpkt->data + pos);    }     ff_af_queue_remove(&s0->afq, frame->nb_samples, &avpkt->pts, &avpkt->duration);    *got_packet_ptr = 1;    return 0;} static av_cold int aptx_close(AVCodecContext *avctx){    AptXEncContext *const s = avctx->priv_data;    ff_af_queue_close(&s->afq);    return 0;} static av_cold int aptx_encode_init(AVCodecContext *avctx){    AptXEncContext *const s = avctx->priv_data;     ff_af_queue_init(avctx, &s->afq);     if (!avctx->frame_size || avctx->frame_size % 4)        avctx->frame_size = 1024;    avctx->internal->pad_samples = 4;     return ff_aptx_init(avctx);} #if CONFIG_APTX_ENCODERconst FFCodec ff_aptx_encoder = {    .p.name                = "aptx",    CODEC_LONG_NAME("aptX (Audio Processing Technology for Bluetooth)"),    .p.type                = AVMEDIA_TYPE_AUDIO,    .p.id                  = AV_CODEC_ID_APTX,    .p.capabilities        = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,    .priv_data_size        = sizeof(AptXEncContext),    .init                  = aptx_encode_init,    FF_CODEC_ENCODE_CB(aptx_encode_frame),    .close                 = aptx_close,    .p.ch_layouts          = (const AVChannelLayout[]) { AV_CHANNEL_LAYOUT_STEREO, { 0 } },    .p.sample_fmts         = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S32P,                                                             AV_SAMPLE_FMT_NONE },    .p.supported_samplerates = (const int[]) {8000, 16000, 24000, 32000, 44100, 48000, 0},};#endif #if CONFIG_APTX_HD_ENCODERconst FFCodec ff_aptx_hd_encoder = {    .p.name                = "aptx_hd",    CODEC_LONG_NAME("aptX HD (Audio Processing Technology for Bluetooth)"),    .p.type                = AVMEDIA_TYPE_AUDIO,    .p.id                  = AV_CODEC_ID_APTX_HD,    .p.capabilities        = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,    .priv_data_size        = sizeof(AptXEncContext),    .init                  = aptx_encode_init,    FF_CODEC_ENCODE_CB(aptx_encode_frame),    .close                 = aptx_close,    .p.ch_layouts          = (const AVChannelLayout[]) { AV_CHANNEL_LAYOUT_STEREO, { 0 } },    .p.sample_fmts         = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S32P,                                                             AV_SAMPLE_FMT_NONE },    .p.supported_samplerates = (const int[]) {8000, 16000, 24000, 32000, 44100, 48000, 0},};#endif