| /* | |
| * 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_inline | |
| static 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_inline | |
| static 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_ENCODER | |
| const 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_ENCODER | |
| const 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 |