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208 lines
8.1 KiB
208 lines
8.1 KiB
/* |
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* Audio Processing Technology codec for Bluetooth (aptX) |
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* |
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* Copyright (C) 2017 Aurelien Jacobs <aurel@gnuage.org> |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include "config_components.h" |
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#include "libavutil/channel_layout.h" |
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#include "aptx.h" |
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#include "codec_internal.h" |
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#include "decode.h" |
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/* |
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* Half-band QMF synthesis filter realized with a polyphase FIR filter. |
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* Join 2 subbands and upsample by 2. |
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* So for each 2 subbands sample that goes in, a pair of samples goes out. |
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*/ |
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av_always_inline |
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static void aptx_qmf_polyphase_synthesis(FilterSignal signal[NB_FILTERS], |
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const int32_t coeffs[NB_FILTERS][FILTER_TAPS], |
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int shift, |
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int32_t low_subband_input, |
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int32_t high_subband_input, |
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int32_t samples[NB_FILTERS]) |
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{ |
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int32_t subbands[NB_FILTERS]; |
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int i; |
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subbands[0] = low_subband_input + high_subband_input; |
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subbands[1] = low_subband_input - high_subband_input; |
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for (i = 0; i < NB_FILTERS; i++) { |
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aptx_qmf_filter_signal_push(&signal[i], subbands[1-i]); |
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samples[i] = aptx_qmf_convolution(&signal[i], coeffs[i], shift); |
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} |
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} |
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/* |
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* Two stage QMF synthesis tree. |
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* Join 4 subbands and upsample by 4. |
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* So for each 4 subbands sample that goes in, a group of 4 samples goes out. |
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*/ |
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static void aptx_qmf_tree_synthesis(QMFAnalysis *qmf, |
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int32_t subband_samples[4], |
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int32_t samples[4]) |
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{ |
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int32_t intermediate_samples[4]; |
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int i; |
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/* Join 4 subbands into 2 intermediate subbands upsampled to 2 samples. */ |
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for (i = 0; i < 2; i++) |
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aptx_qmf_polyphase_synthesis(qmf->inner_filter_signal[i], |
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aptx_qmf_inner_coeffs, 22, |
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subband_samples[2*i+0], |
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subband_samples[2*i+1], |
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&intermediate_samples[2*i]); |
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/* Join 2 samples from intermediate subbands upsampled to 4 samples. */ |
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for (i = 0; i < 2; i++) |
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aptx_qmf_polyphase_synthesis(qmf->outer_filter_signal, |
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aptx_qmf_outer_coeffs, 21, |
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intermediate_samples[0+i], |
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intermediate_samples[2+i], |
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&samples[2*i]); |
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} |
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static void aptx_decode_channel(Channel *channel, int32_t samples[4]) |
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{ |
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int32_t subband_samples[4]; |
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int subband; |
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for (subband = 0; subband < NB_SUBBANDS; subband++) |
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subband_samples[subband] = channel->prediction[subband].previous_reconstructed_sample; |
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aptx_qmf_tree_synthesis(&channel->qmf, subband_samples, samples); |
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} |
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static void aptx_unpack_codeword(Channel *channel, uint16_t codeword) |
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{ |
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channel->quantize[0].quantized_sample = sign_extend(codeword >> 0, 7); |
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channel->quantize[1].quantized_sample = sign_extend(codeword >> 7, 4); |
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channel->quantize[2].quantized_sample = sign_extend(codeword >> 11, 2); |
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channel->quantize[3].quantized_sample = sign_extend(codeword >> 13, 3); |
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channel->quantize[3].quantized_sample = (channel->quantize[3].quantized_sample & ~1) |
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| aptx_quantized_parity(channel); |
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} |
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static void aptxhd_unpack_codeword(Channel *channel, uint32_t codeword) |
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{ |
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channel->quantize[0].quantized_sample = sign_extend(codeword >> 0, 9); |
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channel->quantize[1].quantized_sample = sign_extend(codeword >> 9, 6); |
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channel->quantize[2].quantized_sample = sign_extend(codeword >> 15, 4); |
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channel->quantize[3].quantized_sample = sign_extend(codeword >> 19, 5); |
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channel->quantize[3].quantized_sample = (channel->quantize[3].quantized_sample & ~1) |
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| aptx_quantized_parity(channel); |
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} |
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static int aptx_decode_samples(AptXContext *ctx, |
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const uint8_t *input, |
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int32_t samples[NB_CHANNELS][4]) |
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{ |
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int channel, ret; |
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for (channel = 0; channel < NB_CHANNELS; channel++) { |
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ff_aptx_generate_dither(&ctx->channels[channel]); |
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if (ctx->hd) |
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aptxhd_unpack_codeword(&ctx->channels[channel], |
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AV_RB24(input + 3*channel)); |
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else |
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aptx_unpack_codeword(&ctx->channels[channel], |
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AV_RB16(input + 2*channel)); |
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ff_aptx_invert_quantize_and_prediction(&ctx->channels[channel], ctx->hd); |
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} |
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ret = aptx_check_parity(ctx->channels, &ctx->sync_idx); |
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for (channel = 0; channel < NB_CHANNELS; channel++) |
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aptx_decode_channel(&ctx->channels[channel], samples[channel]); |
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return ret; |
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} |
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static int aptx_decode_frame(AVCodecContext *avctx, AVFrame *frame, |
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int *got_frame_ptr, AVPacket *avpkt) |
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{ |
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AptXContext *s = avctx->priv_data; |
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int pos, opos, channel, sample, ret; |
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if (avpkt->size < s->block_size) { |
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av_log(avctx, AV_LOG_ERROR, "Packet is too small\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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/* get output buffer */ |
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frame->ch_layout.nb_channels = NB_CHANNELS; |
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frame->format = AV_SAMPLE_FMT_S32P; |
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frame->nb_samples = 4 * (avpkt->size / s->block_size); |
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if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) |
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return ret; |
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for (pos = 0, opos = 0; opos < frame->nb_samples; pos += s->block_size, opos += 4) { |
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int32_t samples[NB_CHANNELS][4]; |
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if (aptx_decode_samples(s, &avpkt->data[pos], samples)) { |
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av_log(avctx, AV_LOG_ERROR, "Synchronization error\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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for (channel = 0; channel < NB_CHANNELS; channel++) |
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for (sample = 0; sample < 4; sample++) |
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AV_WN32A(&frame->data[channel][4*(opos+sample)], |
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samples[channel][sample] * 256); |
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} |
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*got_frame_ptr = 1; |
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return s->block_size * frame->nb_samples / 4; |
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} |
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#if CONFIG_APTX_DECODER |
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const FFCodec ff_aptx_decoder = { |
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.p.name = "aptx", |
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CODEC_LONG_NAME("aptX (Audio Processing Technology for Bluetooth)"), |
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.p.type = AVMEDIA_TYPE_AUDIO, |
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.p.id = AV_CODEC_ID_APTX, |
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.priv_data_size = sizeof(AptXContext), |
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.init = ff_aptx_init, |
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FF_CODEC_DECODE_CB(aptx_decode_frame), |
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.p.capabilities = AV_CODEC_CAP_DR1, |
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CODEC_OLD_CHANNEL_LAYOUTS(AV_CH_LAYOUT_STEREO) |
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.p.ch_layouts = (const AVChannelLayout[]) { AV_CHANNEL_LAYOUT_STEREO, { 0 } }, |
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.p.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S32P, |
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AV_SAMPLE_FMT_NONE }, |
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}; |
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#endif |
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#if CONFIG_APTX_HD_DECODER |
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const FFCodec ff_aptx_hd_decoder = { |
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.p.name = "aptx_hd", |
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CODEC_LONG_NAME("aptX HD (Audio Processing Technology for Bluetooth)"), |
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.p.type = AVMEDIA_TYPE_AUDIO, |
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.p.id = AV_CODEC_ID_APTX_HD, |
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.priv_data_size = sizeof(AptXContext), |
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.init = ff_aptx_init, |
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FF_CODEC_DECODE_CB(aptx_decode_frame), |
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.p.capabilities = AV_CODEC_CAP_DR1, |
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CODEC_OLD_CHANNEL_LAYOUTS(AV_CH_LAYOUT_STEREO) |
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.p.ch_layouts = (const AVChannelLayout[]) { AV_CHANNEL_LAYOUT_STEREO, { 0 } }, |
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.p.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S32P, |
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AV_SAMPLE_FMT_NONE }, |
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}; |
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#endif
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