libavcodec/aptxdec.c - third_party/ffmpeg - Git at Google

 /*
  * 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 "aptx.h"

 /*
  * Half-band QMF synthesis filter realized with a polyphase FIR filter.
  * Join 2 subbands and upsample by 2.
  * So for each 2 subbands sample that goes in, a pair of samples goes out.
  */
 av_always_inline
 static void aptx_qmf_polyphase_synthesis(FilterSignal signal[NB_FILTERS],
                                          const int32_t coeffs[NB_FILTERS][FILTER_TAPS],
                                          int shift,
                                          int32_t low_subband_input,
                                          int32_t high_subband_input,
                                          int32_t samples[NB_FILTERS])
 {
     int32_t subbands[NB_FILTERS];
     int i;

     subbands[0] = low_subband_input + high_subband_input;
     subbands[1] = low_subband_input - high_subband_input;

     for (i = 0; i < NB_FILTERS; i++) {
         aptx_qmf_filter_signal_push(&signal[i], subbands[1-i]);
         samples[i] = aptx_qmf_convolution(&signal[i], coeffs[i], shift);
     }
 }

 /*
  * Two stage QMF synthesis tree.
  * Join 4 subbands and upsample by 4.
  * So for each 4 subbands sample that goes in, a group of 4 samples goes out.
  */
 static void aptx_qmf_tree_synthesis(QMFAnalysis *qmf,
                                     int32_t subband_samples[4],
                                     int32_t samples[4])
 {
     int32_t intermediate_samples[4];
     int i;

     /* Join 4 subbands into 2 intermediate subbands upsampled to 2 samples. */
     for (i = 0; i < 2; i++)
         aptx_qmf_polyphase_synthesis(qmf->inner_filter_signal[i],
                                      aptx_qmf_inner_coeffs, 22,
                                      subband_samples[2*i+0],
                                      subband_samples[2*i+1],
                                      &intermediate_samples[2*i]);

     /* Join 2 samples from intermediate subbands upsampled to 4 samples. */
     for (i = 0; i < 2; i++)
         aptx_qmf_polyphase_synthesis(qmf->outer_filter_signal,
                                      aptx_qmf_outer_coeffs, 21,
                                      intermediate_samples[0+i],
                                      intermediate_samples[2+i],
                                      &samples[2*i]);
 }


 static void aptx_decode_channel(Channel *channel, int32_t samples[4])
 {
     int32_t subband_samples[4];
     int subband;
     for (subband = 0; subband < NB_SUBBANDS; subband++)
         subband_samples[subband] = channel->prediction[subband].previous_reconstructed_sample;
     aptx_qmf_tree_synthesis(&channel->qmf, subband_samples, samples);
 }

 static void aptx_unpack_codeword(Channel *channel, uint16_t codeword)
 {
     channel->quantize[0].quantized_sample = sign_extend(codeword >>  0, 7);
     channel->quantize[1].quantized_sample = sign_extend(codeword >>  7, 4);
     channel->quantize[2].quantized_sample = sign_extend(codeword >> 11, 2);
     channel->quantize[3].quantized_sample = sign_extend(codeword >> 13, 3);
     channel->quantize[3].quantized_sample = (channel->quantize[3].quantized_sample & ~1)
                                           | aptx_quantized_parity(channel);
 }

 static void aptxhd_unpack_codeword(Channel *channel, uint32_t codeword)
 {
     channel->quantize[0].quantized_sample = sign_extend(codeword >>  0, 9);
     channel->quantize[1].quantized_sample = sign_extend(codeword >>  9, 6);
     channel->quantize[2].quantized_sample = sign_extend(codeword >> 15, 4);
     channel->quantize[3].quantized_sample = sign_extend(codeword >> 19, 5);
     channel->quantize[3].quantized_sample = (channel->quantize[3].quantized_sample & ~1)
                                           | aptx_quantized_parity(channel);
 }

 static int aptx_decode_samples(AptXContext *ctx,
                                 const uint8_t *input,
                                 int32_t samples[NB_CHANNELS][4])
 {
     int channel, ret;

     for (channel = 0; channel < NB_CHANNELS; channel++) {
         ff_aptx_generate_dither(&ctx->channels[channel]);

         if (ctx->hd)
             aptxhd_unpack_codeword(&ctx->channels[channel],
                                    AV_RB24(input + 3*channel));
         else
             aptx_unpack_codeword(&ctx->channels[channel],
                                  AV_RB16(input + 2*channel));
         ff_aptx_invert_quantize_and_prediction(&ctx->channels[channel], ctx->hd);
     }

     ret = aptx_check_parity(ctx->channels, &ctx->sync_idx);

     for (channel = 0; channel < NB_CHANNELS; channel++)
         aptx_decode_channel(&ctx->channels[channel], samples[channel]);

     return ret;
 }

 static int aptx_decode_frame(AVCodecContext *avctx, void *data,
                              int *got_frame_ptr, AVPacket *avpkt)
 {
     AptXContext *s = avctx->priv_data;
     AVFrame *frame = data;
     int pos, opos, channel, sample, ret;

     if (avpkt->size < s->block_size) {
         av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
         return AVERROR_INVALIDDATA;
     }

     /* get output buffer */
     frame->channels = NB_CHANNELS;
     frame->format = AV_SAMPLE_FMT_S32P;
     frame->nb_samples = 4 * avpkt->size / s->block_size;
     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
         return ret;

     for (pos = 0, opos = 0; opos < frame->nb_samples; pos += s->block_size, opos += 4) {
         int32_t samples[NB_CHANNELS][4];

         if (aptx_decode_samples(s, &avpkt->data[pos], samples)) {
             av_log(avctx, AV_LOG_ERROR, "Synchronization error\n");
             return AVERROR_INVALIDDATA;
         }

         for (channel = 0; channel < NB_CHANNELS; channel++)
             for (sample = 0; sample < 4; sample++)
                 AV_WN32A(&frame->data[channel][4*(opos+sample)],
                          samples[channel][sample] * 256);
     }

     *got_frame_ptr = 1;
     return s->block_size * frame->nb_samples / 4;
 }

 #if CONFIG_APTX_DECODER
 AVCodec ff_aptx_decoder = {
     .name                  = "aptx",
     .long_name             = NULL_IF_CONFIG_SMALL("aptX (Audio Processing Technology for Bluetooth)"),
     .type                  = AVMEDIA_TYPE_AUDIO,
     .id                    = AV_CODEC_ID_APTX,
     .priv_data_size        = sizeof(AptXContext),
     .init                  = ff_aptx_init,
     .decode                = aptx_decode_frame,
     .capabilities          = AV_CODEC_CAP_DR1,
     .caps_internal         = FF_CODEC_CAP_INIT_THREADSAFE,
     .channel_layouts       = (const uint64_t[]) { AV_CH_LAYOUT_STEREO, 0},
     .sample_fmts           = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S32P,
                                                              AV_SAMPLE_FMT_NONE },
 };
 #endif

 #if CONFIG_APTX_HD_DECODER
 AVCodec ff_aptx_hd_decoder = {
     .name                  = "aptx_hd",
     .long_name             = NULL_IF_CONFIG_SMALL("aptX HD (Audio Processing Technology for Bluetooth)"),
     .type                  = AVMEDIA_TYPE_AUDIO,
     .id                    = AV_CODEC_ID_APTX_HD,
     .priv_data_size        = sizeof(AptXContext),
     .init                  = ff_aptx_init,
     .decode                = aptx_decode_frame,
     .capabilities          = AV_CODEC_CAP_DR1,
     .caps_internal         = FF_CODEC_CAP_INIT_THREADSAFE,
     .channel_layouts       = (const uint64_t[]) { AV_CH_LAYOUT_STEREO, 0},
     .sample_fmts           = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S32P,
                                                              AV_SAMPLE_FMT_NONE },
 };
 #endif
	/*
	* 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 "aptx.h"

	/*
	* Half-band QMF synthesis filter realized with a polyphase FIR filter.
	* Join 2 subbands and upsample by 2.
	* So for each 2 subbands sample that goes in, a pair of samples goes out.
	*/
	av_always_inline
	static void aptx_qmf_polyphase_synthesis(FilterSignal signal[NB_FILTERS],
	const int32_t coeffs[NB_FILTERS][FILTER_TAPS],
	int shift,
	int32_t low_subband_input,
	int32_t high_subband_input,
	int32_t samples[NB_FILTERS])
	{
	int32_t subbands[NB_FILTERS];
	int i;

	subbands[0] = low_subband_input + high_subband_input;
	subbands[1] = low_subband_input - high_subband_input;

	for (i = 0; i < NB_FILTERS; i++) {
	aptx_qmf_filter_signal_push(&signal[i], subbands[1-i]);
	samples[i] = aptx_qmf_convolution(&signal[i], coeffs[i], shift);
	}
	}

	/*
	* Two stage QMF synthesis tree.
	* Join 4 subbands and upsample by 4.
	* So for each 4 subbands sample that goes in, a group of 4 samples goes out.
	*/
	static void aptx_qmf_tree_synthesis(QMFAnalysis *qmf,
	int32_t subband_samples[4],
	int32_t samples[4])
	{
	int32_t intermediate_samples[4];
	int i;

	/* Join 4 subbands into 2 intermediate subbands upsampled to 2 samples. */
	for (i = 0; i < 2; i++)
	aptx_qmf_polyphase_synthesis(qmf->inner_filter_signal[i],
	aptx_qmf_inner_coeffs, 22,
	subband_samples[2*i+0],
	subband_samples[2*i+1],
	&intermediate_samples[2*i]);

	/* Join 2 samples from intermediate subbands upsampled to 4 samples. */
	for (i = 0; i < 2; i++)
	aptx_qmf_polyphase_synthesis(qmf->outer_filter_signal,
	aptx_qmf_outer_coeffs, 21,
	intermediate_samples[0+i],
	intermediate_samples[2+i],
	&samples[2*i]);
	}


	static void aptx_decode_channel(Channel *channel, int32_t samples[4])
	{
	int32_t subband_samples[4];
	int subband;
	for (subband = 0; subband < NB_SUBBANDS; subband++)
	subband_samples[subband] = channel->prediction[subband].previous_reconstructed_sample;
	aptx_qmf_tree_synthesis(&channel->qmf, subband_samples, samples);
	}

	static void aptx_unpack_codeword(Channel *channel, uint16_t codeword)
	{
	channel->quantize[0].quantized_sample = sign_extend(codeword >> 0, 7);
	channel->quantize[1].quantized_sample = sign_extend(codeword >> 7, 4);
	channel->quantize[2].quantized_sample = sign_extend(codeword >> 11, 2);
	channel->quantize[3].quantized_sample = sign_extend(codeword >> 13, 3);
	channel->quantize[3].quantized_sample = (channel->quantize[3].quantized_sample & ~1)
	\| aptx_quantized_parity(channel);
	}

	static void aptxhd_unpack_codeword(Channel *channel, uint32_t codeword)
	{
	channel->quantize[0].quantized_sample = sign_extend(codeword >> 0, 9);
	channel->quantize[1].quantized_sample = sign_extend(codeword >> 9, 6);
	channel->quantize[2].quantized_sample = sign_extend(codeword >> 15, 4);
	channel->quantize[3].quantized_sample = sign_extend(codeword >> 19, 5);
	channel->quantize[3].quantized_sample = (channel->quantize[3].quantized_sample & ~1)
	\| aptx_quantized_parity(channel);
	}

	static int aptx_decode_samples(AptXContext *ctx,
	const uint8_t *input,
	int32_t samples[NB_CHANNELS][4])
	{
	int channel, ret;

	for (channel = 0; channel < NB_CHANNELS; channel++) {
	ff_aptx_generate_dither(&ctx->channels[channel]);

	if (ctx->hd)
	aptxhd_unpack_codeword(&ctx->channels[channel],
	AV_RB24(input + 3*channel));
	else
	aptx_unpack_codeword(&ctx->channels[channel],
	AV_RB16(input + 2*channel));
	ff_aptx_invert_quantize_and_prediction(&ctx->channels[channel], ctx->hd);
	}

	ret = aptx_check_parity(ctx->channels, &ctx->sync_idx);

	for (channel = 0; channel < NB_CHANNELS; channel++)
	aptx_decode_channel(&ctx->channels[channel], samples[channel]);

	return ret;
	}

	static int aptx_decode_frame(AVCodecContext avctx, void data,
	int got_frame_ptr, AVPacket avpkt)
	{
	AptXContext *s = avctx->priv_data;
	AVFrame *frame = data;
	int pos, opos, channel, sample, ret;

	if (avpkt->size < s->block_size) {
	av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
	return AVERROR_INVALIDDATA;
	}

	/* get output buffer */
	frame->channels = NB_CHANNELS;
	frame->format = AV_SAMPLE_FMT_S32P;
	frame->nb_samples = 4 * avpkt->size / s->block_size;
	if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
	return ret;

	for (pos = 0, opos = 0; opos < frame->nb_samples; pos += s->block_size, opos += 4) {
	int32_t samples[NB_CHANNELS][4];

	if (aptx_decode_samples(s, &avpkt->data[pos], samples)) {
	av_log(avctx, AV_LOG_ERROR, "Synchronization error\n");
	return AVERROR_INVALIDDATA;
	}

	for (channel = 0; channel < NB_CHANNELS; channel++)
	for (sample = 0; sample < 4; sample++)
	AV_WN32A(&frame->data[channel][4*(opos+sample)],
	samples[channel][sample] * 256);
	}

	*got_frame_ptr = 1;
	return s->block_size * frame->nb_samples / 4;
	}

	#if CONFIG_APTX_DECODER
	AVCodec ff_aptx_decoder = {
	.name = "aptx",
	.long_name = NULL_IF_CONFIG_SMALL("aptX (Audio Processing Technology for Bluetooth)"),
	.type = AVMEDIA_TYPE_AUDIO,
	.id = AV_CODEC_ID_APTX,
	.priv_data_size = sizeof(AptXContext),
	.init = ff_aptx_init,
	.decode = aptx_decode_frame,
	.capabilities = AV_CODEC_CAP_DR1,
	.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
	.channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_STEREO, 0},
	.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S32P,
	AV_SAMPLE_FMT_NONE },
	};
	#endif

	#if CONFIG_APTX_HD_DECODER
	AVCodec ff_aptx_hd_decoder = {
	.name = "aptx_hd",
	.long_name = NULL_IF_CONFIG_SMALL("aptX HD (Audio Processing Technology for Bluetooth)"),
	.type = AVMEDIA_TYPE_AUDIO,
	.id = AV_CODEC_ID_APTX_HD,
	.priv_data_size = sizeof(AptXContext),
	.init = ff_aptx_init,
	.decode = aptx_decode_frame,
	.capabilities = AV_CODEC_CAP_DR1,
	.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
	.channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_STEREO, 0},
	.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S32P,
	AV_SAMPLE_FMT_NONE },
	};
	#endif