FFmpeg
aptxdec.c
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1 /*
2  * Audio Processing Technology codec for Bluetooth (aptX)
3  *
4  * Copyright (C) 2017 Aurelien Jacobs <aurel@gnuage.org>
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
24 #include "aptx.h"
25 
26 /*
27  * Half-band QMF synthesis filter realized with a polyphase FIR filter.
28  * Join 2 subbands and upsample by 2.
29  * So for each 2 subbands sample that goes in, a pair of samples goes out.
30  */
33  const int32_t coeffs[NB_FILTERS][FILTER_TAPS],
34  int shift,
35  int32_t low_subband_input,
36  int32_t high_subband_input,
38 {
40  int i;
41 
42  subbands[0] = low_subband_input + high_subband_input;
43  subbands[1] = low_subband_input - high_subband_input;
44 
45  for (i = 0; i < NB_FILTERS; i++) {
47  samples[i] = aptx_qmf_convolution(&signal[i], coeffs[i], shift);
48  }
49 }
50 
51 /*
52  * Two stage QMF synthesis tree.
53  * Join 4 subbands and upsample by 4.
54  * So for each 4 subbands sample that goes in, a group of 4 samples goes out.
55  */
57  int32_t subband_samples[4],
58  int32_t samples[4])
59 {
60  int32_t intermediate_samples[4];
61  int i;
62 
63  /* Join 4 subbands into 2 intermediate subbands upsampled to 2 samples. */
64  for (i = 0; i < 2; i++)
67  subband_samples[2*i+0],
68  subband_samples[2*i+1],
69  &intermediate_samples[2*i]);
70 
71  /* Join 2 samples from intermediate subbands upsampled to 4 samples. */
72  for (i = 0; i < 2; i++)
75  intermediate_samples[0+i],
76  intermediate_samples[2+i],
77  &samples[2*i]);
78 }
79 
80 
82 {
83  int32_t subband_samples[4];
84  int subband;
85  for (subband = 0; subband < NB_SUBBANDS; subband++)
86  subband_samples[subband] = channel->prediction[subband].previous_reconstructed_sample;
87  aptx_qmf_tree_synthesis(&channel->qmf, subband_samples, samples);
88 }
89 
90 static void aptx_unpack_codeword(Channel *channel, uint16_t codeword)
91 {
92  channel->quantize[0].quantized_sample = sign_extend(codeword >> 0, 7);
93  channel->quantize[1].quantized_sample = sign_extend(codeword >> 7, 4);
94  channel->quantize[2].quantized_sample = sign_extend(codeword >> 11, 2);
95  channel->quantize[3].quantized_sample = sign_extend(codeword >> 13, 3);
96  channel->quantize[3].quantized_sample = (channel->quantize[3].quantized_sample & ~1)
98 }
99 
100 static void aptxhd_unpack_codeword(Channel *channel, uint32_t codeword)
101 {
102  channel->quantize[0].quantized_sample = sign_extend(codeword >> 0, 9);
103  channel->quantize[1].quantized_sample = sign_extend(codeword >> 9, 6);
104  channel->quantize[2].quantized_sample = sign_extend(codeword >> 15, 4);
105  channel->quantize[3].quantized_sample = sign_extend(codeword >> 19, 5);
106  channel->quantize[3].quantized_sample = (channel->quantize[3].quantized_sample & ~1)
108 }
109 
111  const uint8_t *input,
113 {
114  int channel, ret;
115 
116  for (channel = 0; channel < NB_CHANNELS; channel++) {
117  ff_aptx_generate_dither(&ctx->channels[channel]);
118 
119  if (ctx->hd)
120  aptxhd_unpack_codeword(&ctx->channels[channel],
121  AV_RB24(input + 3*channel));
122  else
123  aptx_unpack_codeword(&ctx->channels[channel],
124  AV_RB16(input + 2*channel));
126  }
127 
128  ret = aptx_check_parity(ctx->channels, &ctx->sync_idx);
129 
130  for (channel = 0; channel < NB_CHANNELS; channel++)
132 
133  return ret;
134 }
135 
136 static int aptx_decode_frame(AVCodecContext *avctx, void *data,
137  int *got_frame_ptr, AVPacket *avpkt)
138 {
139  AptXContext *s = avctx->priv_data;
140  AVFrame *frame = data;
141  int pos, opos, channel, sample, ret;
142 
143  if (avpkt->size < s->block_size) {
144  av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
145  return AVERROR_INVALIDDATA;
146  }
147 
148  /* get output buffer */
149  frame->channels = NB_CHANNELS;
150  frame->format = AV_SAMPLE_FMT_S32P;
151  frame->nb_samples = 4 * avpkt->size / s->block_size;
152  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
153  return ret;
154 
155  for (pos = 0, opos = 0; opos < frame->nb_samples; pos += s->block_size, opos += 4) {
157 
158  if (aptx_decode_samples(s, &avpkt->data[pos], samples)) {
159  av_log(avctx, AV_LOG_ERROR, "Synchronization error\n");
160  return AVERROR_INVALIDDATA;
161  }
162 
163  for (channel = 0; channel < NB_CHANNELS; channel++)
164  for (sample = 0; sample < 4; sample++)
165  AV_WN32A(&frame->data[channel][4*(opos+sample)],
166  samples[channel][sample] * 256);
167  }
168 
169  *got_frame_ptr = 1;
170  return s->block_size * frame->nb_samples / 4;
171 }
172 
173 #if CONFIG_APTX_DECODER
174 const AVCodec ff_aptx_decoder = {
175  .name = "aptx",
176  .long_name = NULL_IF_CONFIG_SMALL("aptX (Audio Processing Technology for Bluetooth)"),
177  .type = AVMEDIA_TYPE_AUDIO,
178  .id = AV_CODEC_ID_APTX,
179  .priv_data_size = sizeof(AptXContext),
180  .init = ff_aptx_init,
182  .capabilities = AV_CODEC_CAP_DR1,
183  .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
184  .channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_STEREO, 0},
185  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S32P,
187 };
188 #endif
189 
190 #if CONFIG_APTX_HD_DECODER
191 const AVCodec ff_aptx_hd_decoder = {
192  .name = "aptx_hd",
193  .long_name = NULL_IF_CONFIG_SMALL("aptX HD (Audio Processing Technology for Bluetooth)"),
194  .type = AVMEDIA_TYPE_AUDIO,
195  .id = AV_CODEC_ID_APTX_HD,
196  .priv_data_size = sizeof(AptXContext),
197  .init = ff_aptx_init,
199  .capabilities = AV_CODEC_CAP_DR1,
200  .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
201  .channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_STEREO, 0},
202  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S32P,
204 };
205 #endif
AVCodec
AVCodec.
Definition: codec.h:202
Channel
Definition: aptx.h:83
FF_CODEC_CAP_INIT_THREADSAFE
#define FF_CODEC_CAP_INIT_THREADSAFE
The codec does not modify any global variables in the init function, allowing to call the init functi...
Definition: internal.h:42
init
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:31
FILTER_TAPS
#define FILTER_TAPS
Definition: aptx.h:48
ff_aptx_hd_decoder
const AVCodec ff_aptx_hd_decoder
aptx_quantized_parity
static int32_t aptx_quantized_parity(Channel *channel)
Definition: aptx.h:191
QMFAnalysis
Definition: aptx.h:55
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:303
AVPacket::data
uint8_t * data
Definition: packet.h:373
ff_aptx_generate_dither
void ff_aptx_generate_dither(Channel *channel)
Definition: aptx.c:384
AV_SAMPLE_FMT_S32P
@ AV_SAMPLE_FMT_S32P
signed 32 bits, planar
Definition: samplefmt.h:68
data
const char data[16]
Definition: mxf.c:143
aptx_decode_channel
static void aptx_decode_channel(Channel *channel, int32_t samples[4])
Definition: aptxdec.c:81
AV_WN32A
#define AV_WN32A(p, v)
Definition: intreadwrite.h:538
subbands
subbands
Definition: aptx.h:39
AptXContext
Definition: aptx.h:94
QMFAnalysis::inner_filter_signal
FilterSignal inner_filter_signal[NB_FILTERS][NB_FILTERS]
Definition: aptx.h:57
NB_FILTERS
@ NB_FILTERS
Definition: vf_waveform.c:54
AV_CH_LAYOUT_STEREO
#define AV_CH_LAYOUT_STEREO
Definition: channel_layout.h:91
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
decode
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:71
s
#define s(width, name)
Definition: cbs_vp9.c:257
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
NB_CHANNELS
@ NB_CHANNELS
Definition: aptx.h:36
ctx
AVFormatContext * ctx
Definition: movenc.c:48
aptx_qmf_tree_synthesis
static void aptx_qmf_tree_synthesis(QMFAnalysis *qmf, int32_t subband_samples[4], int32_t samples[4])
Definition: aptxdec.c:56
QMFAnalysis::outer_filter_signal
FilterSignal outer_filter_signal[NB_FILTERS]
Definition: aptx.h:56
aptx_qmf_convolution
static av_always_inline int32_t aptx_qmf_convolution(FilterSignal *signal, const int32_t coeffs[FILTER_TAPS], int shift)
Definition: aptx.h:177
aptx_qmf_outer_coeffs
static const int32_t aptx_qmf_outer_coeffs[NB_FILTERS][FILTER_TAPS]
Definition: aptx.h:135
FilterSignal
Definition: aptx.h:50
aptx.h
ff_get_buffer
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1652
AV_CODEC_CAP_DR1
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
AVPacket::size
int size
Definition: packet.h:374
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
aptx_qmf_inner_coeffs
static const int32_t aptx_qmf_inner_coeffs[NB_FILTERS][FILTER_TAPS]
Definition: aptx.h:150
AV_SAMPLE_FMT_NONE
@ AV_SAMPLE_FMT_NONE
Definition: samplefmt.h:59
sample
#define sample
Definition: flacdsp_template.c:44
ff_aptx_decoder
const AVCodec ff_aptx_decoder
input
and forward the test the status of outputs and forward it to the corresponding return FFERROR_NOT_READY If the filters stores internally one or a few frame for some input
Definition: filter_design.txt:172
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:271
aptx_unpack_codeword
static void aptx_unpack_codeword(Channel *channel, uint16_t codeword)
Definition: aptxdec.c:90
AVSampleFormat
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
av_always_inline
#define av_always_inline
Definition: attributes.h:49
aptxhd_unpack_codeword
static void aptxhd_unpack_codeword(Channel *channel, uint32_t codeword)
Definition: aptxdec.c:100
aptx_qmf_filter_signal_push
static av_always_inline void aptx_qmf_filter_signal_push(FilterSignal *signal, int32_t sample)
Definition: aptx.h:165
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:209
ret
ret
Definition: filter_design.txt:187
frame
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a frame
Definition: filter_design.txt:264
pos
unsigned int pos
Definition: spdifenc.c:412
ff_aptx_init
av_cold int ff_aptx_init(AVCodecContext *avctx)
Definition: aptx.c:507
AVCodecContext
main external API structure.
Definition: avcodec.h:383
channel_layout.h
ff_aptx_invert_quantize_and_prediction
void ff_aptx_invert_quantize_and_prediction(Channel *channel, int hd)
Definition: aptx.c:496
aptx_decode_samples
static int aptx_decode_samples(AptXContext *ctx, const uint8_t *input, int32_t samples[NB_CHANNELS][4])
Definition: aptxdec.c:110
sign_extend
static av_const int sign_extend(int val, unsigned bits)
Definition: mathops.h:130
samples
Filter the word “frame” indicates either a video frame or a group of audio samples
Definition: filter_design.txt:8
aptx_decode_frame
static int aptx_decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt)
Definition: aptxdec.c:136
shift
static int shift(int a, int b)
Definition: sonic.c:83
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:410
AVPacket
This structure stores compressed data.
Definition: packet.h:350
channel_layouts
static const uint16_t channel_layouts[7]
Definition: dca_lbr.c:114
int32_t
int32_t
Definition: audioconvert.c:56
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
AV_CODEC_ID_APTX
@ AV_CODEC_ID_APTX
Definition: codec_id.h:508
NB_SUBBANDS
@ NB_SUBBANDS
Definition: aptx.h:44
AV_RB24
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_RB24
Definition: bytestream.h:97
AV_CODEC_ID_APTX_HD
@ AV_CODEC_ID_APTX_HD
Definition: codec_id.h:509
channel
channel
Definition: ebur128.h:39
AV_RB16
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_WB24 unsigned int_TMPL AV_RB16
Definition: bytestream.h:98
aptx_qmf_polyphase_synthesis
static av_always_inline 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])
Definition: aptxdec.c:32
aptx_check_parity
static int aptx_check_parity(Channel channels[NB_CHANNELS], int32_t *idx)
Definition: aptx.h:204