/*
* Copyright 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define LOG_TAG "a2dp_vendor_aptx_encoder"
#include "a2dp_vendor_aptx_encoder.h"
#include <dlfcn.h>
#include <inttypes.h>
#include <stdio.h>
#include <string.h>
#include "a2dp_vendor.h"
#include "a2dp_vendor_aptx.h"
#include "bt_common.h"
#include "common/time_util.h"
#include "osi/include/log.h"
#include "osi/include/osi.h"
//
// Encoder for aptX Source Codec
//
//
// The aptX encoder shared library, and the functions to use
//
static const char* APTX_ENCODER_LIB_NAME = "libaptX_encoder.so";
static void* aptx_encoder_lib_handle = NULL;
static const char* APTX_ENCODER_INIT_NAME = "aptxbtenc_init";
typedef int (*tAPTX_ENCODER_INIT)(void* state, short endian);
static const char* APTX_ENCODER_ENCODE_STEREO_NAME = "aptxbtenc_encodestereo";
typedef int (*tAPTX_ENCODER_ENCODE_STEREO)(void* state, void* pcmL, void* pcmR,
void* buffer);
static const char* APTX_ENCODER_SIZEOF_PARAMS_NAME = "SizeofAptxbtenc";
typedef int (*tAPTX_ENCODER_SIZEOF_PARAMS)(void);
static tAPTX_ENCODER_INIT aptx_encoder_init_func;
static tAPTX_ENCODER_ENCODE_STEREO aptx_encoder_encode_stereo_func;
static tAPTX_ENCODER_SIZEOF_PARAMS aptx_encoder_sizeof_params_func;
// offset
#if (BTA_AV_CO_CP_SCMS_T == TRUE)
#define A2DP_APTX_OFFSET (AVDT_MEDIA_OFFSET + 1)
#else
// no RTP header for aptX classic
#define A2DP_APTX_OFFSET (AVDT_MEDIA_OFFSET - AVDT_MEDIA_HDR_SIZE)
#endif
#define A2DP_APTX_MAX_PCM_BYTES_PER_READ 4096
typedef struct {
uint64_t sleep_time_ns;
uint32_t pcm_reads;
uint32_t pcm_bytes_per_read;
uint32_t aptx_bytes;
uint32_t frame_size_counter;
} tAPTX_FRAMING_PARAMS;
typedef struct {
uint64_t session_start_us;
size_t media_read_total_expected_packets;
size_t media_read_total_expected_reads_count;
size_t media_read_total_expected_read_bytes;
size_t media_read_total_dropped_packets;
size_t media_read_total_actual_reads_count;
size_t media_read_total_actual_read_bytes;
} a2dp_aptx_encoder_stats_t;
typedef struct {
a2dp_source_read_callback_t read_callback;
a2dp_source_enqueue_callback_t enqueue_callback;
bool use_SCMS_T;
bool is_peer_edr; // True if the peer device supports EDR
bool peer_supports_3mbps; // True if the peer device supports 3Mbps EDR
uint16_t peer_mtu; // MTU of the A2DP peer
uint32_t timestamp; // Timestamp for the A2DP frames
tA2DP_FEEDING_PARAMS feeding_params;
tAPTX_FRAMING_PARAMS framing_params;
void* aptx_encoder_state;
a2dp_aptx_encoder_stats_t stats;
} tA2DP_APTX_ENCODER_CB;
static tA2DP_APTX_ENCODER_CB a2dp_aptx_encoder_cb;
static void a2dp_vendor_aptx_encoder_update(uint16_t peer_mtu,
A2dpCodecConfig* a2dp_codec_config,
bool* p_restart_input,
bool* p_restart_output,
bool* p_config_updated);
static void aptx_init_framing_params(tAPTX_FRAMING_PARAMS* framing_params);
static void aptx_update_framing_params(tAPTX_FRAMING_PARAMS* framing_params);
static size_t aptx_encode_16bit(tAPTX_FRAMING_PARAMS* framing_params,
size_t* data_out_index, uint16_t* data16_in,
uint8_t* data_out);
bool A2DP_VendorLoadEncoderAptx(void) {
if (aptx_encoder_lib_handle != NULL) return true; // Already loaded
// Open the encoder library
aptx_encoder_lib_handle = dlopen(APTX_ENCODER_LIB_NAME, RTLD_NOW);
if (aptx_encoder_lib_handle == NULL) {
LOG_ERROR(LOG_TAG, "%s: cannot open aptX encoder library %s: %s", __func__,
APTX_ENCODER_LIB_NAME, dlerror());
return false;
}
aptx_encoder_init_func = (tAPTX_ENCODER_INIT)dlsym(aptx_encoder_lib_handle,
APTX_ENCODER_INIT_NAME);
if (aptx_encoder_init_func == NULL) {
LOG_ERROR(LOG_TAG,
"%s: cannot find function '%s' in the encoder library: %s",
__func__, APTX_ENCODER_INIT_NAME, dlerror());
A2DP_VendorUnloadEncoderAptx();
return false;
}
aptx_encoder_encode_stereo_func = (tAPTX_ENCODER_ENCODE_STEREO)dlsym(
aptx_encoder_lib_handle, APTX_ENCODER_ENCODE_STEREO_NAME);
if (aptx_encoder_encode_stereo_func == NULL) {
LOG_ERROR(LOG_TAG,
"%s: cannot find function '%s' in the encoder library: %s",
__func__, APTX_ENCODER_ENCODE_STEREO_NAME, dlerror());
A2DP_VendorUnloadEncoderAptx();
return false;
}
aptx_encoder_sizeof_params_func = (tAPTX_ENCODER_SIZEOF_PARAMS)dlsym(
aptx_encoder_lib_handle, APTX_ENCODER_SIZEOF_PARAMS_NAME);
if (aptx_encoder_sizeof_params_func == NULL) {
LOG_ERROR(LOG_TAG,
"%s: cannot find function '%s' in the encoder library: %s",
__func__, APTX_ENCODER_SIZEOF_PARAMS_NAME, dlerror());
A2DP_VendorUnloadEncoderAptx();
return false;
}
return true;
}
void A2DP_VendorUnloadEncoderAptx(void) {
aptx_encoder_init_func = NULL;
aptx_encoder_encode_stereo_func = NULL;
aptx_encoder_sizeof_params_func = NULL;
if (aptx_encoder_lib_handle != NULL) {
dlclose(aptx_encoder_lib_handle);
aptx_encoder_lib_handle = NULL;
}
}
void a2dp_vendor_aptx_encoder_init(
const tA2DP_ENCODER_INIT_PEER_PARAMS* p_peer_params,
A2dpCodecConfig* a2dp_codec_config,
a2dp_source_read_callback_t read_callback,
a2dp_source_enqueue_callback_t enqueue_callback) {
memset(&a2dp_aptx_encoder_cb, 0, sizeof(a2dp_aptx_encoder_cb));
a2dp_aptx_encoder_cb.stats.session_start_us =
bluetooth::common::time_get_os_boottime_us();
a2dp_aptx_encoder_cb.read_callback = read_callback;
a2dp_aptx_encoder_cb.enqueue_callback = enqueue_callback;
a2dp_aptx_encoder_cb.is_peer_edr = p_peer_params->is_peer_edr;
a2dp_aptx_encoder_cb.peer_supports_3mbps = p_peer_params->peer_supports_3mbps;
a2dp_aptx_encoder_cb.peer_mtu = p_peer_params->peer_mtu;
a2dp_aptx_encoder_cb.timestamp = 0;
/* aptX encoder config */
a2dp_aptx_encoder_cb.use_SCMS_T = false; // TODO: should be a parameter
#if (BTA_AV_CO_CP_SCMS_T == TRUE)
a2dp_aptx_encoder_cb.use_SCMS_T = true;
#endif
a2dp_aptx_encoder_cb.aptx_encoder_state =
osi_malloc(aptx_encoder_sizeof_params_func());
if (a2dp_aptx_encoder_cb.aptx_encoder_state != NULL) {
aptx_encoder_init_func(a2dp_aptx_encoder_cb.aptx_encoder_state, 0);
} else {
LOG_ERROR(LOG_TAG, "%s: Cannot allocate aptX encoder state", __func__);
// TODO: Return an error?
}
// NOTE: Ignore the restart_input / restart_output flags - this initization
// happens when the connection is (re)started.
bool restart_input = false;
bool restart_output = false;
bool config_updated = false;
a2dp_vendor_aptx_encoder_update(a2dp_aptx_encoder_cb.peer_mtu,
a2dp_codec_config, &restart_input,
&restart_output, &config_updated);
}
bool A2dpCodecConfigAptx::updateEncoderUserConfig(
const tA2DP_ENCODER_INIT_PEER_PARAMS* p_peer_params, bool* p_restart_input,
bool* p_restart_output, bool* p_config_updated) {
a2dp_aptx_encoder_cb.is_peer_edr = p_peer_params->is_peer_edr;
a2dp_aptx_encoder_cb.peer_supports_3mbps = p_peer_params->peer_supports_3mbps;
a2dp_aptx_encoder_cb.peer_mtu = p_peer_params->peer_mtu;
a2dp_aptx_encoder_cb.timestamp = 0;
if (a2dp_aptx_encoder_cb.peer_mtu == 0) {
LOG_ERROR(LOG_TAG,
"%s: Cannot update the codec encoder for %s: "
"invalid peer MTU",
__func__, name().c_str());
return false;
}
a2dp_vendor_aptx_encoder_update(a2dp_aptx_encoder_cb.peer_mtu, this,
p_restart_input, p_restart_output,
p_config_updated);
return true;
}
// Update the A2DP aptX encoder.
// |peer_mtu| is the peer MTU.
// |a2dp_codec_config| is the A2DP codec to use for the update.
static void a2dp_vendor_aptx_encoder_update(uint16_t peer_mtu,
A2dpCodecConfig* a2dp_codec_config,
bool* p_restart_input,
bool* p_restart_output,
bool* p_config_updated) {
uint8_t codec_info[AVDT_CODEC_SIZE];
*p_restart_input = false;
*p_restart_output = false;
*p_config_updated = false;
if (!a2dp_codec_config->copyOutOtaCodecConfig(codec_info)) {
LOG_ERROR(LOG_TAG,
"%s: Cannot update the codec encoder for %s: "
"invalid codec config",
__func__, a2dp_codec_config->name().c_str());
return;
}
const uint8_t* p_codec_info = codec_info;
// The feeding parameters
tA2DP_FEEDING_PARAMS* p_feeding_params = &a2dp_aptx_encoder_cb.feeding_params;
p_feeding_params->sample_rate =
A2DP_VendorGetTrackSampleRateAptx(p_codec_info);
p_feeding_params->bits_per_sample =
a2dp_codec_config->getAudioBitsPerSample();
p_feeding_params->channel_count =
A2DP_VendorGetTrackChannelCountAptx(p_codec_info);
LOG_DEBUG(LOG_TAG, "%s: sample_rate=%u bits_per_sample=%u channel_count=%u",
__func__, p_feeding_params->sample_rate,
p_feeding_params->bits_per_sample, p_feeding_params->channel_count);
a2dp_vendor_aptx_feeding_reset();
}
void a2dp_vendor_aptx_encoder_cleanup(void) {
osi_free(a2dp_aptx_encoder_cb.aptx_encoder_state);
memset(&a2dp_aptx_encoder_cb, 0, sizeof(a2dp_aptx_encoder_cb));
}
//
// Initialize the framing parameters, and set those that don't change
// while streaming (e.g., 'sleep_time_ns').
//
static void aptx_init_framing_params(tAPTX_FRAMING_PARAMS* framing_params) {
framing_params->sleep_time_ns = 0;
framing_params->pcm_reads = 0;
framing_params->pcm_bytes_per_read = 0;
framing_params->aptx_bytes = 0;
framing_params->frame_size_counter = 0;
if (a2dp_aptx_encoder_cb.feeding_params.sample_rate == 48000) {
if (a2dp_aptx_encoder_cb.use_SCMS_T) {
framing_params->sleep_time_ns = 13000000;
} else {
framing_params->sleep_time_ns = 14000000;
}
} else {
// Assume the sample rate is 44100
if (a2dp_aptx_encoder_cb.use_SCMS_T) {
framing_params->sleep_time_ns = 14000000;
} else {
framing_params->sleep_time_ns = 15000000;
}
}
LOG_DEBUG(LOG_TAG, "%s: sleep_time_ns = %" PRIu64, __func__,
framing_params->sleep_time_ns);
}
//
// Set frame size and transmission interval needed to stream the required
// sample rate using 2-DH5 packets for aptX and 2-DH3 packets for aptX-LL.
// With SCMS-T enabled we need to reserve room for extra headers added later.
// Packets are always sent at equals time intervals but to achieve the
// required sample rate, the frame size needs to change on occasion.
//
// Also need to specify how many of the required PCM samples are read at a
// time:
// aptx_bytes = pcm_reads * pcm_bytes_per_read / 4
// and
// number of aptX samples produced = pcm_bytes_per_read / 16
//
static void aptx_update_framing_params(tAPTX_FRAMING_PARAMS* framing_params) {
if (a2dp_aptx_encoder_cb.feeding_params.sample_rate == 48000) {
if (a2dp_aptx_encoder_cb.use_SCMS_T) {
framing_params->aptx_bytes = 624;
framing_params->pcm_bytes_per_read = 208;
framing_params->pcm_reads = 12;
} else {
framing_params->aptx_bytes = 672;
framing_params->pcm_bytes_per_read = 224;
framing_params->pcm_reads = 12;
}
} else {
// Assume the sample rate is 44100
if (a2dp_aptx_encoder_cb.use_SCMS_T) {
if (++framing_params->frame_size_counter < 20) {
framing_params->aptx_bytes = 616;
framing_params->pcm_bytes_per_read = 224;
framing_params->pcm_reads = 11;
} else {
framing_params->aptx_bytes = 644;
framing_params->pcm_bytes_per_read = 368;
framing_params->pcm_reads = 7;
framing_params->frame_size_counter = 0;
}
} else {
if (++framing_params->frame_size_counter < 8) {
framing_params->aptx_bytes = 660;
framing_params->pcm_bytes_per_read = 240;
framing_params->pcm_reads = 11;
} else {
framing_params->aptx_bytes = 672;
framing_params->pcm_bytes_per_read = 224;
framing_params->pcm_reads = 12;
framing_params->frame_size_counter = 0;
}
}
}
LOG_VERBOSE(LOG_TAG,
"%s: sleep_time_ns = %" PRIu64
" aptx_bytes = %u "
"pcm_bytes_per_read = %u pcm_reads = %u frame_size_counter = %u",
__func__, framing_params->sleep_time_ns,
framing_params->aptx_bytes, framing_params->pcm_bytes_per_read,
framing_params->pcm_reads, framing_params->frame_size_counter);
}
void a2dp_vendor_aptx_feeding_reset(void) {
aptx_init_framing_params(&a2dp_aptx_encoder_cb.framing_params);
}
void a2dp_vendor_aptx_feeding_flush(void) {
aptx_init_framing_params(&a2dp_aptx_encoder_cb.framing_params);
}
uint64_t a2dp_vendor_aptx_get_encoder_interval_ms(void) {
return a2dp_aptx_encoder_cb.framing_params.sleep_time_ns / (1000 * 1000);
}
void a2dp_vendor_aptx_send_frames(uint64_t timestamp_us) {
tAPTX_FRAMING_PARAMS* framing_params = &a2dp_aptx_encoder_cb.framing_params;
// Prepare the packet to send
BT_HDR* p_buf = (BT_HDR*)osi_malloc(BT_DEFAULT_BUFFER_SIZE);
p_buf->offset = A2DP_APTX_OFFSET;
p_buf->len = 0;
p_buf->layer_specific = 0;
uint8_t* encoded_ptr = (uint8_t*)(p_buf + 1);
encoded_ptr += p_buf->offset;
aptx_update_framing_params(framing_params);
//
// Read the PCM data and encode it
//
uint16_t read_buffer16[A2DP_APTX_MAX_PCM_BYTES_PER_READ / sizeof(uint16_t)];
uint32_t expected_read_bytes =
framing_params->pcm_reads * framing_params->pcm_bytes_per_read;
size_t encoded_ptr_index = 0;
size_t pcm_bytes_encoded = 0;
uint32_t bytes_read = 0;
a2dp_aptx_encoder_cb.stats.media_read_total_expected_packets++;
a2dp_aptx_encoder_cb.stats.media_read_total_expected_reads_count++;
a2dp_aptx_encoder_cb.stats.media_read_total_expected_read_bytes +=
expected_read_bytes;
LOG_VERBOSE(LOG_TAG, "%s: PCM read of size %u", __func__,
expected_read_bytes);
bytes_read = a2dp_aptx_encoder_cb.read_callback((uint8_t*)read_buffer16,
expected_read_bytes);
a2dp_aptx_encoder_cb.stats.media_read_total_actual_read_bytes += bytes_read;
if (bytes_read < expected_read_bytes) {
LOG_WARN(LOG_TAG,
"%s: underflow at PCM reading: read %u bytes instead of %u",
__func__, bytes_read, expected_read_bytes);
a2dp_aptx_encoder_cb.stats.media_read_total_dropped_packets++;
osi_free(p_buf);
return;
}
a2dp_aptx_encoder_cb.stats.media_read_total_actual_reads_count++;
for (uint32_t reads = 0, offset = 0; reads < framing_params->pcm_reads;
reads++, offset +=
(framing_params->pcm_bytes_per_read / sizeof(uint16_t))) {
pcm_bytes_encoded += aptx_encode_16bit(framing_params, &encoded_ptr_index,
read_buffer16 + offset, encoded_ptr);
}
// Compute the number of encoded bytes
const int COMPRESSION_RATIO = 4;
size_t encoded_bytes = pcm_bytes_encoded / COMPRESSION_RATIO;
p_buf->len += encoded_bytes;
LOG_VERBOSE(LOG_TAG, "%s: encoded %zu PCM bytes to %zu", __func__,
pcm_bytes_encoded, encoded_bytes);
// Update the RTP timestamp
*((uint32_t*)(p_buf + 1)) = a2dp_aptx_encoder_cb.timestamp;
const uint8_t BYTES_PER_FRAME = 2;
uint32_t rtp_timestamp =
(pcm_bytes_encoded / a2dp_aptx_encoder_cb.feeding_params.channel_count) /
BYTES_PER_FRAME;
a2dp_aptx_encoder_cb.timestamp += rtp_timestamp;
if (p_buf->len > 0) {
a2dp_aptx_encoder_cb.enqueue_callback(p_buf, 1, bytes_read);
} else {
a2dp_aptx_encoder_cb.stats.media_read_total_dropped_packets++;
osi_free(p_buf);
}
}
static size_t aptx_encode_16bit(tAPTX_FRAMING_PARAMS* framing_params,
size_t* data_out_index, uint16_t* data16_in,
uint8_t* data_out) {
size_t pcm_bytes_encoded = 0;
size_t frame = 0;
for (size_t aptx_samples = 0;
aptx_samples < framing_params->pcm_bytes_per_read / 16; aptx_samples++) {
uint32_t pcmL[4];
uint32_t pcmR[4];
uint16_t encoded_sample[2];
for (size_t i = 0, j = frame; i < 4; i++, j++) {
pcmL[i] = (uint16_t) * (data16_in + (2 * j));
pcmR[i] = (uint16_t) * (data16_in + ((2 * j) + 1));
}
aptx_encoder_encode_stereo_func(a2dp_aptx_encoder_cb.aptx_encoder_state,
&pcmL, &pcmR, &encoded_sample);
data_out[*data_out_index + 0] = (uint8_t)((encoded_sample[0] >> 8) & 0xff);
data_out[*data_out_index + 1] = (uint8_t)((encoded_sample[0] >> 0) & 0xff);
data_out[*data_out_index + 2] = (uint8_t)((encoded_sample[1] >> 8) & 0xff);
data_out[*data_out_index + 3] = (uint8_t)((encoded_sample[1] >> 0) & 0xff);
frame += 4;
pcm_bytes_encoded += 16;
*data_out_index += 4;
}
return pcm_bytes_encoded;
}
uint64_t A2dpCodecConfigAptx::encoderIntervalMs() const {
return a2dp_vendor_aptx_get_encoder_interval_ms();
}
int A2dpCodecConfigAptx::getEffectiveMtu() const {
return a2dp_aptx_encoder_cb.peer_mtu;
}
void A2dpCodecConfigAptx::debug_codec_dump(int fd) {
a2dp_aptx_encoder_stats_t* stats = &a2dp_aptx_encoder_cb.stats;
A2dpCodecConfig::debug_codec_dump(fd);
dprintf(fd,
" Packet counts (expected/dropped) : %zu / "
"%zu\n",
stats->media_read_total_expected_packets,
stats->media_read_total_dropped_packets);
dprintf(fd,
" PCM read counts (expected/actual) : %zu / "
"%zu\n",
stats->media_read_total_expected_reads_count,
stats->media_read_total_actual_reads_count);
dprintf(fd,
" PCM read bytes (expected/actual) : %zu / "
"%zu\n",
stats->media_read_total_expected_read_bytes,
stats->media_read_total_actual_read_bytes);
}