[pulseaudio-discuss] SBC XQ for PA 13.0

Hyperion h1p8r10n at yandex.com
Thu Sep 19 09:14:21 UTC 2019


Yes, thanks, you're right, I'm going to do it as soon as I get enough testing feedback.

Talking about tests : I'm going to switch back to Pali's default values for announced bitpool capabilities, cause some (rare) devices produces a few distorsion with dual channel 47 bitpool.

So back to dual 38 / 76 , which should be ok on any device.

New patch : http://download.zenwalk.org/x86_64/testing/pulseaudio-13.0-SBC-XQ_V3.patch

Thanks for testing :)

jp

19.09.2019, 10:27, "Andrey Semashev" <andrey.semashev at gmail.com>:
> I'm not the maintainer, but it might be better to create a merge request
> in GitLab project:
>
> https://gitlab.freedesktop.org/pulseaudio/pulseaudio
>
> and post any additional information there so it doesn't get lost.
>
> On 2019-09-18 14:02, Hyperion wrote:
>>  Patch V2 with added DUAL_CHANNEL as preferred mode.
>>
>>  Works without any issue on more than 10 stereo and mono devices that I have here.
>>
>>  http://download.zenwalk.org/x86_64/testing/pulseaudio-13.0-SBC-XQ_V2.patch
>>
>>  /***
>>     This file is part of PulseAudio.
>>
>>     Copyright 2018-2019 Pali Rohár <pali.rohar at gmail.com>
>>
>>     PulseAudio 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.
>>
>>     PulseAudio 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
>>     General Public License for more details.
>>
>>     You should have received a copy of the GNU Lesser General Public
>>     License along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
>>  ***/
>>
>>  #ifdef HAVE_CONFIG_H
>>  #include <config.h>
>>  #endif
>>
>>  #include <pulsecore/core-util.h>
>>  #include <pulsecore/log.h>
>>  #include <pulsecore/macro.h>
>>  #include <pulsecore/once.h>
>>  #include <pulse/sample.h>
>>  #include <pulse/xmalloc.h>
>>
>>  #include <arpa/inet.h>
>>
>>  #include <sbc/sbc.h>
>>
>>  #include "a2dp-codecs.h"
>>  #include "a2dp-codec-api.h"
>>  #include "rtp.h"
>>
>>  #define SBC_BITPOOL_DEC_LIMIT 32
>>  #define SBC_BITPOOL_DEC_STEP 5
>>
>>  struct sbc_info {
>>       sbc_t sbc; /* Codec data */
>>       size_t codesize, frame_length; /* SBC Codesize, frame_length. We simply cache those values here */
>>       uint16_t seq_num; /* Cumulative packet sequence */
>>       uint8_t frequency;
>>       uint8_t blocks;
>>       uint8_t subbands;
>>       uint8_t mode;
>>       uint8_t allocation;
>>       uint8_t initial_bitpool;
>>       uint8_t min_bitpool;
>>       uint8_t max_bitpool;
>>  };
>>
>>  static bool can_accept_capabilities(const uint8_t *capabilities_buffer, uint8_t capabilities_size, bool for_encoding) {
>>       const a2dp_sbc_t *capabilities = (const a2dp_sbc_t *) capabilities_buffer;
>>
>>       if (capabilities_size != sizeof(*capabilities))
>>           return false;
>>
>>       if (!(capabilities->frequency & (SBC_SAMPLING_FREQ_16000 | SBC_SAMPLING_FREQ_32000 | SBC_SAMPLING_FREQ_44100 | SBC_SAMPLING_FREQ_48000)))
>>           return false;
>>
>>       if (!(capabilities->channel_mode & (SBC_CHANNEL_MODE_MONO | SBC_CHANNEL_MODE_DUAL_CHANNEL | SBC_CHANNEL_MODE_STEREO | SBC_CHANNEL_MODE_JOINT_STEREO)))
>>           return false;
>>
>>       if (!(capabilities->allocation_method & (SBC_ALLOCATION_SNR | SBC_ALLOCATION_LOUDNESS)))
>>           return false;
>>
>>       if (!(capabilities->subbands & (SBC_SUBBANDS_4 | SBC_SUBBANDS_8)))
>>           return false;
>>
>>       if (!(capabilities->block_length & (SBC_BLOCK_LENGTH_4 | SBC_BLOCK_LENGTH_8 | SBC_BLOCK_LENGTH_12 | SBC_BLOCK_LENGTH_16)))
>>           return false;
>>
>>       return true;
>>  }
>>
>>  static const char *choose_remote_endpoint(const pa_hashmap *capabilities_hashmap, const pa_sample_spec *default_sample_spec, bool for_encoding) {
>>       const pa_a2dp_codec_capabilities *a2dp_capabilities;
>>       const char *key;
>>       void *state;
>>
>>       /* There is no preference, just choose random valid entry */
>>       PA_HASHMAP_FOREACH_KV(key, a2dp_capabilities, capabilities_hashmap, state) {
>>           if (can_accept_capabilities(a2dp_capabilities->buffer, a2dp_capabilities->size, for_encoding))
>>               return key;
>>       }
>>
>>       return NULL;
>>  }
>>
>>  static uint8_t fill_capabilities(uint8_t capabilities_buffer[MAX_A2DP_CAPS_SIZE]) {
>>       a2dp_sbc_t *capabilities = (a2dp_sbc_t *) capabilities_buffer;
>>
>>       pa_zero(*capabilities);
>>
>>       capabilities->channel_mode = SBC_CHANNEL_MODE_MONO | SBC_CHANNEL_MODE_DUAL_CHANNEL | SBC_CHANNEL_MODE_STEREO |
>>                                    SBC_CHANNEL_MODE_JOINT_STEREO;
>>       capabilities->frequency = SBC_SAMPLING_FREQ_16000 | SBC_SAMPLING_FREQ_32000 | SBC_SAMPLING_FREQ_44100 |
>>                                 SBC_SAMPLING_FREQ_48000;
>>       capabilities->allocation_method = SBC_ALLOCATION_SNR | SBC_ALLOCATION_LOUDNESS;
>>       capabilities->subbands = SBC_SUBBANDS_4 | SBC_SUBBANDS_8;
>>       capabilities->block_length = SBC_BLOCK_LENGTH_4 | SBC_BLOCK_LENGTH_8 | SBC_BLOCK_LENGTH_12 | SBC_BLOCK_LENGTH_16;
>>       capabilities->min_bitpool = SBC_MIN_BITPOOL;
>>       capabilities->max_bitpool = SBC_BITPOOL_HQ_JOINT_STEREO_44100;
>>
>>       return sizeof(*capabilities);
>>  }
>>
>>  static bool is_configuration_valid(const uint8_t *config_buffer, uint8_t config_size) {
>>       const a2dp_sbc_t *config = (const a2dp_sbc_t *) config_buffer;
>>
>>       if (config_size != sizeof(*config)) {
>>           pa_log_error("Invalid size of config buffer");
>>           return false;
>>       }
>>
>>       if (config->frequency != SBC_SAMPLING_FREQ_16000 && config->frequency != SBC_SAMPLING_FREQ_32000 &&
>>           config->frequency != SBC_SAMPLING_FREQ_44100 && config->frequency != SBC_SAMPLING_FREQ_48000) {
>>           pa_log_error("Invalid sampling frequency in configuration");
>>           return false;
>>       }
>>
>>       if (config->channel_mode != SBC_CHANNEL_MODE_MONO && config->channel_mode != SBC_CHANNEL_MODE_DUAL_CHANNEL &&
>>           config->channel_mode != SBC_CHANNEL_MODE_STEREO && config->channel_mode != SBC_CHANNEL_MODE_JOINT_STEREO) {
>>           pa_log_error("Invalid channel mode in configuration");
>>           return false;
>>       }
>>
>>       if (config->allocation_method != SBC_ALLOCATION_SNR && config->allocation_method != SBC_ALLOCATION_LOUDNESS) {
>>           pa_log_error("Invalid allocation method in configuration");
>>           return false;
>>       }
>>
>>       if (config->subbands != SBC_SUBBANDS_4 && config->subbands != SBC_SUBBANDS_8) {
>>           pa_log_error("Invalid SBC subbands in configuration");
>>           return false;
>>       }
>>
>>       if (config->block_length != SBC_BLOCK_LENGTH_4 && config->block_length != SBC_BLOCK_LENGTH_8 &&
>>           config->block_length != SBC_BLOCK_LENGTH_12 && config->block_length != SBC_BLOCK_LENGTH_16) {
>>           pa_log_error("Invalid block length in configuration");
>>           return false;
>>       }
>>
>>       if (config->min_bitpool > config->max_bitpool) {
>>           pa_log_error("Invalid bitpool in configuration");
>>           return false;
>>       }
>>
>>       return true;
>>  }
>>
>>  static uint8_t default_bitpool(uint8_t freq, uint8_t mode) {
>>       /* These bitpool values were chosen based on the A2DP spec recommendation */
>>       switch (freq) {
>>           case SBC_SAMPLING_FREQ_48000:
>>               switch (mode) {
>>                   case SBC_CHANNEL_MODE_MONO:
>>                   case SBC_CHANNEL_MODE_DUAL_CHANNEL:
>>                       return SBC_BITPOOL_HQ_MONO_48000;
>>
>>                   case SBC_CHANNEL_MODE_STEREO:
>>                   case SBC_CHANNEL_MODE_JOINT_STEREO:
>>                       return SBC_BITPOOL_HQ_JOINT_STEREO_48000;
>>               }
>>               break;
>>           case SBC_SAMPLING_FREQ_44100:
>>               switch (mode) {
>>                   case SBC_CHANNEL_MODE_MONO:
>>                   case SBC_CHANNEL_MODE_DUAL_CHANNEL:
>>                       return SBC_BITPOOL_HQ_MONO_44100;
>>
>>                   case SBC_CHANNEL_MODE_STEREO:
>>                   case SBC_CHANNEL_MODE_JOINT_STEREO:
>>                       return SBC_BITPOOL_HQ_JOINT_STEREO_44100;
>>               }
>>               break;
>>           case SBC_SAMPLING_FREQ_16000:
>>           case SBC_SAMPLING_FREQ_32000:
>>               switch (mode) {
>>                   case SBC_CHANNEL_MODE_MONO:
>>                   case SBC_CHANNEL_MODE_DUAL_CHANNEL:
>>                   case SBC_CHANNEL_MODE_STEREO:
>>                   case SBC_CHANNEL_MODE_JOINT_STEREO:
>>                       return SBC_BITPOOL_HQ_JOINT_STEREO_44100;
>>               }
>>               break;
>>       }
>>
>>       pa_assert_not_reached();
>>  }
>>
>>  static uint8_t fill_preferred_configuration(const pa_sample_spec *default_sample_spec, const uint8_t *capabilities_buffer, uint8_t capabilities_size, uint8_t config_buffer[MAX_A2DP_CAPS_SIZE]) {
>>       a2dp_sbc_t *config = (a2dp_sbc_t *) config_buffer;
>>       const a2dp_sbc_t *capabilities = (const a2dp_sbc_t *) capabilities_buffer;
>>       int i;
>>
>>       static const struct {
>>           uint32_t rate;
>>           uint8_t cap;
>>       } freq_table[] = {
>>           { 16000U, SBC_SAMPLING_FREQ_16000 },
>>           { 32000U, SBC_SAMPLING_FREQ_32000 },
>>           { 44100U, SBC_SAMPLING_FREQ_44100 },
>>           { 48000U, SBC_SAMPLING_FREQ_48000 }
>>       };
>>
>>       if (capabilities_size != sizeof(*capabilities)) {
>>           pa_log_error("Invalid size of capabilities buffer");
>>           return 0;
>>       }
>>
>>       pa_zero(*config);
>>
>>       /* Find the lowest freq that is at least as high as the requested sampling rate */
>>       for (i = 0; (unsigned) i < PA_ELEMENTSOF(freq_table); i++)
>>           if (freq_table[i].rate >= default_sample_spec->rate && (capabilities->frequency & freq_table[i].cap)) {
>>               config->frequency = freq_table[i].cap;
>>               break;
>>           }
>>
>>       if ((unsigned) i == PA_ELEMENTSOF(freq_table)) {
>>           for (--i; i >= 0; i--) {
>>               if (capabilities->frequency & freq_table[i].cap) {
>>                   config->frequency = freq_table[i].cap;
>>                   break;
>>               }
>>           }
>>
>>           if (i < 0) {
>>               pa_log_error("Not suitable sample rate");
>>               return 0;
>>           }
>>       }
>>
>>       pa_assert((unsigned) i < PA_ELEMENTSOF(freq_table));
>>
>>       if (default_sample_spec->channels <= 1) {
>>           if (capabilities->channel_mode & SBC_CHANNEL_MODE_MONO)
>>               config->channel_mode = SBC_CHANNEL_MODE_MONO;
>>           else if (capabilities->channel_mode & SBC_CHANNEL_MODE_JOINT_STEREO)
>>               config->channel_mode = SBC_CHANNEL_MODE_JOINT_STEREO;
>>           else if (capabilities->channel_mode & SBC_CHANNEL_MODE_STEREO)
>>               config->channel_mode = SBC_CHANNEL_MODE_STEREO;
>>           else if (capabilities->channel_mode & SBC_CHANNEL_MODE_DUAL_CHANNEL)
>>               config->channel_mode = SBC_CHANNEL_MODE_DUAL_CHANNEL;
>>           else {
>>               pa_log_error("No supported channel modes");
>>               return 0;
>>           }
>>       } else {
>>           if (capabilities->channel_mode & SBC_CHANNEL_MODE_DUAL_CHANNEL)
>>               config->channel_mode = SBC_CHANNEL_MODE_DUAL_CHANNEL;
>>           else if (capabilities->channel_mode & SBC_CHANNEL_MODE_STEREO)
>>               config->channel_mode = SBC_CHANNEL_MODE_STEREO;
>>           else if (capabilities->channel_mode & SBC_CHANNEL_MODE_JOINT_STEREO)
>>               config->channel_mode = SBC_CHANNEL_MODE_JOINT_STEREO;
>>           else if (capabilities->channel_mode & SBC_CHANNEL_MODE_MONO)
>>               config->channel_mode = SBC_CHANNEL_MODE_MONO;
>>           else {
>>               pa_log_error("No supported channel modes");
>>               return 0;
>>           }
>>       }
>>
>>       if (capabilities->block_length & SBC_BLOCK_LENGTH_16)
>>           config->block_length = SBC_BLOCK_LENGTH_16;
>>       else if (capabilities->block_length & SBC_BLOCK_LENGTH_12)
>>           config->block_length = SBC_BLOCK_LENGTH_12;
>>       else if (capabilities->block_length & SBC_BLOCK_LENGTH_8)
>>           config->block_length = SBC_BLOCK_LENGTH_8;
>>       else if (capabilities->block_length & SBC_BLOCK_LENGTH_4)
>>           config->block_length = SBC_BLOCK_LENGTH_4;
>>       else {
>>           pa_log_error("No supported block lengths");
>>           return 0;
>>       }
>>
>>       if (capabilities->subbands & SBC_SUBBANDS_8)
>>           config->subbands = SBC_SUBBANDS_8;
>>       else if (capabilities->subbands & SBC_SUBBANDS_4)
>>           config->subbands = SBC_SUBBANDS_4;
>>       else {
>>           pa_log_error("No supported subbands");
>>           return 0;
>>       }
>>
>>       if (capabilities->allocation_method & SBC_ALLOCATION_LOUDNESS)
>>           config->allocation_method = SBC_ALLOCATION_LOUDNESS;
>>       else if (capabilities->allocation_method & SBC_ALLOCATION_SNR)
>>           config->allocation_method = SBC_ALLOCATION_SNR;
>>       else {
>>           pa_log_error("No supported allocation method");
>>           return 0;
>>       }
>>
>>       config->min_bitpool = (uint8_t) PA_MAX(SBC_MIN_BITPOOL, capabilities->min_bitpool);
>>       config->max_bitpool = (uint8_t) PA_MIN(default_bitpool(config->frequency, config->channel_mode), capabilities->max_bitpool);
>>
>>       if (config->min_bitpool > config->max_bitpool) {
>>           pa_log_error("No supported bitpool");
>>           return 0;
>>       }
>>
>>       return sizeof(*config);
>>  }
>>
>>  static void set_params(struct sbc_info *sbc_info) {
>>       sbc_info->sbc.frequency = sbc_info->frequency;
>>       sbc_info->sbc.blocks = sbc_info->blocks;
>>       sbc_info->sbc.subbands = sbc_info->subbands;
>>       sbc_info->sbc.mode = sbc_info->mode;
>>       sbc_info->sbc.allocation = sbc_info->allocation;
>>       sbc_info->sbc.bitpool = sbc_info->initial_bitpool;
>>       sbc_info->sbc.endian = SBC_LE;
>>
>>       sbc_info->codesize = sbc_get_codesize(&sbc_info->sbc);
>>       sbc_info->frame_length = sbc_get_frame_length(&sbc_info->sbc);
>>  }
>>
>>  static void *init(bool for_encoding, bool for_backchannel, const uint8_t *config_buffer, uint8_t config_size, pa_sample_spec *sample_spec) {
>>       struct sbc_info *sbc_info;
>>       const a2dp_sbc_t *config = (const a2dp_sbc_t *) config_buffer;
>>       int ret;
>>
>>       pa_assert(config_size == sizeof(*config));
>>       pa_assert(!for_backchannel);
>>
>>       sbc_info = pa_xnew0(struct sbc_info, 1);
>>
>>       ret = sbc_init(&sbc_info->sbc, 0);
>>       if (ret != 0) {
>>           pa_xfree(sbc_info);
>>           pa_log_error("SBC initialization failed: %d", ret);
>>           return NULL;
>>       }
>>
>>       sample_spec->format = PA_SAMPLE_S16LE;
>>
>>       switch (config->frequency) {
>>           case SBC_SAMPLING_FREQ_48000:
>>               sbc_info->frequency = SBC_FREQ_48000;
>>               sample_spec->rate = 48000U;
>>               break;
>>           case SBC_SAMPLING_FREQ_44100:
>>               sbc_info->frequency = SBC_FREQ_44100;
>>               sample_spec->rate = 44100U;
>>               break;
>>           case SBC_SAMPLING_FREQ_32000:
>>               sbc_info->frequency = SBC_FREQ_32000;
>>               sample_spec->rate = 32000U;
>>               break;
>>           case SBC_SAMPLING_FREQ_16000:
>>               sbc_info->frequency = SBC_FREQ_16000;
>>               sample_spec->rate = 16000U;
>>               break;
>>           default:
>>               pa_assert_not_reached();
>>       }
>>
>>       switch (config->channel_mode) {
>>           case SBC_CHANNEL_MODE_DUAL_CHANNEL:
>>               sbc_info->mode = SBC_MODE_DUAL_CHANNEL;
>>               sample_spec->channels = 2;
>>               break;
>>           case SBC_CHANNEL_MODE_STEREO:
>>               sbc_info->mode = SBC_MODE_STEREO;
>>               sample_spec->channels = 2;
>>               break;
>>           case SBC_CHANNEL_MODE_JOINT_STEREO:
>>               sbc_info->mode = SBC_MODE_JOINT_STEREO;
>>               sample_spec->channels = 2;
>>               break;
>>           case SBC_CHANNEL_MODE_MONO:
>>               sbc_info->mode = SBC_MODE_MONO;
>>               sample_spec->channels = 1;
>>               break;
>>           default:
>>               pa_assert_not_reached();
>>       }
>>
>>       switch (config->allocation_method) {
>>           case SBC_ALLOCATION_LOUDNESS:
>>               sbc_info->allocation = SBC_AM_LOUDNESS;
>>               break;
>>           case SBC_ALLOCATION_SNR:
>>               sbc_info->allocation = SBC_AM_SNR;
>>               break;
>>           default:
>>               pa_assert_not_reached();
>>       }
>>
>>       switch (config->subbands) {
>>           case SBC_SUBBANDS_4:
>>               sbc_info->subbands = SBC_SB_4;
>>               break;
>>           case SBC_SUBBANDS_8:
>>               sbc_info->subbands = SBC_SB_8;
>>               break;
>>           default:
>>               pa_assert_not_reached();
>>       }
>>
>>       switch (config->block_length) {
>>           case SBC_BLOCK_LENGTH_4:
>>               sbc_info->blocks = SBC_BLK_4;
>>               break;
>>           case SBC_BLOCK_LENGTH_8:
>>               sbc_info->blocks = SBC_BLK_8;
>>               break;
>>           case SBC_BLOCK_LENGTH_12:
>>               sbc_info->blocks = SBC_BLK_12;
>>               break;
>>           case SBC_BLOCK_LENGTH_16:
>>               sbc_info->blocks = SBC_BLK_16;
>>               break;
>>           default:
>>               pa_assert_not_reached();
>>       }
>>
>>       sbc_info->min_bitpool = config->min_bitpool;
>>       sbc_info->max_bitpool = config->max_bitpool;
>>
>>       /* Set minimum bitpool for source to get the maximum possible block_size
>>        * in get_block_size() function. This block_size is length of buffer used
>>        * for decoded audio data and so is inversely proportional to frame length
>>        * which depends on bitpool value. Bitpool is controlled by other side from
>>        * range [min_bitpool, max_bitpool]. */
>>       sbc_info->initial_bitpool = for_encoding ? sbc_info->max_bitpool : sbc_info->min_bitpool;
>>
>>       set_params(sbc_info);
>>
>>       pa_log_info("SBC parameters: allocation=%s, subbands=%u, blocks=%u, mode=%s bitpool=%u codesize=%u frame_length=%u",
>>                   sbc_info->sbc.allocation ? "SNR" : "Loudness", sbc_info->sbc.subbands ? 8 : 4,
>>                   (sbc_info->sbc.blocks+1)*4, sbc_info->sbc.mode == SBC_MODE_MONO ? "Mono" :
>>                   sbc_info->sbc.mode == SBC_MODE_DUAL_CHANNEL ? "DualChannel" :
>>                   sbc_info->sbc.mode == SBC_MODE_STEREO ? "Stereo" : "JointStereo",
>>                   sbc_info->sbc.bitpool, (unsigned)sbc_info->codesize, (unsigned)sbc_info->frame_length);
>>
>>       return sbc_info;
>>  }
>>
>>  static void deinit(void *codec_info) {
>>       struct sbc_info *sbc_info = (struct sbc_info *) codec_info;
>>
>>       sbc_finish(&sbc_info->sbc);
>>       pa_xfree(sbc_info);
>>  }
>>
>>  static void set_bitpool(struct sbc_info *sbc_info, uint8_t bitpool) {
>>       if (bitpool > sbc_info->max_bitpool)
>>           bitpool = sbc_info->max_bitpool;
>>       else if (bitpool < sbc_info->min_bitpool)
>>           bitpool = sbc_info->min_bitpool;
>>
>>       sbc_info->sbc.bitpool = bitpool;
>>
>>       sbc_info->codesize = sbc_get_codesize(&sbc_info->sbc);
>>       sbc_info->frame_length = sbc_get_frame_length(&sbc_info->sbc);
>>
>>       pa_log_debug("Bitpool has changed to %u", sbc_info->sbc.bitpool);
>>  }
>>
>>  static int reset(void *codec_info) {
>>       struct sbc_info *sbc_info = (struct sbc_info *) codec_info;
>>       int ret;
>>
>>       ret = sbc_reinit(&sbc_info->sbc, 0);
>>       if (ret != 0) {
>>           pa_log_error("SBC reinitialization failed: %d", ret);
>>           return -1;
>>       }
>>
>>       /* sbc_reinit() sets also default parameters, so reset them back */
>>       set_params(sbc_info);
>>
>>       sbc_info->seq_num = 0;
>>       return 0;
>>  }
>>
>>  static size_t get_block_size(void *codec_info, size_t link_mtu) {
>>       struct sbc_info *sbc_info = (struct sbc_info *) codec_info;
>>       size_t rtp_size = sizeof(struct rtp_header) + sizeof(struct rtp_sbc_payload);
>>       size_t frame_count = (link_mtu - rtp_size) / sbc_info->frame_length;
>>
>>       /* frame_count is only 4 bit number */
>>       if (frame_count > 15)
>>           frame_count = 15;
>>
>>       return frame_count * sbc_info->codesize;
>>  }
>>
>>  static size_t reduce_encoder_bitrate(void *codec_info, size_t write_link_mtu) {
>>       struct sbc_info *sbc_info = (struct sbc_info *) codec_info;
>>       uint8_t bitpool;
>>
>>       /* Check if bitpool is already at its limit */
>>       if (sbc_info->sbc.bitpool <= SBC_BITPOOL_DEC_LIMIT)
>>           return 0;
>>
>>       bitpool = sbc_info->sbc.bitpool - SBC_BITPOOL_DEC_STEP;
>>
>>       if (bitpool < SBC_BITPOOL_DEC_LIMIT)
>>           bitpool = SBC_BITPOOL_DEC_LIMIT;
>>
>>       if (sbc_info->sbc.bitpool == bitpool)
>>           return 0;
>>
>>       set_bitpool(sbc_info, bitpool);
>>       return get_block_size(codec_info, write_link_mtu);
>>  }
>>
>>  static size_t encode_buffer(void *codec_info, uint32_t timestamp, const uint8_t *input_buffer, size_t input_size, uint8_t *output_buffer, size_t output_size, size_t *processed) {
>>       struct sbc_info *sbc_info = (struct sbc_info *) codec_info;
>>       struct rtp_header *header;
>>       struct rtp_sbc_payload *payload;
>>       uint8_t *d;
>>       const uint8_t *p;
>>       size_t to_write, to_encode;
>>       uint8_t frame_count;
>>
>>       header = (struct rtp_header*) output_buffer;
>>       payload = (struct rtp_sbc_payload*) (output_buffer + sizeof(*header));
>>
>>       frame_count = 0;
>>
>>       p = input_buffer;
>>       to_encode = input_size;
>>
>>       d = output_buffer + sizeof(*header) + sizeof(*payload);
>>       to_write = output_size - sizeof(*header) - sizeof(*payload);
>>
>>       /* frame_count is only 4 bit number */
>>       while (PA_LIKELY(to_encode > 0 && to_write > 0 && frame_count < 15)) {
>>           ssize_t written;
>>           ssize_t encoded;
>>
>>           encoded = sbc_encode(&sbc_info->sbc,
>>                                p, to_encode,
>>                                d, to_write,
>>                                &written);
>>
>>           if (PA_UNLIKELY(encoded <= 0)) {
>>               pa_log_error("SBC encoding error (%li)", (long) encoded);
>>               break;
>>           }
>>
>>           if (PA_UNLIKELY(written < 0)) {
>>               pa_log_error("SBC encoding error (%li)", (long) written);
>>               break;
>>           }
>>
>>           pa_assert_fp((size_t) encoded <= to_encode);
>>           pa_assert_fp((size_t) encoded == sbc_info->codesize);
>>
>>           pa_assert_fp((size_t) written <= to_write);
>>           pa_assert_fp((size_t) written == sbc_info->frame_length);
>>
>>           p += encoded;
>>           to_encode -= encoded;
>>
>>           d += written;
>>           to_write -= written;
>>
>>           frame_count++;
>>       }
>>
>>       PA_ONCE_BEGIN {
>>           pa_log_debug("Using SBC codec implementation: %s", pa_strnull(sbc_get_implementation_info(&sbc_info->sbc)));
>>       } PA_ONCE_END;
>>
>>       if (PA_UNLIKELY(frame_count == 0)) {
>>           *processed = 0;
>>           return 0;
>>       }
>>
>>       /* write it to the fifo */
>>       pa_memzero(output_buffer, sizeof(*header) + sizeof(*payload));
>>       header->v = 2;
>>
>>       /* A2DP spec: "A payload type in the RTP dynamic range shall be chosen".
>>        * RFC3551 defines the dynamic range to span from 96 to 127, and 96 appears
>>        * to be the most common choice in A2DP implementations. */
>>       header->pt = 96;
>>
>>       header->sequence_number = htons(sbc_info->seq_num++);
>>       header->timestamp = htonl(timestamp);
>>       header->ssrc = htonl(1);
>>       payload->frame_count = frame_count;
>>
>>       *processed = p - input_buffer;
>>       return d - output_buffer;
>>  }
>>
>>  static size_t decode_buffer(void *codec_info, const uint8_t *input_buffer, size_t input_size, uint8_t *output_buffer, size_t output_size, size_t *processed) {
>>       struct sbc_info *sbc_info = (struct sbc_info *) codec_info;
>>
>>       struct rtp_header *header;
>>       struct rtp_sbc_payload *payload;
>>       const uint8_t *p;
>>       uint8_t *d;
>>       size_t to_write, to_decode;
>>       uint8_t frame_count;
>>
>>       header = (struct rtp_header *) input_buffer;
>>       payload = (struct rtp_sbc_payload*) (input_buffer + sizeof(*header));
>>
>>       frame_count = payload->frame_count;
>>
>>       /* TODO: Add support for decoding fragmented SBC frames */
>>       if (payload->is_fragmented) {
>>           pa_log_error("Unsupported fragmented SBC frame");
>>           *processed = 0;
>>           return 0;
>>       }
>>
>>       p = input_buffer + sizeof(*header) + sizeof(*payload);
>>       to_decode = input_size - sizeof(*header) - sizeof(*payload);
>>
>>       d = output_buffer;
>>       to_write = output_size;
>>
>>       while (PA_LIKELY(to_decode > 0 && to_write > 0 && frame_count > 0)) {
>>           size_t written;
>>           ssize_t decoded;
>>
>>           decoded = sbc_decode(&sbc_info->sbc,
>>                                p, to_decode,
>>                                d, to_write,
>>                                &written);
>>
>>           if (PA_UNLIKELY(decoded <= 0)) {
>>               pa_log_error("SBC decoding error (%li)", (long) decoded);
>>               break;
>>           }
>>
>>           /* Reset frame length, it can be changed due to bitpool change */
>>           sbc_info->frame_length = sbc_get_frame_length(&sbc_info->sbc);
>>
>>           pa_assert_fp((size_t) decoded <= to_decode);
>>           pa_assert_fp((size_t) decoded == sbc_info->frame_length);
>>
>>           pa_assert_fp((size_t) written <= to_write);
>>           pa_assert_fp((size_t) written == sbc_info->codesize);
>>
>>           p += decoded;
>>           to_decode -= decoded;
>>
>>           d += written;
>>           to_write -= written;
>>
>>           frame_count--;
>>       }
>>
>>       *processed = p - input_buffer;
>>       return d - output_buffer;
>>  }
>>
>>  const pa_a2dp_codec pa_a2dp_codec_sbc = {
>>       .name = "sbc",
>>       .description = "SBC",
>>       .id = { A2DP_CODEC_SBC, 0, 0 },
>>       .support_backchannel = false,
>>       .can_accept_capabilities = can_accept_capabilities,
>>       .choose_remote_endpoint = choose_remote_endpoint,
>>       .fill_capabilities = fill_capabilities,
>>       .is_configuration_valid = is_configuration_valid,
>>       .fill_preferred_configuration = fill_preferred_configuration,
>>       .init = init,
>>       .deinit = deinit,
>>       .reset = reset,
>>       .get_read_block_size = get_block_size,
>>       .get_write_block_size = get_block_size,
>>       .reduce_encoder_bitrate = reduce_encoder_bitrate,
>>       .encode_buffer = encode_buffer,
>>       .decode_buffer = decode_buffer,
>>  };
>>
>>  17.09.2019, 09:34, "Hyperion" <h1p8r10n at yandex.com>:
>>>  btw here's the updated V12-12 patch in Pali's latest rel95 patchset that applies to PA 13.0.
>>>
>>>    http://download.zenwalk.org/x86_64/testing/v12-12-13-zen-bluetooth-Implement-A2DP-codec-switching-and-backchannel-support-.patch
>>>
>>>  JP
>>>
>>>  16.09.2019, 09:32, "Hyperion" <h1p8r10n at yandex.com>:
>>>>    Hi,
>>>>
>>>>    Following what has already be done in some Android derivatives, here's a simple patch that extend SBP bitpool negociation to XQ quality.
>>>>
>>>>    According to :
>>>>    --> http://soundexpert.org/articles/-/blogs/audio-quality-of-sbc-xq-bluetooth-audio-codec
>>>>    --> https://lineageos.org/engineering/Bluetooth-SBC-XQ/ ,
>>>>    --> and confirmed by my own experimentation on more than 10 different devices,
>>>>
>>>>    here are the features of the (very simple and non intrusive) patch :
>>>>    - allow to use bitpool 76 on devices that support it, aka SBC XQ
>>>>    - harmless for devices limited to bitpool 53
>>>>    - deprecates the need for APTX & APTX HD support, which are not better than SBC XQ, are not Open Source, and less supported by devices
>>>>
>>>>    This patch will be superseded by multi-profiles Pali Rohar A2DP stack implementation, when it's ready for production. Thanks to Pali for the help testing many codec parameters.
>>>>
>>>>    Let me know if I have to clone the git to push my patch, or if a regular PA dev could do it.
>>>>
>>>>    All the best
>>>>    JP
>>>>
>>>>    diff -rNaud pulseaudio-13.0/src/modules/bluetooth/a2dp-codec-sbc.c pulseaudio-13.0-new/src/modules/bluetooth/a2dp-codec-sbc.c
>>>>    --- pulseaudio-13.0/src/modules/bluetooth/a2dp-codec-sbc.c 2019-09-13 15:20:03.000000000 +0200
>>>>    +++ pulseaudio-13.0-new/src/modules/bluetooth/a2dp-codec-sbc.c 2019-09-16 08:57:50.363122019 +0200
>>>>    @@ -290,10 +290,10 @@
>>>>             return 0;
>>>>         }
>>>>
>>>>    - if (capabilities->allocation_method & SBC_ALLOCATION_LOUDNESS)
>>>>    - config->allocation_method = SBC_ALLOCATION_LOUDNESS;
>>>>    - else if (capabilities->allocation_method & SBC_ALLOCATION_SNR)
>>>>    + if (capabilities->allocation_method & SBC_ALLOCATION_SNR)
>>>>             config->allocation_method = SBC_ALLOCATION_SNR;
>>>>    + else if (capabilities->allocation_method & SBC_ALLOCATION_LOUDNESS)
>>>>    + config->allocation_method = SBC_ALLOCATION_LOUDNESS;
>>>>         else {
>>>>             pa_log_error("No supported allocation method");
>>>>             return 0;
>>>>    diff -rNaud pulseaudio-13.0/src/modules/bluetooth/a2dp-codecs.h pulseaudio-13.0-new/src/modules/bluetooth/a2dp-codecs.h
>>>>    --- pulseaudio-13.0/src/modules/bluetooth/a2dp-codecs.h 2019-09-13 15:20:03.000000000 +0200
>>>>    +++ pulseaudio-13.0-new/src/modules/bluetooth/a2dp-codecs.h 2019-09-16 08:44:20.382086305 +0200
>>>>    @@ -61,14 +61,11 @@
>>>>      * Allocation method = Loudness
>>>>      * Subbands = 8
>>>>      */
>>>>    -#define SBC_BITPOOL_MQ_MONO_44100 19
>>>>    -#define SBC_BITPOOL_MQ_MONO_48000 18
>>>>    -#define SBC_BITPOOL_MQ_JOINT_STEREO_44100 35
>>>>    -#define SBC_BITPOOL_MQ_JOINT_STEREO_48000 33
>>>>    -#define SBC_BITPOOL_HQ_MONO_44100 31
>>>>    -#define SBC_BITPOOL_HQ_MONO_48000 29
>>>>    -#define SBC_BITPOOL_HQ_JOINT_STEREO_44100 53
>>>>    -#define SBC_BITPOOL_HQ_JOINT_STEREO_48000 51
>>>>    +
>>>>    +#define SBC_BITPOOL_HQ_MONO_44100 38
>>>>    +#define SBC_BITPOOL_HQ_MONO_48000 38
>>>>    +#define SBC_BITPOOL_HQ_JOINT_STEREO_44100 76
>>>>    +#define SBC_BITPOOL_HQ_JOINT_STEREO_48000 76
>>>>
>>>>     #define MPEG_CHANNEL_MODE_MONO (1 << 3)
>>>>     #define MPEG_CHANNEL_MODE_DUAL_CHANNEL (1 << 2)
>>>>
>>>>    _______________________________________________
>>>>    pulseaudio-discuss mailing list
>>>>    pulseaudio-discuss at lists.freedesktop.org
>>>>    https://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss
>>  _______________________________________________
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>>  pulseaudio-discuss at lists.freedesktop.org
>>  https://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss
>
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