Sco codec. com/en/post/456182/ * Free Software Foundation; either version 2 of the License, or (at your In case both ends support codec negotiation in HFP 1. Bluetooth kernel development tree. plugable. first for normal audio & second for bluetooth sco data & I can see both sound cards are created properly. Is somebody able to explain how above change can allow opening SCO socket? Because without it I'm not able to activate AuriStream codec, could you consider allowing userspace (via some setsockoptň to change bandwidth? Because now it is hardcoded in kernel source code. From reading around the net it's due to OSX using my Airpods as the microphone input. This narrow band audio is called "Bluetooth voice" type. HF Unit and AG device determine which codec to use by exchanging features during service level connection. SCO is For those of you which want to use the full bandwith and do not need to use a microphone this workaround works: When your devices is plugged in, just change the input method to the built-in microphone. huawei. In Catalina, I was able to hold Option and click on the Bluetooth icon in the menu bar and it displayed the codec being used. and realtek rtl8822b bt chip connected via USB interface. For an extended list of codecs, see List of codecs § Bluetooth. Audio from AE is only heard in the left ear and all other system audio sounds like it was encoded at 64kbps. 1 Steps to reproduce Set the correct device address of an HFP A hi， In my usage scenario, the I2S of IMX8MP is connected to the I2S of another MCU, the I2S of IMX8MP is used as the slave, and the I2S of MCU is used as the Master, PCM format 48K/S24 LE / 2 channels, The connection is as follows: Question 1 In this case, does MCLK have to be connected to the MCLK of the MCU? Question 2: My DTS configuration is as follows. PROFILE May be either a2dp or sco. (SAI2 PCM connect to BT chip) And I can get the waveform while "aplay -D plughw:3,0 test. The > connection to the Quectel EG-25G modem via AIF2 works as well, but I do > not include it here because there is no appropriate codec driver in > tree. com The SCO logical transport is a point-to-point transport between the master and a specific slave. - espressif/esp-idf I tried it and I actually got the line "Setting SCO audio codec to AAC-ELD at sample rate of 24000 for device <private>". Linux Bluetooth: Re: HCI Set custom bandwidth for AuriStream SCO codec Nov 9, 2023 · Hi, I have followed the same document and was able to get the HFP call use case working properly through headphone jack. This corresponds to the bandwidth of a conventional telephone connection. In Monterey, that's gone. > So it is possible to "tell" bluetooth chip "hey, I have already prepared > alaw or CVSD packets for you”? actually alaw is an over the air codec. The solution is to switch to the internal microphone, allowing the entire system, including the AirPods to use the AAC CODEC since they're now in a listen-only mode. I'm adding DT > support for it because I want to use > this for W2CBW003 chip and I can use simply "linux,bt-sco" property Does anyone else have this issue? I'm on OSX Sierra and by default when I connect my Airpods they default to the low quality SCO codec. The SCO logical transport, is a symmetric, point-to-point transport between the Central and a specific Peripheral. the device tree entry are as follows: Mar 4, 2025 · Audio accessories: Shall support A2DP version 1. Contribute to pali/hsphfpd-prototype development by creating an account on GitHub. 7 Improve sound quality by disabling audio input from device Devices such as AirPods have both speakers and microphones; they can be used for both audio output and audio input. 9 / . Most modern Macs try to use the AAC audio codec with audio devices. Aug 17, 2020 · When two way audio is requested Bluetooth switches to a different (SCO) codec which limits the quality. But there is Enhanced Setup Synchronous Connection command which does not use Voice Setting structure which seems to be more powerfull in codec handling. But how do I play the music over SCO PCM to BT headset? I'm Associated Part Family: CYW4330 This application note describes how to configure host hardware and software to transmit/receive Bluetooth audio data with the CYW4330 in I2S format. Device names or aliases are not valid here. May 18, 2022 · BT audio on Mac switch to SCO codec when using Mic I've searched everywhere but I can't find a solution on my Mac my BT headset (s) use the awful SCO codec whenever I have the headset set for both input and output. There is a HSP Gateway and a HSP Client profile. dts @@ -40,6 +40,7 @@ aliases { mmc0 = &usdhc1; mmc1 = &usdhc2; serial0 = &lpuart1; + serial4 = &lpuart5; }; bt_sco_codec: audio-codec-bt-sco { -- 2. Mar 3, 2024 · Hello, we are using the firmware suggested by NXP, the driver is trying to be probed after fw load, and it is failing again. > > In Europe all landline phones (and also their SIP non-compressed > > equivalents) use alaw codec. wav" (bluetooth sound card is 3) on SAI2. It’s just very unfortunate that SCO – low-quality as it may be – upon AirPod microphone activation is not only limited to recording but also displaces AAC and audio playback. In the current era of virtual meetings; BT headsets with Mics are a necessity. It sounds terrible and I can't figure out how to resolve this. 3 and linux-kernel version is 4. For the codec, we've tested out the proven configuration also. As we've mentioned, sai drivers are not being probed for codec and BT. I would expect the transmitter (Mac) to adjust the codec depending on the receiver (Airpods). h> #include <bluetooth/sco. Wifi and BT is operational and tested. c blob: 8014e697d5407d0b43f3bf03089a349c31e0b03a [file] [log] [blame] Oct 19, 2023 · Explore the AIROC™ CYW20xxx series with PCM and I2S protocols, empowering seamless audio data transmission in wireless connectivity applications. The SCO Codec provides a sampling rate of 8 kHz. DEV The device Bluetooth address in the form XX:XX:XX:XX:XX:XX. enable-active-high; }; + + bt_sco_codec: bt-sco-codec { + compatible = "linux,bt-sco"; + #sound-dai-cells = <1>; + }; + + sound-bt-sco { + compatible = "simple-audio-card"; + simple-audio-card,name = "bt-sco-audio"; + simple-audio-card,format = "dsp_a"; + simple-audio-card,bitclock-inversion; + simple-audio-card,frame-master = <&btcpu>; Ccing more people do you have idea why for custom SCO HFP codec is needed to change Transmit and Receive bandwidth in HCI Setup Synchronous Connection packet? And how to expose API for userspace applications so they can change hardcoded kernel bandwidth? Why is there value 8000? Without changing hardcoded value 8000 to 4000 I'm unable to open SCO socket for AuriStream codec in HFP profile I tried it and I actually got the line "Setting SCO audio codec to AAC-ELD at sample rate of 24000 for device <private>". 0, 1. Linux kernel source tree. It's just very unfortunate that SCO – low-quality as it may be – upon AirPod microphone activation is not only limited to doing recording, but also displaces AAC and audio playback. Dec 9, 2024 · The 8000 Hz sample rate issue occurs because AirPods switch to a low-quality SCO codec for calls or mic use. Switching on the Wide Nov 6, 2021 · Does it only apply to Facetime or can this codec also be used for two-way communication (mic and speakers) with other applications such as Slack on macOS? (In other words, on macOS, when selecting the Airpods 3 for input and output, will AAC-ELD be used or fall back to the rather crappy SCO codec?) Contribute to machinelinux-root/fluoride development by creating an account on GitHub. we've printed some logs and it seems that the issue is about parsing. I can change mic source to something other than my AirPods, but the problem persists. SDK versions: 1. (Figure attached) Whats happening is that its changing the sound input to the BeatsX which seems to be sending the BeatsX into "headset mode", this is a new occurrence today, but its happening on both my MacBook and MacBook Linux kernel source tree. > > More interesting question would be if alaw codec can be used in > transparent mode by transmitter and in "normal alaw" mode by receiver. 1 Last update: 2025-08-18 03:28 [W:0. Aug 28, 2015 · I have created two sound cards. * Question: can you please confirm that wl1831 is configured as PCM master by default? questing (7) sco. Could you please check? Thank you in advance! Uses CVSD (8kHz) and alternative mSBC (16 kHz) (in HFP v. 82-1ubuntu1_amd64 NAME sco - SCO transport SYNOPSIS #include <sys/socket. We have been using an out * Function bta_ag_create_sco * Description Create a sco connection and is is_orig is TRUE means AG originate * this connection, if FALSE it's peer device originate the connection. But occasionally, Bluetooth-connected devices will “fall back” to the SCO or SBC codec. 3 or newer Should support the AAC LC audio codec May support the aptX™ audio codec For more information about supported audio codecs, see Bluetooth Classic Audio. And then with transparent you get mSBC and AuriStream. May 21, 2024 · Hi i'm working on HFP profile bringup on imx8mp Phytec board using android11 platform. 153 seconds] ©2003-2020 |hosted at and my Meterkast| Cisco Spark Room Kit Series - Find out why a Cisco product has reached its end of life, what product upgrade and substitution options are available, and when these changes will take effect. h and existing codec drivers for example regmap usage. I had create a sound card for PCM(SAI2) on IMX8. Do I need to upgrade the Linux-kernel version? and what is the minimum linux-kernel version for Bluealsa to update the mSBC-Codec. But, mSBC is designed to have a better voice quality through HFP. Apr 22, 2020 · In a nutshell, it’s because of the audio codec. Oct 23, 2019 · Hi, I trying to make the imx8mm board output audio via I2S. Jan 22, 2018 · The AAC codec is normally used when just listening to playback on the AirPods. I made the following changes to the dts file: sound { compatible = "simple-audio-card"; simple-audio-card,name = "CS4344"; Linux kernel source tree. Jan 1, 2018 · Using bluetooth explorer I see that it's using HFP with the SCO codec: AudioDeviceCurrentProtocolName = HFP; HFP = { AudioProtocolCodec = { AudioCodecBitrate = 64; AudioCodecName = SCO; }; Ok fine. 1 or later Assigned numbers) #define ESCO_CODING_FORMAT_ULAW ( (uint8_t)0x00)/* u-Law log */ Poor audio quality (SCO codec) when using with MacBook Pro (2014 and 2017 models) I know there has been a lot of discussion with the very poor audio quality the AirPods switch to when the mic is engaged when paired with a MacBook Pro, but I read that the newer hardware in the 2016+ models fixed the issue. To select which one is in use, we provide Wide Band Speech item in the menuconfig: Component config --> Bluetooth --> Bluedroid Options --> Wide Band Speech. At the time, the codec was changed to SCO. The chip that decodes the audio is CS4344, which has no config so no I2C is present. Limited Bandwidth: SCO's fixed bit rate limits the quality of audio compared to modern Bluetooth audio codecs. cc blob: fc7172373331aa272dfd7c4c8ad2817a25ced188 [file] [log] [blame] However, as soon as I open up After Effects (latest version,) they switch to the "SCO" codec and sound like monotone crap. The Active Codec is SCO. > >>>>> > >>>>> First I want to finish improving A2DP codec support in pulseaudio. My headset supports AAC but I'm convinced it's using SCO right now. May 28, 2023 · [RTL8822CE] SCO with msbc codec enabled requires source code patching to deliver audio to headset #637 May 15, 2017 · So for embedded device (for example a mobile phone), the SCO channel will be directly connected via a PCM interface to the main audio codec. Jan 5, 2017 · When using Airpods for the Macbook Pro, the audio codec remains on SCO. One can also use vendor-specific codecs of your own implementation, not included into A2DP. 7. See here for more details: https://m. For information about the Headset Profile (HSP), a Contribute to Poco-Ye/rk_wifi_bt_android development by creating an account on GitHub. here i have tested A2DP source and sink modes. So the aim is that adding new codec would be very > >>>>> simple But without this patch I'm not able to switch HSP codec from CVSD to AuriStream. It seemed reasonable to start off with modifications on the bt_sco_codec, resulting in be DEV The device Bluetooth address in the form XX:XX:XX:XX:XX:XX. What is the configuration you are using for module-loopback command? Oct 15, 2020 · 2. CODEC Sep 27, 2023 · Describe the bug Hi, I am looking for a possibility to use BT SCO over PCM on RPI4/CM4, in theory it should be possible but might require some config/firmware/kernel changes to work. With many such devices, macOS will normally use the SCO or SBC Bluetooth audio codec because this works with both output and input. We also get the same problem for the other sai when registering our audio codec. Bluetooth:config SCO seting for HFP call 1, enable SCO_USE_I2S_INTERFACE for sturgeon 2, configure audio configuration in hw_sco_config for I2S as SCO_CODEC_CVSD by default BUG=24044548 Change-Id: Id39102ee812eb2b173dfab45f4fb97fd99c5e7b8 Signed-off-by: z00184990 <z00184990@notesmail. As mentioned earlier, SCO channels use CVSD audio encoding due to the high potential for lost or damaged data. The profile standardize one mandatory codec—SBC, a low computational complexity codec created specifically for Bluetooth, and 3 additional codecs. Feb 19, 2024 · As we've mentioned, sai drivers are not being probed for codec and BT. I'm adding DT > support for it because I want to use > this for W2CBW003 chip and I can use simply "linux,bt-sco" property Feb 14, 2023 · Oboe is a C++ library that makes it easy to build high-performance audio apps on Android. Later > >>>>> I can look at HSP/HFP profiles. here i am using wm8960 external audio codec. This drastically reduces audio quality as the bitrate is limited. The use of advanced audio codecs ensures that voice communication is clear and free from distortions. This document describes BTstack's implementation of HFP which supports both roles defined in the specification: Audio Gateway (AG) and Hands-Free (HF) units. c blob: 806191addb44daedc0fbfca98bbabb0be4be8509 [file] [log] [blame] Choice of Codec ESP32 supports both CVSD and mSBC codec. Sep 26, 2023 · The SCO bypass channel transfers audio data via I2S or another connection between the audio codec and the Bluetooth radio, bypassing the Bluetooth HCI typically used to transmit audio data on PCs. Apr 27, 2025 · Hands-Free Profile (HFP) Relevant source files The Hands-Free Profile (HFP) is a Bluetooth profile that enables hands-free operation of mobile phones in vehicles or through headsets. I have to manually switch the microphone input to the default microphone every time in order to force the AAC codec. Sony WH-1000XM3 and MacBook Pro issue - SCO codec and HFP profile I have the WH-1000XM3 headphones which work and sound great with my iPhone but when I connect to my MBP (2019) and play music through Spotify the codec goes to SCO and the profile will be HFP. For no apparent reason, the codec changed and the delay stopped, but sacrificed the quality of the audio. For the codec, we've tested out th Aicsemi aic8800 Wi-Fi driver. The required PCM lines from cc2564 are interfaced to external codec and we are using vendor commands for sco and codec configuration (sco, codec and codec enhanced commands) as per the requirement / suggestion. Contribute to bluez/bluetooth-next development by creating an account on GitHub. Example is music playback through A2DP. 592 / U:0. habr. > > The BT audio connection is represented by the "dummy" bt-sco codec. To fix this, disable the microphone input of AirPods in your sound settings or use them only in playback mode without the mic. 37. - TechNote_BluetoothAudio · google/oboe Wiki Jul 17, 2024 · When i replace the TAS2563 codec node with another bt-sco codec, the problem disappears and the soundcard is registered. I have also tried changing my audio input to Mac's microphone but they still can't hear me right. If the issue persists, check for updates or reconnect your AirPo *******************/ typedefenum{ SCO_CODEC_NONE =0x0000, SCO_CODEC_CVSD =0x0001, SCO_CODEC_MSBC =0x0002, }sco_codec_t; typedefenum{ ESCO_CODEC_CVSD =0, ESCO_CODEC_MSBC_T1, ESCO_CODEC_MSBC_T2, }esco_codec_t; #define ESCO_NUM_CODECS 3 // Coding Formats (BT 4. Please see include/linux/regmap. / sound / soc / codecs / bt-sco. So this is more or less a confirmation. I have tried: Dummy BT SCO codec driver found in sound/soc/codecs/Kconfig The configuration item CONFIG_SND_SOC_BT_SCO: The official Linux kernel from Xilinx. 5. gz Provided by: libbluetooth-dev_5. Ideally it should have modular/plugin > >>>>> extensible design. Why is this? How can I fix it? This can be reproduced by Espressif IoT Development Framework. Other codecs provide better fidelity but behave badly when supplied with faulty data. c,What does init_script mean?Thank you very much for your help In my test ,i have to set I started searching for a solution to this a few weeks ago, and found people disabling the default audio input from their bluetooth headphones to another device, as their headphones were connecting using SCO codec instead of AAC. ko configname: CONFIG_SND_SOC_BT_SCO Linux Kernel Configuration May 30, 2025 · Want to know more about wireless audio? Take our crash course in Bluetooth codecs, bitrate, standards, and uses from SBC to LDAC and more. When I connect to my MacBook Pro, the headphones default to using the SCO codec which sounds pretty close to unlistenable. Sep 16, 2025 · Get the best audio quality. Can see this via "option-click" on the Bluetooth menu and choosing the airpods. I can disconnect and reconnect my Bluetooth devices over and over again, the problem persists. The SCO logical transport reserves slots and can therefore be considered as a circuit-switched connection between the Central and the Peripheral. The choice of codec also depends on the your configuration in menuconfig. 6) audio codecs AT commands can be used for example to control the mobile phone and accept/reject calls dial numbers etc. If I stop using Google hangouts sometimes it switches by itself back to A2DP which uses the SBC protocol (I don't think my headset supports apX): Contribute to mams2836/bluetooth development by creating an account on GitHub. But we can't configure HSP The H ead S et P rofile is used for bi-directional voice transmission. ESP32 supports two types of codec for HFP audio data: CVSD and mSBC. 3 Codec Connection set up Codec connection的建立也很简单，在SLC建立得而时候如果发送过AT BAC,那么AG会发送 BCS选择codec id,HF回复AT BCS回复相同得而codec id，然后AG回复 Prototype of Bluetooth HSP/HFP daemon. 1. Since CVSD is the default codec in HFP, we just show the scenarios using mSBC: Aug 28, 2015 · 已解决: Hi, I have created a module in HAL layer for hfp & modify the audio policy to go to hfp HAL. Jun 4, 2020 · HI I'm trying to bring up the bluetooth SCO voice over PCM. Contribute to torvalds/linux development by creating an account on GitHub. h> sco_socket = socket(PF_BLUETOOTH, SOCK_SEQPACKET, BTPROTO_SCO); DESCRIPTION The SCO logical transport, is a symmetric, point-to-point transport between the Central and a specific Peripheral. The clock rate is the same regardless of the codec. Hope to receive your reply as soon. 参数: codec_type – [in] codec Index @btif_sco_codec_t vol – [in] volume of voice 返回: N/A void app_sco_codec_deinit(void) deinitialize the voice relevant settings reset audio module and free voice relevant settings 返回: N/A uint32_t app_sco_data_process(void) application for handling SCO data get data from ADC buff and encode to SCO Feb 8, 2022 · Looks like the sampling rate for SCO has not been configured. Our boot log and dts is attached. 2 Audio Connection release HF和AG都可以主动断开SCO，主动断开通过HCI command ,remote断开会收到HCI disconnect的event 2. In such as case , this PCM interface has to be supported by Android audio HAL in-order to support Bluetooth SCO connection. Contribute to Xilinx/linux-xlnx development by creating an account on GitHub. 0. Have a nice day!! May 31, 2018 · The default behavior from nougat sends HCI_VSC_ENABLE_WBS first, but as we configure the i2s/pcm interface locally now we don't really need the whole hw_set_SCO_codec () method. - radxa-pkg/aic8800 Aug 18, 2025 · +++ b/arch/arm64/boot/dts/freescale/imx95-19x19-evk. 14. Voice data in Bluetooth hands free kit is an example for this. ToothFairy can ensure that it uses the higher quality AAC codec when you only care about audio output: listening to music or video or playing a game. h> #include <bluetooth/bluetooth. Feb 19, 2024 · Hello, Unfortunately suggested change did not work. The typical HSP Gateway device is a mobile phone. code / linux / torvalds / linux / e8b098fc5747a7c871f113c9eb65453cc2d86e6f / . It’s Apple’s preferred codec and is objectively higher-quality than the SCO or SBC codecs. Feb 10, 2024 · Solved: Hello, We are using AW_CM358 Wifi/BT module on our custom board with i. It is a good choice if you are making a VOIP call where you want to both listen and Dec 12, 2024 · This data sheet describes the benefits, specifications, and ordering information for the Cisco Webex Room Kit Pro. The patent has expired. / system / stack / btm / btm_sco_hfp_hal_linux. The first point, regarding the SCO vs AAC CODEC is addressing solutions for poor audio output (what you hear) when using AirPods as a headset. Codec control IO ¶ The codec can usually be controlled via an I2C or SPI style interface (AC97 combines control with data in the DAI). /* use same codec type as previous SCO connection, skip codec negotiation */ APPL_TRACE_DEBUG("use same codec type as previous SCO connection,skip codec negotiation"); I Would like to know why the airPods works great with my iPhone or iPad but default to SCO Codec when I use them on my Mac? Don't have this problem with wired headphones. SCO would be normal for phone bluetooth headset, but not May 12, 2020 · AirPods stuck on 16kHz/ SCO codec Hey, currently, my AirPods gen 1, and AirPod Pros are stuck in 16kHz/ SCO codec no matter what I do. wm8960-audio-card android / platform / packages / modules / Bluetooth / d5177cafce285b0bd6d237bb5fb4e4eb7cb9bd42 / . There is no need to do any limitation. Official support for Radxa devices only. Force-disabling handsfree mode in Bluetooth Exlorer (Additional Tools for Xcode) did not work for Apr 10, 2024 · hi， In my usage scenario, the I2S of IMX8MP is connected to the I2S of another MCU, the I2S of IMX8MP is used as the slave, and the I2S of MCU is used as the Master, PCM format 48K/S24 LE / 2 channels, The connection is as follows: Question 1 In this case, does MCLK have to be connected to the MCL 4. See full list on kb. So I suspect something is wrong with the TAS2563 codec devicetree node, or something in the driver. Outline #include "hci/hci_audio. Apr 24, 2022 · CC2564MODN: Dual SCO connection codec output questions BRUNEAUX Jerome Prodigy 150 points Part Number: CC2564MODN Other Parts Discussed in Thread: CC2564 Hi, I'd like to have some clarification about the handling of audio when 2 SCO connections are established and the codec interface is used (audio not routed over HCI). macOS will normally use the SCO codec if it thinks you’re going to use the microphone. Background: BT Sep 7, 2021 · [PATCH v15 01/13] Bluetooth: Enumerate local supported codec and cache details From: Kiran K [PATCH v15 01/13] Bluetooth: Enumerate local supported codec and cache details Oct 21, 2020 · The AAC codec is normally used when just listening to playback on the AirPods. The issue seems to be the same with codec and sound for BT. The SCO logical transport reserves slots and can therefore be considered as a circuit-switched connection between the master and the slave. com> May 5, 2025 · Next message (by thread): [PATCH] arm/arm64: dts: mediatek: Add missing "#sound-dai-cells" to linux,bt-sco Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] Indeed, I checked with oscilloscope that wl1831 codec is not moving clock line, which is needed by bt-sco card codec driver to send PCM samples, since host processor is configured in PCM slave mode. Contribute to arkq/bluez-alsa development by creating an account on GitHub. Help? android / kernel / hikey-linaro / android-hikey-linaro-4. by using WM8960 dts node mentioned below. The codec driver should use the Regmap API for all codec IO. Mixers and audio controls ¶ All the codec mixers and audio controls can be defined using the convenience macros Dummy BT SCO codec driver modulename: snd-soc-bt-sco. Sco Bluetooth Codec Hello, I was doing something with bluetooth earbuds, and it had a delay (when playing games). While designed for a one-way audio transfer - CSR has developed a way to transfer a mono stream back (and enable use of headsets with microphones), and incorporated it into FastStream and aptX Low Latency codecs. Could give me some directions on how to start? I see that imx93 doesn't support i2s directly, but i2s over sai. This should force the software to leave handset mode and it changes to the codec you set it to. Linux Bluetooth: Re: HCI Set custom bandwidth for AuriStream SCO codec Linux kernel source tree. Nov 25, 2019 · When I have my bluetooth headphones connected to my mac, if an application is using the Input, the quality of output is extremely degraded. CVSD is the default setting and is also the widely used codec for voice audio. h" set_audio_state (uint16_t, sco_codec_t, sco_state_t) Files > This series uses the additional DAIs added to the sun8i-codec driver to > add hardware routing for BT SCO (headset) audio on the PinePhone. In this case if the HFP side issues the SCO OPEN {link_id} command, it will cause a HFP command to be sent to the HFP-AG. It's just very unfortunate that SCO – low-quality as it may be – upon AirPod microphone activation is not only limited to recording but also displaces AAC and audio playback. Limitations and Evolution Despite its benefits for real-time audio, SCO has limitations: Power Consumption: SCO's continuous transmission can lead to higher power consumption, which is a concern for battery-operated devices. Where as ACL is for all other BT data transfer including High quality audio/video data. Official development framework for Espressif SoCs. Any suggestion on what could be the issue? Sep 8, 2023 · I'm trying to create a device tree for a simple codec available in the linux-imx kernel: pcm5102a. CODEC Other Parts Discussed in Thread: CC2564 Hi we are trying HFP with SCO data for a call terminating at BT controller CC2564. This is high bandwidth data and hence called "Advanced Audio". The default is a2dp. The SCO logical transport, is a symmetric, point-to-point transport between the Central and a specific Peripheral. The default value is 00:00:00:00:00:00 which selects the most recently connected device of the chosen profile. Why is this? How can I fix it? This can be reproduced by Jan 16, 2018 · hi, everyone ,in my test i should set scr bluetooth sco routing to PCM, but i don't know btstack_chipset_csr. May 4, 2017 · The AAC codec is normally used when just listening to playback on the AirPods. I am using petalinux 2018. After receiving this command the HFP-AG will open the SCO connection. And I'm having trouble finding Xcode's Bluetooth Explorer. Mar 20, 2020 · 蓝牙电话之HFP协议中的电话音频 蓝牙技术通信的内容多种多样，其中音频部分包含媒体音频和电话音频。 媒体音频：播放蓝牙音乐的数据，这种音频对质量要求高，数据发送有重传机制，从而以l2cap的数据形式走ACL链路。编码方式有：SBC、AAC、APTX、APTX_HD、LDAC这五种编码方式，最基础的编码方式是 Bluetooth Audio ALSA Backend. For the HFP data, code flow is going to pcm_write May 31, 2018 · hw_set_SCO_codec is useless at this point, as everything goes back to hw_sco_i2spcm_config to configure sample rate for the required codec. Codec setting is per connection and every SCO connection can configure its own codec. Typical HSP Client devices are headsets or SCO 프로토콜의 한계를 우회하고 비트 전송률을 높이기 위해서 양방향 전송이 가능한 SBC를 단방향 전송만 가능한 A2DP처럼 사용할 수 있는 기능을 개발했고, 이 기능의 이름을 “FastStream”이라고 붙였습니다. More specifically, it describes how to configure and use PCM2 intellectual property (IP) on the CYW4330 for Bluetooth audio transmissions over the I2S interface at various sample rates. MX8MP. The SCO logical May 19, 2025 · > }; > > + bt_sco_codec: bt-sco-codec { > + compatible = "linux,bt-sco"; > + #sound-dai-cells = <1>; > + }; > + > chosen { > stdout-path = &lpuart1; > }; > @@ -59,6 +64,25 @@ linux,cma { > }; > }; > > + sound-bt-sco { > + compatible = "simple-audio-card"; > + simple-audio-card,bitclock-inversion; > + simple-audio-card,bitclock-master = <&btcpu>; Hi Pali, > >>>>>> to be honest, I would rather see WBS implementation finally > >>>>>> reach PA before we start digging into this. [1] SBC is a digital audio encoder and decoder used to transfer data to Bluetooth audio output devices like headphones or loudspeakers. sco selects either Hands-Free (HFP) or Headset (HSP) profile, whichever is connected on the selected device. . Jul 21, 2023 · The hfp_hf_demo example from the btstack library stops working once a SCO connection needs to be established after codecs negotiation is successful. 6 the SCO connection must be opened by the HFP-AG. I used ‘aplay -D hw: btscoaudio Dec 9, 2022 · 从这个函数中进入，进行开与关，也就是init跟deinit static int bt_sco_player (bool on, enum APP_SYSFREQ_FREQ_T freq) 首先第一步是 Codec 的配置，mic跟speaker ①上行处理 在这里面可以处理通道数据，BES一般是talk mic的数据在第一位，ff mic在第二位 然后再对数据进行编码处理（编解码的处理函数在初始化的时候有做 Jul 13, 2024 · SCO connections support codecs that enhance audio quality. As of June 2019, we live in XKCD comic with 14 A2DP codecs: SBC ← included into A2DP, supported by all May 28, 2025 · }; + bt_sco_codec: bt-sco-codec { + compatible = "linux,bt-sco"; + #sound-dai-cells = <1>; + }; + chosen { stdout-path = &lpuart1; }; @@ -59,6 +64,25 @@ linux,cma { }; }; + sound-bt-sco { + compatible = "simple-audio-card"; + simple-audio-card,bitclock-inversion; + simple-audio-card,bitclock-master = <&btcpu>; + simple-audio-card,format = "dsp_a"; I have tried using the Bluetooth Explorer to force enable aptX but it still switches to SCO on calls. May 5, 2015 · On Wed, May 06, 2015 at 09:38:55PM +0200, Belisko Marek wrote: > > Is there any burning reason for adding the linux,bt-sco compatible? > No no real reason just want to keep that if somebody would like use it from DT > referenced by bt-sco entry (similar as platform data). May 26, 2017 · SCO is for real-time narrow band signal which does not require retransmission. SBC (codec) SBC, or low-complexity subband codec, is an audio subband codec specified by the Bluetooth Special Interest Group (SIG) for the Advanced Audio Distribution Profile (A2DP). djgebk drgfhgi zfsg nvx osfohvx susfj kwntgign psq jrxar igyc