Sakamakon yawan kera wayoyin hannu ba tare da jakin sauti na milimita 3.5 ba, belun kunne na Bluetooth mara waya ya zama babbar hanyar da mutane da yawa ke sauraron kiɗa da sadarwa cikin yanayin naúrar kai.
Masu kera na'urorin mara waya ba koyaushe suke rubuta cikakkun bayanai dalla-dalla na samfur ba, kuma labarai game da sauti na Bluetooth akan Intanet suna cin karo da juna, wani lokacin ba daidai ba, ba sa magana game da duk fasalulluka, kuma galibi suna kwafi bayanai iri ɗaya waɗanda basu dace da gaskiya ba.
Bari mu yi ƙoƙari mu fahimci ƙa'idar, iyawar takin OS ta Bluetooth, belun kunne da lasifika, codecs na Bluetooth don kiɗa da magana, gano abin da ke shafar ingancin sauti da latency da ake watsawa, koyon yadda ake tattarawa da yanke bayanai game da tallafin codecs da sauran na'urori. iyawa.

TL, DR:

• SBC - codec na al'ada
• Wayoyin kunne suna da nasu mai daidaitawa da kuma aiwatarwa ga kowane codec daban
• aptX ba shi da kyau kamar yadda aka yi talla
• LDAC yana tallata bullshit
• Har yanzu ingancin kira ba shi da kyau
• Kuna iya shigar da masu rikodin sauti na C a cikin burauzar ku ta hanyar haɗa su cikin Gidan Yanar Gizo ta hanyar emscripten, kuma ba za su rage gudu ba.

Kiɗa ta Bluetooth

Abun aiki na Bluetooth an ƙaddara ta bayanan martaba - ƙayyadaddun ayyuka na musamman. Yawo kiɗan Bluetooth yana amfani da ingantaccen bayanin martabar watsa sauti na A2DP unidirectional. An karɓi ma'aunin A2DP a cikin 2003 kuma bai canza sosai ba tun lokacin.
A cikin bayanin martaba, codec 1 na tilas na ƙananan ƙididdigar ƙididdiga na SBC, wanda aka ƙirƙira musamman don Bluetooth, kuma ƙarin guda 3 an daidaita su. Hakanan yana yiwuwa a yi amfani da codecs marasa izini na aiwatar da ku.

Tun daga watan Yuni 2019 muna cikin ban dariya xkcd tare da 14 A2DP codecs:

• SBC ← daidaitacce a cikin A2DP, goyan bayan duk na'urori
• MPEG-1/2 Layer 1/2/3 ← daidaitacce a cikin A2DP: sananne MP3, ana amfani da shi a cikin talabijin na dijital MP2, kuma ba a sani ba MP1
• MPEG-2/4 AAC ← daidaitacce a cikin A2DP
• Farashin ATRAC ← tsohon codec daga Sony, daidaitacce a cikin A2DP
• LDAC ← sabon codec daga Sony
• karkatarwa ← Codec daga 1988
• HD aptX ← iri ɗaya da aptX, kawai tare da zaɓuɓɓukan ɓoye daban-daban
• aptX Latananan Latency ← codec daban-daban, babu aiwatar da software
• aptX Daidaitawa ← wani codec daga Qualcomm
• FastStream ← codec na pseudo, gyara na SBC na bidirectional
• HWA LHDC ← sabon codec daga Huawei
• Samsung HD ← na'urori 2 suna goyan bayan
• Samsung Scalable ← na'urori 2 suna goyan bayan
• Samsung UHQ-BT ← na'urori 3 suna goyan bayan

Me yasa muke buƙatar codecs kwata-kwata, kuna tambaya, lokacin da Bluetooth yana da EDR, wanda ke ba ku damar canja wurin bayanai a cikin saurin 2 da 3 Mbit / s, kuma ga tashoshi biyu na PCM 16-bit mara nauyi, 1.4 Mbit/s ya isa?

Canja wurin bayanai ta Bluetooth

Akwai nau'ikan canja wurin bayanai iri biyu a cikin Bluetooth: Asynchronous Connection Less (ACL) don canja wurin asynchronous ba tare da kafa haɗin haɗi ba, da Haɗin Haɗin kai tsaye (SCO), don canja wurin aiki tare tare da tattaunawar haɗin kai na farko.
Ana aiwatar da watsawa ta amfani da tsarin rarraba lokaci da zaɓar tashar watsawa ga kowane fakiti daban (Frequency-Hop/Time-Division-Duplex, FH/TDD), wanda lokacin ya kasu kashi 625-microsecond intervals da ake kira slots. Ɗayan na'urorin yana watsawa a cikin madaidaitan ramummuka, ɗayan a cikin ramummuka masu ƙima. Fakitin da aka watsa na iya ɗaukar ramummuka 1, 3 ko 5, dangane da girman bayanai da nau'in watsawa, a cikin wannan yanayin, watsawa ta na'ura ɗaya ana aiwatar da shi a cikin madaidaicin ramummuka har zuwa ƙarshen watsawa. A cikin duka, ana iya karɓar fakiti har 1600 kuma a aika su a cikin daƙiƙa guda, idan kowannensu ya mallaki rami 1, kuma duka na'urorin suna watsawa da karɓar wani abu ba tare da tsayawa ba.

2 da 3 Mbit/s don EDR, waɗanda za a iya samu a cikin sanarwar kuma akan gidan yanar gizon Bluetooth, sune matsakaicin adadin canja wurin tashoshi na duk bayanai gabaɗaya (ciki har da shugabannin fasaha na duk ka'idoji waɗanda dole ne a tattara bayanan), a cikin kwatance biyu. lokaci guda. Ainihin saurin canja wurin bayanai zai bambanta sosai.

Don watsa kiɗa, ana amfani da hanyar asynchronous, kusan koyaushe ana amfani da fakiti kamar 2-DH5 da 3-DH5, waɗanda ke ɗaukar matsakaicin adadin bayanai a cikin yanayin EDR na 2 Mbit/s da 3 Mbit/s, bi da bi, kuma suna ɗaukar lokaci 5. - raba ramummuka.

Misalin tsari na watsawa ta amfani da ramummuka 5 ta na'ura ɗaya da ramin 1 ta wata (DH5/DH1):


Saboda ka'idar rarraba lokaci na iska, an tilasta mana mu jira lokacin 625-microsecond bayan watsa fakiti idan na'urar ta biyu ba ta watsa mana wani abu ba ko kuma ta aika da ƙaramin fakiti, da ƙarin lokaci idan na'urar ta biyu ta watsa. a cikin manyan fakiti. Idan an haɗa na'ura fiye da ɗaya zuwa wayar (misali, belun kunne, agogo da kuma munduwa na motsa jiki), to ana raba lokacin canja wuri tsakanin su duka.

Buƙatar ɗaukar sauti a cikin ƙa'idodin sufuri na musamman L2CAP da AVDTP suna ɗaukar bytes 16 daga yuwuwar matsakaicin adadin da ake watsawa.

Nau'in kunshin
Yawan ramummuka
Max. adadin bytes a cikin fakiti
Max. adadin bytes na A2DP biya
Max. A2DP biya bitrate

2-DH3
3
367
351
936 kbps

3-DH3
3
552
536
1429 kbps

2-DH5
5
679
663
1414 kbps

3-DH5
5
1021
1005
2143 kbps

1414 da 1429 kbps ba shakka ba su isa su watsa sautin da ba a haɗa su ba a cikin yanayi na ainihi, tare da kewayon 2.4 GHz mai hayaniya da buƙatar watsa bayanan sabis. EDR 3 Mbit / s yana buƙatar ƙarfin watsawa da amo akan iska, sabili da haka, ko da a cikin yanayin 3-DH5, watsawar PCM mai daɗi ba zai yuwu ba, koyaushe za a sami katsewar ɗan gajeren lokaci, kuma komai zai yi aiki ne kawai a nesa na wani wuri. mita biyu.
A aikace, ko da rafin sauti na 990 kbit/s (LDAC 990 kbit/s) yana da wahalar watsawa.

Bari mu koma ga codecs.

SBC

Ana buƙatar Codec don duk na'urorin da ke goyan bayan ma'aunin A2DP. Mafi kyawun codec kuma mafi muni a lokaci guda.

Mitar samfur
Bit zurfin
Bitrate
Tallafin rufaffiyar
Ƙaddamar da goyan baya

16, 32, 44.1, 48 kHz
16 ragowa
10-1500 kbps
Duk na'urori
Duk na'urori

SBC codec ne mai sauƙi kuma mai sauri mai ƙididdigewa, tare da ƙirar ƙirar psychoacoustic na farko (kawai ana amfani da abin rufe fuska na sautin shiru), ta amfani da daidaita lambar bugun bugun jini (APCM).
Ƙayyadaddun A2DP yana ba da shawarar bayanan martaba guda biyu don amfani: Matsayin Tsaki da Inganci.


Codec yana da saitunan da yawa waɗanda ke ba ku damar sarrafa jinkirin algorithmic, adadin samfuran a cikin toshe, algorithm rarraba bit, amma kusan ko'ina ana amfani da sigogi iri ɗaya da aka ba da shawarar a cikin ƙayyadaddun: Joint Stereo, 8 mitar bands, 16 blocks in firam mai jiwuwa, Hanyar rarraba ƙarar ƙara.
SBC tana goyan bayan canji mai ƙarfi na ma'aunin Bitpool, wanda ke shafar bitrate kai tsaye. Idan igiyoyin iska sun toshe, fakiti sun ɓace, ko kuma na'urori suna a nesa mai nisa, tushen sauti na iya rage Bitpool har sai sadarwa ta dawo daidai.

Yawancin masu kera wayoyin kunne suna saita matsakaicin ƙimar Bitpool zuwa 53, wanda ke iyakance ƙimar bit zuwa kilobits 328 a sakan daya yayin amfani da bayanin martaba da aka ba da shawarar.
Ko da mai kera lasifikan kai ya saita matsakaicin ƙimar Bitpool sama da 53 (ana samun irin waɗannan samfuran, alal misali: Beats Solo³, JBL Everest Elite 750NC, Apple AirPods, kuma ana samun su akan wasu masu karɓa da na'urorin motar mota), to yawancin OS ba za su ƙyale ba. amfani da ƙaramar bitrates saboda saita iyakacin ƙimar ciki a cikin tarin Bluetooth.
Bugu da ƙari, wasu masana'antun suna saita matsakaicin ƙimar Bitpool zuwa ƙasa don wasu na'urori. Misali, na Bluedio T yana da 39, na Samsung Gear IconX 37, wanda ke ba da ingancin sauti mara kyau.

Hane-hane na wucin gadi na masu haɓaka tarin tarin Bluetooth galibi sun tashi saboda rashin jituwa na wasu na'urori masu manyan ƙimar Bitpool ko bayanan martaba, koda sun ba da rahoton tallafi a gare su, da ƙarancin gwaji yayin takaddun shaida. Ya kasance mafi sauƙi ga marubutan tarin Bluetooth su iyakance kansu ga yarda da bayanin martaba da aka ba da shawarar, maimakon ƙirƙirar bayanan na'urorin da ba daidai ba (ko da yake yanzu suna yin wannan don wasu ayyukan aiki da ba daidai ba).

SBC yana keɓance raƙuman ƙididdige ƙididdigewa zuwa maƙallan mitar akan ƙananan-zuwa sama, tare da ma'auni daban-daban. Idan an yi amfani da duk bitrate don ƙananan mitoci da tsakiyar, za a "yanke maɗaukaki" (za a yi shiru maimakon).

Misali SBC 328 kbps. A saman shine na asali, a ƙasa kuma shine SBC, yana canzawa lokaci-lokaci tsakanin waƙoƙi. Sauti a cikin fayil ɗin bidiyo yana amfani da codec ɗin matsawa mara asara na FLAC. Yin amfani da FLAC a cikin kwandon mp4 ba a daidaita shi a hukumance ba, don haka ba a da tabbacin cewa burauzar ku za ta kunna ta, amma ya kamata ta yi aiki a cikin sabbin nau'ikan tebur Chrome da Firefox. Idan ba ku da sauti, kuna iya zazzage fayil ɗin ku buɗe shi a cikin na'urar bidiyo mai cikakken ƙarfi.
ZZ Top - Mutumin Kaifi Mai Tufafi

Siffar sikirin yana nuna lokacin sauyawa: SBC lokaci-lokaci yana yanke sautin shuru sama da 17.5 kHz, kuma baya keɓance ko kaɗan don band ɗin sama da 20 kHz. Ana samun cikakken sikirin ta danna (1.7 MB).

Ban ji wani bambanci tsakanin asali da SBC akan wannan waƙa ba.

Bari mu ɗauki sabon abu kuma mu kwaikwayi sautin da za a samu ta amfani da belun kunne na Samsung Gear IconX tare da Bitpool 37 (a sama - siginar asali, ƙasa - SBC 239 kbps, sauti a cikin FLAC).
Rashin Hankali Mai Girma - Shaida

Ina jin karar fashewar abubuwa, ƙarancin tasirin sitiriyo da kuma sautin “ƙuƙwalwa” mara daɗi a cikin ƙananan muryoyin murya.

Kodayake SBC codec ne mai sassauƙa sosai, ana iya saita shi don ƙarancin latency, yana ba da ingantaccen ingancin sauti a babban bitrates (452+ kbps) kuma yana da kyau ga yawancin mutane a daidaitaccen High Quality (328 kbps), saboda gaskiyar cewa hakan. Ma'aunin A2DP ba ya ƙayyade ƙayyadaddun bayanan martaba (amma kawai yana ba da shawarwari), masu haɓaka tari sun saita ƙuntatawa na wucin gadi akan Bitpool, ba a nuna sigogin sautin da aka watsa a cikin mahallin mai amfani ba, kuma masu kera wayoyin kunne suna da 'yanci don saita saitunan kansu kuma ba za su taɓa yin ba. nuna darajar Bitpool a cikin ƙayyadaddun fasaha na samfurin, codec ya zama sananne don ƙananan ingancin sauti, kodayake wannan ba matsala ba ne tare da codec kamar haka.
Ma'aunin Bitpool kai tsaye yana rinjayar bitrate a cikin bayanan martaba ɗaya kawai. Ƙimar Bitpool 53 iri ɗaya na iya ba da bitrate na 328 kbps tare da ingantaccen bayanin martabar da aka ba da shawarar, da kuma 1212 kbps tare da tashar Dual Channel da 4 mita, wanda shine dalilin da ya sa mawallafin OS, ban da ƙuntatawa akan Bitpool, saita iyaka da kan. Bitrate. Kamar yadda na gani, wannan yanayin ya taso ne saboda rashin daidaituwa a cikin ma'auni na A2DP: ya zama dole don yin shawarwari akan bitrate, ba Bitpool ba.

Tebur na tallafi don damar SBC a cikin OS daban-daban:

OS
Goyan bayan ƙimar ƙima
Iyaka max. Bitpool
Iyaka max. Bitrate
Yawan Bitrate
Daidaita tsayayyen Bitpool

Windows 10
44.1
53
512 kbps
328 kbps
✓*

Linux (BlueZ + PulseAudio)
16, 32, 44.1, 48 kHz
64 (don haɗin da ke shigowa), 53 (don haɗin da ke fita)
Babu iyaka
328 kbps
✓*

Mac Sugar Sierra
44.1
64, tsoho 53 ***
Ba a sani ba
328 kbps
✗

Android 4.4-9
44.1/48 kHz**
53
328 kbps
328 kbps
✗

Android 4.1-4.3.1
44.1, 48 kHz**
53
229 kbps
229 kbps
✗

Blackberry OS 10
48
53
Babu iyaka
328 kbps
✗

* Bitpool yana raguwa kawai, amma baya karuwa ta atomatik, idan yanayin canja wuri ya inganta. Don dawo da Bitpool kuna buƙatar dakatar da sake kunnawa, jira daƙiƙa biyu kuma sake kunna sautin.
** Ƙimar tsoho ta dogara ne akan saitunan tarin da aka ƙayyade lokacin tattara firmware. A cikin Android 8/8.1 mitar ita ce kawai ko dai 44.1 kHz ko 48 kHz, dangane da saitunan yayin haɗawa, a cikin wasu nau'ikan 44.1 kHz da 48 kHz ana tallafawa lokaci guda.
*** Ana iya ƙara ƙimar Bitpool a cikin shirin Bluetooth Explorer.

aptX da aptX HD

aptX codec ne mai sauƙi kuma mai sauri na lissafi, ba tare da psychoacoustics ba, ta amfani da daidaita lambar bugun bugun jini mai daidaitawa (Farashin ADPCM). Ya bayyana a kusa da 1988 (kwanan kwanan wata patent mai kwanan watan Fabrairu 1988), kafin Bluetooth, ana amfani da shi da farko a cikin ƙwararrun kayan sauti mara waya. A halin yanzu mallakar Qualcomm, yana buƙatar lasisi da kuɗin sarauta. Tun daga 2014: $6000 lokaci ɗaya da ≈$1 kowace na'ura, don batches na na'urori 10000 (source, p. 16).
aptX da aptX HD codec iri ɗaya ne, tare da bayanan ɓoye daban-daban.

Codec yana da siga guda ɗaya kawai - zaɓin mitar samfur. Akwai, duk da haka, zaɓi na lamba / yanayin tashoshi, amma a cikin duk na'urorin da aka sani da ni (70+ guda) kawai Stereo ke tallafawa.

Codec
Mitar samfur
Bit zurfin
Bitrate
Tallafin rufaffiyar
Ƙaddamar da goyan baya

karkatarwa
16, 32, 44.1, 48 kHz
16 ragowa
128/256/352/384 kbps (ya danganta da ƙimar samfur)
Windows 10 (tebur da wayar hannu), macOS, Android 4.4+/7*, Blackberry OS 10
Faɗin na'urorin sauti (hardware)

* Sigogi har zuwa 7 suna buƙatar gyara tarin Bluetooth. Ana tallafawa codec ɗin ne kawai idan masana'antar na'urar Android ta ba da lasisin codec daga Qualcomm (idan OS yana da ɗakunan karatu na ɓoye).

aptX yana raba sauti zuwa maƙallan mitar mitar 4 kuma yana ƙididdige su da adadin ragowa iri ɗaya koyaushe: 8 rago don 0-5.5 kHz, 4 rago don 5.5-11 kHz, 2 rago don 11-16.5 kHz, 2 rago don 16.5-22 kHz ( ƙididdiga don ƙididdige ƙimar 44.1 kHz).

Misali na aptX audio (a saman - siginar asali, a ƙasa - aptX, spectrograms na tashoshi na hagu kawai, sauti a FLAC):

Babban tsayi ya zama ɗan ja, amma ba za ku iya jin bambancin ba.

Saboda ƙayyadaddun rarraba raƙuman ƙididdigewa, codec ɗin ba zai iya “canza ragowa” zuwa mitocin da suka fi buƙatun su ba. Ba kamar SBC ba, aptX ba zai “yanke” mitoci ba, amma zai ƙara amon ƙididdige su, yana rage ƙarfin sautin.

Bai kamata a ɗauka cewa yin amfani da, alal misali, 2 ragowa a kowane band yana rage ƙarfin aiki zuwa 12 dB: ADPCM yana ba da damar har zuwa 96 dB na kewayo mai ƙarfi ko da lokacin amfani da 2 quantization bits, amma kawai don wani sigina.
ADPCM yana adana bambancin lamba tsakanin samfurin na yanzu da samfurin na gaba, maimakon adana cikakkiyar ƙimar kamar a cikin PCM. Wannan yana ba ku damar rage abubuwan buƙatu don adadin raƙuman da ake buƙata don adana iri ɗaya (ba tare da asara ba) ko kusan iri ɗaya (tare da ɗan ƙaramin kuskure) bayanai. Don rage kurakuran zagaye, ana amfani da tebur masu ƙima.
Lokacin ƙirƙirar codec, marubutan sun ƙididdige ƙididdigar ADPCM akan saitin fayilolin mai jiwuwa na kiɗa. Mafi kusancin siginar mai jiwuwa shine saitin kiɗan da aka gina allunan akansa, ƙananan kurakuran ƙididdigewa (amo) aptX ke haifarwa.

Saboda wannan, gwaje-gwajen roba koyaushe za su haifar da sakamako mafi muni fiye da kiɗa. Na yi wani misali na musamman na roba wanda aptX ke nuna sakamako mara kyau - igiyoyin sine tare da mitar 12.4 kHz (a sama - siginar asali, ƙasa - aptX. Audio a cikin FLAC. Rage ƙarar!):

Tsarin Spectrum:


Ana iya jin surutu a fili.

Koyaya, idan kun ƙirƙira igiyar sine tare da ƙaramin ƙarami don ta yi shuru, hayaniyar kuma za ta yi shuru, yana nuna kewayo mai ƙarfi:

Don jin bambanci tsakanin waƙar waƙar ta asali da wadda aka matsa, zaku iya juyar da ɗaya daga cikin sigina kuma ƙara tashar waƙoƙi ta tashoshi. Wannan hanya, gabaɗaya, ba daidai ba ce, kuma ba za ta ba da sakamako mai hankali tare da ƙarin hadaddun codecs ba, amma musamman ga ADPCM ya dace sosai.
Bambanci tsakanin asali da aptX
Tushen yana nufin bambancin murabba'i na sigina yana a matakin -37.4 dB, wanda ba shi da yawa don irin wannan matsa lamba.

HD aptX

aptX HD ba codec mai zaman kansa ba ne - ingantaccen bayanin martaba ne na codec aptX. Canje-canjen sun shafi adadin ragi da aka keɓe don keɓaɓɓun kewayon mitar: 10 rago don 0-5.5 kHz, 6 rago don 5.5-11 kHz, 4 rago don 11-16.5 kHz, 4 rago don 16.5-22 kHz (lambobi don 44.1 kHz) .

Codec
Mitar samfur
Bit zurfin
Bitrate
Tallafin rufaffiyar
Ƙaddamar da goyan baya

HD aptX
16, 32, 44.1, 48 kHz
24 bits
192/384/529/576 kbps (ya danganta da ƙimar samfur)
Android 8+*
Wasu na'urorin sauti (hardware)

* Sigogi har zuwa 7 suna buƙatar gyara tarin Bluetooth. Ana tallafawa codec ɗin ne kawai idan masana'antar na'urar Android ta ba da lasisin codec daga Qualcomm (idan OS yana da ɗakunan karatu na ɓoye).

Kasa da gama gari fiye da aptX: a fili yana buƙatar lasisi daban daga Qualcomm, da kuɗin lasisi daban.

Bari mu maimaita misalin tare da igiyar ruwa a 12.4 kHz:


Yafi kyau fiye da aptX, amma har yanzu yana ɗan hayaniya.

aptX Latananan Latency

Codec daga Qualcomm wanda ba shi da wani abu gama gari tare da daidaitaccen aptX da aptX HD, yana yin hukunci ta iyakanceccen bayani daga mutanen da ke da hannu a cikin haɓakarsa. An ƙera shi don watsa sauti mai ƙarancin jinkiri (fina-finai, wasanni), inda software ba za ta iya daidaita jinkirin sauti ba. Babu sanannen aiwatar da software na encoders da dikodi; ana tallafawa su ta hanyar masu watsawa, masu karɓa, belun kunne da lasifika, amma ba ta wayoyin hannu da kwamfutoci ba.

Mitar samfur
Bitrate
Tallafin rufaffiyar
Ƙaddamar da goyan baya

44.1
276/420 kbps
Wasu masu watsawa (hardware)
Wasu na'urorin sauti (hardware)

AAC

AAC, ko Advanced Audio Codec, codec ne mai rikitarwa mai rikitarwa tare da ƙirar psychoacoustic mai tsanani. An yi amfani da shi sosai don sauti akan Intanet, na biyu a shahara bayan MP3. Yana buƙatar lasisi da kuɗin sarauta: $15000 lokaci ɗaya (ko $1000 ga kamfanoni masu ƙasa da ma'aikata 15) + $0.98 don na'urori 500000 na farko (source).
A Codec aka daidaita a cikin MPEG-2 da MPEG-4 bayani dalla-dalla, kuma akasin na kowa kuskure, shi ba na Apple.

Mitar samfur
Bitrate
Tallafin rufaffiyar
Ƙaddamar da goyan baya

8-96 kHz
8 - 576 kbps (na sitiriyo), 256 - 320 kbps (na al'ada don Bluetooth)
macOS, Android 7+*, iOS
Faɗin na'urorin sauti (hardware)

* kawai akan na'urori waɗanda masana'antunsu suka biya kuɗin lasisi

iOS da macOS suna amfani da mafi kyawun rikodin AAC na Apple na yanzu don sadar da mafi girman ingancin sauti mai yiwuwa. Android tana amfani da na biyu mafi inganci Fraunhofer FDK AAC encoder, amma yana iya amfani da kayan aiki daban-daban da aka gina a cikin dandamali (SoC) tare da ingancin ɓoye bayanan da ba a san su ba. Dangane da gwaje-gwajen kwanan nan akan gidan yanar gizon SoundGuys, ingancin shigar da AAC na wayoyin Android daban-daban ya bambanta sosai:

Yawancin na'urorin sauti mara waya suna da matsakaicin bitrate na 320 kbps don AAC, wasu kawai suna tallafawa 256 kbps. Sauran bitrates suna da wuyar gaske.
AAC yana ba da kyakkyawan inganci a 320 da 256 kbps bitrates, amma yana ƙarƙashin asarar rikodi na jere na abubuwan da aka matse, duk da haka, yana da wuya a ji wani bambance-bambance tare da asali a kan iOS a kan bitrate na 256 kbps ko da tare da rufaffiyar tsari da yawa; tare da ɓoye guda ɗaya, misali, MP3 320 kbps zuwa AAC 256 kbps, za a iya yin watsi da hasara.
Kamar yadda yake tare da sauran codecs na Bluetooth, kowace waƙa ana fara ɓarnawa ne sannan kuma codec ɗin yana ɓoyewa. Lokacin sauraron kiɗa a cikin tsarin AAC, OS na farko ne ya ƙirƙira shi, sannan a sake sanya shi cikin AAC don watsawa ta Bluetooth. Wannan wajibi ne don haɗa rafukan sauti masu yawa, kamar kiɗa da sabbin sanarwar saƙo. iOS ba togiya. A Intanet zaku iya samun maganganu da yawa waɗanda akan kiɗan iOS a cikin tsarin AAC ba a canza su lokacin da ake watsa su ta Bluetooth, wanda ba gaskiya bane.

MP1/2/3

The codecs na MPEG-1/2 Part 3 iyali kunshi sanannun da kuma yadu amfani MP3, da kasa na kowa MP2 (amfani yafi dijital TV da rediyo), da kuma gaba daya ba a sani ba MP1.

Tsofaffin codecs na MP1 da MP2 ba su da tallafi kwata-kwata: Ba zan iya samun wani belun kunne ko tari na Bluetooth wanda zai rufa su ko yanke su.
Ƙididdigar MP3 tana samun goyan bayan wasu belun kunne, amma ba a samun goyan bayan rikodi akan kowane tsarin aiki na zamani. Da alama cewa tari na BlueSoleil na ɓangare na uku don Windows na iya ɓoyewa zuwa MP3 idan kun canza fayil ɗin sanyi da hannu, amma a gare ni in shigar da shi yana kaiwa zuwa BSoD akan Windows 10. Kammalawa - codec a zahiri ba za a iya amfani da shi don sauti na Bluetooth ba.
A baya, a cikin 2006-2008, kafin yaduwar ma'aunin A2DP a cikin na'urori, mutane suna sauraron kiɗan MP3 akan lasifikan kai na Nokia BH-501 ta hanyar MSI BluePlayer, wanda ake samu akan Symbian da Windows Mobile. A wancan lokacin, tsarin gine-ginen OS na wayoyin hannu ya ba da damar yin amfani da ayyuka marasa ƙarfi da yawa, kuma a kan Windows Mobile har ma yana yiwuwa a shigar da tarin Bluetooth na ɓangare na uku.

Ƙarshen ikon mallakar codec na MP3 ya ƙare, amfani da codec ɗin baya buƙatar kuɗin lasisi tun 23 ga Afrilu, 2017.

Idan an ɗauki haƙƙin mallaka mafi tsayi da aka ambata a cikin abubuwan da aka ambata a matsayin ma'auni, to, fasahar MP3 ta zama mara izini a Amurka a ranar 16 ga Afrilu, 2017 lokacin da US Patent 6,009,399, wanda Technicolor ke riƙe da kuma gudanarwa, ya ƙare.

source: www.iis.fraunhofer.de/en/ff/amm/prod/audiocodec/audiocodecs/mp3.html

Mitar samfur
Bitrate
Tallafin rufaffiyar
Ƙaddamar da goyan baya

16-48 kHz
8 - 320 kbps
Ba a tallafawa ko'ina
Wasu na'urorin sauti (hardware)

LDAC

Wani sabon codec na "Hi-Res" da aka haɓaka daga Sony, yana tallafawa ƙimar samfurin har zuwa 96 kHz da 24-bit bitrate, tare da bitrates har zuwa 990 kbps. Ana tallata shi azaman codec na audiophile, azaman maye gurbin codecs na Bluetooth na yanzu. Yana da aikin daidaita bitrate mai daidaitawa, dangane da yanayin watsa shirye-shiryen rediyo.

Mai rikodin LDAC (libdac) yana cikin daidaitaccen fakitin Android, don haka ana samun goyan bayan shigar da bayanai akan kowace wayar Android wacce ta fara da sigar OS 8. Babu masu gyara software kyauta, ƙayyadaddun codec ɗin ba ya samuwa ga jama'a gabaɗaya, duk da haka, a kallon farko a mai rikodin, tsarin ciki na codec yayi kama da Farashin ATRAC9 - Codec na Sony da aka yi amfani da shi a cikin PlayStation 4 da Vita: duka biyu suna aiki a cikin yanki na mitar, suna amfani da canza canji mai hankali (MDCT) da matsawa ta amfani da Huffman algorithm.

Ana ba da tallafin LDAC kusan ta hanyar belun kunne daga Sony. Ana samun ikon yanke LDAC wani lokaci akan belun kunne da DACs daga wasu masana'antun, amma da wuya.

Mitar samfur
Bitrate
Tallafin rufaffiyar
Ƙaddamar da goyan baya

44.1-96 kHz
303/606/909 kbit/s (na 44.1 da 88.2 kHz), 330/660/990 kbit/s (na 48 da 96 kHz)
Android 8 +
Wasu belun kunne na Sony da wasu na'urori daga wasu masana'antun (hardware)

Talla LDAC a matsayin codec na Hi-Res yana cutar da sashin fasaha: wauta ne don ciyar da bitrate akan watsa mitoci mara sauti ga kunnen ɗan adam da haɓaka zurfin bit, yayin da bai isa ya watsa ingancin CD ba (44.1/16) ba tare da asara ba. . Abin farin ciki, codec ɗin yana da hanyoyin aiki guda biyu: watsa sauti na CD da watsa sauti na Hi-Res. A cikin yanayin farko, kawai 44.1 kHz / 16 ragowa ana watsa su ta iska.

Tun da software na LDAC ba ya samuwa kyauta, ba shi yiwuwa a gwada codec ɗin ba tare da ƙarin na'urori waɗanda ke yanke LDAC ba. Dangane da sakamakon gwajin LDAC akan DAC tare da goyan bayan sa, wanda injiniyoyin SoundGuys.com sun haɗa ta hanyar fitarwa ta dijital kuma sun yi rikodin sautin fitarwa akan siginar gwaji, LDAC 660 da 990 kbps a cikin yanayin ingancin CD yana ba da sigina-zuwa- rabon amo ya fi na aptX HD kyau.

source: www.soundguys.com/ldac-ultimate-bluetooth-guide-20026

LDAC kuma tana goyan bayan ƙaƙƙarfan bitrates a waje da kafaffun bayanan martaba - daga 138 kbps zuwa 990 kbps, amma kamar yadda zan iya faɗa, Android kawai tana amfani da daidaitattun bayanan martaba 303/606/909 da 330/660/990 kbps.

Sauran codecs

Wasu codecs na A2DP ba a amfani da su sosai. Tallafin su ko dai kusan ba ya nan ko kuma ana samun su ne kawai akan wasu nau'ikan belun kunne da wayoyin hannu.
Codec na ATRAC da aka daidaita a cikin A2DP ba a taɓa amfani dashi azaman codec na Bluetooth ba har ma da Sony da kansu, Samsung HD, Samsung Scalable da Samsung UHQ-BT codecs suna da iyakataccen tallafi daga watsawa da na'urori masu karɓa, kuma HWA LHDC sabo ne kuma yana goyan bayan uku kawai. (?) na'urorin.

Tallafin Codec don na'urorin mai jiwuwa

Ba duk masana'antun ba ne ke buga ingantattun bayanai game da codecs waɗanda ke samun goyan bayan wasu belun kunne, lasifika, masu karɓa ko masu watsawa. Wani lokaci yana faruwa cewa goyan bayan wani codec kawai don watsawa ne, amma ba don liyafar ba (mai dacewa don haɗa masu karɓa-masu karɓa), kodayake masana'anta suna bayyana “tallafi” kawai, ba tare da bayanin kula ba (Ina ɗauka cewa raba lasisin encoders da decoders na wasu codecs shine laifin wannan). A cikin mafi arha na'urori, ƙila ba za ku sami goyan bayan aptX da aka ayyana kwata-kwata ba.

Abin baƙin ciki, musaya na yawancin tsarin aiki ba sa nuna codec ɗin da aka yi amfani da shi a ko'ina. Bayani game da wannan yana samuwa ne kawai a cikin Android, farawa daga sigar 8, da macOS. Duk da haka, ko da a cikin waɗannan OSs, kawai waɗancan codecs waɗanda ke tallafawa ta waya/kwamfuta da kuma belun kunne za a nuna su.

Ta yaya za ku gano waɗanne codecs na na'urar ku ke tallafawa? Yi rikodin kuma bincika juji na zirga-zirga tare da sigogin shawarwari na A2DP!
Ana iya yin wannan akan Linux, macOS da Android. A Linux zaku iya amfani da Wireshark ko hcidump, akan macOS zaku iya amfani da Bluetooth Explorer, kuma akan Android zaku iya amfani da daidaitaccen aikin ceton juji na Bluetooth HCI, wanda yake cikin kayan aikin haɓakawa. Za ku karɓi juji a tsarin btsnoop, wanda za'a iya loda shi cikin mai nazarin Wireshark.
Kula: Za'a iya samun daidaitaccen juji ta hanyar haɗawa daga wayarka/kwamfuta zuwa belun kunne / lasifika (komai ban dariya yana iya sauti)! Wayoyin kunne na iya ƙaddamar da haɗin kai tare da wayar, a cikin wannan yanayin za su buƙaci jerin codecs daga wayar, ba akasin haka ba. Don tabbatar da an yi rikodin madaidaicin juji, da farko cire na'urar sannan ka haɗa wayarka tare da belun kunne yayin yin rikodin juji.

Yi amfani da matattarar nuni mai zuwa don tace zirga-zirgar da bai dace ba:

btavdtp.signal_id

A sakamakon haka, ya kamata ku ga wani abu makamancin haka:

Kuna iya danna kowane abu a cikin umarnin GetCapabilities don duba cikakkun halaye na codec.

Wireshark bai san duk masu gano codec ba, don haka wasu codecs dole ne a lalata su da hannu, suna kallon tebur mai ganowa a ƙasa:

Mandatory:
0x00 - SBC

Optional:
0x01 - MPEG-1,2 (aka MP3)
0x02 - MPEG-2,4 (aka AAC)
0x04 - ATRAC

Vendor specific:
0xFF 0x004F 0x01   - aptX
0xFF 0x00D7 0x24   - aptX HD
0xFF 0x000A 0x02   - aptX Low Latency
0xFF 0x00D7 0x02   - aptX Low Latency
0xFF 0x000A 0x01   - FastStream
0xFF 0x012D 0xAA   - LDAC
0xFF 0x0075 0x0102 - Samsung HD
0xFF 0x0075 0x0103 - Samsung Scalable Codec
0xFF 0x053A 0x484C - Savitech LHDC

0xFF 0x000A 0x0104 - The CSR True Wireless Stereo v3 Codec ID for AAC
0xFF 0x000A 0x0105 - The CSR True Wireless Stereo v3 Codec ID for MP3
0xFF 0x000A 0x0106 - The CSR True Wireless Stereo v3 Codec ID for aptX

Don kada in bincika jujjuyawar da hannu, Na yi sabis wanda zai bincika komai ta atomatik: btcodecs.valdikss.org.ru

Kwatanta codecs. Wane codec ne ya fi kyau?

Kowane codec yana da nasa abũbuwan amfãni da rashin amfani.
aptX da aptX HD suna amfani da bayanan martaba masu ƙarfi waɗanda ba za a iya canza su ba tare da gyaggyara rikodi da dikodi ba. Mai ƙirƙira waya ko mai kera wayar kai ba za su iya canza abubuwan ɓoye bitrate ko aptX ba. Ma'abucin codec, Qualcomm, yana ba da maɓalli na tunani a cikin hanyar ɗakin karatu. Wadannan hujjoji sune ƙarfin aptX - kun san a gaba wane ingancin sauti za ku samu, ba tare da wani "amma".

SBC, akasin haka, yana da sigogi masu daidaitawa da yawa, bitrate mai ƙarfi (mai rikodin rikodin zai iya rage ma'aunin bitpool idan iskar iska tana aiki), kuma ba ta da bayanan martaba masu ƙarfi, kawai shawarar “matsakaici inganci” da “high quality” waɗanda suka kasance. ƙara da ƙayyadaddun A2DP a cikin 2003 shekara. "Maɗaukaki mai inganci" ba ya da girma ta ma'auni na yau, kuma yawancin tarin Bluetooth ba sa ba ku damar amfani da sigogi fiye da bayanin martaba na "high quality", kodayake babu ƙuntatawa na fasaha don wannan.
Bluetooth SIG bashi da alamar SBC encoder azaman ɗakin karatu, kuma masana'antun suna aiwatar da shi da kansu.
Waɗannan su ne raunin SBC - ba a taɓa bayyana a gaba menene ingancin sautin da za a jira daga wata na'ura ba. SBC na iya samar da sauti mai ƙarancin ƙarfi da inganci sosai, amma ba za a iya samun na ƙarshe ba tare da kashewa ko ketare iyakokin wucin gadi na tarin Bluetooth ba.

Halin da ke tare da AAC ba shi da tabbas: a gefe guda, a ka'idar codec ya kamata ya samar da ingancin da ba za a iya bambanta shi da asali ba, amma a aikace, yin la'akari da gwaje-gwaje na dakin gwaje-gwaje na SoundGuys akan na'urorin Android daban-daban, wannan ba a tabbatar ba. Mai yuwuwa, laifin ya ta'allaka ne da ingantattun ingantattun sauti na kayan masarufi da aka gina a cikin kwakwalwan kwamfuta daban-daban na waya. Yana da ma'ana don amfani da AAC akan na'urorin Apple kawai, kuma akan Android don iyakance shi zuwa aptX da LDAC.

Hardware wanda ke goyan bayan madadin codecs yana son ya zama mafi inganci, kawai saboda arha, na'urori marasa inganci, ba shi da ma'ana a biya kuɗin lasisi don amfani da waɗannan codecs. A cikin gwaje-gwaje na, SBC yana da kyau sosai akan kayan aiki masu inganci.

Na yi sabis ɗin gidan yanar gizo wanda ke ɓoye sauti zuwa SBC, aptX da aptX HD a ainihin lokacin, daidai a cikin mai lilo. Tare da shi, zaku iya gwada waɗannan codecs na odiyo ba tare da aika sauti ta zahiri ta Bluetooth ba, akan kowane belun kunne, lasifika, da kiɗan da kuka fi so, da kuma canza sigogin ɓoye kai tsaye yayin kunna sauti:
btcodecs.valdikss.org.ru/sbc-encoder
Sabis ɗin yana amfani da ɗakunan karatu na SBC daga aikin BlueZ da libopenaptx daga ffmpeg, waɗanda aka haɗa su zuwa WebAssembly da JavaScript daga C, ta hanyar emscripten, don aiki a cikin mai lilo. Wanene zai iya mafarkin irin wannan makomar!

Ga yadda yake kama da:

Lura yadda matakin amo ke canzawa bayan 20 kHz don codecs daban-daban. Fayil ɗin MP3 na asali bai ƙunshi mitoci sama da 20 kHz ba.

Gwada canza codecs kuma duba idan kun ji bambanci tsakanin asali, SBC 53 Joint Stereo (misali kuma mafi yawan bayanin martaba), da aptX/aptX HD.

Zan iya jin bambanci tsakanin codecs a belun kunne!

Mutanen da ba sa jin bambanci tsakanin codecs yayin gwaji ta hanyar sabis na yanar gizo suna da'awar cewa suna jin sa lokacin sauraron kiɗa akan belun kunne mara waya. Alas, wannan ba abin dariya ba ne ko tasirin placebo: bambance-bambancen da gaske ake ji, amma ba bambance-bambance ne ya haifar da shi ba. codecs.

Yawancin kwakwalwar kwakwalwar kwamfuta na Bluetooth mai jiwuwa da ake amfani da su a cikin na'urori masu karɓar mara waya suna sanye da na'urar sarrafa siginar Dijital (DSP), wanda ke aiwatar da mai daidaitawa, compander, faɗaɗa sitiriyo, da sauran abubuwan da aka tsara don inganta (ko canza) sauti. Masu kera kayan aikin Bluetooth na iya saita DSP ga kowane codec daban, kuma lokacin canzawa tsakanin codecs, mai sauraro zai yi tunanin cewa suna jin bambanci a cikin aiki na codecs, lokacin da a gaskiya suna sauraron saitunan DSP daban-daban.

DSP Kalimba bututun sarrafa sauti a cikin kwakwalwan kwamfuta da CSR/Qualcomm ke ƙera

Kunna ayyuka daban-daban na DSP don kowane codec da fitarwa daban

Wasu na'urori masu ƙima suna zuwa tare da software wanda ke ba ku damar tsara saitunan DSP, amma yawancin belun kunne masu rahusa ba sa yin hakan, kuma masu amfani ba za su iya kashe sarrafa sauti da hannu ba.

Ayyukan na'urori

Sigar zamani na daidaitattun A2DP yana da "cikakkiyar ikon sarrafa ƙara" aikin - sarrafa ƙarar na'ura ta amfani da umarni na musamman na ka'idar AVRCP, wanda ke daidaita riba na matakin fitarwa, maimakon shirin rage girman sautin sauti. Idan lokacin da kuka canza ƙarar belun kunne, canjin baya daidaitawa da ƙarar wayarku, to belun kunne ko wayar ba sa goyan bayan wannan fasalin. A wannan yanayin, yana da ma'ana koyaushe sauraron kiɗa tare da matsakaicin ƙararrawa akan wayar, daidaita ainihin ƙarar tare da maɓallan belun kunne - a cikin wannan yanayin, rabon siginar-zuwa amo zai fi kyau kuma ingancin sauti. yakamata ya kasance mafi girma.
A gaskiya, akwai yanayi na baƙin ciki. A kan belun kunne na RealForce OverDrive D1 na SBC, ana kunna compander mai ƙarfi, kuma ƙara ƙarar yana haifar da haɓaka matakin sautin shuru, yayin da ƙarar ƙarar sauti ba ta canzawa (siginar an matsa). Saboda haka, dole ne ka saita sautin a kan kwamfutar zuwa kusan rabin, wanda a halin yanzu babu wani tasiri na matsawa.
Bisa ga abin da na lura, duk belun kunne tare da ƙarin codecs suna goyan bayan cikakken aikin sarrafa ƙara, a fili wannan yana ɗaya daga cikin buƙatun don takaddun shaida.

Wasu belun kunne suna goyan bayan haɗa na'urori biyu a lokaci guda. Wannan yana ba ku damar, misali, sauraron kiɗa daga kwamfutarka kuma karɓar kira daga wayarka. Koyaya, yakamata ku sani cewa a cikin wannan yanayin ana kashe madadin codecs kuma ana amfani da SBC kawai.

AVDTP 1.3 Jinkirin Bayar da rahoto yana ba da belun kunne don sadar da jinkiri zuwa na'urar watsawa wacce a zahiri ke kunna sauti. Wannan yana ba ku damar daidaita aiki tare da sauti tare da bidiyo yayin kallon fayilolin bidiyo: idan akwai matsaloli tare da watsa rediyo, sautin ba zai tsaya a bayan bidiyon ba, amma akasin haka, mai kunna bidiyo zai rage jinkirin bidiyo har zuwa lokacin Ana sake daidaita sauti da bidiyo.
Aikin yana da goyan bayan belun kunne da yawa, Android 9+ da Linux tare da PulseAudio 12.0+. Ban san goyan bayan wannan fasalin akan wasu dandamali ba.

Sadarwar hanyar sadarwa ta hanyar Bluetooth. Watsa murya.

Don watsa murya a cikin Bluetooth, ana amfani da Haɗin Haɗin Daidaitawa (SCO) - watsawa tare da tattaunawar farko ta haɗin. Yanayin yana ba ku damar watsa sauti da murya daidai gwargwado, tare da aika ma'auni da karɓan sauri, ba tare da jiran tabbatar da fakitin watsawa da sake aikawa ba. Wannan yana rage jinkirin watsa sauti gabaɗaya akan tashar rediyo, amma yana sanya ƙayyadaddun ƙuntatawa akan adadin bayanan da ake watsa kowane raka'a na lokaci, kuma yana yin mummunan tasiri ga inganci.
Lokacin da ake amfani da wannan yanayin, ana watsa sauti da sauti tare da inganci iri ɗaya.
Abin takaici, har zuwa 2019, ingancin murya akan Bluetooth har yanzu yana da rauni, kuma ba a san dalilin da yasa Bluetooth SIG ba ya yin komai game da shi.

CVSD

Ainihin codec ɗin CVSD na magana an daidaita shi a cikin 2002, kuma ana samun goyan bayan duk na'urorin sadarwar Bluetooth na bidirectional. Yana bayar da watsa sauti tare da mitar samfurin 8 kHz, wanda yayi daidai da ingancin wayar tarho na al'ada.

Misalin rikodin a cikin wannan codec.

mSBC

An daidaita ƙarin mSBC codec a cikin 2009, kuma a cikin 2010 kwakwalwan kwamfuta masu amfani da shi don watsa murya sun riga sun bayyana. mSBC ana samun goyan bayan na'urori daban-daban.
Wannan ba codec mai zaman kansa ba ne, amma SBC na yau da kullun daga ma'aunin A2DP, tare da ingantaccen bayanin martaba: 16 kHz, mono, bitpool 26.

Misalin rikodin a cikin wannan codec.

Ba mai haske ba, amma ya fi CVSD kyau, amma har yanzu yana da ban haushi don amfani da sadarwar kan layi, musamman lokacin da kuke amfani da belun kunne don sadarwa a cikin wasan - kuma za a watsa sautin wasan a ƙimar samfurin 16 kHz.

Kamfanin FastStreamCSR ya yanke shawarar haɓaka ra'ayin yin amfani da SBC. Don samun kusa da iyakokin ka'idar SCO da amfani da mafi girman bitrates, CSR ya tafi wata hanya ta daban - sun gabatar da tallafi don sautin SBC guda biyu a cikin daidaitaccen watsa sauti na A2DP guda ɗaya, daidaitattun bayanan martaba, kuma suna kiransa "FastStream".

FastStream yana watsa sautin sitiriyo a 44.1 ko 48 kHz tare da bitrate na 212 kbps zuwa masu magana, kuma mono, 16 kHz, tare da bitrate na 72 kbps ana amfani dashi don watsa sauti daga makirufo (dan kadan fiye da mSBC). Irin waɗannan sigogi sun fi dacewa da sadarwa a cikin wasanni na kan layi - sautin wasan da masu shiga tsakani za su kasance masu inganci.

Misalin rikodin a cikin wannan codec (+ sauti daga makirufo, daidai da mSBC).

Kamfanin ya fito da wata dabara mai ban sha'awa, amma saboda gaskiyar cewa ya saba wa ka'idar A2DP, ana tallafawa ne kawai a wasu na'urori na kamfanin (wanda ke aiki a matsayin katin sauti na USB, ba na'urar Bluetooth ba), amma ba ya aiki. sami tallafi a cikin tarin Bluetooth. kodayake adadin belun kunne tare da tallafin FastStream ba ƙanƙanta bane.

A halin yanzu, tallafin FastStream a cikin OS shine kawai azaman faci don Linux PulseAudio daga mai haɓaka Pali Rohár, wanda ba a haɗa shi cikin babban reshe na shirin ba.

aptX Latananan Latency

Abin mamaki ga ku, aptX Low Latency shima yana goyan bayan sauti na biyu, yana aiwatar da ƙa'ida ɗaya kamar FastStream.
Ba zai yiwu a yi amfani da wannan fasalin codec ɗin a ko'ina ba - babu tallafi don ƙaddamar da ƙananan Latency a cikin kowane OS ko a cikin kowane tari na Bluetooth da aka sani da ni.

Bluetooth 5, Classic da Low Energy

An sami rudani da yawa game da ƙayyadaddun bayanai da nau'ikan Bluetooth saboda kasancewar ma'auni guda biyu da ba su dace ba a ƙarƙashin alama ɗaya, duka biyun ana amfani da su don dalilai daban-daban.

Akwai mabambanta guda biyu, ka'idojin Bluetooth mara jituwa: Bluetooth Classic da Bluetooth Low Energy (LE, wanda kuma aka sani da Bluetooth Smart). Akwai kuma yarjejeniya ta uku, Bluetooth High Speed, amma ba ta yaɗu ba kuma ba a amfani da ita a cikin na'urorin gida.

An fara tare da Bluetooth 4.0, canje-canje a cikin ƙayyadaddun ƙayyadaddun abin da ya shafi Bluetooth Low Energy, kuma sigar Classic ta sami ƙananan haɓakawa kawai.

Jerin canje-canje tsakanin Bluetooth 4.2 da Bluetooth 5:

9 Canje-canje daga v4.2 ZUWA 5.0

9.1 SABBIN FALALA

An gabatar da sabbin abubuwa da yawa a cikin Sakin Ƙididdigar Ƙididdigar Bluetooth 5.0. Manyan wuraren ingantawa su ne:
Mashin Samar da Ramin (SAM)
• 2 Msym/s PHY na LE
• LE Dogon Rage
• Babban Hakuri da Ba a Haɗe Talla
LE Extensions na Talla
• Zaɓi Algorithm na Channel na LE #2
9.1.1 Abubuwan Haɗawa a cikin CSA5 - Haɗe cikin v5.0
•Mafi girman fitarwa

source: www.bluetooth.org/docman/handlers/DownloadDoc.ashx?doc_id=421043 (shafi na 291)

Canji ɗaya kawai ya shafi sigar Classic a cikin tsarin ƙayyadaddun Bluetooth 5: sun ƙara goyan baya don fasahar Samun Mashin Ramin (SAM), wanda aka ƙera don haɓaka rabuwar watsa shirye-shiryen rediyo. Duk sauran canje-canje suna shafar Bluetooth LE kawai (da Ƙarfin fitarwa mafi girma ma).

All Na'urorin sauti suna amfani da Bluetooth Classic kawai. Ba shi yiwuwa a haɗa belun kunne da lasifika ta Bluetooth Low Energy: babu ma'auni don watsa sauti ta amfani da LE. Ma'auni na A2DP, wanda ake amfani dashi don watsa sauti mai inganci, yana aiki ta hanyar Bluetooth Classic kawai, kuma babu analogue a cikin LE.

Kammalawa - siyan na'urorin mai jiwuwa tare da Bluetooth 5 kawai saboda sabon sigar ka'idar bashi da ma'ana. Bluetooth 4.0/4.1/4.2 a cikin mahallin watsa sauti zai yi aiki daidai da wannan.
Idan sanarwar sabbin belun kunne ta ambaci ninki biyu na aiki da rage amfani da wutar lantarki godiya ga Bluetooth 5, to ya kamata ku sani ko dai ba su fahimce shi da kansu ba ko kuma suna yaudarar ku. Ba abin mamaki bane, domin hatta masana'antun na'urorin Bluetooth a cikin sanarwarsu sun ruɗe game da bambance-bambancen da ke tsakanin sabon sigar daidaitattun, kuma wasu kwakwalwan kwamfuta na Bluetooth 5 suna goyan bayan sigar ta biyar kawai don LE, kuma suna amfani da 4.2 don Classic.

Jinkirin watsa sauti

Adadin jinkiri (lalacewa) a cikin sauti ya dogara da dalilai da yawa: girman ma'ajin a cikin tarin sauti, a cikin tarin Bluetooth da a cikin na'urar sake kunnawa mara waya kanta, da jinkirin algorithmic na codec.

Latency na codecs masu sauƙi kamar SBC, aptX da aptX HD ƙananan ƙananan ne, 3-6 ms, waɗanda za a iya yin watsi da su, amma hadaddun codecs kamar AAC da LDAC na iya haifar da raguwa mai mahimmanci. Latency AAC algorithmic na 44.1 kHz shine 60 ms. LDAC - kusan 30 ms (dangane da ƙaƙƙarfan bincike na lambar tushe. Zan iya yin kuskure, amma ba da yawa ba.)

Sakamakon jinkirin ya dogara sosai akan na'urar sake kunnawa, chipset da buffer. A lokacin gwaje-gwaje, na sami yaduwar 150 zuwa 250 ms akan na'urori daban-daban (tare da lambar SBC). Idan muka ɗauka cewa na'urorin da ke goyan bayan ƙarin codecs aptX, AAC da LDAC suna amfani da ingantattun abubuwan haɗin gwiwa da ƙaramin girman buffer, muna samun latencies masu zuwa:

SBC: 150-250ms
aptX: 130-180 ms
AAC: 190-240 ms
LDAC: 160-210 ms

Bari in tunatar da ku: aptX Low Latency ba shi da tallafi a cikin tsarin aiki, wanda shine dalilin da ya sa za a iya samun ƙananan latency kawai tare da mai aikawa + mai karɓa ko watsawa + belun kunne / haɗin lasifika, kuma duk na'urori dole ne su goyi bayan wannan codec.

Na'urar Bluetooth, takaddun shaida, da batutuwan tambari

Yadda za a bambanta na'urar sauti mai inganci daga sana'a mai arha? A cikin bayyanar, da farko!

Don belun kunne na China mai arha, lasifika da masu karɓa:

1. Kalmar "Bluetooth" ta ɓace akan akwatin da na'urar, "Wireless" da "BT" galibi ana amfani da su.
2. Tambarin Bluetooth ya ɓace akan akwatin ko na'urar
3. Babu LED mai walƙiya blue

Rashin waɗannan abubuwan yana nuna cewa na'urar ba ta da takaddun shaida, wanda ke nufin tana da yuwuwar rashin inganci da matsala. Misali, bluedio belun kunne ba su da bokan Bluetooth kuma basu cika cika ƙayyadaddun A2DP ba. Da ba za su wuce takaddun shaida ba.

Bari mu yi la'akari da na'urori da kwalaye da yawa daga cikinsu:

Waɗannan duk na'urori ne marasa tabbaci. Umarnin na iya ƙunsar tambari da sunan fasahar Bluetooth, amma abu mafi mahimmanci shine suna kan akwatin da/ko na'urar kanta.

Idan belun kunne ko lasifikar ku sun ce "An haɗa bluetooth dewise cikin nasara", wannan kuma baya nuna ingancin su:

ƙarshe

Shin Bluetooth zata iya maye gurbin belun kunne da naúrar kai gaba ɗaya? Yana da iyawa, amma a farashin ƙarancin ingancin kira, ƙara yawan jinkirin sauti wanda zai iya zama mai ban haushi a cikin wasanni, da tarin codecs na mallakar mallaka waɗanda ke buƙatar kuɗaɗen lasisi da haɓaka farashin ƙarshe na wayoyin komai da ruwanka da belun kunne.

Tallace-tallacen madadin codecs yana da ƙarfi sosai: aptX da LDAC an gabatar da su azaman maye gurbin da aka daɗe ana jira don “tsohuwar da mara kyau” SBC, wanda bai kusan zama mummunan kamar yadda mutane suke tsammani ba.

Kamar yadda ya fito, ana iya ƙetare iyakokin wucin gadi na tarin Bluetooth akan bitrate na SBC, ta yadda SBC ba za ta yi ƙasa da aptX HD ba. Na ɗauki matakin a hannuna kuma na yi faci don firmware na LineageOS: Muna canza tarin Bluetooth don inganta sauti akan belun kunne ba tare da AAC, aptX da LDAC codecs ba.

Ana iya samun ƙarin bayani akan gidajen yanar gizon SautiGuys и Kwararrun Sauti.

Kyauta: Encoder na SBC, bayanin bitstream A2DP da fayilolin gwaji. A da ana buga wannan fayil ɗin a bainar jama'a akan gidan yanar gizon Bluetooth, amma yanzu yana samuwa ga membobin Bluetooth SIG.

source: www.habr.com