Nekuda kwekugadzirwa kwakawanda kwemafoni asina 3.5 mm audio jack, mahedhifoni eBluetooth akave nzira huru yekuti vazhinji vateerere mimhanzi uye kutaurirana mune mahedhifoni mode.
Vagadziri vezvishandiso zvisina waya havagare vachinyora zvakatsanangurwa zvechigadzirwa, uye zvinyorwa zveBluetooth odhiyo paInternet zvinopokana, dzimwe nguva zvisirizvo, hazvitauri nezvese maficha, uye kazhinji kukopa iwo mamwe mashoko asingaenderane nechokwadi.
Ngatiedzei kunzwisisa iyo protocol, kugona kweBluetooth OS stacks, mahedhifoni uye vatauri, macodecs eBluetooth emumhanzi uye kutaura, tsvaga izvo zvinokanganisa kunaka kweiyo inotapurira ruzha uye latency, dzidza nzira yekuunganidza uye decode ruzivo nezve inotsigirwa macodecs uye chimwe chishandiso. kugona.

TL; DR:

• SBC - yakajairika codec
• Iwo mahedhifoni ane yavo yakaenzana uye yekumashure-kugadzirisa kune yega codec zvakasiyana
• aptX haina kunaka sekushambadzwa
• LDAC iri kushambadzira bhuru
• Hunhu hwekufona huchiri hurombo
• Iwe unogona kunyudza C odhiyo encoder mubrowser yako nekuiunganidza muWebAssembly kuburikidza neemscripten, uye ivo havazonoke zvakanyanya.

Mimhanzi kuburikidza neBluetooth

Chikamu chinoshanda cheBluetooth chinotemerwa nemaprofile - zvakatemwa zveakananga mabasa. Kutepfenyura mumhanzi weBluetooth kunoshandisa yemhando yepamusoro A2DP unidirectional odhiyo yekufambisa mbiri. Iyo A2DP standard yakagamuchirwa muna 2003 uye haina kuchinja zvakanyanya kubva ipapo.
Mukati meiyo mbiri, 1 inosungirwa codec yeyakaderera computational kuomarara SBC, yakagadzirwa yakanangana neBluetooth, uye matatu ekuwedzera akajairwa. Zvinogoneka zvakare kushandisa macodecs asina kunyorwa ega ega kuita kwako.

Kubva munaJune 2019 tiri mune xkcd comic ine 14 A2DP macodecs:

• SBC ← yakamisikidzwa muA2DP, inotsigirwa nemidziyo yese
• MPEG-1/2 Layer 1/2/3 ← yakamisikidzwa muA2DP: inozivikanwa MP3, inoshandiswa mu digital TV MP2, uye zvisingazivikanwi MP1
• MPEG-2/4 AAC ← yakamisikidzwa muA2DP
• ATTRAC ← yekare codec kubva kuSony, yakamisikidzwa muA2DP
• LDAC ← new codec kubva kuSony
• aptX ← codec kubva 1988
• aptXHD ← zvakafanana neaptX, chete iine akasiyana encoding sarudzo
• aptX Yakadzika Latency ← yakasiyana zvachose codec, hapana kushandiswa kwesoftware
• aptX Inoenderana ← imwe codec kubva kuQualcomm
• FastStream ← pseudo codec, bidirectional SBC shanduko
• HWA LHDC ← new codec kubva kuHuawei
• Samsung HD ← inotsigirwa nemidziyo miviri
• Samsung Scalable ← inotsigirwa nemidziyo miviri
• Samsung UHQ-BT ← inotsigirwa nemidziyo miviri

Sei tichida macodecs zvachose, iwe unobvunza, kana Bluetooth ine EDR, iyo inokubvumira kuendesa data nekumhanya kwe2 uye 3 Mbit / s, uye kune uncompressed maviri-channel 16-bit PCM, 1.4 Mbit / s yakakwana?

Kuendesa data kuburikidza neBluetooth

Kune marudzi maviri ekufambisa data muBluetooth: Asynchronous Connection Less (ACL) yekuchinjisa asynchronous pasina kubatanidza kumisikidzwa, uye Synchronous Connection Oriented (SCO), yekuchinjisa kuchinjika nekutanga kubatanidza nhaurirano.
Kutumira kunoitwa pachishandiswa chirongwa chekupatsanura nguva uye kusarudza nzira yekufambisa yepakiti imwe neimwe zvakasiyana (Frequency-Hop/Time-Division-Duplex, FH/TDD), iyo nguva yakakamurwa kuita 625-microsecond intervals inonzi slots. Imwe yezvishandiso inofambisa mune nyangwe-nhamba inotsvedza, imwe yacho mune isinganzwisisike-nhamba slots. Paketi inotapurirwa inogona kutora 1, 3 kana 5 slots, zvichienderana nehukuru hwe data uye yakatarwa mhando yekutapurirana, mune iyi kesi, kutapurirana nemudziyo mumwe kunoitwa mune kunyange uye isinganzwisisike slots kusvika pakupera kwekutapurirana. Pakazara, anosvika 1600 mapaketi anogona kugamuchirwa uye kutumirwa pasekondi, kana imwe neimwe yadzo iine 1 slot, uye ese ari maviri maturusi anotapurirana uye kugamuchira chimwe chinhu pasina kumira.

2 uye 3 Mbit/s yeEDR, iyo inogona kuwanikwa muzviziviso uye pawebhusaiti yeBluetooth, ndiyo yakanyanya kuchinjisa chiteshi chiyero che data yese muhuwandu (kusanganisira tekinoroji misoro yezvibvumirano zvese zvinofanirwa kuiswa data), munzira mbiri. panguva imwe chete. Kumhanyisa data chaiko kunosiyana zvakanyanya.

Kutumira mimhanzi, nzira yeasynchronous inoshandiswa, inenge nguva dzose uchishandisa mapaketi akaita se2-DH5 uye 3-DH5, anotakura huwandu hwehuwandu hwe data muEDR mode ye 2 Mbit / s uye 3 Mbit / s, zvichienderana, uye inotora nguva 5. -kugovana slots.

Schematic inomiririra kutapurirana uchishandisa 5 slots neimwe mudziyo uye 1 slot neimwe (DH5/DH1):


Nekuda kweiyo musimboti wenguva yekukamurwa kwemafungu emhepo, tinomanikidzwa kumirira 625-microsecond nguva slot mushure mekutumira pakiti kana yechipiri mudziyo usingafambisi chero chinhu kwatiri kana kutumira diki packet, uye nguva yakawanda kana yechipiri mudziyo mumapaketi makuru. Kana inopfuura imwe mudziyo yakabatana nefoni (semuenzaniso, mahedhifoni, mawachi uye bracelet yekusimba), ipapo nguva yekufambisa inogoverwa pakati pavo vese.

Iko kudikanwa kwekubatanidza odhiyo mune yakakosha maprotocol ekufambisa L2CAP uye AVDTP inotora gumi nematanhatu mabhayithi kubva kune inokwanisika huwandu hwehuwandu hwekutumira odhiyo payload.

Package type
Nhamba ye slots
Max. nhamba yemabhaiti muhomwe
Max. nhamba yemabhaiti eA2DP payload
Max. A2DP payload 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 uye 1429 kbps hazvina kukwana kufambisa uncompressed odhiyo mumamiriro chaiwo, ine ruzha 2.4 GHz renji uye kukosha kwekufambisa data sevhisi. EDR 3 Mbit / s inoda simba rekufambisa uye ruzha pamhepo, saka, kunyange mu 3-DH5 mode, kufambisa PCM yakagadzikana haigoneki, pachagara paine kukanganisa kwenguva pfupi, uye zvose zvinongoshanda kure kure. mamita maviri.
Mukuita, kunyangwe 990 kbit/s audio stream (LDAC 990 kbit/s) inonetsa kufambisa.

Ngatidzokerei kumakodheki.

SBC

Codec inodiwa kune ese maturusi anotsigira iyo A2DP standard. Iyo yakanakisa uye yakaipisisa codec panguva imwe chete.

Sampling frequency
Kugona
Bitrate
Encoding rutsigiro
Decoding rutsigiro

16, 32, 44.1, 48 kHz
16 zvishoma
10-1500 kbps
Zvese zvishandiso
Zvese zvishandiso

SBC iri nyore uye inokurumidza kukurumidza kodheki, ine primitive psychoacoustic modhi (inongoiswa masking yemanzwi akanyarara), uchishandisa adaptive pulse code modulation (APCM).
Iyo A2DP yakatarwa inokurudzira mbiri mbiri dzekushandisa: Hunhu Hwepakati uye Hunhu Hwepamusoro.


Iyo codec ine akawanda marongero ayo anobvumidza iwe kudzora kunonoka kwealgorithmic, huwandu hwemasampuli mubhuroka, iyo diki yekugovera algorithm, asi pese pese maparamita akafanana anokurudzirwa mune yakatarwa anoshandiswa: Joint Stereo, 8 frequency mabhendi, gumi nematanhatu mabhuroka mukati. an audio frame, Loudness bit distribution nzira.
SBC inotsigira shanduko ine simba yeBitpool parameter, inobata zvakananga bitrate. Kana masaisai emhepo akavharwa, mapaketi akarasika, kana midziyo iri kure kure, iyo inonzwika sosi inogona kuderedza Bitpool kusvika kutaurirana kwadzokera kune zvakajairika.

Vazhinji vanogadzira mahedhifoni vanoisa iyo yepamusoro Bitpool kukosha ku53, iyo inoganhura bitrate kusvika 328 kilobits pasekondi kana uchishandisa yakakurudzirwa mbiri.
Kunyangwe kana mugadziri wehedhifoni akaisa iyo yepamusoro Bitpool kukosha pamusoro pe53 (akadaro mamodheru anowanikwa, semuenzaniso: Beats Solo³, JBL Everest Elite 750NC, Apple AirPods, inowanikwawo pane mamwe anogashira uye emota head units), saka mazhinji OS haazobvumiri. kushandiswa kwekuwedzera bitrate nekuda kwekuseta yemukati kukosha muganho muBluetooth stacks.
Pamusoro pezvo, vamwe vagadziri vanoisa iyo yakanyanya Bitpool kukosha kune yakaderera kune mamwe maturusi. Semuenzaniso, yeBluedio T ndeye 39, yeSamsung Gear IconX ndeye makumi matatu nemanomwe, inopa hurombo husina kunaka.

Zvirambidzo zveArtificial padivi revagadziri veBlue stacks zvingangove zvakamuka nekuda kwekusapindirana kwemamwe maturusi ane hombe Bitpool kukosha kana atypical profiles, kunyangwe ivo vakashuma rutsigiro rwavo, uye kusakwana kuyedzwa panguva yekupihwa chitupa. Zvakanga zviri nyore kune vanyori veBlue stacks kuti vazvigadzirise ivo pachavo kubvumirana pane yakakurudzirwa mbiri, pane kugadzira dhatabhesi yezvisizvo zvishandiso (kunyangwe izvozvi vanoita izvi kune mamwe mabasa asiri iwo anoshanda).

SBC inogovera zvine simba quantization bits kune frequency mabhendi pane yakaderera-kusvika-yepamusoro hwaro, ine huremu hwakasiyana. Kana iyo bitrate yese yakashandiswa kune yakaderera uye yepakati frequencies, iyo yakakwira frequencies "inogurwa" (kuchave nekunyarara panzvimbo).

Muenzaniso SBC 328 kbps. Kumusoro ndiko kwekutanga, pazasi pane SBC, nguva nenguva ichichinja pakati pemakwara. Odhiyo iri muvhidhiyo faira inoshandisa iyo FLAC isingarasikike compression codec. Kushandisa FLAC mumudziyo we mp4 hakuna kuomeswa zviri pamutemo, saka haina kuvimbiswa kuti browser yako ichairidza, asi inofanirwa kushanda mumashanduro azvino edesktop Chrome neFirefox. Kana iwe usina ruzha, unogona kudhawunirodha faira worivhura mune yakazara-yakazara vhidhiyo inoridza.
ZZ Top - Akapfekwa Murume

Iyo spectrogram inoratidza nguva yekuchinja: SBC nguva nenguva inocheka manzwi akanyarara pamusoro pe17.5 kHz, uye haigoveri chero mabhiti kubhendi pamusoro pe20 kHz. Iyo yakazara spectrogram inowanikwa nekudzvanya (1.7 MB).

Ini handinzwe mutsauko pakati peyekutanga neSBC pane iyi track.

Ngatitorei chimwe chinhu chitsva uye titevedzere odhiyo yaizowanikwa uchishandisa Samsung Gear IconX mahedhifoni neBitpool 37 (pamusoro - chiratidzo chepakutanga, pazasi - SBC 239 kbps, odhiyo muFLAC).
Mindless Self Indulgence - Chapupu

Ini ndinonzwa kurira, kushoma stereo maitiro uye isingafadze "clunking" ruzha mukukwirira kwemazwi.

Kunyange zvazvo SBC iri codec inoshanduka zvikuru, inogona kugadzirwa kuti iite yakaderera latency, inopa yakanakisa ruzha rwemhando yepamusoro-bitrate (452+ kbps) uye yakanakira vanhu vazhinji pamhando yepamusoro Yemhando yepamusoro (328 kbps), nekuda kwekuti izvozvo. iyo A2DP yakajairwa haitsanangure maprofiles akagadziriswa (asi anongopa kurudziro), vanogadzira stack vakaisa zvirambidzo zvekugadzira paBitpool, maparamendi eiyo inofambiswa odhiyo haina kuratidzwa mune yevashandisi interface, uye vanogadzira mahedhifoni vakasununguka kuzviseta ivo pachavo uye kusambofa. ratidza kukosha kweBitpool muhunyanzvi hwekutsanangurwa kwechigadzirwa, codec yakave nemukurumbira nekuda kwayo yakaderera ruzha, kunyangwe iri risiri dambudziko nekodeki yakadaro.
Iyo Bitpool parameter inobata zvakananga bitrate chete mukati meimwe mbiri. Iyo imwecheteyo Bitpool 53 kukosha inogona kupa zvese bitrate ye328 kbps ine yakakurudzirwa High Quality profile, uye 1212 kbps ine Dual Channel uye 4 frequency mabhendi, ndosaka vanyori veOS, kunze kwezvirambidzo paBitpool, vakaisa muganhu uye pa Bitrate. Sezvandinozviona, mamiriro ezvinhu aya akamuka nekuda kwekukanganisa muyero yeA2DP: zvaive zvakafanira kutaurirana bitrate, kwete Bitpool.

Tafura yekutsigira SBC kugona mune akasiyana OS:

OS
Inotsigirwa sampling rates
Limit max. Bitpool
Limit max. Bitrate
Typical Bitrate
Bitpool dynamic kugadzirisa

Windows 10
44.1 кГц
53
512 kbps
328 kbps
✓*

Linux (BlueZ + PulseAudio)
16, 32, 44.1, 48 kHz
64 (yekubatana kunouya), 53 (yekubuda kwekubatanidza)
Hapana muganho
328 kbps
✓*

macOS High Sierra
44.1 кГц
64, default 53***
Hazvizivikanwe
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 кГц
53
Hapana muganho
328 kbps
✗

* Bitpool inongodzikira, asi haiwedzere otomatiki, kana mamiriro ekutamisa achivandudza. Kuti udzorere Bitpool unofanirwa kumisa kutamba, mirira mashoma mashoma uye wotanga odhiyo zvakare.
** Iko kukosha kweiyo yakasarudzika kunoenderana neyakagadzika marongero anotsanangurwa paunenge uchigadzira iyo firmware. Mu Android 8/8.1 frequency inongove 44.1 kHz kana 48 kHz, zvichienderana nezvirongwa panguva yekubatanidza, mune dzimwe shanduro 44.1 kHz uye 48 kHz zvinotsigirwa panguva imwe chete.
*** Iko kukosha kweBitpool kunogona kuwedzerwa muchirongwa cheBluetooth Explorer.

aptX uye aptX HD

aptX iri nyore uye computationally inokurumidza codec, isina psychoacoustics, uchishandisa inochinja inosiyanisa pulse code modulation (ADPCM) Yakaonekwa kutenderera 1988 (zuva rekunyora bvumidzwa yaFebruary 1988), pamberi peBluetooth, yaishandiswa zvakanyanya muunyanzvi husina waya hwekuteerera. Parizvino yeQualcomm, inoda marezinesi uye mari. Kubva muna 2014: $6000 imwe-nguva uye ≈$1 pamudziyo mumwe, pamabheji anosvika zviuru gumi (10000)tsime, peji. 16).
aptX uye aptX HD akafanana codec, ane akasiyana encoding profiles.

Iyo codec ine chete parameter - kusarudza sampling frequency. Pane, zvisinei, sarudzo yenhamba/modhi yemachaneli, asi mumidziyo yese inozivikanwa kwandiri (70+ zvidimbu) chete Stereo inotsigirwa.

Codec
Sampling frequency
Kugona
Bitrate
Encoding rutsigiro
Decoding rutsigiro

aptX
16, 32, 44.1, 48 kHz
16 zvishoma
128 / 256 / 352 / 384 kbps (zvichienderana nesampling rate)
Windows 10 (desktop uye nhare), macOS, Android 4.4+/7*, Blackberry OS 10
Yakasiyana-siyana yemidziyo yekuteerera (hardware)

* Mavhezheni anosvika 7 anoda kugadziridzwa kweiyo Bluetooth stack. Iyo codec inotsigirwa chete kana mugadziri wemidziyo yeAroid akapa rezinesi kukodheki kubva kuQualcomm (kana iyo OS ine maraibhurari ekukodha).

aptX inokamura odhiyo kuita 4 frequency mabhendi uye inoaverengera nenhamba yakafanana yemabhiti nguva dzose: 8 bits ye0-5.5 kHz, 4 bits ye 5.5-11 kHz, 2 bits ye11-16.5 kHz, 2 bits ye16.5-22 kHz ( nhamba dzesampling rate 44.1 kHz).

Muenzaniso weaptX odhiyo (kumusoro - chiratidzo chepakutanga, pazasi - aptX, spectrograms ematanho ekuruboshwe chete, ruzha muFLAC):

Makwiriro akaita kutsvuka zvishoma, asi waisanzwa mutsauko.

Nekuda kwekugadzika kwakagadzika kwe quantization bits, iyo codec haigone "kuchinja mabits" kune ma frequency anoida zvakanyanya. Kusiyana neSBC, aptX haizo "cheka" mafambisirwo, asi inowedzera quantization ruzha kwavari, ichideredza simba reiyo odhiyo.

Izvo hazvifanirwe kufungidzirwa kuti kushandisa, semuenzaniso, 2 bits pabhendi kunoderedza dhigirii renji kusvika 12 dB: ADPCM inobvumira kusvika ku96 dB yehudhinha dhizaini kunyangwe uchishandisa 2 quantization bits, asi chete kune imwe chiratidzo.
ADPCM inochengetedza mutsauko wenhamba pakati peyezvino sampuli uye inotevera sampu, pachinzvimbo chekuchengetedza iyo yakakwana kukosha sePCM. Izvi zvinokutendera kuti udzikise zvinodiwa pahuwandu hwemabhiti anodiwa kuchengetedza akafanana (pasina kurasikirwa) kana zvakada kufanana (nechikanganiso chidiki chekutenderera) ruzivo. Kuti uderedze zvikanganiso zvekutenderera, coefficient matafura anoshandiswa.
Paunenge uchigadzira iyo codec, vanyori vakaverenga ADPCM coefficients pane seti yemafaira emimhanzi. Iyo iri padyo neodhiyo chiratidzo kune seti yemimhanzi pakavakirwa matafura, iwo mashoma quantization zvikanganiso (ruzha) aptX inogadzira.

Nekuda kweizvi, bvunzo dzekugadzira dzichagara dzichiburitsa mhedzisiro yakaipa kupfuura mimhanzi. Ini ndakagadzira yakakosha yekugadzira muenzaniso umo aptX inoratidza yakashata mhedzisiro - sine wave ine frequency ye12.4 kHz (pamusoro - chiratidzo chepakutanga, pazasi - aptX. Audio muFLAC. Dzikisa vhoriyamu!):

Spectrum graph:


Mitsindo inonzwika zvakajeka.

Nekudaro, kana iwe ukagadzira sine wave ine diki amplitude kuitira kuti inyarare, ruzha rwunozodzikama, zvichiratidza huwandu hwakakura hwesimba:

Kuti unzwe mutsauko uripo pakati peyekutanga mimhanzi track uye yakamanikidzwa, unogona kutenderedza imwe yemasaini uye wowedzera matiraki chiteshi nechiteshi. Iyi nzira, kazhinji, haina kururama, uye haipe mibairo ine hunyoro ine mamwe macodecs akaomarara, asi zvakanangana neADPCM yakanyatsokodzera.
Musiyano pakati pepakutanga uye aptX
Mudzi unoreva masikweya musiyano wemasaini ari pamwero we -37.4 dB, iyo isiri yakawanda kune yakadaro yakamanikidzwa mimhanzi.

aptXHD

aptX HD haisi yakamira codec - ndeye yakagadziridzwa encoding mbiri yeaptX codec. Shanduko idzi dzakakanganisa huwandu hwemabhiti akagoverwa encoding frequency range: 10 bits for 0-5.5 kHz, 6 bits for 5.5-11 kHz, 4 bits for 11-16.5 kHz, 4 bits for 16.5-22 kHz (manhamba e44.1 kHz). .

Codec
Sampling frequency
Kugona
Bitrate
Encoding rutsigiro
Decoding rutsigiro

aptXHD
16, 32, 44.1, 48 kHz
24 bits
192 / 384 / 529 / 576 kbps (zvichienderana nesampling rate)
Android 8+*
Zvimwe zvigadziriso zvekuteerera (hardware)

* Mavhezheni anosvika 7 anoda kugadziridzwa kweiyo Bluetooth stack. Iyo codec inotsigirwa chete kana mugadziri wemidziyo yeAroid akapa rezinesi kukodheki kubva kuQualcomm (kana iyo OS ine maraibhurari ekukodha).

Zvishoma pane aptX: sezviri pachena inoda marezenisi akaparadzana kubva kuQualcomm, uye kupatsanura mari yerezinesi.

Ngatidzokororei muenzaniso ne sine wave pa12.4 kHz:


Zvirinani pane aptX, asi ichiri ruzha.

aptX Yakadzika Latency

Iyo codec kubva kuQualcomm isina chinhu chakaenzana neyakajairwa aptX uye aptX HD, tichitonga neruzivo rushoma kubva kuvanhu vanobatanidzwa mukusimudzira kwayo. Yakagadzirirwa yekudyidzana yakaderera-latency odhiyo kutapurirana (mafirimu, mitambo), uko kunonoka kweaudhiyo hakugone kugadziridzwa nesoftware. Iko hakuna inozivikanwa mashandisirwo esoftware eencoder uye decoder; ivo vanotsigirwa chete nevatambi, vanogamuchira, mahedhifoni uye vatauri, asi kwete nemafoni nemakomputa.

Sampling frequency
Bitrate
Encoding rutsigiro
Decoding rutsigiro

44.1 кГц
276/420 kbps
Mamwe ma transmitters (hardware)
Zvimwe zvigadziriso zvekuteerera (hardware)

AAC

AAC, kana Advanced Audio Coding, ndeye computationally yakaoma codec ine yakakomba psychoacoustic modhi. Inoshandiswa zvakanyanya kune odhiyo paInternet, yechipiri mukuzivikanwa mushure meMP3. Inoda marezenisi uye zvikwereti: $15000 kamwe-kamwe (kana $1000 kumakambani ane vashandi vasingasviki gumi nevashanu) + $15 yezvigadzirwa zve0.98 zvekutanga (tsime).
Iyo codec yakamisikidzwa mukati meMPEG-2 uye MPEG-4 zvakatemwa, uye zvinopesana nemafungiro asiriwo akajairika, haisi yeApple.

Sampling frequency
Bitrate
Encoding rutsigiro
Decoding rutsigiro

8 - 96 kHz
8 - 576 kbps (yestereo), 256 - 320 kbps (yakajairika kuBluetooth)
macOS, Android 7+*, iOS
Yakasiyana-siyana yemidziyo yekuteerera (hardware)

* chete pamidziyo ine vagadziri vakabhadhara mari yerezinesi

iOS uye macOS dzinoshandisa Apple yazvino yakanakisa AAC encoder kuendesa yakanyanya kunaka mhando yekuteerera. Android inoshandisa yechipiri-yepamusoro mhando yeFraunhofer FDK AAC encoder, asi inogona kushandisa dzakasiyana siyana dzakavakwa mupuratifomu (SoC) ine isingazivikanwe encoding mhando. Zvinoenderana neazvino bvunzo paSoundGuys webhusaiti, iyo AAC encoding mhando yeakasiyana Android mafoni anosiyana zvakanyanya:

Midziyo mizhinji isina waya yekuteerera ine bitrate yepamusoro ye320 kbps yeAAC, zvimwe zvinongotsigira 256 kbps. Mamwe ma bitrate haanyanyi kuitika.
AAC inopa yakanakisa mhando pa320 uye 256 kbps bitrates, asi inozviisa pasi kurasikirwa kwesequential encoding yezvakatodzvanywa zvemukati, zvisinei, zvinonetsa kunzwa chero misiyano neyepakutanga paIOS pa bitrate ye256 kbps kunyangwe iine akati wandei encodings; ine encoding imwechete, semuenzaniso, MP3 320 kbps kusvika AAC 256 kbps, kurasikirwa kunogona kuregeredzwa.
Sezvimwe nemamwe macodecs eBluetooth, chero mimhanzi inotanga kudhindwa uye yobva yavharwa necodec. Kana uchiteerera mimhanzi muAAC fomati, inotanga kudhindwa neOS, yobva yaiswa muAAC zvakare kuti itumirwe kuburikidza neBluetooth. Izvi zvinodikanwa pakusanganisa akawanda maodhiyo hova, senge mimhanzi uye mitsva yekuzivisa meseji. iOS haina mutsauko. PaInternet unogona kuwana zvirevo zvakawanda kuti paIOS mimhanzi muAAC fomati haina kuchinjirwa kana ichitumirwa kuburikidza neBluetooth, izvo zvisiri zvechokwadi.

MP1/2/3

Macodecs emhuri yeMPEG-1/2 Chikamu 3 ane MP3 inozivikanwa uye inoshandiswa zvakanyanya, iyo isinganyanyi kuzivikanwa MP2 (inoshandiswa zvakanyanya mudhijitari TV neredhiyo), uye MP1 isingazivikanwe zvachose.

Iwo ekare MP1 uye MP2 macodec haatsigirwe zvachose: Ini handina kuwana chero mahedhifoni kana Bluetooth stack yaigona encode kana decode iwo.
MP3 decoding inotsigirwa nemamwe mahedhifoni, asi encoding haitsigirwe pane chero yemazuva ano yekushandisa system stack. Zvinoita sekuti yechitatu-bato BlueSoleil stack yeWindows inogona encode kuMP3 kana iwe pachako uchinje faira yekumisikidza, asi kwandiri kuiisa inotungamira kuBSoD paWindows 10. Mhedziso - iyo codec haigone kushandiswa kuBluetooth audio.
Kare, muna 2006-2008, kusati kwapararira chiyero cheA2DP mumidziyo, vanhu vaiteerera mimhanzi yeMP3 paNokia BH-501 headset kuburikidza nechirongwa cheMSI BluePlayer, chaiwanikwa paSymbian neWindows Mobile. Panguva iyoyo, dhizaini yeOS yemafoni emafoni aibvumira kupinda kune akawanda-akaderera-chikamu mabasa, uye paWindows Mobile zvaitokwanisika kuisa yechitatu-bato reBluetooth stacks.

Iyo yekupedzisira patent yeMP3 codec yapera, kushandiswa kwecodec hakudi muripo werezinesi kubva muna Kubvumbi 23, 2017.

Kana iyo patent yenguva refu yakataurwa mune zvataurwa pamusoro ichitorwa sechiyero, saka tekinoroji yeMP3 yakazove isina patent muUnited States musi wa16 Kubvumbi, 2017 apo US Patent 6,009,399, yakabatwa uye kutungamirwa neTechnicolor, yapera.

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

Sampling frequency
Bitrate
Encoding rutsigiro
Decoding rutsigiro

16 - 48 kHz
8 - 320 kbps
Haitsigirwi chero kupi zvako
Zvimwe zvigadziriso zvekuteerera (hardware)

LDAC

Nyowani uye inoshingairira yakasimudzirwa "Hi-Res" codec kubva kuSony, inotsigira sampling rates kusvika 96 kHz uye 24-bit bitrate, ine bitrate inosvika 990 kbps. Inoshambadzirwa seaudiophile codec, sechinzvimbo cheiyo iripo Bluetooth codecs. Iine basa rekugadzirisa bitrate kugadzirisa, zvichienderana neredhiyo nhepfenyuro mamiriro.

LDAC encoder (libldac) inosanganisirwa mune yakajairwa Android package, saka encoding inotsigirwa pane chero Android smartphone kutanga ne OS vhezheni 8. Iko hakuna yakasununguka inowanika software decoder, iyo codec yakatarwa haiwanikwe kune veruzhinji, zvisinei, pakutanga kutarisa kune encoder, chimiro chemukati checodec chakafanana ATRAC9 -Sony's codec inoshandiswa muPlayStation 4 neVita: ese ari maviri anoshanda mu frequency domain, shandisa yakagadziridzwa discrete cosine shanduko (MDCT) uye compression uchishandisa iyo Huffman algorithm.

Tsigiro yeLDAC inopihwa chete nemahedhifoni kubva kuSony. Iko kugona kutsanangura LDAC dzimwe nguva kunowanikwa pamahedhifoni uye maDAC kubva kune vamwe vagadziri, asi kashoma.

Sampling frequency
Bitrate
Encoding rutsigiro
Decoding rutsigiro

44.1 - 96 kHz
303/606/909 kbit/s (ye44.1 uye 88.2 kHz), 330/660/990 kbit/s (ye48 uye 96 kHz)
Android 8 +
Mamwe mahedhifoni eSony uye mamwe madivayiri kubva kune vamwe vagadziri (hardware)

Kushambadzira LDAC seHi-Res codec kunokuvadza chikamu chayo chehunyanzvi: hupenzi kushandisa bitrate pakutumira ma frequency asinganzwike panzeve yemunhu uye kuwedzera kudzika kwakadzika, nepo isina kukwana kutumira CD-mhando (44.1/16) pasina kurasikirwa. . Neraki, iyo codec ine maviri ekushandisa modes: CD odhiyo kutapurirana uye Hi-Res odhiyo kutapurirana. Muchiitiko chekutanga, chete 44.1 kHz / 16 bits inofambiswa pamusoro pemhepo.

Sezvo software yeLDAC decoder isingawanikwe pachena, hazvigoneke kuyedza codec pasina mimwe michina inodhinda LDAC. Zvinoenderana nemhedzisiro yekuyedzwa kweLDAC paDAC nerutsigiro rwayo, iyo SoundGuys.com mainjiniya akabatanidza kuburikidza nekubuda kwedhijitari uye akarekodha ruzha rwekubuda pamasaini ebvunzo, LDAC 660 uye 990 kbps muCD-mhando modhi inopa chiratidzo-ku-. ruzha reshiyo iri nani pane iyo yeaptX HD.

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

LDAC inotsigirawo dynamic bitrates kunze kwemaprofiles akatangwa - kubva pa138 kbps kusvika 990 kbps, asi sekutaura kwangu, Android inongoshandisa maprofiles akamisikidzwa 303/606/909 uye 330/660/990 kbps.

Mamwe macodecs

Mamwe macodecs eA2DP haashandiswe zvakanyanya. Tsigiro yavo inogona kunge isipo zvachose kana inongowanikwa pane mamwe maehedhifoni uye mafoni.
Iyo ATRAC codec yakamisikidzwa muA2DP haisati yamboshandiswa seBluetooth codec kunyangwe naSony ivo pachavo, Samsung HD, Samsung Scalable uye Samsung UHQ-BT macodecs ane rutsigiro rwakashomeka kubva pakufambisa nekugamuchira michina, uye HWA LHDC inyowani uye inongotsigirwa matatu chete. (?) zvishandiso.

Codec tsigiro yemidziyo yekuteerera

Havasi vese vanogadzira vanoburitsa ruzivo rwechokwadi nezve macodecs anotsigirwa nemamwe mahedhifoni asina waya, vatauri, vanogamuchira kana vanotumira. Dzimwe nguva zvinoitika kuti tsigiro yeimwe codec ndeyekutapurirana chete, asi kwete yekugamuchira (inoenderana neyakasanganiswa-vanogamuchira), kunyangwe mugadziri achingotaura "rutsigiro", pasina manotsi (ndinofunga kuti kupatsanurwa kwerezinesi kwe encoder uye decoder yevamwe. macodecs ane mhosva pane izvi). Mumidziyo yakachipa, unogona kusawana yakaziviswa aptX rutsigiro zvachose.

Nehurombo, iyo inopindirana yeakawanda anoshanda masisitimu haaratidze iyo codec inoshandiswa chero kupi. Ruzivo nezve izvi runowanikwa chete mu Android, kutanga kubva vhezheni 8, uye macOS. Nekudaro, kunyangwe mumaOS aya, iwo chete macodec anotsigirwa nefoni/kombuta uye mahedhifoni ndiwo acharatidzwa.

Ungaziva sei kuti ndeapi macodecs anotsigira mudziyo wako? Rekodha uye ongorora traffic dump neA2DP nhaurirano paramita!
Izvi zvinogona kuitwa paLinux, macOS uye Android. PaLinux unogona kushandisa Wireshark kana hcidump, paMacOS unogona kushandisa Bluetooth Explorer, uye paAroid unogona kushandisa yakajairwa Bluetooth HCI dump saving function, inowanikwa mumaturusi ekuvandudza. Iwe unogashira dump mu btsnoop fomati, iyo inogona kuiswa muWireshark analyzer.
Ngwarira+ Iwo mahedhifoni anogona kuzvimiririra kumisikidza kubatana nefoni, mune iyo kesi ivo vanokumbira runyoro rwekodhi kubva pafoni, uye kwete zvinopesana. Kuti uve nechokwadi chekuraswa chaiko kwakarekodhwa, tanga wasunungura mudziyo uye wobatanidza foni yako nemahedhifoni paunenge uchirekodha kuraswa.

Shandisa iyo inotevera sefa yekusefa isina basa traffic:

btavdtp.signal_id

Nekuda kweizvozvo, iwe unofanirwa kuona chimwe chinhu chakafanana neichi:

Iwe unogona kudzvanya pane chimwe nechimwe chinhu muGetCapabilities command kuti uone zvakadzama maitiro eiyo codec.

Wireshark haizive ese macodec identifiers, saka mamwe macodecs anozofanirwa kudhipfenyurwa nemaoko, uchitarisa patafura yekuzvizivisa pazasi:

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

Kuti ndisaongorore marasira nemaoko, ndakaita sevhisi inozoongorora zvese otomatiki: btcodecs.valdikss.org.ru

Kuenzanisa macodecs. Ndeipi codec iri nani?

Imwe neimwe codec ine zvayakanakira nezvayakaipira.
aptX uye aptX HD shandisa ma-hard-coded profiles ayo asingagone kuchinjwa pasina kugadzirisa encoder uye decoder. Hapana mugadziri wefoni kana mugadziri wemusoro anogona kushandura bitrate kana aptX encoding zvinhu. Muridzi wecodec, Qualcomm, anopa referensi encoder muchimiro cheraibhurari. Idzi chokwadi isimba reaptX - iwe unofanoziva kuti ndeupi mhando yeruzha yauchawana, pasina chero "buts".

SBC, zvakasiyana, ine zvakawanda zvinogadziriswa parameters, dynamic bitrate (iyo encoder inogona kuderedza bitpool parameter kana airwaves yakabatikana), uye isina hard-coded profiles, chete inokurudzirwa "yepakati mhando" uye "yemhando yepamusoro" yaive yakawedzerwa kune iyo A2DP yakatarwa muna 2003 gore. "High quality" haisisiri iyo yakakwira nemaitiro emazuva ano, uye akawanda maBluetooth stacks haakubvumiri kushandisa paramita zviri nani pane "yepamusoro mhando" mbiri, kunyangwe pasina zvirambidzo zvehunyanzvi zveizvi.
Bluetooth SIG haina referensi SBC encoder seraibhurari, uye vagadziri vanozviita ivo pachavo.
Uku ndiko kusasimba kweSBC - hazvisati zvanyatsojeka kuti ndeupi mhando yemhando yekutarisira kubva kune chimwe chishandiso. SBC inogona kuburitsa zvese zvakaderera uye zvemhando yepamusoro odhiyo, asi iyo yekupedzisira haigoneke pasina kudzima kana kunzvenga zvipimo zvekugadzira zveBluetooth stacks.

Mamiriro ezvinhu neAAC haanzwisisike: kune rumwe rutivi, zvinoti codec inofanirwa kuburitsa hunhu husingazivikanwe kubva kune yekutanga, asi mukuita, tichitonga nemiedzo yeLabhoritari yeSoundGuys pamidziyo yakasiyana yeAroid, izvi hazvina kusimbiswa. Zvingangodaro, kukanganisa kuri neakaderera-mhando yeaudhiyo encoder yakavakirwa mumachipset efoni akasiyana. Zvine musoro kushandisa AAC chete paApple madivayiri, uye paAndroid kuimisa kune aptX uye LDAC.

Hardware inotsigira mamwe macodecs anowanzo kuve emhando yepamusoro, nekuda kwekuti kune yakachipa, yakaderera-mhando michina, hazvina musoro kubhadhara mari yerezinesi yekushandisa iwo macodec. Mune bvunzo dzangu, SBC inonzwika yakanaka kwazvo pamidziyo yemhando.

Ndakagadzira sevhisi yewebhu inokodha odhiyo kuSBC, aptX uye aptX HD munguva chaiyo, mubrowser chaipo. Nayo, unogona kuyedza aya maodhiyo macodec pasina kunyatso fambisa odhiyo kuburikidza neBluetooth, pane chero mahedhifoni ane waya, vatauri, uye mimhanzi yaunofarira, uye zvakare shandura encoding paramita zvakananga uchiridza odhiyo:
btcodecs.valdikss.org.ru/sbc-encoder
Iyo sevhisi inoshandisa maSBC kukodha maraibhurari kubva kuBlueZ purojekiti uye libopenaptx kubva kuffmpeg, iyo inounganidzwa muWebAssembly uye JavaScript kubva kuC, kuburikidza neemscripten, kumhanya mubrowser. Ndiani angarota ramangwana rakadai!

Heano maitiro ayo

Ziva kuti huwandu hweruzha hunochinja sei mushure me20 kHz kumakodeki akasiyana. Iyo yekutanga MP3 faira haina ma frequency ari pamusoro pe20 kHz.

Edza kushandura macodecs uye uone kana iwe uchinzwa mutsauko uripo pakati peyekutanga, SBC 53 Joint Stereo (iyo yakajairwa uye yakajairika mbiri), uye aptX/aptX HD.

Ndiri kunzwa mutsauko uripo pakati pemacodecs mumahedhifoni!

Vanhu vasinganzwe mutsauko pakati pemacodecs panguva yekuyedzwa kuburikidza newebhu sevhisi vanoti vanozvinzwa kana vachiteerera mimhanzi pamahedhifoni asina waya. Maiwe, iyi haisi joke kana placebo mhedzisiro: mutsauko unonzwika chaizvo, asi haukonzerwi nekusiyana. codecs.

Iyo yakawanda yakawanda yeBluetooth audio chipsets inoshandiswa mumagetsi ekugamuchira isina waya ine Digital Signal processor (DSP), iyo inoshandisa yakaenzana, compander, stereo expander, uye zvimwe zvinhu zvakagadzirirwa kuvandudza (kana kuchinja) ruzha. Vagadziri vemidziyo yeBluetooth vanogona kugadzirisa DSP kune imwe neimwe codec zvakasiyana, uye kana uchichinja pakati pemakodheki, muteereri achafunga kuti ari kunzwa mutsauko mukushanda kwekodeki, apo chaizvoizvo vari kuteerera zvirongwa zvakasiyana zveDSP.

DSP Kalimba audio processing pombi mumachipisi anogadzirwa neCSR/Qualcomm

Activate akasiyana DSP mabasa kune yega yega codec uye inobuda zvakasiyana

Mamwe maturusi ekutanga anouya nesoftware inokutendera kuti ugadzirise marongero eDSP, asi mahedhifoni mazhinji anochipa haadaro, uye vashandisi havagone kudzima odhiyo post-processing nemaoko.

Zvishandiso zvezvishandiso

Iyo yazvino vhezheni yeiyo A2DP standard ine "Absolute volume control" basa -Kudzora vhoriyamu yemudziyo uchishandisa yakakosha mirairo yeAVRCP protocol, iyo inogadzirisa kuwana kweiyo nhanho yekubuda, panzvimbo yekudzikisa zvine hurongwa huwandu hwerukova rweodhiyo. Kana iwe ukachinja vhoriyamu pamahedhifoni ako, shanduko yacho haiwirirani nevhoriyamu pafoni yako, ipapo mahedhifoni ako kana foni haitsigire chinhu ichi. Muchiitiko ichi, zvine musoro kugara uchiteerera mimhanzi ine vhoriyamu yakanyanya pafoni, kugadzirisa iyo chaiyo vhoriyamu nemabhatani ehedhifoni - mune iyi kesi, chiratidzo-ku-ruzha chiyero chichava nani uye mhando yekuteerera. dzinofanira kuva yakakwirira.
Kutaura zvazviri, pane mamiriro ezvinhu anosuruvarisa. Pane yangu RealForce OverDrive D1 mahedhifoni eSBC, compander yakasimba inovhurwa, uye kuwedzera vhoriyamu kunounza kuwedzera kweyero yekunyarara, nepo vhoriyamu yekurira inonzwika isingachinji (chiratidzo chinomanikidzwa). Nekuda kweizvi, iwe unofanirwa kuseta vhoriyamu pakombuta kusvika inenge hafu, mune iyo kesi iyo inenge isina kumanikidza maitiro.
Zvinoenderana nekuona kwangu, ese mahedhifoni ane mamwe macodec anotsigira iyo yakakwana yekudzora vhoriyamu basa, sezviri pachena ichi ndicho chimwe chezvinodiwa zvecodec certification.

Mamwe mahedhifoni anotsigira kubatanidza michina miviri panguva imwe chete. Izvi zvinokutendera iwe, semuenzaniso, kuteerera mimhanzi kubva pakombuta yako uye kugamuchira mafoni kubva pafoni yako. Nekudaro, iwe unofanirwa kuziva kuti mune ino modhi mamwe macodecs akavharwa uye chete SBC ndiyo inoshandiswa.

AVDTP 1.3 Kunonoka Kushuma basa inobvumira mahedhifoni kuti ataure kunonoka kune mudziyo wekutumira panoridzwa ruzha. Izvi zvinokutendera kuti ugadzirise kuwiriraniswa kweodhiyo nevhidhiyo uchiona mafaera evhidhiyo: kana paine matambudziko nekufambiswa kweredhiyo, odhiyo haizosaririra kuseri kwevhidhiyo, asi zvinopesana, vhidhiyo inodzikiswa nemutambi wevhidhiyo kusvika odhiyo nevhidhiyo zvinowiriraniswa zvakare.
Basa racho rinotsigirwa nemahedhifoni akawanda, Android 9+ uye Linux ine PulseAudio 12.0+. Ini handizive rutsigiro rwechinhu ichi pane mamwe mapuratifomu.

Bidirectional kutaurirana kuburikidza neBluetooth. Kutumira inzwi.

Nekufambisa kwezwi muBluetooth, Synchronous Connection Oriented (SCO) inoshandiswa - synchronous kuendesa nekutanga kutaurirana kwekubatanidza. Iyo modhi inobvumidza iwe kuendesa ruzha uye izwi zvakanyatsorongeka, neiyo symmetrical kutumira uye kugamuchira kumhanya, pasina kumirira kusimbiswa kwekutapurirana uye kutumirazve mapaketi. Izvi zvinoderedza kunonoka kwese kwekutapurirana kweredhiyo, asi zvinoisa zvirambidzo zvakakomba pahuwandu hwe data inofambiswa pachikamu chenguva, uye zvinokanganisa kunaka.
Kana iyi modhi ikashandiswa, zvese izwi uye odhiyo zvinofambiswa nemhando imwechete.
Nehurombo, kubva muna 2019, kunaka kwezwi pamusoro peBluetooth kuchiri kushomeka, uye hazvizivikanwe kuti sei iyo Bluetooth SIG isiri kuita chero chinhu nezvazvo.

CVSD

Iyo yakakosha CVSD yekutaura codec yakamisikidzwa muna 2002, uye inotsigirwa neese bidirectional Bluetooth yekutaurirana zvishandiso. Inopa kutapurirana odhiyo ine sampling frequency ye8 kHz, iyo inoenderana nemhando yeyakajairwa wired telephony.

Muenzaniso wekurekodhwa mune iyi codec.

mSBC

Iyo yekuwedzera mSBC codec yakamisikidzwa muna 2009, uye muna 2010 machipi achiishandisa kutapurirana nezwi yakatoonekwa. mSBC inotsigirwa zvakanyanya nemhando dzakasiyana siyana.
Iyi haisi codec yakazvimiririra, asi yenguva dzose SBC kubva kuA2DP chiyero, ine yakagadziriswa encoding mbiri: 16 kHz, mono, bitpool 26.

Muenzaniso wekurekodhwa mune iyi codec.

Haina kujeka, asi iri nani kupfuura CVSD, asi zvichiri kutsamwisa kushandisa pamhepo kutaurirana, kunyanya kana iwe uchishandisa mahedhifoni kutaurirana mumutambo - mutambo wemutambo unozofambiswawo pamwero wesampling we16 kHz.

FastStreamCSR kambani yakafunga kukudziridza pfungwa yekushandisa SBC. Kuti utenderere zvipimo zveSCO protocol uye kushandisa yakakwira bitrate, CSR yakaenda neimwe nzira - ivo vakaunza tsigiro yenzira mbiri SBC odhiyo muA2DP imwe-nzira yekuparadzira chiyero, yakamisikidzwa encoding profiles, ndokuidaidza kuti "FastStream".

FastStream inotumira stereo audio pa44.1 kana 48 kHz ine bitrate ye212 kbps kune vatauri, uye mono, 16 kHz, ine bitrate ye72 kbps inoshandiswa kufambisa odhiyo kubva kumakrofoni (zvishoma zviri nani pane mSBC). Maparamita akadaro anonyatsokodzera kutaurirana mumitambo yepamhepo - ruzha rwemutambo uye vanopindirana vachave vemhando yepamusoro.

Muenzaniso wekurekodhwa mune iyi codec (+ ruzha kubva kumaikorofoni, zvakafanana nemSBC).

Iyo kambani yakauya necrutch inonakidza, asi nekuda kwekuti inopesana neiyo A2DP chiyero, inotsigirwa chete mune mamwe emakambani ekutumira (anoshanda se USB kadhi redhiyo, kwete mudziyo weBluetooth), asi haadaro. Gamuchira rutsigiro mumatatu eBluetooth kunyangwe iyo nhamba yemahedhifoni ane FastStream rutsigiro haina kudiki.

Parizvino, FastStream rutsigiro muOS chete sechigamba cheLinux PulseAudio kubva kumugadziri Pali Rohár, uyo asina kubatanidzwa mubazi guru rechirongwa.

aptX Yakadzika Latency

Zvakawanda zvinokushamisa, aptX Low Latency zvakare inotsigira bidirectional odhiyo, ichiita iyo imwechete musimboti seFastStream.
Izvo hazvigoneke kushandisa iyi ficha yecodec chero kupi - hapana rutsigiro rweLow Latency decoding mune chero OS kana mune chero Bluetooth stack yandinoziva ini.

Bluetooth 5, Classic uye Yakaderera Simba

Pakave nekuvhiringika kwakawanda kwakatenderedza Bluetooth zvirevo uye shanduro nekuda kwekuvapo kwezviyero zviviri zvisingaenderane pasi peiyo mhando, ese ari maviri anoshandiswa zvakanyanya kune zvakasiyana zvinangwa.

Kune maviri akasiyana, asingaenderane neBluetooth mapuroteni: Bluetooth Classic uye Bluetooth Low Energy (LE, inozivikanwawo seBluetooth Smart). Kune zvakare yechitatu protocol, Bluetooth High Speed, asi haina kupararira uye haishandiswe mumidziyo yemumba.

Kutanga neBluetooth 4.0, shanduko mune zvakatemwa zvakanyanya neBluetooth Low Energy, uye iyo Classic vhezheni yakangogamuchira diki gadziriso.

Rondedzero yekuchinja pakati peBluetooth 4.2 neBluetooth 5:

9 KUCHINJA KUBVA KUBVA V4.2 KUTI 5.0

9.1 ZVITSVA

Zvizhinji zvitsva zvinounzwa muBluetooth Core Specification 5.0 Release. Nzvimbo huru dzekuvandudza ndeidzi:
• Slot Availability Mask (SAM)
• 2 Msym/s PHY ye LE
•LE Long Range
• High Duty Cycle Non-Connectable Advertising
• LE Advertising Extensions
• LE Channel Selection Algorithm #2
9.1.1 Zvimiro Zvakawedzerwa muCSA5 - Yakabatanidzwa muv5.0
•Higher Output Power

Source: www.bluetooth.org/docman/handlers/DownloadDoc.ashx?doc_id=421043 (peji 291)

Shanduko imwe chete yakakanganisa iyo yeClass vhezheni mukati meiyo dhizaini yeBluetooth 5: ivo vakawedzera rutsigiro rweSlot Availability Mask (SAM) tekinoroji, yakagadzirirwa kuvandudza kupatsanurwa kweredhiyo. Dzimwe shanduko dzese dzinobata chete Bluetooth LE (uye Yepamusoro Kubuda Simba zvakare).

zvose Zvishandiso zvinonzwika zvinoshandisa chete Bluetooth Classic. Hazvibviri kubatanidza mahedhifoni uye vatauri kuburikidza neBluetooth Low Energy: hapana chiyero chekutumira odhiyo uchishandisa LE. Iyo A2DP chiyero, inoshandiswa kufambisa yemhando yepamusoro odhiyo, inoshanda chete kuburikidza neBluetooth Classic, uye hapana analogue muLE.

Mhedziso - kutenga michina yekuteerera neBluetooth 5 chete nekuda kweiyo vhezheni itsva yeprotocol haina maturo. Bluetooth 4.0/4.1/4.2 mumamiriro ekutumira odhiyo ichashanda zvakafanana.
Kana chiziviso chemahedhifoni matsva chichitaura zvakapetwa kaviri kushanda uye kuderedzwa kwesimba rekushandisa nekuda kweBluetooth 5, saka iwe unofanirwa kuziva kuti ivo havazvinzwisise ivo pachavo kana vari kukutsausa. Hazvishamisi, nekuti kunyange vagadziri veBluetooth machipi muzviziviso zvavo vanovhiringika pamusoro pemisiyano pakati peiyo vhezheni itsva yechiyero, uye mamwe maBlue 5 machipi anotsigira yechishanu vhezheni yeLE chete, uye shandisa 4.2 yeClassic.

Audio kutapurirana kunonoka

Huwandu hwekunonoka (lag) muodhiyo zvinoenderana nezvakawanda zvinhu: saizi yebhafa muodhiyo stack, muBluetooth stack uye mune isina waya yekuridza mudziyo pachayo, uye algorithmic kunonoka kweiyo codec.

Iyo latency yemacodecs akareruka senge SBC, aptX uye aptX HD idiki kwazvo, 3-6 ms, iyo inogona kuregeredzwa, asi yakaoma macodecs seAAC neLDAC inogona kukonzera inooneka lag. Iyo AAC algorithmic latency ye44.1 kHz ndeye 60 ms. LDAC - ingangoita 30 ms (zvichienderana nekuongorora kwakaoma kweiyo kodhi kodhi. Ndinogona kunge ndisina kururama, asi kwete zvakawanda.)

Iyo inokonzeresa latency inotsamira pane yekutamba mudziyo, chipset yayo uye buffer. Panguva yekuedzwa, ndakagamuchira kupararira kwe150 kusvika ku250 ms pamidziyo yakasiyana (ine SBC codec). Kana isu tikafungidzira kuti zvishandiso zvinotsigira mamwe macodecs aptX, AAC uye LDAC anoshandisa emhando yepamusoro zvikamu uye diki buffer size, tinowana anotevera akajairwa latencies:

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

Rega ndikuyeuchidze: aptX Low Latency haitsigirwe mumasisitimu anoshanda, ndosaka yakaderera latency ichigona kuwanikwa chete neiyo transmitter + receiver kana transmitter + mahedhifoni / mutauri musanganiswa, uye zvese zvishandiso zvinofanirwa kutsigira iyi codec.

Bluetooth mudziyo, certification, uye logo nyaya

Nzira yekusiyanisa yemhando yepamusoro yekuteerera mudziyo kubva kune yakachipa craft? Muchitarisiko, chekutanga!

Kune mahedhifoni echiChinese akachipa, vatauri uye vanogamuchira:

1. Izwi rekuti "Bluetooth" haripo pabhokisi uye mudziyo, "Wireless" uye "BT" rinonyanya kushandiswa
2. Bluetooth logo haipo pabhokisi kana mudziyo
3. Hapana bhuruu inopenya LED

Kusavapo kwezvinhu izvi kunoratidza kuti mudziyo hausati wapihwa certification, zvinoreva kuti unogona kunge wemhando yakaderera uye inonetsa. Semuenzaniso, mahedhifoni eBluedio haana kubvumidzwa neBluetooth uye haatevedzere zvizere neA2DP yakatarwa. Vangadai vasina kupasa zvitupa.

Ngatitarisei akati wandei maturusi uye mabhokisi kubva kwavari:

Aya ese midziyo isina kuvimbiswa. Mirayiridzo inogona kunge iine logo uye zita reBluetooth tekinoroji, asi chinonyanya kukosha ndechekuti ivo vari pabhokisi uye / kana mudziyo pachawo.

Kana mahedhifoni ako kana mutauri akati "Ze bluetooth dewise yakabatana zvinobudirira", izvi zvakare hazviratidze hunhu hwavo:

mhedziso

Ko Bluetooth inogona kutsiva zvachose mahedhifoni ane waya uye mahedhifoni? Inokwanisa, asi nemutengo wehurombo hwekufona mhando, yakawedzera odhiyo latency inogona kutsamwisa mumitambo, uye akawanda evaridzi macodecs anoda mari yerezinesi uye kuwedzera mutengo wekupedzisira wezvose zviri zviviri smartphones uye mahedhifoni.

Kushambadzira kwemamwe macodecs kwakasimba kwazvo: aptX neLDAC zvinoratidzwa seyakamirirwa kwenguva refu yekutsiva iyo "yechinyakare uye yakaipa" SBC, iyo isina kupotsa yakashata sekufunga kunoita vanhu.

Sezvazvakazoitika, izvo zvisiri zvekugadzira zveBlue stacks paSBC bitrate zvinogona kupfuudzwa, kuitira kuti SBC isaite yakaderera kune aptX HD. Ndakatora danho mumaoko angu ndokugadzira chigamba cheLineageOS firmware: Isu tinogadzirisa iyo Bluetooth stack kuvandudza ruzha pamahedhifoni pasina AAC, aptX uye LDAC macodecs.

Rumwe ruzivo runogona kuwanikwa pawebhusaiti Sound Guys и SoundExpert.

Bonus: SBC referensi encoder, A2DP bitstream ruzivo uye bvunzo mafaera. Iri faira raimboiswa pachena pawebhusaiti yeBluetooth, asi rave kuwanikwa kunhengo dzeBluetooth SIG chete.

Source: www.habr.com