• AccurateRip
• Acoustid
• AES/EBU
• AirPlay
• Amplifier
• aptX
• Audio file formats
• • AAC
  • AIFF
  • ALAC
  • APE
  • DSD
  • DXD
  • FLAC
  • MP3
  • MQA
  • M4A
  • WAV
  • WMAL
• ASRC
• AVB
• Bit perfect jitter
• Bits: 16 or 24
• Bit perfect playback
• Bitrate
• Bluetooth
• Burn-in
• BWF
• Cables
  • Analog
  • Speaker
  • Bi-wiring
  • Digital
• CDtext
• Chromecast
• Clipping
• Clock
• Codec
• Compression
• CRC
• Crossover
• Cue sheet
• DAC
• Damping
• DASH
• Digital
• Digital Room Correction
• Dither
• DLNA
• Drivers
  • ASIO
  • Direct Sound
  • Kernel Streaming
  • WASAPI
  • Wave Out
• DoP
• DSP
• EBU R128 (loudness)
• FFT
• FireWire
• Freedb
• Gapless playback
• Generation loss
• HDMI
• Headphone listening
• Hearing
  • Single-sided deafness
  • Hard of hearing
• Hires recording
• Homeplug
• I2S
• ID3
• Inter sample peak
• LDAC
• Linearity (DAC)
• Memory playback
• Music Server
• OCF
• OFC
• PCM
• Perception
• RAID
• ReplayGain
• Ripping
• RFI
• RIAA
• Router
• Sampling, up and over
• Sample Rate Conversion
• Speakers
  • Driver design
  • Crossover
  • Amplification
  • Connecting
  • Measurement
  • Placement
• S/PDIF
• Storage
• Sync
• Tagging
• Toslink
• Transcoding
• UAA
• Units
• UPnP
• USB
• VST
• WiFi
• WiSA

aptX

A proprietary Bluetooth codec developed by CSR (Qualcomm today).

As it is not a mandatory part of the standard you need both a sender and a receiver (SouRCe and SiNK in Bluetooth lingo) supporting this protocol.

Although many think so, aptX is not lossless. It is an alternative for the standard SBC codec.

It has a fixed compression ration of 4:1 and a data rate of 352kbps.

aptX HD

In January 2016 Qualcomm announced aptX HD, it support 24 bits / 48 kHz LPCM audio over Bluetooth.

Compression remains at a ratio of 4:1, with a bit rate of 576kbps.

Although the data rate is substantially higher compared with aptX, it is and remains a lossy codec.

aptX LL

Bluetooth latency is a bit high.
If you are sensitive to it, lip sync will be a problem.
Values are in the 200 ms range.
Aptx Low Latency cuts this down to 40 ms.

 

There are other proprietary codecs today offering an even higher bit-rate.

Bluetooth is covered in more detail here.

 

 

aptX - Qualcom