1. 30 Apr, 2020 3 commits
  2. 28 Apr, 2020 3 commits
  3. 26 Apr, 2020 30 commits
  4. 17 Apr, 2020 1 commit
  5. 15 Apr, 2020 3 commits
    • pali's avatar
      bluetooth: Add more variants of SBC codec · 8c1a6eec
      pali authored
      Specify configuration for Low, Middle, High and eXtreme Quality of SBC
      codec. SBC codec in eXtreme Quality has higher quality than aptX.
      
      Automatic Quality mode matches configuration of SBC codec which was used
      before this change. Which means that it accept configuration between Low
      and High quality.
      
      Current SBC code was extended to allow definitions of arbitrary
      configuration variants of SBC codec parameters.
      
      SBC XQ testing is in following article:
      http://soundexpert.org/articles/-/blogs/audio-quality-of-sbc-xq-bluetooth-audio-codec
      8c1a6eec
    • pali's avatar
      bluetooth: Add A2DP FastStream codec support · 3f3d3a0f
      pali authored
      This patch provides support for FastStream codec in bluetooth A2DP profile.
      FastStream codec is bi-directional, which means that it supports both music
      playback and microphone voice at the same time.
      
      FastStream codec is just SBC codec with fixed parameters. For playback are
      used following parameters: 48.0kHz or 44.1kHz, Blocks 16, Sub-bands 8,
      Joint Stereo, Loudness, Bitpool = 29 (data rate = 212kbps, packet size =
      (71+1)*3 <= DM5 = 220, with 3 SBC frames). SBC frame size is 71 bytes, but
      FastStream is zero-padded to the even size (72). For microphone are used
      following SBC parameters: 16kHz, Mono, Blocks 16, Sub-bands 8, Loudness,
      Bitpool = 32 (data rate = 72kbps, packet size = 72*3 <= DM5 = 220, with
      3 SBC frames).
      
      So FastStream codec is equivalent to SBC in Low Quality settings. But the
      main benefit of FastStream codec is support for microphone voice channel
      for audio calls. Compared to bluetooth HSP profile (with CVSD codec), it
      provides better audio quality for both playback and recording.
      3f3d3a0f
    • pali's avatar
      bluetooth: Add A2DP aptX and aptX HD codecs support · 09e87210
      pali authored
      This patch provides support for aptX and aptX HD codecs in bluetooth A2DP
      profile. It uses open source LGPLv2.1+ licensed libopenaptx library which
      can be found at https://github.com/pali/libopenaptx.
      
      aptX for s24 stereo samples provides fixed 6:1 compression ratio and
      bitrate 352.8 kbit/s, aptX HD provides fixed 4:1 compression ratio and
      bitrate 529.2 kbit/s.
      
      According to soundexpert research, aptX codec used in bluetooth A2DP is no
      better than SBC High Quality settings. And you cannot hear difference
      between aptX and SBC High Quality, aptX is just a copper-less overpriced
      audio cable.
      
      aptX HD is high-bitrate version of aptX. It has clearly noticeable increase
      in sound quality (not dramatic though taking into account the increase in
      bitrate).
      
      http://soundexpert.org/news/-/blogs/audio-quality-of-bluetooth-aptx
      09e87210