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README.md

Know bugs

None

Recording locations

Android has several storage locations:

  • /data/data/ - internal user storage on new android
  • /storage/self/primary/ - internal storage
  • /storage/emulated/0/ - external storage (sdcard formated as internal or emulated external)
  • /storage/1D13-0F08/ - sdcard formated as portable

Some Androids can have more:

/storage/sdcard - emulated external sdcard /data/user/0/ - internal user storage /sdcard - link for default extenral storage /storage/emulated/0/

Plus application / user specified folders (all combinations of):

  • .../Android/data/com.github.axet.audiorecorder/files
  • .../com.github.axet.audiorecorder/files
  • .../Audio Recorder

For example:

  • /data/data/com.github.axet.audiorecorder/files
  • /data/user/0/com.github.axet.audiorecorder/files
  • /sdcard/Android/data/com.github.axet.audiorecorder/files
  • /sdcard/Audio Recorder

Raw format

  • Signed 16-bit PCM or float (depends on user settings)
  • Big Endian
  • 1 or 2 channels (depends on user settings). First 2 bytes for left channel, Second 2 bytes for right channel.
  • 16hz to 48hz Sample Rate / Frequincy (depends on user settings)

Android supports 16-bit PCM format or PCM float. Android recomends to use PCM float over 24-bit PCM format or 16-bit PCM if possible.

float mantisa is 23 bits (plus sign bit and float point bits) persition in range from 0..1 can hold about 1,065,353,215 unique numbers which is equivalent to 29 bits integer. When 24-bit PCM only gives you 2^24=16,777,216 unique values.

Adb commands

# adb shell am start -n com.github.axet.audiorecorder/.activities.RecordingActivity

# adb shell am broadcast -a com.github.axet.audiorecorder.STOP_RECORDING