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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.

https://developer.android.com/reference/android/media/AudioFormat#encoding

float mantisa is 23 bits (plus sign bit and float point bits) persition in range from -1..1 can hold about 2130706431 unique numbers which is equivalent to 31 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