lockstep/TODO.md

TODO

• PlaybackEngine - Buffer overrun on output for channel (1.000000)

  • we are feeding too much data into 'stretcher'

• E attributionTag not declared in manifest of at.lockstep

• analyze the (secondly or so) noise beeps in the mp3 playback

  • introduced with this commit
  • is it librubberband, my failure to feed it properly (buffer exhaustion), or sth else?
  • the sizes of my buffers?

• correct sampling rate of libmpg123 vs. 48000 Hz using librubberband

• record accelero and write recording to file

• set feedForDelay in musicFeedThread() in PlaybackEngine.cpp

  • LOGI("feed %d silence samples", num_samples);
  • set the sleep delay
  • ideally, set the buf size

• check playback buf size, and reduce buffer sizes

  • LOGI("onAudioReady() frames=%d", frames);

• reduce lib size, librubberband is 1.3 M (one .so file)

  • maybe we are compiling too many source files

  • TODO: see Android.mk in librubberband and copy options from LOCAL_CFLAGS

O> 16 KB paging for NDK libs

• target SDK level 35

• record the accelero and check why repeated fast beats result in occasional detection outages

  • guess: the threshold gets pushed so high that the later beats are not detected properly
  • maybe we need the *0.6 factor after all (but verify this!)

• minimum amplitude for accelero (avoid detecting e.g. when phone is lying flat and you hammer on the table)

• filter away bad SQI areas of the signal (do not detect steps if we have bad SQI)

Nice-To

• myband PlaybackEngine.cpp has latency management and other audio performance related features. Check if the app can be improved (audio wise) by using that code instead.

• Sampling rate for accelerometer - do we need to measure actual sensor FPS, or is it stable 50 Hz?

• re-calculate IIR filter coefficients. probably not critical for 50 Hz vs. 60 Hz.

• re-visit sampling rate and channel count. MixingPlayer currently forces both to 48000 and 2 respectively, regardless of what Android says would be optimal.

• nice-to nice-to: ramp up audio pipelines twice - once to collect params, another one to use those

Technical Debt

• remove duplication of mp3file_open() in mp3file_open_fd()
• malloc() nullptr result handling

Before release

• check librubberband license