Hard-coded buffer length in play_sd_wav.cpp

[StephanLuik]

Description

In the update() method of play_sd_wav.cpp, the buffer array size is hard-coded to 512 samples. When using a value other than 128 for AUDIO_BLOCK_SAMPLES, the buffer length is no longer a multiple and for some files it will introduce audible gaps in the playback.

Steps To Reproduce Problem

Change the AUDIO_BLOCK_SAMPLES constant to 160 and play back a simple sine wave file.

Hardware & Software

Teensy 4.1 with pins
Audio Adaptor rev. D
Arduino version 1.8.13
Teensyduino version 1.53
Windows 10 Pro 21H1

Arduino Sketch

Errors or Incorrect Output

[FrankBoesing]

AUDIO_BLOCK_SAMPLES has to be a power of two anyway, for other parts of the library.

[StephanLuik]

Still, if you change AUDIO_BLOCK_SAMPLES to a power of two, say 256, then the hard coded array size of 512 will fail also. It is never a good idea to use hard-coded constants in source code.

[h4yn0nnym0u5e]

I think this is fixed in PR #448