Tinyalsa - Tinycap not working

I try to record audio using Tinycap (from Tinyalsa-NDK), I encounter the following issues:

• On a Nexus 5 device, capturing seems to start but generated wav file is always invalid


• On an Samsung Galaxy S4 device, Tinycap always hangs until PCM is released, and then device crashes and restarts.

I tried various pcm configurations but all result in the same behavior. Am I missing something? Is there something else to apply before capturing?