Hi all, While developing an audio software based on PortAudio, I discovered a surprising problem related to ALSA: I'm getting short pauses in the audio playback (sounding like typical buffer underruns) depending on the audio amplitude. As a test, I have generated two wave files containing pure white noise. One of them with an amplitude of 0.5 the other one using a full range amplitude of 1.0. I'm playing both files with aplay, but I'm getting the same behavior with other players and also with the software I'm developing: The 0.5 amplitude files plays without any issues. But the 1.0 amplitude file plays with short breaks in the audio stream. I'm getting about two of these breaks per minute, but there does not seem to be a deterministic pattern. I would guess the pauses are <100 ms in duration, which is why I was debugging in the direction of buffer underruns for many days until I discovered this amplitude effect. I have xruns logging enabled, so I'm pretty sure this is not related to that. Do you have any idea what could be causing this? System specs: - Ubuntu 14.04. with the default libportaudio2 (based on the last 2014 release) - Standard Intel onboard sound: PCH [HDA Intel PCH], device 0: ALC892 Analog [ALC892 Analog] Another test: Amplitude 0.9 also has breaks, so it is not just the full range amplitude. Thanks, Fabian ------------------------------------------------------------------------------ Developer Access Program for Intel Xeon Phi Processors Access to Intel Xeon Phi processor-based developer platforms. With one year of Intel Parallel Studio XE. Training and support from Colfax. Order your platform today. http://sdm.link/xeonphi _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
