/* * Copyright (C) 2020 Mark Hills * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * version 2, as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License version 2 for more details. * * You should have received a copy of the GNU General Public License * version 2 along with this program; if not, write to the Free * Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, * MA 02110-1301, USA. * */ #include #include #define CHK(call, r) { \ if (r < 0) { \ aerror(call, r); \ return -1; \ } \ } void aerror(const char *msg, int r) { fputs(msg, stderr); fputs(": ", stderr); fputs(snd_strerror(r), stderr); fputc('\n', stderr); } int set_alsa_hw(snd_pcm_t *pcm, unsigned int rate, unsigned int channels, unsigned int buffer) { int r, dir; snd_pcm_hw_params_t *hw; snd_pcm_hw_params_alloca(&hw); r = snd_pcm_hw_params_any(pcm, hw); CHK("snd_pcm_hw_params_any", r); r = snd_pcm_hw_params_set_rate_resample(pcm, hw, 1); CHK("snd_pcm_hw_params_set_rate_resample", r); r = snd_pcm_hw_params_set_access(pcm, hw, SND_PCM_ACCESS_RW_INTERLEAVED); CHK("snd_pcm_hw_params_set_access", r); r = snd_pcm_hw_params_set_format(pcm, hw, SND_PCM_FORMAT_S16); CHK("snd_pcm_hw_params_set_format", r); r = snd_pcm_hw_params_set_rate(pcm, hw, rate, 0); CHK("snd_pcm_hw_params_set_rate", r); r = snd_pcm_hw_params_set_channels(pcm, hw, channels); CHK("snd_pcm_hw_params_set_channels", r); dir = -1; r = snd_pcm_hw_params_set_buffer_time_near(pcm, hw, &buffer, &dir); CHK("snd_pcm_hw_params_set_buffer_time_near", r); r = snd_pcm_hw_params(pcm, hw); CHK("hw_params", r); return 0; } int set_alsa_sw(snd_pcm_t *pcm) { int r; snd_pcm_sw_params_t *sw; snd_pcm_uframes_t boundary; snd_pcm_sw_params_alloca(&sw); r = snd_pcm_sw_params_current(pcm, sw); CHK("snd_pcm_sw_params_current", r); r = snd_pcm_sw_params_get_boundary(sw, &boundary); CHK("snd_pcm_sw_params_get_boundary", r); r = snd_pcm_sw_params_set_stop_threshold(pcm, sw, boundary); CHK("snd_pcm_sw_params_set_stop_threshold", r); r = snd_pcm_sw_params(pcm, sw); CHK("snd_pcm_sw_params", r); return 0; }