ALSAInput::ALSAInput(const char *device, unsigned sample_rate, unsigned num_channels, audio_callback_t audio_callback)
: device(device), sample_rate(sample_rate), num_channels(num_channels), audio_callback(audio_callback)
{
- die_on_error(device, snd_pcm_open(&pcm_handle,device, SND_PCM_STREAM_CAPTURE, 0));
+ die_on_error(device, snd_pcm_open(&pcm_handle, device, SND_PCM_STREAM_CAPTURE, 0));
// Set format.
snd_pcm_hw_params_t *hw_params;
snd_pcm_hw_params_alloca(&hw_params);
- die_on_error("snd_pcm_hw_params_any()", snd_pcm_hw_params_any(pcm_handle, hw_params));
- die_on_error("snd_pcm_hw_params_set_access()", snd_pcm_hw_params_set_access(pcm_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED));
- snd_pcm_format_mask_t *format_mask;
- snd_pcm_format_mask_alloca(&format_mask);
- snd_pcm_format_mask_set(format_mask, SND_PCM_FORMAT_S16_LE);
- snd_pcm_format_mask_set(format_mask, SND_PCM_FORMAT_S24_LE);
- snd_pcm_format_mask_set(format_mask, SND_PCM_FORMAT_S32_LE);
- die_on_error("snd_pcm_hw_params_set_format()", snd_pcm_hw_params_set_format_mask(pcm_handle, hw_params, format_mask));
- die_on_error("snd_pcm_hw_params_set_rate_near()", snd_pcm_hw_params_set_rate_near(pcm_handle, hw_params, &sample_rate, 0));
- die_on_error("snd_pcm_hw_params_set_channels()", snd_pcm_hw_params_set_channels(pcm_handle, hw_params, num_channels));
+ if (!set_base_params(device, pcm_handle, hw_params, &sample_rate)) {
+ exit(1);
+ }
die_on_error("snd_pcm_hw_params_set_channels()", snd_pcm_hw_params_set_channels(pcm_handle, hw_params, num_channels));
}
}
+bool ALSAInput::set_base_params(const char *device_name, snd_pcm_t *pcm_handle, snd_pcm_hw_params_t *hw_params, unsigned *sample_rate)
+{
+ int err;
+ err = snd_pcm_hw_params_any(pcm_handle, hw_params);
+ if (err < 0) {
+ fprintf(stderr, "[%s] snd_pcm_hw_params_any(): %s\n", device_name, snd_strerror(err));
+ return false;
+ }
+ err = snd_pcm_hw_params_set_access(pcm_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
+ if (err < 0) {
+ fprintf(stderr, "[%s] snd_pcm_hw_params_set_access(): %s\n", device_name, snd_strerror(err));
+ return false;
+ }
+ snd_pcm_format_mask_t *format_mask;
+ snd_pcm_format_mask_alloca(&format_mask);
+ snd_pcm_format_mask_set(format_mask, SND_PCM_FORMAT_S16_LE);
+ snd_pcm_format_mask_set(format_mask, SND_PCM_FORMAT_S24_LE);
+ snd_pcm_format_mask_set(format_mask, SND_PCM_FORMAT_S32_LE);
+ err = snd_pcm_hw_params_set_format_mask(pcm_handle, hw_params, format_mask);
+ if (err < 0) {
+ fprintf(stderr, "[%s] snd_pcm_hw_params_set_format_mask(): %s\n", device_name, snd_strerror(err));
+ return false;
+ }
+ err = snd_pcm_hw_params_set_rate_near(pcm_handle, hw_params, sample_rate, 0);
+ if (err < 0) {
+ fprintf(stderr, "[%s] snd_pcm_hw_params_set_rate_near(): %s\n", device_name, snd_strerror(err));
+ return false;
+ }
+ return true;
+}
+
vector<ALSAInput::Device> ALSAInput::enumerate_devices()
{
vector<Device> ret;
snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
+ unsigned num_channels = 0;
+
// Find all channel maps for this device, and pick out the one
// with the most channels.
snd_pcm_chmap_query_t **cmaps = snd_pcm_query_chmaps_from_hw(card_index, dev_index, 0, SND_PCM_STREAM_CAPTURE);
- unsigned num_channels = 0;
- for (snd_pcm_chmap_query_t **ptr = cmaps; *ptr; ++ptr) {
- num_channels = max(num_channels, (*ptr)->map.channels);
+ if (cmaps != nullptr) {
+ for (snd_pcm_chmap_query_t **ptr = cmaps; *ptr; ++ptr) {
+ num_channels = max(num_channels, (*ptr)->map.channels);
+ }
+ snd_pcm_free_chmaps(cmaps);
+ }
+ if (num_channels == 0) {
+ // Device had no channel maps. We need to open it to query.
+ snd_pcm_t *pcm_handle;
+ int err = snd_pcm_open(&pcm_handle, address, SND_PCM_STREAM_CAPTURE, 0);
+ if (err < 0) {
+ // TODO: When we go to hotplug support, we should support some
+ // retry here, as the device could legitimately be busy.
+ printf("%s: %s\n", address, snd_strerror(err));
+ continue;
+ }
+ snd_pcm_hw_params_t *hw_params;
+ snd_pcm_hw_params_alloca(&hw_params);
+ unsigned sample_rate;
+ if (!set_base_params(address, pcm_handle, hw_params, &sample_rate)) {
+ snd_pcm_close(pcm_handle);
+ continue;
+ }
+ err = snd_pcm_hw_params_get_channels_max(hw_params, &num_channels);
+ if (err < 0) {
+ fprintf(stderr, "[%s] snd_pcm_hw_params_get_channels_max(): %s\n",
+ address, snd_strerror(err));
+ snd_pcm_close(pcm_handle);
+ continue;
+ }
+ snd_pcm_close(pcm_handle);
}
-
- snd_pcm_free_chmaps(cmaps);
if (num_channels == 0) {
printf("%s: No channel maps with channels\n", address);