bool TinyAlsaCtlPortConfig::doOpenStream(StreamDirection streamDirection, std::string &error)
{
struct pcm *&streamHandle = _streamHandle[streamDirection];
struct pcm_config pcmConfig;
const AlsaCtlPortConfig::PortConfig &portConfig = getPortConfig();
// Fill PCM configuration structure
pcmConfig.channels = portConfig.channelNumber;
pcmConfig.rate = portConfig.sampleRate;
// Check Format is supported by the plugin
if (portConfig.format >= pcmFormatTranslationTableSize) {
error = "The format n°" + asString(portConfig.format) +
" is not supported by the TinyAlsa plugin";
return false;
}
uint8_t format = pcmFormatTranslationTable[portConfig.format].formatAsNumerical;
// Check format is supported by Tinyalsa
if (format == std::numeric_limits<uint8_t>::max()) {
error = "The format " + pcmFormatTranslationTable[portConfig.format].formatAsString +
" is not supported by Tinyalsa";
return false;
}
pcmConfig.format = static_cast<pcm_format>(format);
pcmConfig.period_size = _periodTimeMs * pcmConfig.rate / _msPerSec;
pcmConfig.period_count = _nbRingBuffer;
pcmConfig.start_threshold = 0;
pcmConfig.stop_threshold = 0;
pcmConfig.silence_threshold = 0;
pcmConfig.silence_size = 0;
pcmConfig.avail_min = 0;
// Open and configure
streamHandle = pcm_open(getCardNumber(),
getDeviceNumber(),
streamDirection == Capture ? PCM_IN : PCM_OUT,
&pcmConfig);
// Prepare the stream
if (!pcm_is_ready(streamHandle) || (pcm_prepare(streamHandle) != 0)) {
// Format error
error = formatAlsaError(streamDirection, "open", pcm_get_error(streamHandle));
doCloseStream(streamDirection);
return false;
}
return true;
}
void AlsaCtlPortConfig::closeStream(StreamDirection streamDirection)
{
// Stream needs to be closed only if it was opened previously
if (_portConfig.isStreamEnabled[streamDirection]) {
// Stream has to be closed
doCloseStream(streamDirection);
_portConfig.isStreamEnabled[streamDirection] = false;
}
}