Refactor part of PortAudioIO::pcm_setup into new method
[ardour.git] / libs / backends / portaudio / portaudio_io.cc
index 6693c88af9d1bb70a32cc16dd7b52894043b46c2..18eae36fd9b8936462dfb2ce7edbee6f084f72c8 100644 (file)
@@ -22,6 +22,7 @@
 #include <string.h>
 #include <assert.h>
 #include <glibmm.h>
+
 #include "portaudio_io.h"
 
 #ifdef WITH_ASIO
 
 #include "pbd/compose.h"
 
+#include "ardour/audio_backend.h"
+
 #include "debug.h"
 
 #define INTERLEAVED_INPUT
 #define INTERLEAVED_OUTPUT
 
+using namespace PBD;
 using namespace ARDOUR;
 
 PortAudioIO::PortAudioIO ()
-       : _state (-1)
-       , _initialized (false)
-       , _capture_channels (0)
+       : _capture_channels (0)
        , _playback_channels (0)
        , _stream (0)
        , _input_buffer (0)
@@ -54,13 +56,9 @@ PortAudioIO::PortAudioIO ()
 
 PortAudioIO::~PortAudioIO ()
 {
-       if (_state == 0) {
-               pcm_stop();
-       }
-       if (_initialized) {
-               Pa_Terminate();
-       }
+       pcm_stop();
 
+       pa_deinitialize ();
        clear_device_lists ();
 
        free (_input_buffer); _input_buffer = NULL;
@@ -70,25 +68,14 @@ PortAudioIO::~PortAudioIO ()
 std::string
 PortAudioIO::control_app_name (int device_id) const
 {
-       const PaHostApiInfo* info = Pa_GetHostApiInfo (_host_api_index);
-       std::string app_name;
-
-       if (info == NULL) {
-               DEBUG_AUDIO (string_compose ("Unable to determine Host API from index %1\n",
-                                            _host_api_index));
-               return app_name;
-       }
-
-       PaHostApiTypeId type_id = info->type;
-
 #ifdef WITH_ASIO
-       if (type_id == paASIO) {
+       if (get_current_host_api_type() == paASIO) {
                // is this used for anything, or just acts as a boolean?
                return "PortaudioASIO";
        }
 #endif
 
-       return app_name;
+       return std::string();
 }
 
 void
@@ -105,15 +92,34 @@ PortAudioIO::launch_control_app (int device_id)
 #endif
 }
 
+void
+PortAudioIO::get_default_sample_rates (std::vector<float>& rates)
+{
+       rates.push_back(8000.0);
+       rates.push_back(22050.0);
+       rates.push_back(24000.0);
+       rates.push_back(44100.0);
+       rates.push_back(48000.0);
+       rates.push_back(88200.0);
+       rates.push_back(96000.0);
+       rates.push_back(176400.0);
+       rates.push_back(192000.0);
+}
+
 int
 PortAudioIO::available_sample_rates(int device_id, std::vector<float>& sampleRates)
 {
-       static const float ardourRates[] = { 8000.0, 22050.0, 24000.0, 44100.0, 48000.0, 88200.0, 96000.0, 176400.0, 192000.0};
+       if (!pa_initialize()) return -1;
 
-       if (!initialize_pa()) return -1;
+#ifdef WITH_ASIO
+       if (get_current_host_api_type() == paASIO) {
+               get_default_sample_rates(sampleRates);
+               return 0;
+       }
+#endif
 
        // TODO use  separate int device_input, int device_output ?!
-       if (device_id == -1) {
+       if (device_id == DeviceDefault) {
                device_id = get_default_input_device ();
        }
 
@@ -139,20 +145,23 @@ PortAudioIO::available_sample_rates(int device_id, std::vector<float>& sampleRat
                outputParam.suggestedLatency = 0;
                outputParam.hostApiSpecificStreamInfo = 0;
 
-               for (uint32_t i = 0; i < sizeof(ardourRates)/sizeof(float); ++i) {
-                       if (paFormatIsSupported == Pa_IsFormatSupported(
-                                               nfo->maxInputChannels > 0 ? &inputParam : NULL,
-                                               nfo->maxOutputChannels > 0 ? &outputParam : NULL,
-                                               ardourRates[i])) {
-                               sampleRates.push_back (ardourRates[i]);
+               std::vector<float> rates;
+               get_default_sample_rates(rates);
+
+               for (std::vector<float>::const_iterator i = rates.begin(); i != rates.end();
+                    ++i) {
+                       if (paFormatIsSupported ==
+                           Pa_IsFormatSupported(nfo->maxInputChannels > 0 ? &inputParam : NULL,
+                                                nfo->maxOutputChannels > 0 ? &outputParam : NULL,
+                                                *i)) {
+                               sampleRates.push_back(*i);
                        }
                }
        }
 
        if (sampleRates.empty()) {
                // fill in something..
-               sampleRates.push_back (44100.0);
-               sampleRates.push_back (48000.0);
+               get_default_sample_rates(sampleRates);
        }
 
        return 0;
@@ -175,15 +184,7 @@ PortAudioIO::get_asio_buffer_properties (int device_id,
                return false;
        }
 
-       const PaHostApiInfo* info = Pa_GetHostApiInfo (device_info->hostApi);
-
-       if (info == NULL) {
-               DEBUG_AUDIO (string_compose (
-                   "Unable to determine Host API from device index %1\n", device_id));
-               return false;
-       }
-
-       if (info->type != paASIO) {
+       if (get_current_host_api_type() != paASIO) {
                DEBUG_AUDIO (string_compose (
                    "ERROR device_id %1 is not an ASIO device\n", device_id));
                return false;
@@ -254,38 +255,30 @@ PortAudioIO::get_asio_buffer_sizes (int device_id, std::vector<uint32_t>& buffer
 }
 #endif
 
-bool
-PortAudioIO::get_default_buffer_sizes (int device_id, std::vector<uint32_t>& buffer_sizes)
+void
+PortAudioIO::get_default_buffer_sizes(std::vector<uint32_t>& buffer_sizes)
 {
-       static const uint32_t ardourSizes[] = { 64, 128, 256, 512, 1024, 2048, 4096 };
-       for(uint32_t i = 0; i < sizeof(ardourSizes)/sizeof(uint32_t); ++i) {
-               buffer_sizes.push_back (ardourSizes[i]);
-       }
-       return true;
+       buffer_sizes.push_back(64);
+       buffer_sizes.push_back(128);
+       buffer_sizes.push_back(256);
+       buffer_sizes.push_back(512);
+       buffer_sizes.push_back(1024);
+       buffer_sizes.push_back(2048);
+       buffer_sizes.push_back(4096);
 }
 
 int
 PortAudioIO::available_buffer_sizes(int device_id, std::vector<uint32_t>& buffer_sizes)
 {
 #ifdef WITH_ASIO
-       const PaHostApiInfo* info = Pa_GetHostApiInfo (_host_api_index);
-
-       if (info == NULL) {
-               DEBUG_AUDIO (string_compose ("Unable to determine Host API from index %1\n",
-                                            _host_api_index));
-               return -1;
-       }
-
-       PaHostApiTypeId type_id = info->type;
-
-       if (type_id == paASIO) {
+       if (get_current_host_api_type() == paASIO) {
                if (get_asio_buffer_sizes (device_id, buffer_sizes)) {
                        return 0;
                }
        }
 #endif
 
-       get_default_buffer_sizes (device_id, buffer_sizes);
+       get_default_buffer_sizes (buffer_sizes);
 
        return 0;
 }
@@ -310,26 +303,44 @@ PortAudioIO::output_device_list(std::map<int, std::string> &devices) const
        }
 }
 
+bool&
+PortAudioIO::pa_initialized()
+{
+       static bool s_initialized = false;
+       return s_initialized;
+}
+
 bool
-PortAudioIO::initialize_pa ()
+PortAudioIO::pa_initialize()
 {
-       PaError err = paNoError;
+       if (pa_initialized()) return true;
 
-       if (!_initialized) {
-               err = Pa_Initialize();
-               if (err != paNoError) {
-                       return false;
-               }
-               _initialized = true;
+       PaError err = Pa_Initialize();
+       if (err != paNoError) {
+               return false;
        }
+       pa_initialized() = true;
 
        return true;
 }
 
+bool
+PortAudioIO::pa_deinitialize()
+{
+       if (!pa_initialized()) return true;
+
+       PaError err = Pa_Terminate();
+       if (err != paNoError) {
+               return false;
+       }
+       pa_initialized() = false;
+       return true;
+}
+
 void
 PortAudioIO::host_api_list (std::vector<std::string>& api_list)
 {
-       if (!initialize_pa()) return;
+       if (!pa_initialize()) return;
 
        PaHostApiIndex count = Pa_GetHostApiCount();
 
@@ -343,6 +354,29 @@ PortAudioIO::host_api_list (std::vector<std::string>& api_list)
        }
 }
 
+
+PaHostApiTypeId
+PortAudioIO::get_current_host_api_type () const
+{
+       const PaHostApiInfo* info = Pa_GetHostApiInfo (_host_api_index);
+
+       if (info == NULL) {
+               DEBUG_AUDIO(string_compose(
+                   "Unable to determine Host API type from index %1\n", _host_api_index));
+               return (PaHostApiTypeId)0;
+       }
+
+       return info->type;
+}
+
+std::string
+PortAudioIO::get_host_api_name_from_index (PaHostApiIndex index)
+{
+       std::vector<std::string> api_list;
+       host_api_list(api_list);
+       return api_list[index];
+}
+
 bool
 PortAudioIO::set_host_api (const std::string& host_api_name)
 {
@@ -360,7 +394,7 @@ PortAudioIO::set_host_api (const std::string& host_api_name)
 PaHostApiIndex
 PortAudioIO::get_host_api_index_from_name (const std::string& name)
 {
-       if (!initialize_pa()) return -1;
+       if (!pa_initialize()) return -1;
 
        PaHostApiIndex count = Pa_GetHostApiCount();
 
@@ -383,7 +417,7 @@ PortAudioIO::get_host_api_index_from_name (const std::string& name)
 }
 
 PaDeviceIndex
-PortAudioIO::get_default_input_device ()
+PortAudioIO::get_default_input_device () const
 {
        const PaHostApiInfo* info = Pa_GetHostApiInfo (_host_api_index);
        if (info == NULL) return -1;
@@ -391,7 +425,7 @@ PortAudioIO::get_default_input_device ()
 }
 
 PaDeviceIndex
-PortAudioIO::get_default_output_device ()
+PortAudioIO::get_default_output_device () const
 {
        const PaHostApiInfo* info = Pa_GetHostApiInfo (_host_api_index);
        if (info == NULL) return -1;
@@ -412,6 +446,15 @@ PortAudioIO::clear_device_lists ()
        _output_devices.clear();
 }
 
+void
+PortAudioIO::add_none_devices ()
+{
+       _input_devices.insert(std::pair<int, paDevice*>(
+           DeviceNone, new paDevice(AudioBackend::get_standard_device_name(AudioBackend::DeviceNone), 0, 0)));
+       _output_devices.insert(std::pair<int, paDevice*>(
+           DeviceNone, new paDevice(AudioBackend::get_standard_device_name(AudioBackend::DeviceNone), 0, 0)));
+}
+
 void
 PortAudioIO::add_default_devices ()
 {
@@ -421,13 +464,13 @@ PortAudioIO::add_default_devices ()
        const PaDeviceInfo* nfo_i = Pa_GetDeviceInfo(get_default_input_device());
        const PaDeviceInfo* nfo_o = Pa_GetDeviceInfo(get_default_output_device());
        if (nfo_i && nfo_o) {
-               _input_devices.insert (std::pair<int, paDevice*> (-1,
-                                       new paDevice("Default",
+               _input_devices.insert (std::pair<int, paDevice*> (DeviceDefault,
+                                       new paDevice(AudioBackend::get_standard_device_name(AudioBackend::DeviceDefault),
                                                nfo_i->maxInputChannels,
                                                nfo_o->maxOutputChannels
                                                )));
-               _output_devices.insert (std::pair<int, paDevice*> (-1,
-                                       new paDevice("Default",
+               _output_devices.insert (std::pair<int, paDevice*> (DeviceDefault,
+                                       new paDevice(AudioBackend::get_standard_device_name(AudioBackend::DeviceDefault),
                                                nfo_i->maxInputChannels,
                                                nfo_o->maxOutputChannels
                                                )));
@@ -488,13 +531,23 @@ void
 PortAudioIO::discover()
 {
        DEBUG_AUDIO ("PortAudio: discover\n");
-       if (!initialize_pa()) return;
+       if (!pa_initialize()) return;
 
        clear_device_lists ();
-       add_default_devices ();
+       add_none_devices ();
        add_devices ();
 }
 
+void
+PortAudioIO::reset_stream_dependents ()
+{
+       _capture_channels = 0;
+       _playback_channels = 0;
+       _cur_sample_rate = 0;
+       _cur_input_latency = 0;
+       _cur_output_latency = 0;
+}
+
 void
 PortAudioIO::pcm_stop ()
 {
@@ -503,15 +556,10 @@ PortAudioIO::pcm_stop ()
        }
        _stream = NULL;
 
-       _capture_channels = 0;
-       _playback_channels = 0;
-       _cur_sample_rate = 0;
-       _cur_input_latency = 0;
-       _cur_output_latency = 0;
+       reset_stream_dependents();
 
        free (_input_buffer); _input_buffer = NULL;
        free (_output_buffer); _output_buffer = NULL;
-       _state = -1;
 }
 
 int
@@ -520,126 +568,183 @@ PortAudioIO::pcm_start()
        PaError err = Pa_StartStream (_stream);
 
        if (err != paNoError) {
-               _state = -1;
                return -1;
        }
        return 0;
 }
 
-#ifdef __APPLE__
-static uint32_t lower_power_of_two (uint32_t v) {
-       v--;
-       v |= v >> 1;
-       v |= v >> 2;
-       v |= v >> 4;
-       v |= v >> 8;
-       v |= v >> 16;
-       v++;
-       return v >> 1;
+bool
+PortAudioIO::set_sample_rate_and_latency_from_stream ()
+{
+       const PaStreamInfo* nfo_s = Pa_GetStreamInfo(_stream);
+
+       if (nfo_s == NULL) {
+               return false;
+       }
+
+       _cur_sample_rate = nfo_s->sampleRate;
+       _cur_input_latency = nfo_s->inputLatency * _cur_sample_rate;
+       _cur_output_latency = nfo_s->outputLatency * _cur_sample_rate;
+
+       DEBUG_AUDIO (string_compose ("PA Sample Rate %1 SPS\n", _cur_sample_rate));
+
+       DEBUG_AUDIO (string_compose ("PA Input Latency %1ms, %2 spl\n",
+                                    1e3 * nfo_s->inputLatency,
+                                    _cur_input_latency));
+
+       DEBUG_AUDIO (string_compose ("PA Output Latency %1ms, %2 spl\n",
+                                    1e3 * nfo_s->outputLatency,
+                                    _cur_output_latency));
+       return true;
 }
-#endif
 
-int
-PortAudioIO::pcm_setup (
-               int device_input, int device_output,
-               double sample_rate, uint32_t samples_per_period)
+bool
+PortAudioIO::allocate_buffers_for_blocking_api (uint32_t samples_per_period)
 {
-       _state = -2;
+       if (_capture_channels > 0) {
+               _input_buffer =
+                   (float*)malloc(samples_per_period * _capture_channels * sizeof(float));
+               if (!_input_buffer) {
+                       DEBUG_AUDIO("PortAudio failed to allocate input buffer.\n");
+                       return false;
+               }
+       }
 
-       PaError err = paNoError;
-       const PaDeviceInfo *nfo_in;
-       const PaDeviceInfo *nfo_out;
-       const PaStreamInfo *nfo_s;
-               
-       if (!initialize_pa()) {
-               DEBUG_AUDIO ("PortAudio Initialization Failed\n");
-               goto error;
+       if (_playback_channels > 0) {
+               _output_buffer =
+                   (float*)calloc(samples_per_period * _playback_channels, sizeof(float));
+               if (!_output_buffer) {
+                       DEBUG_AUDIO("PortAudio failed to allocate output buffer.\n");
+                       return false;
+               }
        }
+       return true;
+}
+
+bool
+PortAudioIO::get_input_stream_params(int device_input,
+                                     PaStreamParameters& inputParam) const
+{
+       const PaDeviceInfo *nfo_in = NULL;
 
-       if (device_input == -1) {
+       if (device_input == DeviceDefault) {
                device_input = get_default_input_device ();
        }
-       if (device_output == -1) {
-               device_output = get_default_output_device ();
+
+       if (device_input == DeviceNone) {
+               return false;
        }
 
-       _capture_channels = 0;
-       _playback_channels = 0;
-       _cur_sample_rate = 0;
-       _cur_input_latency = 0;
-       _cur_output_latency = 0;
+       nfo_in = Pa_GetDeviceInfo(device_input);
 
-       DEBUG_AUDIO (string_compose (
-           "PortAudio Device IDs: i:%1 o:%2\n", device_input, device_output));
+       if (nfo_in == NULL) {
+               DEBUG_AUDIO ("PortAudio Cannot Query Input Device Info\n");
+               return false;
+       }
+
+       inputParam.device = device_input;
+       inputParam.channelCount = nfo_in->maxInputChannels;
+#ifdef INTERLEAVED_INPUT
+       inputParam.sampleFormat = paFloat32;
+#else
+       inputParam.sampleFormat = paFloat32 | paNonInterleaved;
+#endif
+       inputParam.suggestedLatency = nfo_in->defaultLowInputLatency;
+       inputParam.hostApiSpecificStreamInfo = NULL;
+
+       return true;
+}
+
+bool
+PortAudioIO::get_output_stream_params(int device_output,
+                                      PaStreamParameters& outputParam) const
+{
+       const PaDeviceInfo *nfo_out = NULL;
+
+       if (device_output == DeviceDefault) {
+               device_output = get_default_output_device ();
+       }
+
+       if (device_output == DeviceNone) {
+               return false;
+       }
 
-       nfo_in = Pa_GetDeviceInfo(device_input);
        nfo_out = Pa_GetDeviceInfo(device_output);
 
-       if (!nfo_in && ! nfo_out) {
-               DEBUG_AUDIO ("PortAudio Cannot Query Device Info\n");
-               goto error;
+       if (nfo_out == NULL) {
+               DEBUG_AUDIO ("PortAudio Cannot Query Output Device Info\n");
+               return false;
        }
 
-       if (nfo_in) {
-               _capture_channels = nfo_in->maxInputChannels;
+       outputParam.device = device_output;
+       outputParam.channelCount = nfo_out->maxOutputChannels;
+#ifdef INTERLEAVED_OUTPUT
+       outputParam.sampleFormat = paFloat32;
+#else
+       outputParam.sampleFormat = paFloat32 | paNonInterleaved;
+#endif
+       outputParam.suggestedLatency = nfo_out->defaultLowOutputLatency;
+       outputParam.hostApiSpecificStreamInfo = NULL;
+
+       return true;
+}
+
+PortAudioIO::ErrorCode
+PortAudioIO::pre_stream_open(int device_input,
+                             PaStreamParameters& inputParam,
+                             int device_output,
+                             PaStreamParameters& outputParam)
+{
+       if (!pa_initialize()) {
+               DEBUG_AUDIO ("PortAudio Initialization Failed\n");
+               return InitializationError;
        }
-       if (nfo_out) {
-               _playback_channels = nfo_out->maxOutputChannels;
+
+       reset_stream_dependents ();
+
+       DEBUG_AUDIO (string_compose (
+           "PortAudio Device IDs: i:%1 o:%2\n", device_input, device_output));
+
+       if (device_input == DeviceNone && device_output == DeviceNone) {
+               return DeviceConfigNotSupportedError;
        }
 
-       if(_capture_channels == 0 && _playback_channels == 0) {
-               DEBUG_AUDIO ("PortAudio no input or output channels.\n");
-               goto error;
+       if (get_input_stream_params(device_input, inputParam)) {
+               _capture_channels = inputParam.channelCount;
        }
 
-#ifdef __APPLE__
-       // pa_mac_core_blocking.c pa_stable_v19_20140130
-       // BUG: ringbuffer alloc requires power-of-two chn count.
-       if ((_capture_channels & (_capture_channels - 1)) != 0) {
-               DEBUG_AUDIO (
-                   "Adjusted capture channels to power of two (portaudio rb bug)\n");
-               _capture_channels = lower_power_of_two (_capture_channels);
+       if (get_output_stream_params(device_output, outputParam)) {
+               _playback_channels = outputParam.channelCount;
        }
 
-       if ((_playback_channels & (_playback_channels - 1)) != 0) {
-               DEBUG_AUDIO (
-                   "Adjusted capture channels to power of two (portaudio rb bug)\n");
-               _playback_channels = lower_power_of_two (_playback_channels);
+       if (_capture_channels == 0 && _playback_channels == 0) {
+               DEBUG_AUDIO("PortAudio no input or output channels.\n");
+               return DeviceConfigNotSupportedError;
        }
-#endif
 
        DEBUG_AUDIO (string_compose ("PortAudio Channels: in:%1 out:%2\n",
                                     _capture_channels,
                                     _playback_channels));
 
+       return NoError;
+}
+
+PortAudioIO::ErrorCode
+PortAudioIO::pcm_setup(int device_input,
+                       int device_output,
+                       double sample_rate,
+                       uint32_t samples_per_period)
+{
        PaStreamParameters inputParam;
        PaStreamParameters outputParam;
 
-       if (nfo_in) {
-               inputParam.device = device_input;
-               inputParam.channelCount = _capture_channels;
-#ifdef INTERLEAVED_INPUT
-               inputParam.sampleFormat = paFloat32;
-#else
-               inputParam.sampleFormat = paFloat32 | paNonInterleaved;
-#endif
-               inputParam.suggestedLatency = nfo_in->defaultLowInputLatency;
-               inputParam.hostApiSpecificStreamInfo = NULL;
-       }
+       ErrorCode error_code =
+           pre_stream_open(device_input, inputParam, device_output, outputParam);
 
-       if (nfo_out) {
-               outputParam.device = device_output;
-               outputParam.channelCount = _playback_channels;
-#ifdef INTERLEAVED_OUTPUT
-               outputParam.sampleFormat = paFloat32;
-#else
-               outputParam.sampleFormat = paFloat32 | paNonInterleaved;
-#endif
-               outputParam.suggestedLatency = nfo_out->defaultLowOutputLatency;
-               outputParam.hostApiSpecificStreamInfo = NULL;
-       }
+       if (error_code != NoError) return error_code;
+
+       PaError err = paNoError;
 
-       // XXX re-consider using callback API, testing needed.
        err = Pa_OpenStream (
                        &_stream,
                        _capture_channels > 0 ? &inputParam: NULL,
@@ -651,58 +756,20 @@ PortAudioIO::pcm_setup (
 
        if (err != paNoError) {
                DEBUG_AUDIO ("PortAudio failed to start stream.\n");
-               goto error;
+               return StreamOpenError;
        }
 
-       nfo_s = Pa_GetStreamInfo (_stream);
-       if (!nfo_s) {
+       if (!set_sample_rate_and_latency_from_stream()) {
                DEBUG_AUDIO ("PortAudio failed to query stream information.\n");
                pcm_stop();
-               goto error;
-       }
-
-       _cur_sample_rate = nfo_s->sampleRate;
-       _cur_input_latency = nfo_s->inputLatency * _cur_sample_rate;
-       _cur_output_latency = nfo_s->outputLatency * _cur_sample_rate;
-
-       DEBUG_AUDIO (string_compose ("PA Sample Rate %1 SPS\n", _cur_sample_rate));
-
-       DEBUG_AUDIO (string_compose ("PA Input Latency %1ms, %2 spl\n",
-                                    1e3 * nfo_s->inputLatency,
-                                    _cur_input_latency));
-
-       DEBUG_AUDIO (string_compose ("PA Output Latency %1ms, %2 spl\n",
-                                    1e3 * nfo_s->outputLatency,
-                                    _cur_output_latency));
-
-       _state = 0;
-
-       if (_capture_channels > 0) {
-               _input_buffer = (float*) malloc (samples_per_period * _capture_channels * sizeof(float));
-               if (!_input_buffer) {
-                       DEBUG_AUDIO ("PortAudio failed to allocate input buffer.\n");
-                       pcm_stop();
-                       goto error;
-               }
+               return StreamOpenError;
        }
 
-       if (_playback_channels > 0) {
-               _output_buffer = (float*) calloc (samples_per_period * _playback_channels, sizeof(float));
-               if (!_output_buffer) {
-                       DEBUG_AUDIO ("PortAudio failed to allocate output buffer.\n");
-                       pcm_stop();
-                       goto error;
-               }
+       if (!allocate_buffers_for_blocking_api(samples_per_period)) {
+               pcm_stop();
+               return StreamOpenError;
        }
-
-       return 0;
-
-error:
-       _capture_channels = 0;
-       _playback_channels = 0;
-       free (_input_buffer); _input_buffer = NULL;
-       free (_output_buffer); _output_buffer = NULL;
-       return -1;
+       return NoError;
 }
 
 int