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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "media/audio/cras/cras_input.h"
      6 
      7 #include <math.h>
      8 
      9 #include "base/basictypes.h"
     10 #include "base/logging.h"
     11 #include "base/time/time.h"
     12 #include "media/audio/audio_manager.h"
     13 #include "media/audio/cras/audio_manager_cras.h"
     14 
     15 namespace media {
     16 
     17 CrasInputStream::CrasInputStream(const AudioParameters& params,
     18                                  AudioManagerCras* manager,
     19                                  const std::string& device_id)
     20     : audio_manager_(manager),
     21       bytes_per_frame_(0),
     22       callback_(NULL),
     23       client_(NULL),
     24       params_(params),
     25       started_(false),
     26       stream_id_(0),
     27       stream_direction_(device_id == AudioManagerBase::kLoopbackInputDeviceId ?
     28                             CRAS_STREAM_POST_MIX_PRE_DSP : CRAS_STREAM_INPUT) {
     29   DCHECK(audio_manager_);
     30   audio_bus_ = AudioBus::Create(params_);
     31 }
     32 
     33 CrasInputStream::~CrasInputStream() {
     34   DCHECK(!client_);
     35 }
     36 
     37 bool CrasInputStream::Open() {
     38   if (client_) {
     39     NOTREACHED() << "CrasInputStream already open";
     40     return false;  // Already open.
     41   }
     42 
     43   // Sanity check input values.
     44   if (params_.sample_rate() <= 0) {
     45     DLOG(WARNING) << "Unsupported audio frequency.";
     46     return false;
     47   }
     48 
     49   if (AudioParameters::AUDIO_PCM_LINEAR != params_.format() &&
     50       AudioParameters::AUDIO_PCM_LOW_LATENCY != params_.format()) {
     51     DLOG(WARNING) << "Unsupported audio format.";
     52     return false;
     53   }
     54 
     55   snd_pcm_format_t pcm_format =
     56       AudioManagerCras::BitsToFormat(params_.bits_per_sample());
     57   if (pcm_format == SND_PCM_FORMAT_UNKNOWN) {
     58     DLOG(WARNING) << "Unsupported bits/sample: " << params_.bits_per_sample();
     59     return false;
     60   }
     61 
     62   // Create the client and connect to the CRAS server.
     63   if (cras_client_create(&client_) < 0) {
     64     DLOG(WARNING) << "Couldn't create CRAS client.\n";
     65     client_ = NULL;
     66     return false;
     67   }
     68 
     69   if (cras_client_connect(client_)) {
     70     DLOG(WARNING) << "Couldn't connect CRAS client.\n";
     71     cras_client_destroy(client_);
     72     client_ = NULL;
     73     return false;
     74   }
     75 
     76   // Then start running the client.
     77   if (cras_client_run_thread(client_)) {
     78     DLOG(WARNING) << "Couldn't run CRAS client.\n";
     79     cras_client_destroy(client_);
     80     client_ = NULL;
     81     return false;
     82   }
     83 
     84   return true;
     85 }
     86 
     87 void CrasInputStream::Close() {
     88   Stop();
     89 
     90   if (client_) {
     91     cras_client_stop(client_);
     92     cras_client_destroy(client_);
     93     client_ = NULL;
     94   }
     95 
     96   // Signal to the manager that we're closed and can be removed.
     97   // Should be last call in the method as it deletes "this".
     98   audio_manager_->ReleaseInputStream(this);
     99 }
    100 
    101 void CrasInputStream::Start(AudioInputCallback* callback) {
    102   DCHECK(client_);
    103   DCHECK(callback);
    104 
    105   // If already playing, stop before re-starting.
    106   if (started_)
    107     return;
    108 
    109   StartAgc();
    110 
    111   callback_ = callback;
    112 
    113   // Prepare |audio_format| and |stream_params| for the stream we
    114   // will create.
    115   cras_audio_format* audio_format = cras_audio_format_create(
    116       AudioManagerCras::BitsToFormat(params_.bits_per_sample()),
    117       params_.sample_rate(),
    118       params_.channels());
    119   if (!audio_format) {
    120     DLOG(WARNING) << "Error setting up audio parameters.";
    121     callback_->OnError(this);
    122     callback_ = NULL;
    123     return;
    124   }
    125 
    126   unsigned int frames_per_packet = params_.frames_per_buffer();
    127   cras_stream_params* stream_params = cras_client_stream_params_create(
    128       stream_direction_,
    129       frames_per_packet,  // Total latency.
    130       frames_per_packet,  // Call back when this many ready.
    131       frames_per_packet,  // Minimum Callback level ignored for capture streams.
    132       CRAS_STREAM_TYPE_DEFAULT,
    133       0,  // Unused flags.
    134       this,
    135       CrasInputStream::SamplesReady,
    136       CrasInputStream::StreamError,
    137       audio_format);
    138   if (!stream_params) {
    139     DLOG(WARNING) << "Error setting up stream parameters.";
    140     callback_->OnError(this);
    141     callback_ = NULL;
    142     cras_audio_format_destroy(audio_format);
    143     return;
    144   }
    145 
    146   // Before starting the stream, save the number of bytes in a frame for use in
    147   // the callback.
    148   bytes_per_frame_ = cras_client_format_bytes_per_frame(audio_format);
    149 
    150   // Adding the stream will start the audio callbacks.
    151   if (cras_client_add_stream(client_, &stream_id_, stream_params)) {
    152     DLOG(WARNING) << "Failed to add the stream.";
    153     callback_->OnError(this);
    154     callback_ = NULL;
    155   }
    156 
    157   // Done with config params.
    158   cras_audio_format_destroy(audio_format);
    159   cras_client_stream_params_destroy(stream_params);
    160 
    161   started_ = true;
    162 }
    163 
    164 void CrasInputStream::Stop() {
    165   DCHECK(client_);
    166 
    167   if (!callback_ || !started_)
    168     return;
    169 
    170   StopAgc();
    171 
    172   // Removing the stream from the client stops audio.
    173   cras_client_rm_stream(client_, stream_id_);
    174 
    175   started_ = false;
    176   callback_ = NULL;
    177 }
    178 
    179 // Static callback asking for samples.  Run on high priority thread.
    180 int CrasInputStream::SamplesReady(cras_client* client,
    181                                   cras_stream_id_t stream_id,
    182                                   uint8* samples,
    183                                   size_t frames,
    184                                   const timespec* sample_ts,
    185                                   void* arg) {
    186   CrasInputStream* me = static_cast<CrasInputStream*>(arg);
    187   me->ReadAudio(frames, samples, sample_ts);
    188   return frames;
    189 }
    190 
    191 // Static callback for stream errors.
    192 int CrasInputStream::StreamError(cras_client* client,
    193                                  cras_stream_id_t stream_id,
    194                                  int err,
    195                                  void* arg) {
    196   CrasInputStream* me = static_cast<CrasInputStream*>(arg);
    197   me->NotifyStreamError(err);
    198   return 0;
    199 }
    200 
    201 void CrasInputStream::ReadAudio(size_t frames,
    202                                 uint8* buffer,
    203                                 const timespec* sample_ts) {
    204   DCHECK(callback_);
    205 
    206   timespec latency_ts = {0, 0};
    207 
    208   // Determine latency and pass that on to the sink.  sample_ts is the wall time
    209   // indicating when the first sample in the buffer was captured.  Convert that
    210   // to latency in bytes.
    211   cras_client_calc_capture_latency(sample_ts, &latency_ts);
    212   double latency_usec =
    213       latency_ts.tv_sec * base::Time::kMicrosecondsPerSecond +
    214       latency_ts.tv_nsec / base::Time::kNanosecondsPerMicrosecond;
    215   double frames_latency =
    216       latency_usec * params_.sample_rate() / base::Time::kMicrosecondsPerSecond;
    217   unsigned int bytes_latency =
    218       static_cast<unsigned int>(frames_latency * bytes_per_frame_);
    219 
    220   // Update the AGC volume level once every second. Note that, |volume| is
    221   // also updated each time SetVolume() is called through IPC by the
    222   // render-side AGC.
    223   double normalized_volume = 0.0;
    224   GetAgcVolume(&normalized_volume);
    225 
    226   audio_bus_->FromInterleaved(
    227       buffer, audio_bus_->frames(), params_.bits_per_sample() / 8);
    228   callback_->OnData(this, audio_bus_.get(), bytes_latency, normalized_volume);
    229 }
    230 
    231 void CrasInputStream::NotifyStreamError(int err) {
    232   if (callback_)
    233     callback_->OnError(this);
    234 }
    235 
    236 double CrasInputStream::GetMaxVolume() {
    237   DCHECK(client_);
    238 
    239   // Capture gain is returned as dB * 100 (150 => 1.5dBFS).  Convert the dB
    240   // value to a ratio before returning.
    241   double dB = cras_client_get_system_max_capture_gain(client_) / 100.0;
    242   return GetVolumeRatioFromDecibels(dB);
    243 }
    244 
    245 void CrasInputStream::SetVolume(double volume) {
    246   DCHECK(client_);
    247 
    248   // Convert from the passed volume ratio, to dB * 100.
    249   double dB = GetDecibelsFromVolumeRatio(volume);
    250   cras_client_set_system_capture_gain(client_, static_cast<long>(dB * 100.0));
    251 
    252   // Update the AGC volume level based on the last setting above. Note that,
    253   // the volume-level resolution is not infinite and it is therefore not
    254   // possible to assume that the volume provided as input parameter can be
    255   // used directly. Instead, a new query to the audio hardware is required.
    256   // This method does nothing if AGC is disabled.
    257   UpdateAgcVolume();
    258 }
    259 
    260 double CrasInputStream::GetVolume() {
    261   if (!client_)
    262     return 0.0;
    263 
    264   long dB = cras_client_get_system_capture_gain(client_) / 100.0;
    265   return GetVolumeRatioFromDecibels(dB);
    266 }
    267 
    268 double CrasInputStream::GetVolumeRatioFromDecibels(double dB) const {
    269   return pow(10, dB / 20.0);
    270 }
    271 
    272 double CrasInputStream::GetDecibelsFromVolumeRatio(double volume_ratio) const {
    273   return 20 * log10(volume_ratio);
    274 }
    275 
    276 }  // namespace media
    277