src/media/base/audio_buffer.cc

   1 // Copyright 2013 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/base/audio_buffer.h"
   6
   7 #include "base/logging.h"
   8 #include "media/base/audio_bus.h"
   9 #include "media/base/buffers.h"
  10 #include "media/base/limits.h"
  11
  12 namespace media {
  13
  14 static base::TimeDelta CalculateDuration(int frames, double sample_rate) {
  15   DCHECK_GT(sample_rate, 0);
  16   return base::TimeDelta::FromMicroseconds(
  17       frames * base::Time::kMicrosecondsPerSecond / sample_rate);
  18 }
  19
  20 AudioBuffer::AudioBuffer(SampleFormat sample_format,
  21                          ChannelLayout channel_layout,
  22                          int channel_count,
  23                          int sample_rate,
  24                          int frame_count,
  25                          bool create_buffer,
  26                          const uint8* const* data,
  27                          const base::TimeDelta timestamp)
  28     : sample_format_(sample_format),
  29       channel_layout_(channel_layout),
  30       channel_count_(channel_count),
  31       sample_rate_(sample_rate),
  32       adjusted_frame_count_(frame_count),
  33       trim_start_(0),
  34       end_of_stream_(!create_buffer && data == NULL && frame_count == 0),
  35       timestamp_(timestamp),
  36       duration_(end_of_stream_
  37                     ? base::TimeDelta()
  38                     : CalculateDuration(adjusted_frame_count_, sample_rate_)) {
  39   CHECK_GE(channel_count_, 0);
  40   CHECK_LE(channel_count_, limits::kMaxChannels);
  41   CHECK_GE(frame_count, 0);
  42   DCHECK(channel_layout == CHANNEL_LAYOUT_DISCRETE ||
  43          ChannelLayoutToChannelCount(channel_layout) == channel_count);
  44
  45   int bytes_per_channel = SampleFormatToBytesPerChannel(sample_format);
  46   DCHECK_LE(bytes_per_channel, kChannelAlignment);
  47   int data_size = frame_count * bytes_per_channel;
  48
  49   // Empty buffer?
  50   if (!create_buffer)
  51     return;
  52
  53   if (sample_format == kSampleFormatPlanarF32 ||
  54       sample_format == kSampleFormatPlanarS16) {
  55     // Planar data, so need to allocate buffer for each channel.
  56     // Determine per channel data size, taking into account alignment.
  57     int block_size_per_channel =
  58         (data_size + kChannelAlignment - 1) & ~(kChannelAlignment - 1);
  59     DCHECK_GE(block_size_per_channel, data_size);
  60
  61     // Allocate a contiguous buffer for all the channel data.
  62     data_.reset(static_cast<uint8*>(base::AlignedAlloc(
  63         channel_count_ * block_size_per_channel, kChannelAlignment)));
  64     channel_data_.reserve(channel_count_);
  65
  66     // Copy each channel's data into the appropriate spot.
  67     for (int i = 0; i < channel_count_; ++i) {
  68       channel_data_.push_back(data_.get() + i * block_size_per_channel);
  69       if (data)
  70         memcpy(channel_data_[i], data[i], data_size);
  71     }
  72     return;
  73   }
  74
  75   // Remaining formats are interleaved data.
  76   DCHECK(sample_format_ == kSampleFormatU8 ||
  77          sample_format_ == kSampleFormatS16 ||
  78          sample_format_ == kSampleFormatS32 ||
  79          sample_format_ == kSampleFormatF32) << sample_format_;
  80   // Allocate our own buffer and copy the supplied data into it. Buffer must
  81   // contain the data for all channels.
  82   data_size *= channel_count_;
  83   data_.reset(
  84       static_cast<uint8*>(base::AlignedAlloc(data_size, kChannelAlignment)));
  85   channel_data_.reserve(1);
  86   channel_data_.push_back(data_.get());
  87   if (data)
  88     memcpy(data_.get(), data[0], data_size);
  89 }
  90
  91 AudioBuffer::~AudioBuffer() {}
  92
  93 // static
  94 scoped_refptr<AudioBuffer> AudioBuffer::CopyFrom(
  95     SampleFormat sample_format,
  96     ChannelLayout channel_layout,
  97     int channel_count,
  98     int sample_rate,
  99     int frame_count,
 100     const uint8* const* data,
 101     const base::TimeDelta timestamp) {
 102   // If you hit this CHECK you likely have a bug in a demuxer. Go fix it.
 103   CHECK_GT(frame_count, 0);  // Otherwise looks like an EOF buffer.
 104   CHECK(data[0]);
 105   return make_scoped_refptr(new AudioBuffer(sample_format,
 106                                             channel_layout,
 107                                             channel_count,
 108                                             sample_rate,
 109                                             frame_count,
 110                                             true,
 111                                             data,
 112                                             timestamp));
 113 }
 114
 115 // static
 116 scoped_refptr<AudioBuffer> AudioBuffer::CreateBuffer(
 117     SampleFormat sample_format,
 118     ChannelLayout channel_layout,
 119     int channel_count,
 120     int sample_rate,
 121     int frame_count) {
 122   CHECK_GT(frame_count, 0);  // Otherwise looks like an EOF buffer.
 123   return make_scoped_refptr(new AudioBuffer(sample_format,
 124                                             channel_layout,
 125                                             channel_count,
 126                                             sample_rate,
 127                                             frame_count,
 128                                             true,
 129                                             NULL,
 130                                             kNoTimestamp()));
 131 }
 132
 133 // static
 134 scoped_refptr<AudioBuffer> AudioBuffer::CreateEmptyBuffer(
 135     ChannelLayout channel_layout,
 136     int channel_count,
 137     int sample_rate,
 138     int frame_count,
 139     const base::TimeDelta timestamp) {
 140   CHECK_GT(frame_count, 0);  // Otherwise looks like an EOF buffer.
 141   // Since data == NULL, format doesn't matter.
 142   return make_scoped_refptr(new AudioBuffer(kSampleFormatF32,
 143                                             channel_layout,
 144                                             channel_count,
 145                                             sample_rate,
 146                                             frame_count,
 147                                             false,
 148                                             NULL,
 149                                             timestamp));
 150 }
 151
 152 // static
 153 scoped_refptr<AudioBuffer> AudioBuffer::CreateEOSBuffer() {
 154   return make_scoped_refptr(new AudioBuffer(kUnknownSampleFormat,
 155                                             CHANNEL_LAYOUT_NONE,
 156                                             0,
 157                                             0,
 158                                             0,
 159                                             false,
 160                                             NULL,
 161                                             kNoTimestamp()));
 162 }
 163
 164 // Convert int16 values in the range [kint16min, kint16max] to [-1.0, 1.0].
 165 static inline float ConvertS16ToFloat(int16 value) {
 166   return value * (value < 0 ? -1.0f / kint16min : 1.0f / kint16max);
 167 }
 168
 169 void AudioBuffer::ReadFrames(int frames_to_copy,
 170                              int source_frame_offset,
 171                              int dest_frame_offset,
 172                              AudioBus* dest) {
 173   // Deinterleave each channel (if necessary) and convert to 32bit
 174   // floating-point with nominal range -1.0 -> +1.0 (if necessary).
 175
 176   // |dest| must have the same number of channels, and the number of frames
 177   // specified must be in range.
 178   DCHECK(!end_of_stream());
 179   DCHECK_EQ(dest->channels(), channel_count_);
 180   DCHECK_LE(source_frame_offset + frames_to_copy, adjusted_frame_count_);
 181   DCHECK_LE(dest_frame_offset + frames_to_copy, dest->frames());
 182
 183   // Move the start past any frames that have been trimmed.
 184   source_frame_offset += trim_start_;
 185
 186   if (!data_) {
 187     // Special case for an empty buffer.
 188     dest->ZeroFramesPartial(dest_frame_offset, frames_to_copy);
 189     return;
 190   }
 191
 192   if (sample_format_ == kSampleFormatPlanarF32) {
 193     // Format is planar float32. Copy the data from each channel as a block.
 194     for (int ch = 0; ch < channel_count_; ++ch) {
 195       const float* source_data =
 196           reinterpret_cast<const float*>(channel_data_[ch]) +
 197           source_frame_offset;
 198       memcpy(dest->channel(ch) + dest_frame_offset,
 199              source_data,
 200              sizeof(float) * frames_to_copy);
 201     }
 202     return;
 203   }
 204
 205   if (sample_format_ == kSampleFormatPlanarS16) {
 206     // Format is planar signed16. Convert each value into float and insert into
 207     // output channel data.
 208     for (int ch = 0; ch < channel_count_; ++ch) {
 209       const int16* source_data =
 210           reinterpret_cast<const int16*>(channel_data_[ch]) +
 211           source_frame_offset;
 212       float* dest_data = dest->channel(ch) + dest_frame_offset;
 213       for (int i = 0; i < frames_to_copy; ++i) {
 214         dest_data[i] = ConvertS16ToFloat(source_data[i]);
 215       }
 216     }
 217     return;
 218   }
 219
 220   if (sample_format_ == kSampleFormatF32) {
 221     // Format is interleaved float32. Copy the data into each channel.
 222     const float* source_data = reinterpret_cast<const float*>(data_.get()) +
 223                                source_frame_offset * channel_count_;
 224     for (int ch = 0; ch < channel_count_; ++ch) {
 225       float* dest_data = dest->channel(ch) + dest_frame_offset;
 226       for (int i = 0, offset = ch; i < frames_to_copy;
 227            ++i, offset += channel_count_) {
 228         dest_data[i] = source_data[offset];
 229       }
 230     }
 231     return;
 232   }
 233
 234   // Remaining formats are integer interleaved data. Use the deinterleaving code
 235   // in AudioBus to copy the data.
 236   DCHECK(sample_format_ == kSampleFormatU8 ||
 237          sample_format_ == kSampleFormatS16 ||
 238          sample_format_ == kSampleFormatS32);
 239   int bytes_per_channel = SampleFormatToBytesPerChannel(sample_format_);
 240   int frame_size = channel_count_ * bytes_per_channel;
 241   const uint8* source_data = data_.get() + source_frame_offset * frame_size;
 242   dest->FromInterleavedPartial(
 243       source_data, dest_frame_offset, frames_to_copy, bytes_per_channel);
 244 }
 245
 246 void AudioBuffer::TrimStart(int frames_to_trim) {
 247   CHECK_GE(frames_to_trim, 0);
 248   CHECK_LE(frames_to_trim, adjusted_frame_count_);
 249
 250   // Adjust the number of frames in this buffer and where the start really is.
 251   adjusted_frame_count_ -= frames_to_trim;
 252   trim_start_ += frames_to_trim;
 253
 254   // Adjust timestamp_ and duration_ to reflect the smaller number of frames.
 255   const base::TimeDelta old_duration = duration_;
 256   duration_ = CalculateDuration(adjusted_frame_count_, sample_rate_);
 257   timestamp_ += old_duration - duration_;
 258 }
 259
 260 void AudioBuffer::TrimEnd(int frames_to_trim) {
 261   CHECK_GE(frames_to_trim, 0);
 262   CHECK_LE(frames_to_trim, adjusted_frame_count_);
 263
 264   // Adjust the number of frames and duration for this buffer.
 265   adjusted_frame_count_ -= frames_to_trim;
 266   duration_ = CalculateDuration(adjusted_frame_count_, sample_rate_);
 267 }
 268
 269 void AudioBuffer::TrimRange(int start, int end) {
 270   CHECK_GE(start, 0);
 271   CHECK_LE(end, adjusted_frame_count_);
 272
 273   const int frames_to_trim = end - start;
 274   CHECK_GE(frames_to_trim, 0);
 275   CHECK_LE(frames_to_trim, adjusted_frame_count_);
 276
 277   const int bytes_per_channel = SampleFormatToBytesPerChannel(sample_format_);
 278   const int frames_to_copy = adjusted_frame_count_ - end;
 279   if (frames_to_copy > 0) {
 280     switch (sample_format_) {
 281       case kSampleFormatPlanarS16:
 282       case kSampleFormatPlanarF32:
 283         // Planar data must be shifted per channel.
 284         for (int ch = 0; ch < channel_count_; ++ch) {
 285           memmove(channel_data_[ch] + (trim_start_ + start) * bytes_per_channel,
 286                   channel_data_[ch] + (trim_start_ + end) * bytes_per_channel,
 287                   bytes_per_channel * frames_to_copy);
 288         }
 289         break;
 290       case kSampleFormatU8:
 291       case kSampleFormatS16:
 292       case kSampleFormatS32:
 293       case kSampleFormatF32: {
 294         // Interleaved data can be shifted all at once.
 295         const int frame_size = channel_count_ * bytes_per_channel;
 296         memmove(channel_data_[0] + (trim_start_ + start) * frame_size,
 297                 channel_data_[0] + (trim_start_ + end) * frame_size,
 298                 frame_size * frames_to_copy);
 299         break;
 300       }
 301       case kUnknownSampleFormat:
 302         NOTREACHED() << "Invalid sample format!";
 303     }
 304   } else {
 305     CHECK_EQ(frames_to_copy, 0);
 306   }
 307
 308   // Trim the leftover data off the end of the buffer and update duration.
 309   TrimEnd(frames_to_trim);
 310 }
 311
 312 }  // namespace media