Expose SampleFormat -> bytes per frame calculations.

First part of converting audio streams to reduce copying the data.

BUG=248989

Review URL: https://chromiumcodereview.appspot.com/16404013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@205937 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 82 insertions, 47 deletions

diff --git a/media/base/audio_decoder_config.cc b/media/base/audio_decoder_config.cc
index a4e57c2..38db05d 100644
--- a/media/base/audio_decoder_config.cc
+++ b/media/base/audio_decoder_config.cc
@@ -8,34 +8,14 @@
 #include "base/metrics/histogram.h"
 #include "media/audio/sample_rates.h"
 #include "media/base/limits.h"
+#include "media/base/sample_format.h"
 
 namespace media {
 
-static int SampleFormatToBitsPerChannel(SampleFormat sample_format) {
-  switch (sample_format) {
-    case kUnknownSampleFormat:
-      return 0;
-    case kSampleFormatU8:
-      return 8;
-    case kSampleFormatS16:
-    case kSampleFormatPlanarS16:
-      return 16;
-    case kSampleFormatS32:
-    case kSampleFormatF32:
-    case kSampleFormatPlanarF32:
-      return 32;
-    case kSampleFormatMax:
-      break;
-  }
-
-  NOTREACHED() << "Invalid sample format provided: " << sample_format;
-  return 0;
-}
-
 AudioDecoderConfig::AudioDecoderConfig()
     : codec_(kUnknownAudioCodec),
       sample_format_(kUnknownSampleFormat),
-      bits_per_channel_(0),
+      bytes_per_channel_(0),
       channel_layout_(CHANNEL_LAYOUT_UNSUPPORTED),
       samples_per_second_(0),
       bytes_per_frame_(0),
@@ -83,12 +63,12 @@ void AudioDecoderConfig::Initialize(AudioCodec codec,
   channel_layout_ = channel_layout;
   samples_per_second_ = samples_per_second;
   sample_format_ = sample_format;
-  bits_per_channel_ = SampleFormatToBitsPerChannel(sample_format);
+  bytes_per_channel_ = SampleFormatToBytesPerChannel(sample_format);
   extra_data_.assign(extra_data, extra_data + extra_data_size);
   is_encrypted_ = is_encrypted;
 
   int channels = ChannelLayoutToChannelCount(channel_layout_);
-  bytes_per_frame_ = channels * bits_per_channel_ / 8;
+  bytes_per_frame_ = channels * bytes_per_channel_;
 }
 
 AudioDecoderConfig::~AudioDecoderConfig() {}
@@ -96,8 +76,8 @@ AudioDecoderConfig::~AudioDecoderConfig() {}
 bool AudioDecoderConfig::IsValidConfig() const {
   return codec_ != kUnknownAudioCodec &&
          channel_layout_ != CHANNEL_LAYOUT_UNSUPPORTED &&
-         bits_per_channel_ > 0 &&
-         bits_per_channel_ <= limits::kMaxBitsPerSample &&
+         bytes_per_channel_ > 0 &&
+         bytes_per_channel_ <= limits::kMaxBytesPerSample &&
          samples_per_second_ > 0 &&
          samples_per_second_ <= limits::kMaxSampleRate &&
          sample_format_ != kUnknownSampleFormat;
@@ -105,7 +85,7 @@ bool AudioDecoderConfig::IsValidConfig() const {
 
 bool AudioDecoderConfig::Matches(const AudioDecoderConfig& config) const {
   return ((codec() == config.codec()) &&
-          (bits_per_channel() == config.bits_per_channel()) &&
+          (bytes_per_channel() == config.bytes_per_channel()) &&
           (channel_layout() == config.channel_layout()) &&
           (samples_per_second() == config.samples_per_second()) &&
           (extra_data_size() == config.extra_data_size()) &&
diff --git a/media/base/audio_decoder_config.h b/media/base/audio_decoder_config.h
index 5b886e0..1c61e70 100644
--- a/media/base/audio_decoder_config.h
+++ b/media/base/audio_decoder_config.h
@@ -10,6 +10,7 @@
 #include "base/basictypes.h"
 #include "media/base/channel_layout.h"
 #include "media/base/media_export.h"
+#include "media/base/sample_format.h"
 
 namespace media {
 
@@ -40,22 +41,6 @@ enum AudioCodec {
   kAudioCodecMax
 };
 
-enum SampleFormat {
-  // These values are histogrammed over time; do not change their ordinal
-  // values.  When deleting a sample format replace it with a dummy value; when
-  // adding a sample format, do so at the bottom before kSampleFormatMax.
-  kUnknownSampleFormat = 0,
-  kSampleFormatU8,         // Unsigned 8-bit w/ bias of 128.
-  kSampleFormatS16,        // Signed 16-bit.
-  kSampleFormatS32,        // Signed 32-bit.
-  kSampleFormatF32,        // Float 32-bit.
-  kSampleFormatPlanarS16,  // Signed 16-bit planar.
-  kSampleFormatPlanarF32,  // Float 32-bit planar.
-
-  // Must always be last!
-  kSampleFormatMax
-};
-
 // TODO(dalecurtis): FFmpeg API uses |bytes_per_channel| instead of
 // |bits_per_channel|, we should switch over since bits are generally confusing
 // to work with.
@@ -89,7 +74,8 @@ class MEDIA_EXPORT AudioDecoderConfig {
   bool Matches(const AudioDecoderConfig& config) const;
 
   AudioCodec codec() const { return codec_; }
-  int bits_per_channel() const { return bits_per_channel_; }
+  int bits_per_channel() const { return bytes_per_channel_ * 8; }
+  int bytes_per_channel() const { return bytes_per_channel_; }
   ChannelLayout channel_layout() const { return channel_layout_; }
   int samples_per_second() const { return samples_per_second_; }
   SampleFormat sample_format() const { return sample_format_; }
@@ -110,7 +96,7 @@ class MEDIA_EXPORT AudioDecoderConfig {
  private:
   AudioCodec codec_;
   SampleFormat sample_format_;
-  int bits_per_channel_;
+  int bytes_per_channel_;
   ChannelLayout channel_layout_;
   int samples_per_second_;
   int bytes_per_frame_;
diff --git a/media/base/limits.h b/media/base/limits.h
index 309635f..ed7ac51 100644
--- a/media/base/limits.h
+++ b/media/base/limits.h
@@ -34,10 +34,11 @@ enum {
   kMaxSampleRate = 192000,
   kMinSampleRate = 3000,
   kMaxChannels = 32,
-  kMaxBitsPerSample = 32,
+  kMaxBytesPerSample = 4,
+  kMaxBitsPerSample = kMaxBytesPerSample * 8,
   kMaxSamplesPerPacket = kMaxSampleRate,
   kMaxPacketSizeInBytes =
-      (kMaxBitsPerSample / 8) * kMaxChannels * kMaxSamplesPerPacket,
+      kMaxBytesPerSample * kMaxChannels * kMaxSamplesPerPacket,
 
   // This limit is used by ParamTraits<VideoCaptureParams>.
   kMaxFramesPerSecond = 1000,
diff --git a/media/base/sample_format.cc b/media/base/sample_format.cc
new file mode 100644
index 0000000..3fdcf101
--- /dev/null
+++ b/media/base/sample_format.cc
@@ -0,0 +1,32 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/base/sample_format.h"
+
+#include "base/logging.h"
+
+namespace media {
+
+int SampleFormatToBytesPerChannel(SampleFormat sample_format) {
+  switch (sample_format) {
+    case kUnknownSampleFormat:
+      return 0;
+    case kSampleFormatU8:
+      return 1;
+    case kSampleFormatS16:
+    case kSampleFormatPlanarS16:
+      return 2;
+    case kSampleFormatS32:
+    case kSampleFormatF32:
+    case kSampleFormatPlanarF32:
+      return 4;
+    case kSampleFormatMax:
+      break;
+  }
+
+  NOTREACHED() << "Invalid sample format provided: " << sample_format;
+  return 0;
+}
+
+}  // namespace media
diff --git a/media/base/sample_format.h b/media/base/sample_format.h
new file mode 100644
index 0000000..bcaa5b2
--- /dev/null
+++ b/media/base/sample_format.h
@@ -0,0 +1,34 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_BASE_SAMPLE_FORMAT_H
+#define MEDIA_BASE_SAMPLE_FORMAT_H
+
+#include "media/base/media_export.h"
+
+namespace media {
+
+enum SampleFormat {
+  // These values are histogrammed over time; do not change their ordinal
+  // values.  When deleting a sample format replace it with a dummy value; when
+  // adding a sample format, do so at the bottom before kSampleFormatMax.
+  kUnknownSampleFormat = 0,
+  kSampleFormatU8,         // Unsigned 8-bit w/ bias of 128.
+  kSampleFormatS16,        // Signed 16-bit.
+  kSampleFormatS32,        // Signed 32-bit.
+  kSampleFormatF32,        // Float 32-bit.
+  kSampleFormatPlanarS16,  // Signed 16-bit planar.
+  kSampleFormatPlanarF32,  // Float 32-bit planar.
+
+  // Must always be last!
+  kSampleFormatMax
+};
+
+// Returns the number of bytes used per channel for the specified
+// |sample_format|.
+MEDIA_EXPORT int SampleFormatToBytesPerChannel(SampleFormat sample_format);
+
+}  // namespace media
+
+#endif  // MEDIA_BASE_SAMPLE_FORMAT_H
diff --git a/media/media.gyp b/media/media.gyp
index 955d0c8..d71454e 100644
--- a/media/media.gyp
+++ b/media/media.gyp
@@ -275,6 +275,8 @@
         'base/pipeline_status.h',
         'base/ranges.cc',
         'base/ranges.h',
+        'base/sample_format.cc',
+        'base/sample_format.h',
         'base/scoped_histogram_timer.h',
         'base/seekable_buffer.cc',
         'base/seekable_buffer.h',