Fix MSE ADTS parsing on Android.

media/formats/mpeg/adts_header_parser.cc

-// Copyright 2016 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/formats/mpeg/adts_header_parser.h"
-
-#include <algorithm>
-#include <vector>
-#include "base/logging.h"
-#include "media/base/audio_codecs.h"
-#include "media/base/audio_decoder_config.h"
-#include "media/base/media_util.h"
-#include "media/base/sample_format.h"
-#include "media/formats/mpeg/adts_constants.h"
-
-namespace media {
-
-namespace {
-
-size_t ExtractAdtsFrequencyIndex(const uint8_t* adts_header) {
-  return ((adts_header[2] >> 2) & 0xf);
-}
-
-size_t ExtractAdtsChannelConfig(const uint8_t* adts_header) {
-  return (((adts_header[3] >> 6) & 0x3) | ((adts_header[2] & 0x1) << 2));
-}
-
-}  // namespace (anonymous)
-
-bool ParseAdtsHeader(const uint8_t* adts_header,
-                     bool is_sbr,
-                     AudioDecoderConfig* config,
-                     size_t* orig_sample_freq) {
-  DCHECK(adts_header);
-  DCHECK(orig_sample_freq);
-
-  size_t frequency_index = ExtractAdtsFrequencyIndex(adts_header);
-  if (frequency_index >= kADTSFrequencyTableSize) {
-    // Frequency index 13 & 14 are reserved
-    // while 15 means that the frequency is explicitly written
-    // (not supported).
-    return false;
-  }
-
-  size_t channel_configuration = ExtractAdtsChannelConfig(adts_header);
-  if (channel_configuration == 0 ||
-      channel_configuration >= kADTSChannelLayoutTableSize) {
-    // TODO(damienv): Add support for inband channel configuration.
-    return false;
-  }
-
-  // TODO(damienv): support HE-AAC frequency doubling (SBR)
-  // based on the incoming ADTS profile.
-  int samples_per_second = kADTSFrequencyTable[frequency_index];
-  int adts_profile = (adts_header[2] >> 6) & 0x3;
-
-  // The following code is written according to ISO 14496 Part 3 Table 1.11 and
-  // Table 1.22. (Table 1.11 refers to the capping to 48000, Table 1.22 refers
-  // to SBR doubling the AAC sample rate.)
-  // TODO(damienv) : Extend sample rate cap to 96kHz for Level 5 content.
-  int extended_samples_per_second =
-      is_sbr ? std::min(2 * samples_per_second, 48000) : samples_per_second;
-  *orig_sample_freq = samples_per_second;
-
-  // The following code is written according to ISO 14496 Part 3 Table 1.13 -
-  // Syntax of AudioSpecificConfig.
-  uint16_t extra_data_int = static_cast<uint16_t>(
-      // Note: adts_profile is in the range [0,3], since the ADTS header only
-      // allows two bits for its value.
-      ((adts_profile + 1) << 11) +
-      // frequency_index is [0..13], per early out above.
-      (frequency_index << 7) +
-      // channel_configuration is [0..7], per early out above.
-      (channel_configuration << 3));
-  std::vector<uint8_t> extra_data;
-  extra_data.push_back(static_cast<uint8_t>(extra_data_int >> 8));
-  extra_data.push_back(static_cast<uint8_t>(extra_data_int & 0xff));
-
-  DCHECK(config);
-  *config = AudioDecoderConfig(kCodecAAC, kSampleFormatS16,
-                               kADTSChannelLayoutTable[channel_configuration],
-                               extended_samples_per_second, extra_data,
-                               Unencrypted());
-
-  return true;
-}
-
-}  // namespace media