290 lines
8.8 KiB
C++
290 lines
8.8 KiB
C++
// Copyright 2016 Google Inc. All rights reserved.
|
|
//
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file or at
|
|
// https://developers.google.com/open-source/licenses/bsd
|
|
|
|
#include "packager/media/codecs/ec3_audio_util.h"
|
|
|
|
#include "packager/base/macros.h"
|
|
#include "packager/base/strings/string_number_conversions.h"
|
|
#include "packager/media/base/bit_reader.h"
|
|
#include "packager/media/base/rcheck.h"
|
|
|
|
namespace shaka {
|
|
namespace media {
|
|
|
|
namespace {
|
|
|
|
// Channels bit map. 16 bits.
|
|
// Bit, Location
|
|
// 0(MSB), Left
|
|
// 1, Center
|
|
// 2, Right
|
|
// 3, Left Surround
|
|
// 4, Right Surround
|
|
// 5, Left center/Right center pair
|
|
// 6, Left rear surround/Right rear surround pair
|
|
// 7, Center surround
|
|
// 8, Top center surround
|
|
// 9, Left surround direct/Right surround direct pair
|
|
// 10, Left wide/Right wide pair
|
|
// 11, Lvertical height/Right vertical height pair
|
|
// 12, Center vertical height
|
|
// 13, Lts/Rts pair
|
|
// 14, LFE2
|
|
// 15, LFE
|
|
enum kEC3AudioChannelMap {
|
|
kLeft = 0x8000,
|
|
kCenter = 0x4000,
|
|
kRight = 0x2000,
|
|
kLeftSurround = 0x1000,
|
|
kRightSurround = 0x800,
|
|
kLcRcPair = 0x400,
|
|
kLrsRrsPair = 0x200,
|
|
kCenterSurround = 0x100,
|
|
kTopCenterSurround = 0x80,
|
|
kLsdRsdPair = 0x40,
|
|
kLwRwPair = 0x20,
|
|
kLvhRvhPair = 0x10,
|
|
kCenterVerticalHeight = 0x8,
|
|
kLtsRtsPair = 0x4,
|
|
kLFE2 = 0x2,
|
|
kLFEScreen = 0x1
|
|
};
|
|
// Number of channels for the channel bit above. The first entry corresponds to
|
|
// kLeft, which has one channel. All the XxxPairs bits have two channels.
|
|
const size_t kChannelCountArray[] = {
|
|
1, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2, 2, 1, 2, 1, 1,
|
|
};
|
|
static_assert(arraysize(kChannelCountArray) == 16u,
|
|
"Channel count array should have 16 entries.");
|
|
|
|
// EC3 Audio coding mode map (acmod) to determine EC3 audio channel layout. The
|
|
// value stands for the existence of Left, Center, Right, Left surround, and
|
|
// Right surround.
|
|
const uint16_t kEC3AudioCodingModeMap[] = {
|
|
kLeft | kRight,
|
|
kCenter,
|
|
kLeft | kRight,
|
|
kLeft | kCenter | kRight,
|
|
kLeft | kRight | kLeftSurround | kRightSurround,
|
|
kLeft | kCenter | kRight | kLeftSurround | kRightSurround,
|
|
kLeft | kRight | kLeftSurround | kRightSurround,
|
|
kLeft | kCenter | kRight | kLeftSurround | kRightSurround,
|
|
};
|
|
|
|
// Reverse bit order.
|
|
uint8_t ReverseBits8(uint8_t n) {
|
|
n = ((n >> 1) & 0x55) | ((n & 0x55) << 1);
|
|
n = ((n >> 2) & 0x33) | ((n & 0x33) << 2);
|
|
return ((n >> 4) & 0x0f) | ((n & 0x0f) << 4);
|
|
}
|
|
|
|
// Mapping of channel configurations to the MPEG audio value based on
|
|
// ETSI TS 102 366 V1.4.1 Digital Audio Compression (AC-3, Enhanced AC-3)
|
|
// Standard Table I.1.1
|
|
uint32_t EC3ChannelMaptoMPEGValue(uint32_t channel_map) {
|
|
uint32_t ret = 0;
|
|
|
|
switch (channel_map) {
|
|
case kCenter:
|
|
ret = 1;
|
|
break;
|
|
case kLeft | kRight:
|
|
ret = 2;
|
|
break;
|
|
case kCenter| kLeft | kRight:
|
|
ret = 3;
|
|
break;
|
|
case kCenter | kLeft | kRight | kCenterSurround:
|
|
ret = 4;
|
|
break;
|
|
case kCenter | kLeft | kRight | kLeftSurround | kRightSurround:
|
|
ret = 5;
|
|
break;
|
|
case kCenter | kLeft | kRight | kLeftSurround | kRightSurround |
|
|
kLFEScreen:
|
|
ret = 6;
|
|
break;
|
|
case kCenter | kLeft | kRight | kLwRwPair | kLeftSurround | kRightSurround |
|
|
kLFEScreen:
|
|
ret = 7;
|
|
break;
|
|
case kLeft | kRight | kCenterSurround:
|
|
ret = 9;
|
|
break;
|
|
case kLeft | kRight | kLeftSurround | kRightSurround:
|
|
ret = 10;
|
|
break;
|
|
case kCenter | kLeft | kRight | kLrsRrsPair | kCenterSurround | kLFEScreen:
|
|
ret = 11;
|
|
break;
|
|
case kCenter | kLeft | kRight | kLeftSurround | kRightSurround |
|
|
kLrsRrsPair | kLFEScreen:
|
|
ret = 12;
|
|
break;
|
|
case kCenter | kLeft | kRight | kLeftSurround | kRightSurround |
|
|
kLFEScreen | kLvhRvhPair:
|
|
ret = 14;
|
|
break;
|
|
case kCenter | kLeft | kRight | kLeftSurround | kRightSurround |
|
|
kLFEScreen | kLvhRvhPair | kLtsRtsPair:
|
|
ret = 16;
|
|
break;
|
|
case kCenter | kLeft | kRight | kLeftSurround | kRightSurround |
|
|
kLFEScreen | kLvhRvhPair | kCenterVerticalHeight | kLtsRtsPair |
|
|
kTopCenterSurround:
|
|
ret = 17;
|
|
break;
|
|
case kCenter | kLeft | kRight | kLsdRsdPair | kLrsRrsPair | kLFEScreen |
|
|
kLvhRvhPair | kLtsRtsPair:
|
|
ret = 19;
|
|
break;
|
|
default:
|
|
ret = 0xFFFFFFFF;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
bool ExtractEc3Data(const std::vector<uint8_t>& ec3_data,
|
|
uint8_t* audio_coding_mode,
|
|
bool* lfe_channel_on,
|
|
uint16_t* dependent_substreams_layout,
|
|
uint32_t* ec3_joc_complexity) {
|
|
BitReader bit_reader(ec3_data.data(), ec3_data.size());
|
|
// Read number of independent substreams and parse the independent substreams.
|
|
uint8_t number_independent_substreams;
|
|
RCHECK(bit_reader.SkipBits(13) &&
|
|
bit_reader.ReadBits(3, &number_independent_substreams));
|
|
// The value of this field is one less than the number of independent
|
|
// substreams present.
|
|
++number_independent_substreams;
|
|
|
|
// Parse audio_coding_mode, dependent_substreams_layout and lfe_channel_on
|
|
// from the first independent substream.
|
|
// Independent substream in EC3Specific box:
|
|
// fscod: 2 bits
|
|
// bsid: 5 bits
|
|
// reserved_1: 1 bit
|
|
// asvc: 1 bit
|
|
// bsmod: 3 bits
|
|
// acmod: 3 bits
|
|
// lfeon: 1 bit
|
|
// reserved_2: 3 bits
|
|
// num_dep_sub: 4 bits
|
|
// If num_dep_sub > 0, chan_loc is present and the size is 9 bits.
|
|
// Otherwise, reserved_3 is present and the size is 1 bit.
|
|
// chan_loc: 9 bits
|
|
// reserved_3: 1 bit
|
|
RCHECK(bit_reader.SkipBits(12));
|
|
RCHECK(bit_reader.ReadBits(3, audio_coding_mode));
|
|
RCHECK(bit_reader.ReadBits(1, lfe_channel_on));
|
|
|
|
uint8_t number_dependent_substreams = 0;
|
|
RCHECK(bit_reader.SkipBits(3));
|
|
RCHECK(bit_reader.ReadBits(4, &number_dependent_substreams));
|
|
|
|
*dependent_substreams_layout = 0;
|
|
if (number_dependent_substreams > 0) {
|
|
RCHECK(bit_reader.ReadBits(9, dependent_substreams_layout));
|
|
} else {
|
|
RCHECK(bit_reader.SkipBits(1));
|
|
}
|
|
*ec3_joc_complexity = 0;
|
|
if (bit_reader.bits_available() < 16) {
|
|
return true;
|
|
}
|
|
|
|
RCHECK(bit_reader.SkipBits(7));
|
|
bool ec3_joc_flag;
|
|
RCHECK(bit_reader.ReadBits(1, &ec3_joc_flag));
|
|
if (ec3_joc_flag) {
|
|
RCHECK(bit_reader.ReadBits(8, ec3_joc_complexity));
|
|
}
|
|
return true;
|
|
}
|
|
|
|
} // namespace
|
|
|
|
bool CalculateEC3ChannelMap(const std::vector<uint8_t>& ec3_data,
|
|
uint32_t* channel_map) {
|
|
uint8_t audio_coding_mode;
|
|
bool lfe_channel_on;
|
|
uint16_t dependent_substreams_layout;
|
|
uint32_t ec3_joc_complexity;
|
|
if (!ExtractEc3Data(ec3_data, &audio_coding_mode, &lfe_channel_on,
|
|
&dependent_substreams_layout, &ec3_joc_complexity)) {
|
|
LOG(WARNING) << "Seeing invalid EC3 data: "
|
|
<< base::HexEncode(ec3_data.data(), ec3_data.size());
|
|
return false;
|
|
}
|
|
|
|
// Dependent substreams layout bit map:
|
|
// Bit, Location
|
|
// 0, Lc/Rc pair
|
|
// 1, Lrs/Rrs pair
|
|
// 2, Cs
|
|
// 3, Ts
|
|
// 4, Lsd/Rsd pair
|
|
// 5, Lw/Rw pair
|
|
// 6, Lvh/Rvh pair
|
|
// 7, Cvh
|
|
// 8(MSB), LFE2
|
|
// Reverse bit order of dependent substreams channel layout (LFE2 not
|
|
// included) to apply on channel_map bit 5 - 12.
|
|
const uint8_t reversed_dependent_substreams_layout =
|
|
ReverseBits8(dependent_substreams_layout & 0xFF);
|
|
|
|
*channel_map = kEC3AudioCodingModeMap[audio_coding_mode] |
|
|
(reversed_dependent_substreams_layout << 3);
|
|
if (dependent_substreams_layout & 0x100)
|
|
*channel_map |= kLFE2;
|
|
if (lfe_channel_on)
|
|
*channel_map |= kLFEScreen;
|
|
return true;
|
|
}
|
|
|
|
bool CalculateEC3ChannelMPEGValue(const std::vector<uint8_t>& ec3_data,
|
|
uint32_t* ec3_channel_mpeg_value) {
|
|
uint32_t channel_map;
|
|
if (!CalculateEC3ChannelMap(ec3_data, &channel_map))
|
|
return false;
|
|
*ec3_channel_mpeg_value = EC3ChannelMaptoMPEGValue(channel_map);
|
|
return true;
|
|
}
|
|
|
|
size_t GetEc3NumChannels(const std::vector<uint8_t>& ec3_data) {
|
|
uint32_t channel_map;
|
|
if (!CalculateEC3ChannelMap(ec3_data, &channel_map))
|
|
return 0;
|
|
|
|
size_t num_channels = 0;
|
|
int bit = kLeft;
|
|
for (size_t channel_count : kChannelCountArray) {
|
|
if (channel_map & bit)
|
|
num_channels += channel_count;
|
|
bit >>= 1;
|
|
}
|
|
DCHECK_EQ(bit, 0);
|
|
return num_channels;
|
|
}
|
|
|
|
bool GetEc3JocComplexity(const std::vector<uint8_t>& ec3_data,
|
|
uint32_t* ec3_joc_complexity) {
|
|
uint8_t audio_coding_mode;
|
|
bool lfe_channel_on;
|
|
uint16_t dependent_substreams_layout;
|
|
|
|
if (!ExtractEc3Data(ec3_data, &audio_coding_mode, &lfe_channel_on,
|
|
&dependent_substreams_layout, ec3_joc_complexity)) {
|
|
LOG(WARNING) << "Seeing invalid EC3 data: "
|
|
<< base::HexEncode(ec3_data.data(), ec3_data.size());
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
} // namespace media
|
|
} // namespace shaka
|