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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.mozilla.thirdparty.com.google.android.exoplayer2.audio;
import androidx.annotation.Nullable;
import org.mozilla.thirdparty.com.google.android.exoplayer2.Format;
import org.mozilla.thirdparty.com.google.android.exoplayer2.drm.DrmInitData;
import org.mozilla.thirdparty.com.google.android.exoplayer2.util.MimeTypes;
import org.mozilla.thirdparty.com.google.android.exoplayer2.util.ParsableBitArray;
import java.nio.ByteBuffer;
import java.util.Arrays;
/**
* Utility methods for parsing DTS frames.
*/
public final class DtsUtil {
private static final int SYNC_VALUE_BE = 0x7FFE8001;
private static final int SYNC_VALUE_14B_BE = 0x1FFFE800;
private static final int SYNC_VALUE_LE = 0xFE7F0180;
private static final int SYNC_VALUE_14B_LE = 0xFF1F00E8;
private static final byte FIRST_BYTE_BE = (byte) (SYNC_VALUE_BE >>> 24);
private static final byte FIRST_BYTE_14B_BE = (byte) (SYNC_VALUE_14B_BE >>> 24);
private static final byte FIRST_BYTE_LE = (byte) (SYNC_VALUE_LE >>> 24);
private static final byte FIRST_BYTE_14B_LE = (byte) (SYNC_VALUE_14B_LE >>> 24);
/**
* Maps AMODE to the number of channels. See ETSI TS 102 114 table 5.4.
*/
private static final int[] CHANNELS_BY_AMODE = new int[] {1, 2, 2, 2, 2, 3, 3, 4, 4, 5, 6, 6, 6,
7, 8, 8};
/**
* Maps SFREQ to the sampling frequency in Hz. See ETSI TS 102 144 table 5.5.
*/
private static final int[] SAMPLE_RATE_BY_SFREQ = new int[] {-1, 8000, 16000, 32000, -1, -1,
11025, 22050, 44100, -1, -1, 12000, 24000, 48000, -1, -1};
/**
* Maps RATE to 2 * bitrate in kbit/s. See ETSI TS 102 144 table 5.7.
*/
private static final int[] TWICE_BITRATE_KBPS_BY_RATE = new int[] {64, 112, 128, 192, 224, 256,
384, 448, 512, 640, 768, 896, 1024, 1152, 1280, 1536, 1920, 2048, 2304, 2560, 2688, 2816,
2823, 2944, 3072, 3840, 4096, 6144, 7680};
/**
* Returns whether a given integer matches a DTS sync word. Synchronization and storage modes are
* defined in ETSI TS 102 114 V1.1.1 (2002-08), Section 5.3.
*
* @param word An integer.
* @return Whether a given integer matches a DTS sync word.
*/
public static boolean isSyncWord(int word) {
return word == SYNC_VALUE_BE
|| word == SYNC_VALUE_LE
|| word == SYNC_VALUE_14B_BE
|| word == SYNC_VALUE_14B_LE;
}
/**
* Returns the DTS format given {@code data} containing the DTS frame according to ETSI TS 102 114
* subsections 5.3/5.4.
*
* @param frame The DTS frame to parse.
* @param trackId The track identifier to set on the format.
* @param language The language to set on the format.
* @param drmInitData {@link DrmInitData} to be included in the format.
* @return The DTS format parsed from data in the header.
*/
public static Format parseDtsFormat(
byte[] frame, String trackId, @Nullable String language, @Nullable DrmInitData drmInitData) {
ParsableBitArray frameBits = getNormalizedFrameHeader(frame);
frameBits.skipBits(32 + 1 + 5 + 1 + 7 + 14); // SYNC, FTYPE, SHORT, CPF, NBLKS, FSIZE
int amode = frameBits.readBits(6);
int channelCount = CHANNELS_BY_AMODE[amode];
int sfreq = frameBits.readBits(4);
int sampleRate = SAMPLE_RATE_BY_SFREQ[sfreq];
int rate = frameBits.readBits(5);
int bitrate = rate >= TWICE_BITRATE_KBPS_BY_RATE.length ? Format.NO_VALUE
: TWICE_BITRATE_KBPS_BY_RATE[rate] * 1000 / 2;
frameBits.skipBits(10); // MIX, DYNF, TIMEF, AUXF, HDCD, EXT_AUDIO_ID, EXT_AUDIO, ASPF
channelCount += frameBits.readBits(2) > 0 ? 1 : 0; // LFF
return Format.createAudioSampleFormat(trackId, MimeTypes.AUDIO_DTS, null, bitrate,
Format.NO_VALUE, channelCount, sampleRate, null, drmInitData, 0, language);
}
/**
* Returns the number of audio samples represented by the given DTS frame.
*
* @param data The frame to parse.
* @return The number of audio samples represented by the frame.
*/
public static int parseDtsAudioSampleCount(byte[] data) {
int nblks;
switch (data[0]) {
case FIRST_BYTE_LE:
nblks = ((data[5] & 0x01) << 6) | ((data[4] & 0xFC) >> 2);
break;
case FIRST_BYTE_14B_LE:
nblks = ((data[4] & 0x07) << 4) | ((data[7] & 0x3C) >> 2);
break;
case FIRST_BYTE_14B_BE:
nblks = ((data[5] & 0x07) << 4) | ((data[6] & 0x3C) >> 2);
break;
default:
// We blindly assume FIRST_BYTE_BE if none of the others match.
nblks = ((data[4] & 0x01) << 6) | ((data[5] & 0xFC) >> 2);
}
return (nblks + 1) * 32;
}
/**
* Like {@link #parseDtsAudioSampleCount(byte[])} but reads from a {@link ByteBuffer}. The
* buffer's position is not modified.
*
* @param buffer The {@link ByteBuffer} from which to read.
* @return The number of audio samples represented by the syncframe.
*/
public static int parseDtsAudioSampleCount(ByteBuffer buffer) {
// See ETSI TS 102 114 subsection 5.4.1.
int position = buffer.position();
int nblks;
switch (buffer.get(position)) {
case FIRST_BYTE_LE:
nblks = ((buffer.get(position + 5) & 0x01) << 6) | ((buffer.get(position + 4) & 0xFC) >> 2);
break;
case FIRST_BYTE_14B_LE:
nblks = ((buffer.get(position + 4) & 0x07) << 4) | ((buffer.get(position + 7) & 0x3C) >> 2);
break;
case FIRST_BYTE_14B_BE:
nblks = ((buffer.get(position + 5) & 0x07) << 4) | ((buffer.get(position + 6) & 0x3C) >> 2);
break;
default:
// We blindly assume FIRST_BYTE_BE if none of the others match.
nblks = ((buffer.get(position + 4) & 0x01) << 6) | ((buffer.get(position + 5) & 0xFC) >> 2);
}
return (nblks + 1) * 32;
}
/**
* Returns the size in bytes of the given DTS frame.
*
* @param data The frame to parse.
* @return The frame's size in bytes.
*/
public static int getDtsFrameSize(byte[] data) {
int fsize;
boolean uses14BitPerWord = false;
switch (data[0]) {
case FIRST_BYTE_14B_BE:
fsize = (((data[6] & 0x03) << 12) | ((data[7] & 0xFF) << 4) | ((data[8] & 0x3C) >> 2)) + 1;
uses14BitPerWord = true;
break;
case FIRST_BYTE_LE:
fsize = (((data[4] & 0x03) << 12) | ((data[7] & 0xFF) << 4) | ((data[6] & 0xF0) >> 4)) + 1;
break;
case FIRST_BYTE_14B_LE:
fsize = (((data[7] & 0x03) << 12) | ((data[6] & 0xFF) << 4) | ((data[9] & 0x3C) >> 2)) + 1;
uses14BitPerWord = true;
break;
default:
// We blindly assume FIRST_BYTE_BE if none of the others match.
fsize = (((data[5] & 0x03) << 12) | ((data[6] & 0xFF) << 4) | ((data[7] & 0xF0) >> 4)) + 1;
}
// If the frame is stored in 14-bit mode, adjust the frame size to reflect the actual byte size.
return uses14BitPerWord ? fsize * 16 / 14 : fsize;
}
private static ParsableBitArray getNormalizedFrameHeader(byte[] frameHeader) {
if (frameHeader[0] == FIRST_BYTE_BE) {
// The frame is already 16-bit mode, big endian.
return new ParsableBitArray(frameHeader);
}
// Data is not normalized, but we don't want to modify frameHeader.
frameHeader = Arrays.copyOf(frameHeader, frameHeader.length);
if (isLittleEndianFrameHeader(frameHeader)) {
// Change endianness.
for (int i = 0; i < frameHeader.length - 1; i += 2) {
byte temp = frameHeader[i];
frameHeader[i] = frameHeader[i + 1];
frameHeader[i + 1] = temp;
}
}
ParsableBitArray frameBits = new ParsableBitArray(frameHeader);
if (frameHeader[0] == (byte) (SYNC_VALUE_14B_BE >> 24)) {
// Discard the 2 most significant bits of each 16 bit word.
ParsableBitArray scratchBits = new ParsableBitArray(frameHeader);
while (scratchBits.bitsLeft() >= 16) {
scratchBits.skipBits(2);
frameBits.putInt(scratchBits.readBits(14), 14);
}
}
frameBits.reset(frameHeader);
return frameBits;
}
private static boolean isLittleEndianFrameHeader(byte[] frameHeader) {
return frameHeader[0] == FIRST_BYTE_LE || frameHeader[0] == FIRST_BYTE_14B_LE;
}
private DtsUtil() {}
}
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