Here you can find the source of getTsStartSyncByte(ByteBuffer packet, boolean synced)
| Parameter | Description |
|---|---|
| packet | This is the ByteBuffer to be processed. |
| synced | <i>true</i> if the current position matches the beginning of a packet and detection does not need to be done. |
public static int getTsStartSyncByte(ByteBuffer packet, boolean synced)
//package com.java2s; /*/* www . j a v a2 s .com*/ * Copyright 2015 The OpenDCT Authors. All Rights Reserved * * 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. */ import java.nio.ByteBuffer; public class Main { public static final int MTS_SYNC_BYTE = 0x47; public static final int MTS_PACKET_LEN = 188; /** * Get the index of the sync byte of the first detected start packet. * <p/> * The index is relative to the beginning of the array. * * @param packet This is the byte array to be processed. * @param offset This if the offset of the actual data to be processed. * @param length This is the length of data to be processed from the provided offset, it must be * at least 752 bytes (4 188 byte TS packets). * @param synced <i>true</i> if the offset matches the beginning of a packet and detection does * not need to be done. * @return The index value of the first located packet start byte or -1 if a packet start byte * was not found. */ public static int getTsStartSyncByte(byte packet[], int offset, int length, boolean synced) { int returnByte = -1; int firstSyncByte = offset; if (!synced) { firstSyncByte = getTsSyncByte(packet, offset, length); } if (firstSyncByte < 0) { return returnByte; } int limit = offset + length; for (int i = firstSyncByte; i < limit; i += MTS_PACKET_LEN) { if (i + 1 > length) { break; } int tsPayloadUnitStartIndicator = packet[i + 1] & 0x40; if (tsPayloadUnitStartIndicator != 0) { returnByte = i; break; } } return returnByte; } /** * Get the index of the sync byte of the first detected start packet. * <p/> * This will search the buffer without actually incrementing the position of the buffer. The * index is relative to the beginning of the buffer. * * @param packet This is the ByteBuffer to be processed. * @param synced <i>true</i> if the current position matches the beginning of a packet and * detection does not need to be done. * @return The index value of the first located packet start byte or -1 if a packet start byte * was not found. */ public static int getTsStartSyncByte(ByteBuffer packet, boolean synced) { int returnByte = -1; int firstSyncByte = packet.position(); if (!synced) { firstSyncByte = getTsSyncByte(packet); } if (firstSyncByte < 0) { return returnByte; } int limit = packet.remaining(); for (int i = firstSyncByte; i < limit; i += MTS_PACKET_LEN) { if (i + 1 > packet.remaining()) { break; } int tsPayloadUnitStartIndicator = packet.get(i + 1) & 0x40; if (tsPayloadUnitStartIndicator != 0) { returnByte = i; break; } } return returnByte; } /** * Returns the index of the first a TS sync byte. * <p/> * According to the standard finding a valid sync byte is done by locating a byte with the value * 0x47 and then checking if the sync byte can be found two more times in the right places. The * index is relative to the beginning of the array. * * @param packet This is the byte array to be processed. * @param offset This if the offset of the actual data to be processed. * @param length This is the length of data to be processed from the provided offset, it must be * at least 752 bytes (4 188 byte TS packets). * @return The index value of the first located sync byte or -1 if a sync byte was not found. */ public static int getTsSyncByte(byte packet[], int offset, int length) { int returnValue = -1; if (length < 752) { return returnValue; } int limit = offset + length; for (int i = offset; i < limit; i++) { if (packet[i] == MTS_SYNC_BYTE) { if (i + (MTS_PACKET_LEN * 2) < limit) { byte sync1 = packet[i + MTS_PACKET_LEN]; byte sync2 = packet[i + (MTS_PACKET_LEN * 2)]; if (sync1 == MTS_SYNC_BYTE && sync2 == MTS_SYNC_BYTE) { returnValue = i; break; } } else { // If this is not true now, it won't be later either, so we should just return // that we didn't find it. break; } } } return returnValue; } /** * Returns the index of the first a TS sync byte. * <p/> * According to the standard finding a valid sync byte is done by locating a byte with the value * 0x47 and then checking if the sync byte can be found two more times in the right places. This * will not increment the position of the buffer. The index is relative to the beginning of the * buffer. * * @param packet This is the ByteBuffer to be processed. * @return The index value of the first located sync byte or -1 if a sync byte was not found. */ public static int getTsSyncByte(ByteBuffer packet) { int returnValue = -1; if (packet.remaining() < 752) { return returnValue; } int limit = packet.limit(); for (int i = packet.position(); i < limit; i++) { if (packet.get(i) == MTS_SYNC_BYTE) { if (i + (MTS_PACKET_LEN * 2) < limit) { byte sync1 = packet.get(i + MTS_PACKET_LEN); byte sync2 = packet.get(i + (MTS_PACKET_LEN * 2)); if (sync1 == MTS_SYNC_BYTE && sync2 == MTS_SYNC_BYTE) { returnValue = i; break; } } else { // If this is not true now, it won't be later either, so we should just return // that we didn't find it. break; } } } return returnValue; } }