| /* |
| Copyright (c) 2011 Stanislav Vitvitskiy |
| |
| Permission is hereby granted, free of charge, to any person obtaining a copy of this |
| software and associated documentation files (the "Software"), to deal in the Software |
| without restriction, including without limitation the rights to use, copy, modify, |
| merge, publish, distribute, sublicense, and/or sell copies of the Software, and to |
| permit persons to whom the Software is furnished to do so, subject to the following |
| conditions: |
| |
| The above copyright notice and this permission notice shall be included in all copies or |
| substantial portions of the Software. |
| |
| THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, |
| INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR |
| PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE |
| FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, |
| TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE |
| OR OTHER DEALINGS IN THE SOFTWARE. |
| */ |
| package com.googlecode.mp4parser.h264.read; |
| |
| import com.googlecode.mp4parser.h264.CharCache; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| |
| /** |
| * A dummy implementation of H264 RBSP reading |
| * |
| * @author Stanislav Vitvitskiy |
| */ |
| public class BitstreamReader { |
| private InputStream is; |
| private int curByte; |
| private int nextByte; |
| int nBit; |
| protected static int bitsRead; |
| |
| protected CharCache debugBits = new CharCache(50); |
| |
| public BitstreamReader(InputStream is) throws IOException { |
| this.is = is; |
| curByte = is.read(); |
| nextByte = is.read(); |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see ua.org.jplayer.javcodec.h264.RBSPInputStream#read1Bit() |
| */ |
| public int read1Bit() throws IOException { |
| if (nBit == 8) { |
| advance(); |
| if (curByte == -1) { |
| return -1; |
| } |
| } |
| int res = (curByte >> (7 - nBit)) & 1; |
| nBit++; |
| |
| debugBits.append(res == 0 ? '0' : '1'); |
| ++bitsRead; |
| |
| return res; |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see ua.org.jplayer.javcodec.h264.RBSPInputStream#readNBit(int) |
| */ |
| public long readNBit(int n) throws IOException { |
| if (n > 64) |
| throw new IllegalArgumentException("Can not readByte more then 64 bit"); |
| |
| long val = 0; |
| |
| for (int i = 0; i < n; i++) { |
| val <<= 1; |
| val |= read1Bit(); |
| } |
| |
| return val; |
| } |
| |
| private void advance() throws IOException { |
| curByte = nextByte; |
| nextByte = is.read(); |
| nBit = 0; |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see ua.org.jplayer.javcodec.h264.RBSPInputStream#readByte() |
| */ |
| public int readByte() throws IOException { |
| if (nBit > 0) { |
| advance(); |
| } |
| |
| int res = curByte; |
| |
| advance(); |
| |
| return res; |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see ua.org.jplayer.javcodec.h264.RBSPInputStream#moreRBSPData() |
| */ |
| public boolean moreRBSPData() throws IOException { |
| if (nBit == 8) { |
| advance(); |
| } |
| int tail = 1 << (8 - nBit - 1); |
| int mask = ((tail << 1) - 1); |
| boolean hasTail = (curByte & mask) == tail; |
| |
| return !(curByte == -1 || (nextByte == -1 && hasTail)); |
| } |
| |
| public long getBitPosition() { |
| return (bitsRead * 8 + (nBit % 8)); |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see ua.org.jplayer.javcodec.h264.RBSPInputStream#readRemainingByte() |
| */ |
| public long readRemainingByte() throws IOException { |
| return readNBit(8 - nBit); |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see ua.org.jplayer.javcodec.h264.RBSPInputStream#next_bits(int) |
| */ |
| public int peakNextBits(int n) throws IOException { |
| if (n > 8) |
| throw new IllegalArgumentException("N should be less then 8"); |
| if (nBit == 8) { |
| advance(); |
| if (curByte == -1) { |
| return -1; |
| } |
| } |
| int[] bits = new int[16 - nBit]; |
| |
| int cnt = 0; |
| for (int i = nBit; i < 8; i++) { |
| bits[cnt++] = (curByte >> (7 - i)) & 0x1; |
| } |
| |
| for (int i = 0; i < 8; i++) { |
| bits[cnt++] = (nextByte >> (7 - i)) & 0x1; |
| } |
| |
| int result = 0; |
| for (int i = 0; i < n; i++) { |
| result <<= 1; |
| result |= bits[i]; |
| } |
| |
| return result; |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see ua.org.jplayer.javcodec.h264.RBSPInputStream#byte_aligned() |
| */ |
| public boolean isByteAligned() { |
| return (nBit % 8) == 0; |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see ua.org.jplayer.javcodec.h264.RBSPInputStream#close() |
| */ |
| public void close() throws IOException { |
| } |
| |
| public int getCurBit() { |
| return nBit; |
| } |
| } |