1 /*
2 * Copyright (c) 1999, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package com.sun.media.sound;
27
28 import java.io.IOException;
29 import java.util.Objects;
30 import java.util.Vector;
31
32 import javax.sound.sampled.AudioFormat;
33 import javax.sound.sampled.AudioInputStream;
34 import javax.sound.sampled.AudioSystem;
35
36 /**
37 * A-law encodes linear data, and decodes a-law data to linear data.
38 *
39 * @author Kara Kytle
40 */
41 public final class AlawCodec extends SunCodec {
42
43 /* Tables used for A-law decoding */
44
45 private static final byte[] ALAW_TABH = new byte[256];
46 private static final byte[] ALAW_TABL = new byte[256];
47
48 private static final AudioFormat.Encoding[] alawEncodings = { AudioFormat.Encoding.ALAW, AudioFormat.Encoding.PCM_SIGNED };
49
50 private static final short seg_end [] = {0xFF, 0x1FF, 0x3FF,
51 0x7FF, 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF};
52
53 /**
54 * Initializes the decode tables.
55 */
56 static {
57 for (int i=0;i<256;i++) {
58 int input = i ^ 0x55;
59 int mantissa = (input & 0xf ) << 4;
60 int segment = (input & 0x70) >> 4;
61 int value = mantissa+8;
62
63 if(segment>=1)
64 value+=0x100;
65 if(segment>1)
66 value <<= (segment -1);
67
68 if( (input & 0x80)==0 )
69 value = -value;
70
71 ALAW_TABL[i] = (byte)value;
72 ALAW_TABH[i] = (byte)(value>>8);
73 }
74 }
75
76
77 /**
78 * Constructs a new ALAW codec object.
79 */
80 public AlawCodec() {
81
82 super(alawEncodings, alawEncodings);
83 }
84
85 @Override
86 public AudioFormat.Encoding[] getTargetEncodings(AudioFormat sourceFormat){
87
88 if( sourceFormat.getEncoding().equals( AudioFormat.Encoding.PCM_SIGNED )) {
89
90 if( sourceFormat.getSampleSizeInBits() == 16 ) {
91
92 AudioFormat.Encoding enc[] = new AudioFormat.Encoding[1];
93 enc[0] = AudioFormat.Encoding.ALAW;
94 return enc;
95
96 } else {
97 return new AudioFormat.Encoding[0];
98 }
99 } else if( sourceFormat.getEncoding().equals( AudioFormat.Encoding.ALAW ) ) {
100
101 if( sourceFormat.getSampleSizeInBits() == 8 ) {
102
103 AudioFormat.Encoding enc[] = new AudioFormat.Encoding[1];
104 enc[0] = AudioFormat.Encoding.PCM_SIGNED;
105 return enc;
106
107 } else {
108 return new AudioFormat.Encoding[0];
109 }
110
111 } else {
112 return new AudioFormat.Encoding[0];
113 }
114 }
115
116 @Override
117 public AudioFormat[] getTargetFormats(AudioFormat.Encoding targetEncoding, AudioFormat sourceFormat){
118 Objects.requireNonNull(sourceFormat);
119 if( (targetEncoding.equals( AudioFormat.Encoding.PCM_SIGNED ) && sourceFormat.getEncoding().equals( AudioFormat.Encoding.ALAW)) ||
120 (targetEncoding.equals( AudioFormat.Encoding.ALAW) && sourceFormat.getEncoding().equals( AudioFormat.Encoding.PCM_SIGNED)) ) {
121 return getOutputFormats( sourceFormat );
122 } else {
123 return new AudioFormat[0];
124 }
125 }
126
127 @Override
128 public AudioInputStream getAudioInputStream(AudioFormat.Encoding targetEncoding, AudioInputStream sourceStream){
129 AudioFormat sourceFormat = sourceStream.getFormat();
130 AudioFormat.Encoding sourceEncoding = sourceFormat.getEncoding();
131
132 if( !isConversionSupported(targetEncoding,sourceStream.getFormat()) ) {
133 throw new IllegalArgumentException("Unsupported conversion: " + sourceStream.getFormat().toString() + " to " + targetEncoding.toString());
134 }
135 if( sourceEncoding.equals( targetEncoding ) ) {
136 return sourceStream;
137 }
138 AudioFormat targetFormat = null;
139 if( sourceEncoding.equals( AudioFormat.Encoding.ALAW ) &&
140 targetEncoding.equals( AudioFormat.Encoding.PCM_SIGNED ) ) {
141
142 targetFormat = new AudioFormat( targetEncoding,
143 sourceFormat.getSampleRate(),
144 16,
145 sourceFormat.getChannels(),
146 2*sourceFormat.getChannels(),
147 sourceFormat.getSampleRate(),
148 sourceFormat.isBigEndian());
149
150 } else if( sourceEncoding.equals( AudioFormat.Encoding.PCM_SIGNED ) &&
151 targetEncoding.equals( AudioFormat.Encoding.ALAW ) ) {
152
153 targetFormat = new AudioFormat( targetEncoding,
154 sourceFormat.getSampleRate(),
155 8,
156 sourceFormat.getChannels(),
157 sourceFormat.getChannels(),
158 sourceFormat.getSampleRate(),
159 false);
160 } else {
161 throw new IllegalArgumentException("Unsupported conversion: " + sourceStream.getFormat().toString() + " to " + targetEncoding.toString());
162 }
163 return getConvertedStream(targetFormat, sourceStream);
164 }
165
166 @Override
167 public AudioInputStream getAudioInputStream(AudioFormat targetFormat, AudioInputStream sourceStream){
168 if (!isConversionSupported(targetFormat, sourceStream.getFormat()))
169 throw new IllegalArgumentException("Unsupported conversion: "
170 + sourceStream.getFormat().toString() + " to "
171 + targetFormat.toString());
172 return getConvertedStream( targetFormat, sourceStream );
173 }
174
175 /**
176 * Opens the codec with the specified parameters.
177 * @param stream stream from which data to be processed should be read
178 * @param outputFormat desired data format of the stream after processing
179 * @return stream from which processed data may be read
180 * @throws IllegalArgumentException if the format combination supplied is
181 * not supported.
182 */
183 private AudioInputStream getConvertedStream(AudioFormat outputFormat, AudioInputStream stream) {
184
185 AudioInputStream cs = null;
186 AudioFormat inputFormat = stream.getFormat();
187
188 if( inputFormat.matches(outputFormat) ) {
189 cs = stream;
190 } else {
191 cs = new AlawCodecStream(stream, outputFormat);
192 }
193
194 return cs;
195 }
196
197 /**
198 * Obtains the set of output formats supported by the codec
199 * given a particular input format.
200 * If no output formats are supported for this input format,
201 * returns an array of length 0.
202 * @return array of supported output formats.
203 */
204 private AudioFormat[] getOutputFormats(AudioFormat inputFormat) {
205
206
207 Vector<AudioFormat> formats = new Vector<>();
208 AudioFormat format;
209
210 if (inputFormat.getSampleSizeInBits() == 16
211 && AudioFormat.Encoding.PCM_SIGNED.equals(inputFormat.getEncoding())) {
212 format = new AudioFormat(AudioFormat.Encoding.ALAW,
213 inputFormat.getSampleRate(), 8,
214 inputFormat.getChannels(),
215 inputFormat.getChannels(),
216 inputFormat.getSampleRate(), false);
217 formats.addElement(format);
218 }
219 if (inputFormat.getSampleSizeInBits() == 8
220 && AudioFormat.Encoding.ALAW.equals(inputFormat.getEncoding())) {
221 format = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED,
222 inputFormat.getSampleRate(), 16,
223 inputFormat.getChannels(),
224 inputFormat.getChannels() * 2,
225 inputFormat.getSampleRate(), false);
226 formats.addElement(format);
227 format = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED,
228 inputFormat.getSampleRate(), 16,
229 inputFormat.getChannels(),
230 inputFormat.getChannels() * 2,
231 inputFormat.getSampleRate(), true);
232 formats.addElement(format);
233 }
234
235 AudioFormat[] formatArray = new AudioFormat[formats.size()];
236 for (int i = 0; i < formatArray.length; i++) {
237 formatArray[i] = formats.elementAt(i);
238 }
239 return formatArray;
240 }
241
242
243 private final class AlawCodecStream extends AudioInputStream {
244
245 // tempBuffer required only for encoding (when encode is true)
246 private static final int tempBufferSize = 64;
247 private byte tempBuffer [] = null;
248
249 /**
250 * True to encode to a-law, false to decode to linear
251 */
252 boolean encode = false;
253
254 AudioFormat encodeFormat;
255 AudioFormat decodeFormat;
256
257 byte tabByte1[] = null;
258 byte tabByte2[] = null;
259 int highByte = 0;
260 int lowByte = 1;
261
262 AlawCodecStream(AudioInputStream stream, AudioFormat outputFormat) {
263
264 super(stream, outputFormat, -1);
265
266 AudioFormat inputFormat = stream.getFormat();
267
268 // throw an IllegalArgumentException if not ok
269 if ( ! (isConversionSupported(outputFormat, inputFormat)) ) {
270
271 throw new IllegalArgumentException("Unsupported conversion: " + inputFormat.toString() + " to " + outputFormat.toString());
272 }
273
274 //$$fb 2002-07-18: fix for 4714846: JavaSound ULAW (8-bit) encoder erroneously depends on endian-ness
275 boolean PCMIsBigEndian;
276
277 // determine whether we are encoding or decoding
278 if (AudioFormat.Encoding.ALAW.equals(inputFormat.getEncoding())) {
279 encode = false;
280 encodeFormat = inputFormat;
281 decodeFormat = outputFormat;
282 PCMIsBigEndian = outputFormat.isBigEndian();
283 } else {
284 encode = true;
285 encodeFormat = outputFormat;
286 decodeFormat = inputFormat;
287 PCMIsBigEndian = inputFormat.isBigEndian();
288 tempBuffer = new byte[tempBufferSize];
289 }
290
291 if (PCMIsBigEndian) {
292 tabByte1 = ALAW_TABH;
293 tabByte2 = ALAW_TABL;
294 highByte = 0;
295 lowByte = 1;
296 } else {
297 tabByte1 = ALAW_TABL;
298 tabByte2 = ALAW_TABH;
299 highByte = 1;
300 lowByte = 0;
301 }
302
303 // set the AudioInputStream length in frames if we know it
304 if (stream instanceof AudioInputStream) {
305 frameLength = stream.getFrameLength();
306 }
307
308 // set framePos to zero
309 framePos = 0;
310 frameSize = inputFormat.getFrameSize();
311 if( frameSize==AudioSystem.NOT_SPECIFIED ) {
312 frameSize=1;
313 }
314 }
315
316
317 /*
318 * $$jb 2/23/99
319 * Used to determine segment number in aLaw encoding
320 */
321 private short search(short val, short table[], short size) {
322 for(short i = 0; i < size; i++) {
323 if (val <= table[i]) { return i; }
324 }
325 return size;
326 }
327
328 /**
329 * Note that this won't actually read anything; must read in
330 * two-byte units.
331 */
332 @Override
333 public int read() throws IOException {
334
335 byte[] b = new byte[1];
336 return read(b, 0, b.length);
337 }
338
339 @Override
340 public int read(byte[] b) throws IOException {
341
342 return read(b, 0, b.length);
343 }
344
345 @Override
346 public int read(byte[] b, int off, int len) throws IOException {
347
348 // don't read fractional frames
349 if( len%frameSize != 0 ) {
350 len -= (len%frameSize);
351 }
352
353 if (encode) {
354
355 short QUANT_MASK = 0xF;
356 short SEG_SHIFT = 4;
357 short mask;
358 short seg;
359 int adj;
360 int i;
361
362 short sample;
363 byte enc;
364
365 int readCount = 0;
366 int currentPos = off;
367 int readLeft = len*2;
368 int readLen = ( (readLeft>tempBufferSize) ? tempBufferSize : readLeft );
369
370 while ((readCount = super.read(tempBuffer,0,readLen))>0) {
371
372 for (i = 0; i < readCount; i+=2) {
373
374 /* Get the sample from the tempBuffer */
375 sample = (short)(( (tempBuffer[i + highByte]) << 8) & 0xFF00);
376 sample |= (short)( (tempBuffer[i + lowByte]) & 0xFF);
377
378 if(sample >= 0) {
379 mask = 0xD5;
380 } else {
381 mask = 0x55;
382 sample = (short)(-sample - 8);
383 }
384 /* Convert the scaled magnitude to segment number. */
385 seg = search(sample, seg_end, (short) 8);
386 /*
387 * Combine the sign, segment, quantization bits
388 */
389 if (seg >= 8) { /* out of range, return maximum value. */
390 enc = (byte) (0x7F ^ mask);
391 } else {
392 enc = (byte) (seg << SEG_SHIFT);
393 if(seg < 2) {
394 enc |= (byte) ( (sample >> 4) & QUANT_MASK);
395 } else {
396 enc |= (byte) ( (sample >> (seg + 3)) & QUANT_MASK );
397 }
398 enc ^= mask;
399 }
400 /* Now put the encoded sample where it belongs */
401 b[currentPos] = enc;
402 currentPos++;
403 }
404 /* And update pointers and counters for next iteration */
405 readLeft -= readCount;
406 readLen = ( (readLeft>tempBufferSize) ? tempBufferSize : readLeft );
407 }
408
409 if( currentPos==off && readCount<0 ) { // EOF or error
410 return readCount;
411 }
412
413 return (currentPos - off); /* Number of bytes written to new buffer */
414
415 } else {
416
417 int i;
418 int readLen = len/2;
419 int readOffset = off + len/2;
420 int readCount = super.read(b, readOffset, readLen);
421
422 for (i = off; i < (off + (readCount*2)); i+=2) {
423 b[i] = tabByte1[b[readOffset] & 0xFF];
424 b[i+1] = tabByte2[b[readOffset] & 0xFF];
425 readOffset++;
426 }
427
428 if( readCount<0 ) { // EOF or error
429 return readCount;
430 }
431
432 return (i - off);
433 }
434 }
435
436 @Override
437 public long skip(final long n) throws IOException {
438 // Implementation of this method assumes that we support
439 // encoding/decoding from/to 8/16 bits only
440 return encode ? super.skip(n * 2) / 2 : super.skip(n / 2) * 2;
441 }
442 } // end class AlawCodecStream
443 } // end class ALAW