1 /*
2 * Copyright (c) 1999, 2016, 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.AudioFormat.Encoding;
34 import javax.sound.sampled.AudioInputStream;
35 import javax.sound.sampled.AudioSystem;
36 import javax.sound.sampled.spi.FormatConversionProvider;
37
38 /**
39 * A-law encodes linear data, and decodes a-law data to linear data.
40 *
41 * @author Kara Kytle
42 */
43 public final class AlawCodec extends FormatConversionProvider {
44
45 /* Tables used for A-law decoding */
46
47 private static final byte[] ALAW_TABH = new byte[256];
48 private static final byte[] ALAW_TABL = new byte[256];
49
50 private static final short seg_end[] = {
51 0xFF, 0x1FF, 0x3FF, 0x7FF, 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF
52 };
53
54 /**
55 * Initializes the decode tables.
56 */
57 static {
58 for (int i=0;i<256;i++) {
59 int input = i ^ 0x55;
60 int mantissa = (input & 0xf ) << 4;
61 int segment = (input & 0x70) >> 4;
62 int value = mantissa+8;
63
64 if(segment>=1)
65 value+=0x100;
66 if(segment>1)
67 value <<= (segment -1);
68
69 if( (input & 0x80)==0 )
70 value = -value;
71
72 ALAW_TABL[i] = (byte)value;
73 ALAW_TABH[i] = (byte)(value>>8);
74 }
75 }
76
77 @Override
78 public AudioFormat.Encoding[] getSourceEncodings() {
79 return new Encoding[]{Encoding.ALAW, Encoding.PCM_SIGNED};
80 }
81
82 @Override
83 public AudioFormat.Encoding[] getTargetEncodings() {
84 return getSourceEncodings();
85 }
86
87 @Override
88 public AudioFormat.Encoding[] getTargetEncodings(AudioFormat sourceFormat){
89
90 if( sourceFormat.getEncoding().equals( AudioFormat.Encoding.PCM_SIGNED )) {
91
92 if( sourceFormat.getSampleSizeInBits() == 16 ) {
93
94 AudioFormat.Encoding enc[] = new AudioFormat.Encoding[1];
95 enc[0] = AudioFormat.Encoding.ALAW;
96 return enc;
97
98 } else {
99 return new AudioFormat.Encoding[0];
100 }
101 } else if( sourceFormat.getEncoding().equals( AudioFormat.Encoding.ALAW ) ) {
102
103 if( sourceFormat.getSampleSizeInBits() == 8 ) {
104
105 AudioFormat.Encoding enc[] = new AudioFormat.Encoding[1];
106 enc[0] = AudioFormat.Encoding.PCM_SIGNED;
107 return enc;
108
109 } else {
110 return new AudioFormat.Encoding[0];
111 }
112
113 } else {
114 return new AudioFormat.Encoding[0];
115 }
116 }
117
118 @Override
119 public AudioFormat[] getTargetFormats(AudioFormat.Encoding targetEncoding, AudioFormat sourceFormat){
120 Objects.requireNonNull(sourceFormat);
121 if( (targetEncoding.equals( AudioFormat.Encoding.PCM_SIGNED ) && sourceFormat.getEncoding().equals( AudioFormat.Encoding.ALAW)) ||
122 (targetEncoding.equals( AudioFormat.Encoding.ALAW) && sourceFormat.getEncoding().equals( AudioFormat.Encoding.PCM_SIGNED)) ) {
123 return getOutputFormats( sourceFormat );
124 } else {
125 return new AudioFormat[0];
126 }
127 }
128
129 @Override
130 public AudioInputStream getAudioInputStream(AudioFormat.Encoding targetEncoding, AudioInputStream sourceStream){
131 AudioFormat sourceFormat = sourceStream.getFormat();
132 AudioFormat.Encoding sourceEncoding = sourceFormat.getEncoding();
133
134 if( !isConversionSupported(targetEncoding,sourceStream.getFormat()) ) {
135 throw new IllegalArgumentException("Unsupported conversion: " + sourceStream.getFormat().toString() + " to " + targetEncoding.toString());
136 }
137 if( sourceEncoding.equals( targetEncoding ) ) {
138 return sourceStream;
139 }
140 AudioFormat targetFormat = null;
141 if( sourceEncoding.equals( AudioFormat.Encoding.ALAW ) &&
142 targetEncoding.equals( AudioFormat.Encoding.PCM_SIGNED ) ) {
143
144 targetFormat = new AudioFormat( targetEncoding,
145 sourceFormat.getSampleRate(),
146 16,
147 sourceFormat.getChannels(),
148 2*sourceFormat.getChannels(),
149 sourceFormat.getSampleRate(),
150 sourceFormat.isBigEndian());
151
152 } else if( sourceEncoding.equals( AudioFormat.Encoding.PCM_SIGNED ) &&
153 targetEncoding.equals( AudioFormat.Encoding.ALAW ) ) {
154
155 targetFormat = new AudioFormat( targetEncoding,
156 sourceFormat.getSampleRate(),
157 8,
158 sourceFormat.getChannels(),
159 sourceFormat.getChannels(),
160 sourceFormat.getSampleRate(),
161 false);
162 } else {
163 throw new IllegalArgumentException("Unsupported conversion: " + sourceStream.getFormat().toString() + " to " + targetEncoding.toString());
164 }
165 return getConvertedStream(targetFormat, sourceStream);
166 }
167
168 @Override
169 public AudioInputStream getAudioInputStream(AudioFormat targetFormat, AudioInputStream sourceStream){
170 if (!isConversionSupported(targetFormat, sourceStream.getFormat()))
171 throw new IllegalArgumentException("Unsupported conversion: "
172 + sourceStream.getFormat().toString() + " to "
173 + targetFormat.toString());
174 return getConvertedStream( targetFormat, sourceStream );
175 }
176
177 /**
178 * Opens the codec with the specified parameters.
179 * @param stream stream from which data to be processed should be read
180 * @param outputFormat desired data format of the stream after processing
181 * @return stream from which processed data may be read
182 * @throws IllegalArgumentException if the format combination supplied is
183 * not supported.
184 */
185 private AudioInputStream getConvertedStream(AudioFormat outputFormat, AudioInputStream stream) {
186
187 AudioInputStream cs = null;
188 AudioFormat inputFormat = stream.getFormat();
189
190 if( inputFormat.matches(outputFormat) ) {
191 cs = stream;
192 } else {
193 cs = new AlawCodecStream(stream, outputFormat);
194 }
195
196 return cs;
197 }
198
199 /**
200 * Obtains the set of output formats supported by the codec
201 * given a particular input format.
202 * If no output formats are supported for this input format,
203 * returns an array of length 0.
204 * @return array of supported output formats.
205 */
206 private AudioFormat[] getOutputFormats(AudioFormat inputFormat) {
207
208
209 Vector<AudioFormat> formats = new Vector<>();
210 AudioFormat format;
211
212 if (inputFormat.getSampleSizeInBits() == 16
213 && AudioFormat.Encoding.PCM_SIGNED.equals(inputFormat.getEncoding())) {
214 format = new AudioFormat(AudioFormat.Encoding.ALAW,
215 inputFormat.getSampleRate(), 8,
216 inputFormat.getChannels(),
217 inputFormat.getChannels(),
218 inputFormat.getSampleRate(), false);
219 formats.addElement(format);
220 }
221 if (inputFormat.getSampleSizeInBits() == 8
222 && AudioFormat.Encoding.ALAW.equals(inputFormat.getEncoding())) {
223 format = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED,
224 inputFormat.getSampleRate(), 16,
225 inputFormat.getChannels(),
226 inputFormat.getChannels() * 2,
227 inputFormat.getSampleRate(), false);
228 formats.addElement(format);
229 format = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED,
230 inputFormat.getSampleRate(), 16,
231 inputFormat.getChannels(),
232 inputFormat.getChannels() * 2,
233 inputFormat.getSampleRate(), true);
234 formats.addElement(format);
235 }
236
237 AudioFormat[] formatArray = new AudioFormat[formats.size()];
238 for (int i = 0; i < formatArray.length; i++) {
239 formatArray[i] = formats.elementAt(i);
240 }
241 return formatArray;
242 }
243
244
245 private final class AlawCodecStream extends AudioInputStream {
246
247 // tempBuffer required only for encoding (when encode is true)
248 private static final int tempBufferSize = 64;
249 private byte tempBuffer [] = null;
250
251 /**
252 * True to encode to a-law, false to decode to linear
253 */
254 boolean encode = false;
255
256 AudioFormat encodeFormat;
257 AudioFormat decodeFormat;
258
259 byte tabByte1[] = null;
260 byte tabByte2[] = null;
261 int highByte = 0;
262 int lowByte = 1;
263
264 AlawCodecStream(AudioInputStream stream, AudioFormat outputFormat) {
265
266 super(stream, outputFormat, -1);
267
268 AudioFormat inputFormat = stream.getFormat();
269
270 // throw an IllegalArgumentException if not ok
271 if ( ! (isConversionSupported(outputFormat, inputFormat)) ) {
272
273 throw new IllegalArgumentException("Unsupported conversion: " + inputFormat.toString() + " to " + outputFormat.toString());
274 }
275
276 //$$fb 2002-07-18: fix for 4714846: JavaSound ULAW (8-bit) encoder erroneously depends on endian-ness
277 boolean PCMIsBigEndian;
278
279 // determine whether we are encoding or decoding
280 if (AudioFormat.Encoding.ALAW.equals(inputFormat.getEncoding())) {
281 encode = false;
282 encodeFormat = inputFormat;
283 decodeFormat = outputFormat;
284 PCMIsBigEndian = outputFormat.isBigEndian();
285 } else {
286 encode = true;
287 encodeFormat = outputFormat;
288 decodeFormat = inputFormat;
289 PCMIsBigEndian = inputFormat.isBigEndian();
290 tempBuffer = new byte[tempBufferSize];
291 }
292
293 if (PCMIsBigEndian) {
294 tabByte1 = ALAW_TABH;
295 tabByte2 = ALAW_TABL;
296 highByte = 0;
297 lowByte = 1;
298 } else {
299 tabByte1 = ALAW_TABL;
300 tabByte2 = ALAW_TABH;
301 highByte = 1;
302 lowByte = 0;
303 }
304
305 // set the AudioInputStream length in frames if we know it
306 if (stream instanceof AudioInputStream) {
307 frameLength = stream.getFrameLength();
308 }
309
310 // set framePos to zero
311 framePos = 0;
312 frameSize = inputFormat.getFrameSize();
313 if( frameSize==AudioSystem.NOT_SPECIFIED ) {
314 frameSize=1;
315 }
316 }
317
318
319 /*
320 * $$jb 2/23/99
321 * Used to determine segment number in aLaw encoding
322 */
323 private short search(short val, short table[], short size) {
324 for(short i = 0; i < size; i++) {
325 if (val <= table[i]) { return i; }
326 }
327 return size;
328 }
329
330 /**
331 * Note that this won't actually read anything; must read in
332 * two-byte units.
333 */
334 @Override
335 public int read() throws IOException {
336
337 byte[] b = new byte[1];
338 return read(b, 0, b.length);
339 }
340
341 @Override
342 public int read(byte[] b) throws IOException {
343
344 return read(b, 0, b.length);
345 }
346
347 @Override
348 public int read(byte[] b, int off, int len) throws IOException {
349
350 // don't read fractional frames
351 if( len%frameSize != 0 ) {
352 len -= (len%frameSize);
353 }
354
355 if (encode) {
356
357 short QUANT_MASK = 0xF;
358 short SEG_SHIFT = 4;
359 short mask;
360 short seg;
361 int adj;
362 int i;
363
364 short sample;
365 byte enc;
366
367 int readCount = 0;
368 int currentPos = off;
369 int readLeft = len*2;
370 int readLen = ( (readLeft>tempBufferSize) ? tempBufferSize : readLeft );
371
372 while ((readCount = super.read(tempBuffer,0,readLen))>0) {
373
374 for (i = 0; i < readCount; i+=2) {
375
376 /* Get the sample from the tempBuffer */
377 sample = (short)(( (tempBuffer[i + highByte]) << 8) & 0xFF00);
378 sample |= (short)( (tempBuffer[i + lowByte]) & 0xFF);
379
380 if(sample >= 0) {
381 mask = 0xD5;
382 } else {
383 mask = 0x55;
384 sample = (short)(-sample - 8);
385 }
386 /* Convert the scaled magnitude to segment number. */
387 seg = search(sample, seg_end, (short) 8);
388 /*
389 * Combine the sign, segment, quantization bits
390 */
391 if (seg >= 8) { /* out of range, return maximum value. */
392 enc = (byte) (0x7F ^ mask);
393 } else {
394 enc = (byte) (seg << SEG_SHIFT);
395 if(seg < 2) {
396 enc |= (byte) ( (sample >> 4) & QUANT_MASK);
397 } else {
398 enc |= (byte) ( (sample >> (seg + 3)) & QUANT_MASK );
399 }
400 enc ^= mask;
401 }
402 /* Now put the encoded sample where it belongs */
403 b[currentPos] = enc;
404 currentPos++;
405 }
406 /* And update pointers and counters for next iteration */
407 readLeft -= readCount;
408 readLen = ( (readLeft>tempBufferSize) ? tempBufferSize : readLeft );
409 }
410
411 if( currentPos==off && readCount<0 ) { // EOF or error
412 return readCount;
413 }
414
415 return (currentPos - off); /* Number of bytes written to new buffer */
416
417 } else {
418
419 int i;
420 int readLen = len/2;
421 int readOffset = off + len/2;
422 int readCount = super.read(b, readOffset, readLen);
423
424 for (i = off; i < (off + (readCount*2)); i+=2) {
425 b[i] = tabByte1[b[readOffset] & 0xFF];
426 b[i+1] = tabByte2[b[readOffset] & 0xFF];
427 readOffset++;
428 }
429
430 if( readCount<0 ) { // EOF or error
431 return readCount;
432 }
433
434 return (i - off);
435 }
436 }
437
438 @Override
439 public long skip(final long n) throws IOException {
440 // Implementation of this method assumes that we support
441 // encoding/decoding from/to 8/16 bits only
442 return encode ? super.skip(n * 2) / 2 : super.skip(n / 2) * 2;
443 }
444 } // end class AlawCodecStream
445 } // end class ALAW