// Near Infinity - An Infinity Engine Browser and Editor
// Copyright (C) 2001 - 2005 Jon Olav Hauglid
// See LICENSE.txt for license information
package org.infinity.resource.video;
import java.util.Arrays;
import javax.sound.sampled.AudioFormat;
import org.infinity.resource.video.MveDecoder.MveInfo;
import org.infinity.resource.video.MveDecoder.MveSegment;
/**
* Decodes a single frame of audio data. (Internally used by MveDecoder)
*/
public class MveAudioDecoder
{
// 256 delta entries for compressed audio
private static short[] DELTA = {
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 47, 51, 56, 61,
66, 72, 79, 86, 94, 102, 112, 122, 133, 145, 158, 173, 189, 206, 225, 245,
267, 292, 318, 348, 379, 414, 452, 493, 538, 587, 640, 699, 763, 832, 908, 991,
1081, 1180, 1288, 1405, 1534, 1673, 1826, 1993, 2175, 2373, 2590, 2826, 3084, 3365, 3672, 4008,
4373, 4772, 5208, 5683, 6202, 6767, 7385, 8059, 8794, 9597, 10472, 11428, 12471, 13609, 14851, 16206,
17685, 19298, 21060, 22981, 25078, 27367, 29864, 32589, -29973, -26728, -23186, -19322, -15105, -10503, -5481, -1,
1, 1, 5481, 10503, 15105, 19322, 23186, 26728, 29973, -32589, -29864, -27367, -25078, -22981, -21060, -19298,
-17685, -16206, -14851, -13609, -12471, -11428, -10472, -9597, -8794, -8059, -7385, -6767, -6202, -5683, -5208, -4772,
-4373, -4008, -3672, -3365, -3084, -2826, -2590, -2373, -2175, -1993, -1826, -1673, -1534, -1405, -1288, -1180,
-1081, -991, -908, -832, -763, -699, -640, -587, -538, -493, -452, -414, -379, -348, -318, -292,
-267, -245, -225, -206, -189, -173, -158, -145, -133, -122, -112, -102, -94, -86, -79, -72,
-66, -61, -56, -51, -47, -43, -42, -41, -40, -39, -38, -37, -36, -35, -34, -33,
-32, -31, -30, -29, -28, -27, -26, -25, -24, -23, -22, -21, -20, -19, -18, -17,
-16, -15, -14, -13, -12, -11, -10, -9, -8, -7, -6, -5, -4, -3, -2, -1
};
// the currently used MVE info structure
private final MveInfo info;
private boolean isAudioInit; // set when audio initialization occured in the current chunk
/**
* Creates a new MveAudioDecoder object. Constructor is not publicly accessible.
* @param info Info structure containing all MVE related data.
* @return An MveAudioDecoder object on success, {@code null} otherwise.
*/
public static MveAudioDecoder createDecoder(MveInfo info)
{
if (info != null) {
return new MveAudioDecoder(info);
} else {
return null;
}
}
/**
* Processes audio specific segments.
* @param segment The current segment to process.
* @return {@code true} if the segment has been processed successfully,
* {@code false} if the segment did not fit into the audio category.
* @throws Exception On error.
*/
public boolean processAudio(MveSegment segment) throws Exception
{
if (info == null || segment == null)
throw new NullPointerException();
switch (segment.getOpcode()) {
case MveDecoder.MVE_OC_END_OF_STREAM: // do final clean up
shutDown();
break;
case MveDecoder.MVE_OC_END_OF_CHUNK: // do some temporary clean up
cleanUp();
break;
case MveDecoder.MVE_OC_AUDIO_BUFFERS: // initializes audio properties
processInitAudio(segment);
break;
case MveDecoder.MVE_OC_PLAY_AUDIO: // ignored
break;
case MveDecoder.MVE_OC_AUDIO_DATA: // decodes a frame worth of audio data
if (info.audioCompressed) {
processCompressedAudio(segment);
} else {
processUncompressedAudio(segment);
}
break;
case MveDecoder.MVE_OC_AUDIO_SILENCE: // generates a frame worth of silence
processSilence(segment);
break;
default:
return false;
}
return true;
}
/**
* Properly releases temporary resources.
*/
public void close()
{
shutDown();
}
private MveAudioDecoder(MveInfo info)
{
if (info == null)
throw new NullPointerException();
this.info = info;
}
// cleans up temporary data
private void cleanUp()
{
info.audioInitialized = isAudioInit;
isAudioInit = false;
}
// cleans up all MVE specific
private void shutDown()
{
// nothing to do (yet)
}
// initializes audio properties
private void processInitAudio(MveSegment segment) throws Exception
{
isAudioInit = true;
if (segment != null && segment.getOpcode() == MveDecoder.MVE_OC_AUDIO_BUFFERS) {
int flags, channels, bitsPerSample, sampleRate;
switch (segment.getVersion()) {
case 0:
segment.getBits(16); // bogus data
flags = segment.getBits(16);
channels = ((flags & MveDecoder.MVE_AUDIO_STEREO) != 0) ? 2 : 1;
bitsPerSample = ((flags & MveDecoder.MVE_AUDIO_16BIT) != 0) ? 16 : 8;
sampleRate = segment.getBits(16);
info.audioCompressed = false;
segment.getBits(16); // buffer length (not needed)
break;
case 1:
segment.getBits(16); // bogus data
flags = segment.getBits(16);
channels = ((flags & MveDecoder.MVE_AUDIO_STEREO) != 0) ? 2 : 1;
bitsPerSample = ((flags & MveDecoder.MVE_AUDIO_16BIT) != 0) ? 16 : 8;
info.audioCompressed = ((flags & MveDecoder.MVE_AUDIO_COMPRESSED) != 0);
sampleRate = segment.getBits(16);
segment.getBits(32); // buffer length (not needed)
break;
default:
throw new Exception("Unsupported version: " + segment.getVersion());
}
info.audioFormat = new AudioFormat((float)sampleRate, bitsPerSample, channels, (bitsPerSample != 8), false);
}
}
// writes an audio frame worth of silent data
private void processSilence(MveSegment segment) throws Exception
{
int index = segment.getBits(16); // sequential index of the audio frame
int mask = segment.getBits(16); // channel mask
int len = segment.getBits(16); // total size of the uncompressed audio block in bytes
if (len < 0)
len = 0;
updateTimer(len);
byte[] block = null;
AudioQueue queue;
for (int i = 0; i < MveInfo.AUDIOSTREAMS_MAX; i++) {
if ((mask & (1 << i)) != 0) {
queue = info.audioOutput.get(i);
if (queue != null) {
if (block == null) {
block = new byte[len];
Arrays.fill(block, (byte)0);
}
queue.addAudioBlock(index, block);
}
}
}
}
// writes an audio frame worth of uncompressed audio data
private void processUncompressedAudio(MveSegment segment) throws Exception
{
int index = segment.getBits(16); // sequential index of the audio frame
int mask = segment.getBits(16); // channel mask
int len = segment.getBits(16); // total size of the uncompressed audio block in bytes
if (len < 0)
len = 0;
updateTimer(len);
byte[] block = null;
AudioQueue queue;
for (int i = 0; i < MveInfo.AUDIOSTREAMS_MAX; i++) {
if ((mask & (1 << i)) != 0) {
queue = info.audioOutput.get(i);
if (queue != null) {
if (block == null) {
block = new byte[len];
System.arraycopy(segment.getData(), 6, block, 0, len);
}
queue.addAudioBlock(index, block);
}
}
}
}
// decodes and writes an audio frame worth of compressed audio data
private void processCompressedAudio(MveSegment segment) throws Exception
{
if (info.audioFormat.getSampleSizeInBits() != 16)
throw new Exception("Unsupported bits per samples: " + info.audioFormat.getSampleSizeInBits());
int index = segment.getBits(16); // sequential index of the audio frame
int mask = segment.getBits(16); // channel mask
int len = segment.getBits(16); // total size of the uncompressed audio block in bytes
if (len < 0)
len = 0;
updateTimer(len);
short[] predictor = null;
byte[] block = null;
AudioQueue queue;
for (int i = 0; i < MveInfo.AUDIOSTREAMS_MAX; i++) {
if ((mask & (1 << i)) != 0) {
queue = info.audioOutput.get(i);
if (queue != null) {
if (block == null) {
int channelMask = info.audioFormat.getChannels() >>> 1;
int outOfs = 0;
block = new byte[len];
predictor = new short[2];
// initializing start value
for (int j = 0; j < info.audioFormat.getChannels(); j++) {
predictor[j] = (short)segment.getBits(16);
block[outOfs++] = (byte)(predictor[j] & 0xff);
block[outOfs++] = (byte)(predictor[j] >>> 8);
}
// decoding deltas
int channel = 0;
while (outOfs < len) {
predictor[channel] += DELTA[segment.getBits(8)];
block[outOfs++] = (byte)(predictor[channel] & 0xff);
block[outOfs++] = (byte)(predictor[channel] >>> 8);
channel = (channel + 1) & channelMask;
}
}
queue.addAudioBlock(index, block);
}
}
}
}
private void updateTimer(int frameSize)
{
if (!info.isFrameDelayStable) {
info.frameDelay = (int)((1000000L * frameSize) / ((long)info.audioFormat.getSampleRate() *
info.audioFormat.getChannels() *
info.audioFormat.getSampleSizeInBits() / 8L));
}
}
}