SampleFrequency.java

package net.sourceforge.jaad.aac;

/**
 * This class is part of JAAD ( jaadec.sourceforge.net ) that is distributed
 * under the Public Domain license. Code changes provided by the JCodec project
 * are distributed under FreeBSD license.
 * 
 * An enumeration that represents all possible sample frequencies AAC data can
 * have.
 * 
 * @author in-somnia
 */
public final class SampleFrequency {

    public final static SampleFrequency SAMPLE_FREQUENCY_96000 = new SampleFrequency(0, 96000, new int[] { 33, 512 },
            new int[] { 31, 9 });
    public final static SampleFrequency SAMPLE_FREQUENCY_88200 = new SampleFrequency(1, 88200, new int[] { 33, 512 },
            new int[] { 31, 9 });
    public final static SampleFrequency SAMPLE_FREQUENCY_64000 = new SampleFrequency(2, 64000, new int[] { 38, 664 },
            new int[] { 34, 10 });
    public final static SampleFrequency SAMPLE_FREQUENCY_48000 = new SampleFrequency(3, 48000, new int[] { 40, 672 },
            new int[] { 40, 14 });
    public final static SampleFrequency SAMPLE_FREQUENCY_44100 = new SampleFrequency(4, 44100, new int[] { 40, 672 },
            new int[] { 42, 14 });
    public final static SampleFrequency SAMPLE_FREQUENCY_32000 = new SampleFrequency(5, 32000, new int[] { 40, 672 },
            new int[] { 51, 14 });
    public final static SampleFrequency SAMPLE_FREQUENCY_24000 = new SampleFrequency(6, 24000, new int[] { 41, 652 },
            new int[] { 46, 14 });
    public final static SampleFrequency SAMPLE_FREQUENCY_22050 = new SampleFrequency(7, 22050, new int[] { 41, 652 },
            new int[] { 46, 14 });
    public final static SampleFrequency SAMPLE_FREQUENCY_16000 = new SampleFrequency(8, 16000, new int[] { 37, 664 },
            new int[] { 42, 14 });
    public final static SampleFrequency SAMPLE_FREQUENCY_12000 = new SampleFrequency(9, 12000, new int[] { 37, 664 },
            new int[] { 42, 14 });
    public final static SampleFrequency SAMPLE_FREQUENCY_11025 = new SampleFrequency(10, 11025, new int[] { 37, 664 },
            new int[] { 42, 14 });
    public final static SampleFrequency SAMPLE_FREQUENCY_8000 = new SampleFrequency(11, 8000, new int[] { 34, 664 },
            new int[] { 39, 14 });
    public final static SampleFrequency SAMPLE_FREQUENCY_NONE = new SampleFrequency(-1, 0, new int[] { 0, 0 },
            new int[] { 0, 0 });

    private final static SampleFrequency[] _values = new SampleFrequency[] { SAMPLE_FREQUENCY_96000,
            SAMPLE_FREQUENCY_88200, SAMPLE_FREQUENCY_64000, SAMPLE_FREQUENCY_48000, SAMPLE_FREQUENCY_44100,
            SAMPLE_FREQUENCY_32000, SAMPLE_FREQUENCY_24000, SAMPLE_FREQUENCY_22050, SAMPLE_FREQUENCY_16000,
            SAMPLE_FREQUENCY_12000, SAMPLE_FREQUENCY_11025, SAMPLE_FREQUENCY_8000, SAMPLE_FREQUENCY_NONE };

    public static SampleFrequency[] values() {
        return _values;
    }

    /**
     * Returns a sample frequency instance for the given index. If the index is
     * not between 0 and 11 inclusive, SAMPLE_FREQUENCY_NONE is returned.
     * 
     * @return a sample frequency with the given index
     */
    public static SampleFrequency forInt(int i) {
        final SampleFrequency freq;
        if (i >= 0 && i < 12)
            freq = values()[i];
        else
            freq = SAMPLE_FREQUENCY_NONE;
        return freq;
    }

    public static SampleFrequency forFrequency(int i) {
        final SampleFrequency[] all = values();

        SampleFrequency freq = null;
        for (int j = 0; freq == null && j < 12; j++) {
            if (i == all[j].frequency)
                freq = all[j];
        }

        if (freq == null)
            freq = SAMPLE_FREQUENCY_NONE;
        return freq;
    }

    private final int index, frequency;
    private final int[] prediction, maxTNS_SFB;

    private SampleFrequency(int index, int freqency, int[] prediction, int[] maxTNS_SFB) {
        this.index = index;
        this.frequency = freqency;
        this.prediction = prediction;
        this.maxTNS_SFB = maxTNS_SFB;
    }

    /**
     * Returns this sample frequency's index between 0 (96000) and 11 (8000) or
     * -1 if this is SAMPLE_FREQUENCY_NONE.
     * 
     * @return the sample frequency's index
     */
    public int getIndex() {
        return index;
    }

    /**
     * Returns the sample frequency as integer value. This may be a value
     * between 96000 and 8000, or 0 if this is SAMPLE_FREQUENCY_NONE.
     * 
     * @return the sample frequency
     */
    public int getFrequency() {
        return frequency;
    }

    /**
     * Returns the highest scale factor band allowed for ICPrediction at this
     * sample frequency. This method is mainly used internally.
     * 
     * @return the highest prediction SFB
     */
    public int getMaximalPredictionSFB() {
        return prediction[0];
    }

    /**
     * Returns the number of predictors allowed for ICPrediction at this sample
     * frequency. This method is mainly used internally.
     * 
     * @return the number of ICPredictors
     */
    public int getPredictorCount() {
        return prediction[1];
    }

    /**
     * Returns the highest scale factor band allowed for TNS at this sample
     * frequency. This method is mainly used internally.
     * 
     * @return the highest SFB for TNS
     */
    public int getMaximalTNS_SFB(boolean shortWindow) {
        return maxTNS_SFB[shortWindow ? 1 : 0];
    }

    /**
     * Returns a string representation of this sample frequency. The method is
     * identical to <code>getDescription()</code>.
     * 
     * @return the sample frequency's description
     */
    @Override
    public String toString() {
        return Integer.toString(frequency);
    }
}