net.sourceforge.javaflacencoder

Class Subframe_Fixed

java.lang.Object

net.sourceforge.javaflacencoder.Subframe

net.sourceforge.javaflacencoder.Subframe_Fixed

public class Subframe_Fixed
extends Subframe

Implements the Subframe abstract class, providing encoding support for the FLAC Fixed-predictor Subframe.

Author:

Preston Lacey

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEBUG_LEV For debugging: Higher values equals greater output, generally in increments of 10
static EncodingConfiguration.SubframeType	type Subframe type supported by this implementation.

Fields inherited from class net.sourceforge.javaflacencoder.Subframe

ec, lastEncodedSize, sc

Constructor Summary

Constructors

Constructor and Description
Subframe_Fixed(StreamConfiguration sc) Constructor.

Method Summary

Modifier and Type	Method and Description
int	encodeSamples(int[] samples, int count, int start, int skip, EncodedElement dataEle, int offset, int unencSampleSize) Encodes samples into the appropriate compressed format, saving the result in the given “data” EncodedElement list.
int	encodeSamples(int[] samples, int count, int start, int skip, int offset, int unencSampleSize)
int	estimatedSize() Return the estimated size of the previous encode attempt in bits.
EncodedElement	getData()
EncodedElement	getData(EncodedElement dataEle) Get the data from the last encode attempt.
boolean	registerConfiguration(EncodingConfiguration ec) This method is used to set the encoding configuration.

Methods inherited from class net.sourceforge.javaflacencoder.Subframe

getEncodedSize

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEBUG_LEV

public static int DEBUG_LEV

For debugging: Higher values equals greater output, generally in increments of 10

type

public static final EncodingConfiguration.SubframeType type

Subframe type supported by this implementation.

Constructor Detail

Subframe_Fixed

public Subframe_Fixed(StreamConfiguration sc)

Constructor. Sets StreamConfiguration to use. If the StreamConfiguration must later be changed, a new Subframe object must be created as well.

Parameters:

sc - StreamConfiguration to use for encoding.

Method Detail

registerConfiguration

public boolean registerConfiguration(EncodingConfiguration ec)

This method is used to set the encoding configuration.

Overrides:

registerConfiguration in class Subframe

Parameters:

ec - encoding configuration to use.

Returns:

true if configuration was changed, false otherwise

encodeSamples

public int encodeSamples(int[] samples,
                         int count,
                         int start,
                         int skip,
                         int offset,
                         int unencSampleSize)

estimatedSize

public int estimatedSize()

Return the estimated size of the previous encode attempt in bits. Since returning the data from an encode is costly(due to the rice encoding and FLAC compliant bit-packing), this allows us to estimate the size first, and therefore choose another subframe type if this is larger.

Returns:

estimated size in bits of encoded subframe.

getData

public EncodedElement getData()

getData

public EncodedElement getData(EncodedElement dataEle)

Get the data from the last encode attempt. Data is returned in an EncodedElement, properly packed at the bit-level to be added directly to a FLAC stream.

Returns:

EncodedElement containing encoded subframe

encodeSamples

public int encodeSamples(int[] samples,
                         int count,
                         int start,
                         int skip,
                         EncodedElement dataEle,
                         int offset,
                         int unencSampleSize)

Description copied from class: Subframe

Encodes samples into the appropriate compressed format, saving the result in the given “data” EncodedElement list. Encodes 'count' samples, from index 'start', to index 'start' times 'skip', where “skip” is the format that samples may be packed in an array. For example, 'samples' may include both left and right samples of a stereo stream, while this SubFrame is only encoding the 'right' channel(channel 2). Therefore, “skip” would equal 2, resulting in the valid indices being only those where “index mod 2 equals 1”.

Specified by:

encodeSamples in class Subframe

Parameters:

samples - the audio samples to encode. This array may contain samples for multiple channels, interleaved; only one of these channels is encoded by a subframe.

count - the number of samples to encode.

start - the index to start at in the array.

skip - the number of indices to skip between successive samples (for use when channels are interleaved in the given array).

dataEle - the EncodedElement to attach encoded data to. Data in EncodedElement given is not altered. New data is attached starting with “data.getNext()”. If “data” already has a “next” set, it will be lost!

unencSampleSize - Number of bits per single-channel sample. This may differ from the StreamConfiguration's sample size, depending on the subframe used(i.e, the "side-channel" of a FLAC stream uses one extra bit compared to the input channels).

Returns:

number of encoded samples, or negative value indicating an error has occurred.