SubtitleExtractor

@UnstableApi
public class SubtitleExtractor implements Extractor


Generic extractor for extracting subtitles from various subtitle formats.

Summary

Public constructors

SubtitleExtractor(SubtitleParser subtitleParser, Format format)

Creates an instance.

Public methods

void

Initializes the extractor with an ExtractorOutput.

int
read(ExtractorInput input, PositionHolder seekPosition)

Extracts data read from a provided ExtractorInput.

void

Releases the extractor's resources, including resetting the SubtitleParser.

void
seek(long position, long timeUs)

Notifies the extractor that a seek has occurred.

boolean

Returns whether this extractor can extract samples from the ExtractorInput, which must provide data from the start of the stream.

Inherited Constants

From androidx.media3.extractor.Extractor
static final int

Returned by read if the ExtractorInput passed to the next read is required to provide data continuing from the position in the stream reached by the returning call.

static final int

Returned by read if the end of the was reached.

static final int

Returned by read if the ExtractorInput passed to the next read is required to provide data starting from a specified position in the stream.

Inherited methods

From androidx.media3.extractor.Extractor
Extractor

Returns the 'real' Extractor implementation if this is a delegating instance, or this if this instance does the extraction directly without delegating (the default behaviour).

Public constructors

SubtitleExtractor

public SubtitleExtractor(SubtitleParser subtitleParser, Format format)

Creates an instance.

Parameters
SubtitleParser subtitleParser

The parser used for parsing the subtitle data. The extractor will reset the parser in release.

Format format

Format that describes subtitle data.

Public methods

init

public void init(ExtractorOutput output)

Initializes the extractor with an ExtractorOutput. Called at most once.

Parameters
ExtractorOutput output

An ExtractorOutput to receive extracted data.

read

public int read(ExtractorInput input, PositionHolder seekPosition)

Extracts data read from a provided ExtractorInput. Must not be called before init.

A single call to this method will block until some progress has been made, but will not block for longer than this. Hence each call will consume only a small amount of input data.

In the common case, RESULT_CONTINUE is returned to indicate that the passed to the next read is required to provide data continuing from the position in the stream reached by the returning call. If the extractor requires data to be provided from a different position, then that position is set in seekPosition and RESULT_SEEK is returned. If the extractor reached the end of the data provided by the ExtractorInput, then RESULT_END_OF_INPUT is returned.

When this method throws an IOException, extraction may continue by providing an ExtractorInput with an unchanged read position to a subsequent call to this method.

Parameters
ExtractorInput input

The ExtractorInput from which data should be read.

PositionHolder seekPosition

If RESULT_SEEK is returned, this holder is updated to hold the position of the required data.

Returns
int

One of the RESULT_ values defined in this interface.

Throws
java.io.IOException

If an error occurred reading from or parsing the input.

release

public void release()

Releases the extractor's resources, including resetting the SubtitleParser.

seek

public void seek(long position, long timeUs)

Notifies the extractor that a seek has occurred.

Following a call to this method, the ExtractorInput passed to the next invocation of read is required to provide data starting from position in the stream. Valid random access positions are the start of the stream and positions that can be obtained from any SeekMap passed to the ExtractorOutput.

Parameters
long position

The byte offset in the stream from which data will be provided.

long timeUs

The seek time in microseconds.

sniff

public boolean sniff(ExtractorInput input)

Returns whether this extractor can extract samples from the ExtractorInput, which must provide data from the start of the stream.

If true is returned, the input's reading position may have been modified. Otherwise, only its peek position may have been modified.

Parameters
ExtractorInput input

The ExtractorInput from which data should be peeked/read.

Returns
boolean

Whether this extractor can read the provided input.

Throws
java.io.IOException

If an error occurred reading from the input.