# WebvttExtractor

Artifact: [androidx.media3:media3-exoplayer-hls](https://developer.android.com/jetpack/androidx/releases/media3) [View Source](https://cs.android.com/search?q=file:androidx/media3/exoplayer/hls/WebvttExtractor.java+class:androidx.media3.exoplayer.hls.WebvttExtractor)

*** ** * ** ***


```
@UnstableApi
public final class WebvttExtractor implements Extractor
```

<br />

*** ** * ** ***

A special purpose extractor for WebVTT content in HLS.

This extractor passes through non-empty WebVTT files untouched, however derives the correct sample timestamp for each by sniffing the X-TIMESTAMP-MAP header along with the start timestamp of the first cue header. Empty WebVTT files are not passed through, since it's not possible to derive a sample timestamp in this case.

## Summary

| ### Public constructors |
|---|
| `[WebvttExtractor](https://developer.android.com/reference/androidx/media3/exoplayer/hls/WebvttExtractor#WebvttExtractor(java.lang.String,androidx.media3.common.util.TimestampAdjuster))( @https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/java/lang/String.html language, https://developer.android.com/reference/androidx/media3/common/util/TimestampAdjuster timestampAdjuster )` **This method is deprecated.** Use `https://developer.android.com/reference/androidx/media3/exoplayer/hls/WebvttExtractor#WebvttExtractor(java.lang.String,androidx.media3.common.util.TimestampAdjuster,androidx.media3.extractor.text.SubtitleParser.Factory,boolean)` instead. <br /> |
| `https://developer.android.com/reference/androidx/media3/exoplayer/hls/WebvttExtractor#WebvttExtractor(java.lang.String,androidx.media3.common.util.TimestampAdjuster,androidx.media3.extractor.text.SubtitleParser.Factory,boolean)( @https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/java/lang/String.html language, https://developer.android.com/reference/androidx/media3/common/util/TimestampAdjuster timestampAdjuster, https://developer.android.com/reference/androidx/media3/extractor/text/SubtitleParser.Factory subtitleParserFactory, boolean parseSubtitlesDuringExtraction )` |

| ### Public methods |
|---|---|
| `void` | `https://developer.android.com/reference/androidx/media3/exoplayer/hls/WebvttExtractor#init(androidx.media3.extractor.ExtractorOutput)(https://developer.android.com/reference/androidx/media3/extractor/ExtractorOutput output)` Initializes the extractor with an `https://developer.android.com/reference/androidx/media3/extractor/ExtractorOutput`. |
| `int` | `https://developer.android.com/reference/androidx/media3/exoplayer/hls/WebvttExtractor#read(androidx.media3.extractor.ExtractorInput,androidx.media3.extractor.PositionHolder)(https://developer.android.com/reference/androidx/media3/extractor/ExtractorInput input, https://developer.android.com/reference/androidx/media3/extractor/PositionHolder seekPosition)` Extracts data read from a provided `https://developer.android.com/reference/androidx/media3/extractor/ExtractorInput`. |
| `void` | `https://developer.android.com/reference/androidx/media3/exoplayer/hls/WebvttExtractor#release()()` Releases all kept resources. |
| `void` | `https://developer.android.com/reference/androidx/media3/exoplayer/hls/WebvttExtractor#seek(long,long)(long position, long timeUs)` Notifies the extractor that a seek has occurred. |
| `boolean` | `https://developer.android.com/reference/androidx/media3/exoplayer/hls/WebvttExtractor#sniff(androidx.media3.extractor.ExtractorInput)(https://developer.android.com/reference/androidx/media3/extractor/ExtractorInput input)` Returns whether this extractor can extract samples from the `https://developer.android.com/reference/androidx/media3/extractor/ExtractorInput`, which must provide data from the start of the stream. |

| ### Inherited Constants |
|---|
| From [androidx.media3.extractor.Extractor](https://developer.android.com/reference/androidx/media3/extractor/Extractor) |---|---| | `static final int` | `https://developer.android.com/reference/androidx/media3/extractor/Extractor#RESULT_CONTINUE() = 0` Returned by `https://developer.android.com/reference/androidx/media3/extractor/Extractor#read(androidx.media3.extractor.ExtractorInput,androidx.media3.extractor.PositionHolder)` if the `https://developer.android.com/reference/androidx/media3/extractor/ExtractorInput` passed to the next `https://developer.android.com/reference/androidx/media3/extractor/Extractor#read(androidx.media3.extractor.ExtractorInput,androidx.media3.extractor.PositionHolder)` is required to provide data continuing from the position in the stream reached by the returning call. | | `static final int` | `https://developer.android.com/reference/androidx/media3/extractor/Extractor#RESULT_END_OF_INPUT() = -1` Returned by `https://developer.android.com/reference/androidx/media3/extractor/Extractor#read(androidx.media3.extractor.ExtractorInput,androidx.media3.extractor.PositionHolder)` if the end of the `https://developer.android.com/reference/androidx/media3/extractor/ExtractorInput` was reached. | | `static final int` | `https://developer.android.com/reference/androidx/media3/extractor/Extractor#RESULT_SEEK() = 1` Returned by `https://developer.android.com/reference/androidx/media3/extractor/Extractor#read(androidx.media3.extractor.ExtractorInput,androidx.media3.extractor.PositionHolder)` if the `https://developer.android.com/reference/androidx/media3/extractor/ExtractorInput` passed to the next `https://developer.android.com/reference/androidx/media3/extractor/Extractor#read(androidx.media3.extractor.ExtractorInput,androidx.media3.extractor.PositionHolder)` is required to provide data starting from a specified position in the stream. | |

| ### Inherited methods |
|---|
| From [androidx.media3.extractor.Extractor](https://developer.android.com/reference/androidx/media3/extractor/Extractor) |---|---| | `https://developer.android.com/reference/java/util/List.html<https://developer.android.com/reference/androidx/media3/extractor/SniffFailure>` | `https://developer.android.com/reference/androidx/media3/extractor/Extractor#getSniffFailureDetails()()` Returns additional details about the last call to `https://developer.android.com/reference/androidx/media3/extractor/Extractor#sniff(androidx.media3.extractor.ExtractorInput)`. | | `https://developer.android.com/reference/androidx/media3/extractor/Extractor` | `@https://checkerframework.org/api/org/checkerframework/dataflow/qual/SideEffectFree.html https://developer.android.com/reference/androidx/media3/extractor/Extractor#getUnderlyingImplementation()()` 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

### WebvttExtractor

```
public [WebvttExtractor](https://developer.android.com/reference/androidx/media3/exoplayer/hls/WebvttExtractor#WebvttExtractor(java.lang.String,androidx.media3.common.util.TimestampAdjuster))(
    @Nullable String language,
    TimestampAdjuster timestampAdjuster
)
```

> [!CAUTION]
> **This method is deprecated.**   
>
> Use `https://developer.android.com/reference/androidx/media3/exoplayer/hls/WebvttExtractor#WebvttExtractor(java.lang.String,androidx.media3.common.util.TimestampAdjuster,androidx.media3.extractor.text.SubtitleParser.Factory,boolean)` instead.

### WebvttExtractor

```
public WebvttExtractor(
    @Nullable String language,
    TimestampAdjuster timestampAdjuster,
    SubtitleParser.Factory subtitleParserFactory,
    boolean parseSubtitlesDuringExtraction
)
```

## Public methods

### init

```
public void init(ExtractorOutput output)
```

Initializes the extractor with an `https://developer.android.com/reference/androidx/media3/extractor/ExtractorOutput`. Called at most once.

| Parameters |
|---|---|
| `https://developer.android.com/reference/androidx/media3/extractor/ExtractorOutput output` | An `https://developer.android.com/reference/androidx/media3/extractor/ExtractorOutput` to receive extracted data. |

### read

```
public int read(ExtractorInput input, PositionHolder seekPosition)
```

Extracts data read from a provided `https://developer.android.com/reference/androidx/media3/extractor/ExtractorInput`. Must not be called before `https://developer.android.com/reference/androidx/media3/extractor/Extractor#init(androidx.media3.extractor.ExtractorOutput)`.

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, `https://developer.android.com/reference/androidx/media3/extractor/Extractor#RESULT_CONTINUE()` is returned to indicate that the `https://developer.android.com/reference/androidx/media3/extractor/ExtractorInput` 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 `https://developer.android.com/reference/androidx/media3/extractor/Extractor#RESULT_SEEK()` is returned. If the extractor reached the end of the data provided by the `https://developer.android.com/reference/androidx/media3/extractor/ExtractorInput`, then `https://developer.android.com/reference/androidx/media3/extractor/Extractor#RESULT_END_OF_INPUT()` is returned.

When this method throws an `https://developer.android.com/reference/java/io/IOException.html`, extraction may continue by providing an `https://developer.android.com/reference/androidx/media3/extractor/ExtractorInput` with an unchanged `https://developer.android.com/reference/androidx/media3/extractor/ExtractorInput#getPosition()` to a subsequent call to this method.

| Parameters |
|---|---|
| `https://developer.android.com/reference/androidx/media3/extractor/ExtractorInput input` | The `https://developer.android.com/reference/androidx/media3/extractor/ExtractorInput` from which data should be read. |
| `https://developer.android.com/reference/androidx/media3/extractor/PositionHolder seekPosition` | If `https://developer.android.com/reference/androidx/media3/extractor/Extractor#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 |
|---|---|
| `https://developer.android.com/reference/java/io/IOException.html` | If an error occurred reading from or parsing the input. |

### release

```
public void release()
```

Releases all kept resources.

### seek

```
public void seek(long position, long timeUs)
```

Notifies the extractor that a seek has occurred.

Following a call to this method, the `https://developer.android.com/reference/androidx/media3/extractor/ExtractorInput` passed to the next invocation of `https://developer.android.com/reference/androidx/media3/extractor/Extractor#read(androidx.media3.extractor.ExtractorInput,androidx.media3.extractor.PositionHolder)` 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 `https://developer.android.com/reference/androidx/media3/extractor/SeekMap` passed to the `https://developer.android.com/reference/androidx/media3/extractor/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 `https://developer.android.com/reference/androidx/media3/extractor/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 |
|---|---|
| `https://developer.android.com/reference/androidx/media3/extractor/ExtractorInput input` | The `https://developer.android.com/reference/androidx/media3/extractor/ExtractorInput` from which data should be peeked/read. |

| Returns |
|---|---|
| `boolean` | Whether this extractor can read the provided input. |

| Throws |
|---|---|
| `https://developer.android.com/reference/java/io/IOException.html` | If an error occurred reading from the input. |