java.lang.Object
- com.google.android.exoplayer2.transformer.Transformer

```
public final class Transformer
extends Object
```
A transformer to transform media inputs.
The same Transformer instance can be used to transform multiple inputs (sequentially, not concurrently).
Transformer instances must be accessed from a single application thread. For the vast majority of cases this should be the application's main thread. The thread on which a Transformer instance must be accessed can be explicitly specified by passing a Looper when creating the transformer. If no Looper is specified, then the Looper of the thread that the Transformer.Builder is created on is used, or if that thread does not have a Looper, the Looper of the application's main thread is used. In all cases the Looper of the thread from which the transformer must be accessed can be queried using getApplicationLooper().

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static class`	`Transformer.Builder`	A builder for `Transformer` instances.
`static interface`	`Transformer.Listener`	A listener for the transformation events.
`static interface`	`Transformer.ProgressState`	Progress state.

Field Summary

Fields
Modifier and Type	Field	Description
`static int`	`PROGRESS_STATE_AVAILABLE`	Indicates that the progress is available.
`static int`	`PROGRESS_STATE_NO_TRANSFORMATION`	Indicates that there is no current transformation.
`static int`	`PROGRESS_STATE_UNAVAILABLE`	Indicates that the progress is permanently unavailable for the current transformation.
`static int`	`PROGRESS_STATE_WAITING_FOR_AVAILABILITY`	Indicates that the progress is unavailable for the current transformation, but might become available.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`Transformer.Builder`	`buildUpon()`	Returns a `Transformer.Builder` initialized with the values of this instance.
`void`	`cancel()`	Cancels the transformation that is currently in progress, if any.
`Looper`	`getApplicationLooper()`	Returns the `Looper` associated with the application thread that's used to access the transformer and on which transformer events are received.
`int`	`getProgress(ProgressHolder progressHolder)`	Returns the current `Transformer.ProgressState` and updates `progressHolder` with the current progress if it is `available`.
`void`	`setListener(Transformer.Listener listener)`	Sets the `Transformer.Listener` to listen to the transformation events.
`void`	`startTransformation(MediaItem mediaItem, ParcelFileDescriptor parcelFileDescriptor)`	Starts an asynchronous operation to transform the given `MediaItem`.
`void`	`startTransformation(MediaItem mediaItem, String path)`	Starts an asynchronous operation to transform the given `MediaItem`.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - PROGRESS_STATE_WAITING_FOR_AVAILABILITY
```
public static final int PROGRESS_STATE_WAITING_FOR_AVAILABILITY
```
    Indicates that the progress is unavailable for the current transformation, but might become available.
    
    See Also:
    
    Constant Field Values
  - PROGRESS_STATE_AVAILABLE
```
public static final int PROGRESS_STATE_AVAILABLE
```
    Indicates that the progress is available.
    
    See Also:
    
    Constant Field Values
  - PROGRESS_STATE_UNAVAILABLE
```
public static final int PROGRESS_STATE_UNAVAILABLE
```
    Indicates that the progress is permanently unavailable for the current transformation.
    
    See Also:
    
    Constant Field Values
  - PROGRESS_STATE_NO_TRANSFORMATION
```
public static final int PROGRESS_STATE_NO_TRANSFORMATION
```
    Indicates that there is no current transformation.
    
    See Also:
    
    Constant Field Values
- Method Detail
  - buildUpon
```
public Transformer.Builder buildUpon()
```
    Returns a Transformer.Builder initialized with the values of this instance.
  - setListener
```
public void setListener(Transformer.Listener listener)
```
    Sets the Transformer.Listener to listen to the transformation events.
    
    Parameters:
    
    listener - A Transformer.Listener.
    
    Throws:
    
    IllegalStateException - If this method is called from the wrong thread.
  - startTransformation
```
public void startTransformation(MediaItem mediaItem,
                                String path)
                         throws IOException
```
    Starts an asynchronous operation to transform the given MediaItem.
    The transformation state is notified through the listener.
    Concurrent transformations on the same Transformer object are not allowed.
    The output can contain at most one video track and one audio track. Other track types are ignored. For adaptive bitrate media sources, the highest bitrate video and audio streams are selected.
    
    Parameters:
    
    mediaItem - The MediaItem to transform. The supported sample formats depend on the output container format and are described in MediaMuxer.addTrack(MediaFormat).
    
    path - The path to the output file.
    
    Throws:
    
    IllegalArgumentException - If the path is invalid.
    
    IllegalStateException - If this method is called from the wrong thread.
    
    IllegalStateException - If a transformation is already in progress.
    
    IOException - If an error occurs opening the output file for writing.
  - startTransformation
```
public void startTransformation(MediaItem mediaItem,
                                ParcelFileDescriptor parcelFileDescriptor)
                         throws IOException
```
    Starts an asynchronous operation to transform the given MediaItem.
    The transformation state is notified through the listener.
    Concurrent transformations on the same Transformer object are not allowed.
    The output can contain at most one video track and one audio track. Other track types are ignored. For adaptive bitrate media sources, the highest bitrate video and audio streams are selected.
    
    Parameters:
    
    mediaItem - The MediaItem to transform. The supported sample formats depend on the output container format and are described in MediaMuxer.addTrack(MediaFormat).
    
    parcelFileDescriptor - A readable and writable ParcelFileDescriptor of the output. The file referenced by this ParcelFileDescriptor should not be used before the transformation is completed. It is the responsibility of the caller to close the ParcelFileDescriptor. This can be done after this method returns.
    
    Throws:
    
    IllegalArgumentException - If the file descriptor is invalid.
    
    IllegalStateException - If this method is called from the wrong thread.
    
    IllegalStateException - If a transformation is already in progress.
    
    IOException - If an error occurs opening the output file for writing.
  - getApplicationLooper
```
public Looper getApplicationLooper()
```
    Returns the Looper associated with the application thread that's used to access the transformer and on which transformer events are received.
  - getProgress
```
@ProgressState
public int getProgress(ProgressHolder progressHolder)
```
    Returns the current Transformer.ProgressState and updates progressHolder with the current progress if it is available.
    After a transformation completes, this method returns PROGRESS_STATE_NO_TRANSFORMATION.
    
    Parameters:
    
    progressHolder - A ProgressHolder, updated to hold the percentage progress if available.
    
    Returns:
    
    The Transformer.ProgressState.
    
    Throws:
    
    IllegalStateException - If this method is called from the wrong thread.
  - cancel
```
public void cancel()
```
    Cancels the transformation that is currently in progress, if any.
    
    Throws:
    
    IllegalStateException - If this method is called from the wrong thread.

Class Transformer

Nested Class Summary

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

PROGRESS_STATE_WAITING_FOR_AVAILABILITY

PROGRESS_STATE_AVAILABLE

PROGRESS_STATE_UNAVAILABLE

PROGRESS_STATE_NO_TRANSFORMATION

Method Detail

buildUpon

setListener

startTransformation

startTransformation

getApplicationLooper

getProgress

cancel