io.humble.video.customio

Class ReadableWritableChannelHandler

java.lang.Object

io.humble.video.customio.ReadableWritableChannelHandler

All Implemented Interfaces:

IURLProtocolHandler

public class ReadableWritableChannelHandler
extends Object
implements IURLProtocolHandler

Implementation of URLProtocolHandler that can read from ReadableByteChannel objects or write to WritableByteChannel object.

The IURLProtocolHandler.URL_RDWR mode is not supported, and isStreamed(String, int) will always return true.

Author:

aclarke

Field Summary

Fields

Modifier and Type	Field and Description
static boolean	CLOSE_STREAM_ON_CLOSE Whether or not this class will default calling Closeable.close() on a stream when close() is called on this method.

Fields inherited from interface io.humble.video.customio.IURLProtocolHandler

SEEK_CUR, SEEK_END, SEEK_SET, SEEK_SIZE, URL_RDONLY_MODE, URL_RDWR, URL_WRONLY_MODE

Constructor Summary

Constructors

Constructor and Description
ReadableWritableChannelHandler(ReadableByteChannel channel) Create a handler that can only be opened for reading.
ReadableWritableChannelHandler(ReadableByteChannel in, WritableByteChannel out, boolean closeStreamOnClose) Creates a new handler.
ReadableWritableChannelHandler(WritableByteChannel channel) Create a handler that can only be opened for writing.

Method Summary

Modifier and Type	Method and Description
int	close() A request to close() from FFMPEG
Channel	getOpenChannel() Returns the channel currently open(String, int).
ReadableByteChannel	getReadChannel() Returns the channel we'd input from if asked.
WritableByteChannel	getWriteChannel() Returns the channel we'd output to if asked.
boolean	isCloseStreamOnClose() Will this handler call Closeable.close() automatically when its close() method is called by Humble Video?
boolean	isStreamed(String url, int flags) Special callback made by Humble Video in order to determine if your stream supports streaming.
int	open(String url, int flags) This method gets called by FFMPEG when it opens a file.
int	read(byte[] buf, int size) This method gets called by FFMPEG when it tries to read data.
long	seek(long offset, int whence) A request from FFMPEG to seek to a position in the stream.
int	write(byte[] buf, int size) This method gets called by FFMPEG when it tries to write data.

Methods inherited from class java.lang.Object

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

Field Detail

CLOSE_STREAM_ON_CLOSE

public static final boolean CLOSE_STREAM_ON_CLOSE

Whether or not this class will default calling Closeable.close() on a stream when close() is called on this method. Can be overriden in constructors.

See Also:

Constant Field Values

Constructor Detail

ReadableWritableChannelHandler

public ReadableWritableChannelHandler(ReadableByteChannel channel)

Create a handler that can only be opened for reading.

Parameters:

channel - an input channel.

ReadableWritableChannelHandler

public ReadableWritableChannelHandler(WritableByteChannel channel)

Create a handler that can only be opened for writing.

Parameters:

channel - an output channel

ReadableWritableChannelHandler

public ReadableWritableChannelHandler(ReadableByteChannel in,
                                      WritableByteChannel out,
                                      boolean closeStreamOnClose)

Creates a new handler. If you pass in non null arguments for both in and out, the handler may be opened in either IURLProtocolHandler.URL_RDONLY_MODE or IURLProtocolHandler.URL_WRONLY_MODE, but not at the same time.

IURLProtocolHandler.URL_RDWR mode is not supported by this handler.

Parameters:

in - The channel to read from if asked to.

out - The channel to write from if asked to.

closeStreamOnClose - Whether or not to automatically call Closeable.close() on the given channel when close() is called.

Method Detail

close

public int close()

A request to close() from FFMPEG

Specified by:

close in interface IURLProtocolHandler

Returns:

-1 on error; else >= 0

open

public int open(String url,
                int flags)

This method gets called by FFMPEG when it opens a file.

Specified by:

open in interface IURLProtocolHandler

Parameters:

url - The URL to open

flags - The flags (e.g. IURLProtocolHandler.URL_RDONLY_MODE)

Returns:

>= 0 for success; -1 for error.

read

public int read(byte[] buf,
                int size)

This method gets called by FFMPEG when it tries to read data.

For non-blocking IO, return: io.humble.video.Error#typeToErrorNumber(io.humble.video.Error.Type) pass in io.humble.video.Error.Type#ERROR_AGAIN for the error type. This returns the platform specific number for EAGAIN on your platform signaling that callers should try again later.

Alternately implementors may block until data is returning, but they should then respect the Thread.isInterrupted() setting.

Specified by:

read in interface IURLProtocolHandler

Parameters:

buf - The buffer to write your data to.

size - The number of bytes in buf data available for you to write the data that FFMPEG will read.

Returns:

0 for end of file, else number of bytes you wrote to the buffer, or -1 if error.

seek

public long seek(long offset,
                 int whence)

A request from FFMPEG to seek to a position in the stream. This method is not supported on this class and always return -1;

Specified by:

seek in interface IURLProtocolHandler

Parameters:

offset - The offset in bytes.

whence - Where that offset is relative to. Follow the C stdlib fseek() conventions EXCEPT IURLProtocolHandler.SEEK_SIZE should return back the size of the stream in bytes if known without adjusting the seek pointer.

Returns:

-1 if not supported, else the position relative to whence

write

public int write(byte[] buf,
                 int size)

This method gets called by FFMPEG when it tries to write data.

For non-blocking IO, return: io.humble.video.Error#typeToErrorNumber(io.humble.video.Error.Type) pass in io.humble.video.Error.Type#ERROR_AGAIN for the error type. This returns the platform specific number for EAGAIN on your platform signaling that callers should try again later.

Alternately implementators may block until data is returning, but they should then respect the Thread.isInterrupted() setting.

Specified by:

write in interface IURLProtocolHandler

Parameters:

buf - The data you should write.

size - The number of bytes in buf.

Returns:

0 for end of file, else number of bytes you read from buf, or -1 if error.

isStreamed

public boolean isStreamed(String url,
                          int flags)

Special callback made by Humble Video in order to determine if your stream supports streaming.

If this method returns true, Humble Video will assume it cannot seek backwards in this container.

This has one main practical consequence. When writing it means certain container formats (e.g. the MOV container) will not be usable as it requires seeking back to the start of a file to write MOV required header information once the entire file has been encoded.

But if your medium is streaming, you'll want to return true for this, and then FFMPEG will not attempt to seek back in time.

Always true for this class.

Specified by:

isStreamed in interface IURLProtocolHandler

Parameters:

url - The URL that would be passed to IURLProtocolHandler.open(String, int)

flags - The flags that would be passed to IURLProtocolHandler.open(String, int)

Returns:

true if you can stream that URL; false if not.

getReadChannel

public ReadableByteChannel getReadChannel()

Returns the channel we'd input from if asked.

Returns:

the channel

getWriteChannel

public WritableByteChannel getWriteChannel()

Returns the channel we'd output to if asked.

Returns:

the channel

getOpenChannel

public Channel getOpenChannel()

Returns the channel currently open(String, int).

Returns:

the openStream

isCloseStreamOnClose

public boolean isCloseStreamOnClose()

Will this handler call Closeable.close() automatically when its close() method is called by Humble Video?

Returns:

the closeStreamOnClose setting