io.humble.video.customio

Class NullProtocolHandler

java.lang.Object

io.humble.video.customio.NullProtocolHandler

All Implemented Interfaces:

IURLProtocolHandler

public class NullProtocolHandler
extends Object
implements IURLProtocolHandler

The NullProtocolHandler implements IURLProtocolHandler, but discards any data written and always returns 0 for reading.

This can be useful if your operating system doesn't have the unix equivalent of /dev/null or you want to cheaply discard data.

Author:

aclarke

Field Summary

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

Method Summary

Modifier and Type	Method and Description
int	close() A request to close() from FFMPEG
boolean	isStreamed(String aUrl, int aFlags) Special callback made by Humble Video in order to determine if your stream supports streaming.
int	open(String aUrl, int aFlags) This method gets called by FFMPEG when it opens a file.
int	read(byte[] aBuf, int aSize) This method gets called by FFMPEG when it tries to read data.
long	seek(long aOffset, int aWhence) A request from FFMPEG to seek to a position in the stream.
int	write(byte[] aBuf, int aSize) 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

Method Detail

close

public int close()

Description copied from interface: IURLProtocolHandler

A request to close() from FFMPEG

Specified by:

close in interface IURLProtocolHandler

Returns:

-1 on error; else >= 0

isStreamed

public boolean isStreamed(String aUrl,
                          int aFlags)

Description copied from interface: IURLProtocolHandler

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.

Specified by:

isStreamed in interface IURLProtocolHandler

Parameters:

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

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

Returns:

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

open

public int open(String aUrl,
                int aFlags)

Description copied from interface: IURLProtocolHandler

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

Specified by:

open in interface IURLProtocolHandler

Parameters:

aUrl - The URL to open

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

Returns:

>= 0 for success; -1 for error.

read

public int read(byte[] aBuf,
                int aSize)

Description copied from interface: IURLProtocolHandler

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:

aBuf - The buffer to write your data to.

aSize - 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 aOffset,
                 int aWhence)

Description copied from interface: IURLProtocolHandler

A request from FFMPEG to seek to a position in the stream.

Specified by:

seek in interface IURLProtocolHandler

Parameters:

aOffset - The offset in bytes.

aWhence - 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[] aBuf,
                 int aSize)

Description copied from interface: IURLProtocolHandler

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:

aBuf - The data you should write.

aSize - The number of bytes in buf.

Returns:

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