This version of this document is no longer maintained. For the latest documentation, see http://www.qnx.com/developers/docs.

About This Reference

The Multimedia Developer's Guide is intended for users who want to:

use the library of multimedia interfaces and filters in their applications to work with multimedia data
create their own multimedia filters.

If you're familiar with earlier versions, you should read the "What's new" sections to find out how the multimedia API has changed in this release.

This table may help you find what you need in the Multimedia Developer's Guide:

When you want to:	Go to:
Read an overview of the Multimedia library	Multimedia Framework Overview
Learn about using the Multimedia library and QNX-provided components in your applications	Using the Multimedia library
See sample code of using the library	"Examples of using the Multimedia library" in Using the Multimedia Library
See a list of all Mm()* library functions your application can use	Multimedia Library
See more detailed information about the filters provided by QNX	Multimedia Filters reference
Learn about writing your own filters to extend the framework	Extending the Multimedia Framework
Find out more about interfaces you need to implement to write your own filters	Multimedia Interface Reference
Find out more about structures required to write your own filters	Multimedia library Structure Reference
Find out more about configuring MIDI with `midi.cfg`	The MIDI Configuration File

What's new in the Multimedia TDK 1.1

The CDDA reader has new resources to optimize performance:

MM_CDDA_BUFFER_SIZE -- buffer size, in bytes
MM_CDDA_NSECTORS_READ -- number of sectors to access on each read
MM_CDDA_NSECTORS_WRITE -- size of the output buffer, in sectors
MM_CDDA_REFILL_LOW_MARK -- bytes in the buffer below which a refill is initiated
MM_CDDA_START_PERCENT -- percent of buffer that needs to be filled before playing begins
MM_CDDA_THREAD_PRIO_INC -- reader thread priority increment

The CDDA reader also has several optimizations to improve performance.

A new Windows Media Audio (WMA) filter is included with the TDK.

In the MediaBufferAllocator interface, the second argument to the AllocateBuffers() method is now unused.

The Multimedia Developer's Guide has been substantially reorganized and rewritten:

The Using Graphs chapter is now Using the Multimedia library, and includes new information including an example of building an MPEG1 System graph.
The Writing Filters chapter is now Extending the Multimedia library, and includes new information.
Functions and structures are now separated onto their own reference pages.

The Multimedia Developer's Guide has these changes:

The Overview now lists additional supported formats, AIF, IFF, MIDI. There are two additional MPEG-1 parsers.
The MIDI parser's configuration file is described in a new appendix.