Welcome to the YAPI home page !

Y-chart Application Programmer's Interface

What is YAPI

Abstract

YAPI is an application programmer's interface to write signal and stream processing applications as process networks. The communication between processes is based on Kahn Process Networks with blocking reads on theoretically unbounded fifos. The library contains a C++ run-time environment to execute applications on desktops and workstations.

History

YAPI has been developed at Philips Research. The Electronic Design and Tools department maintained and supported YAPI up to 2005. Currently, the project is hosted at SourceForge.net

Documentation

User's Guides

YAPI ( HTML | PDF | PS)

VYA: Applying YAPI to Video ( HTML | PDF | PS)

Publications

E.A. de Kock, G. Essink, W.J.M Smits, P. van der Wolf, J.-Y. Brunel, W.M. Kruijtzer, P. Lieverse, K.A. Vissers, YAPI: Application Modeling for Signal Processing Systems, Proceedings 37th Design Automation Conference, Los Angeles, 2000. PDF

Getting and Installing YAPI

Releases

The latest release is yapi-2.1.0 (Release Notes). You can browse the sources using doxygen.

YAPI Applications

We provide a few example applications. You can browse the sources using doxygen. The examples use VYA and a parsing utility.

Producer-Consumer is the hello world type of application.
Bytestream frontend and backend. The frontend converts a file to a stream of bytes. The backend converts a stream of bytes to a file.
PFSPD frontend and backend. PFSPD (Philips File Standard for Pictoral Data) is a file format for the storage of uncompressed video sequences with arbitrary word width, color space and number of components. The PFSPD frontend and backend require the CPFSPD package. They convert the PFSPD format to the VYA (Video YApi) format for streaming video data.
Video scaling. This scaling process network provides a skeleton for two dimensional video scaling of VYA compiant video streams by means of horizontal and vertical sample rate conversion. The sample rate conversion algorithms for a single color component are coded in the files src/hs.cc and src/vs.cc for horizontal and vertical scaling, respectively. The currently coded algorithms are based on sample removal for compression and sample duplication for expansion. Please insert your own sample rate convertors to obtain better quality. The test example uses the PFSPD frontend and backend.
Video multiplexing combines several VYA compliant video streams into one video streaming based on the given screen positions and depths of the images. The test example uses the PFSPD frontend and backend.
JPEG decoding of a JPEG compressed file in JFIF format into a VYA compliant video stream. In the test example the input is read from file by a bytestream frontend. The output of JPEG decoding is converted to the 4:4:4 sampling scheme using the video scaling process network. Subsequently the output is converted to the RGB format and written to file in PFSPD format by a PFSPD backend.

Contact

You can subscribe to the YAPI user's mailinglist. Please submit bugs, support requests, and feature requests through the SourceForge.net site.

Acknowledgement

We gratefully acknowledge the contributions to the development of YAPI from Jean-Yves Brunel, Arjan Kenter, Wido Kruijtzer, Paul Lieverse, Wim Smits, Kees Vissers, and Pieter van der Wolf.

We thank Kees van Zon for being our first enthousiastic user and for setting up the Philips internal website with YAPI applications.

We thank Martin Klompstra and Eric Kamps for maintaining and supporting YAPI the last four years.

We thank Jan Hoogerbrugge for allowing us to use TRT as the underlying cooperative multithreading kernel.

Finally, we thank SourceForge.net for hosting this project.