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BERKELEY MPEG TOOLS (Version 1.0, Release 2; August 1995)

Lawrence A. Rowe, Steve Smoot, Ketan Patel, Brian Smith, Kevin Gong,

Eugene Hung, Doug Banks, Sam Tze-San Fung, Darryl Brown, and Dan Wallach

--------------------

Changes since release one:

  mpeg_encode - important bug fixes

  mpeg_play   - simple user interface added

  others - small bugfixes

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Computer Science Division-EECS University of California at Berkeley

Berkeley, CA 94720-1776

This distribution is a combined release of tools developed at

Berkeley and elsewhere for manipulating MPEG-1 video.

This release includes the following tools:

  mpeg_play - software-only MPEG-1 video decoder

  mpeg_encode - software-only MPEG-1 video encoder

  mpeg_stat - a bitstream analysis tool

  mpeg_blocks - an interactive tool to examine macroblock coding

  mpeg_bits - an interactive tool to examine bit allocation to blocks

The package is available at the URL

  ftp://mm-ftp.cs.berkeley.edu/pub/multimedia/mpeg/bmt1r1.tar.gz

For more information on MPEG standards and other MPEG software and

hardware, see http://www-plateau.cs.berkeley.edu/mpeg/index.html.

Other sites where you can find interesting MPEG related software

and movies are:

  ftp://sunsite.unc.edu/pub/multimedia/utilities

  ftp://netcom.com:/pub/cf/cfogg/

  http://www.acm.uiuc.edu/rml/Mpeg

The remainder of this file describes each tool including changes,

if any, from previous releases and other information about the

release.  In the descriptions below reference is made to papers

describing various aspects of these programs.  These papers are

also available at the Plateau WWW site (http://www-plateau.cs.berkeley.edu/)

or in our FTP site in the directory pub/multimedia/papers.

MPEG_PLAY (V2.3)

This program decodes and displays an MPEG-1 video stream.  The

program has been written to be portable, which means it has not

been optimized for specific platforms.  The decoder is implemented

as a library that will take a video stream and display it in an X

window on an 8, 24 or 32 bit deep display.  The main routine is

supplied to demonstrate the use of the decoder library.  Several

dithering algorithms are supplied based on the Floyd-Steinberg,

ordered dither, and half-toning algorithms that tradeoff quality

and performance.  Neither the library nor the main routine handle

real-time synchronization or audio streams.

A paper published at ACM Multimedia 93 describes the decoder and

compares the performance of the program on several platforms (see

pub/multimedia/papers/MM93.ps.Z).  An updated version of this

comparison is included in the file doc/mpegperf.ps in this

distribution.  This code has also been included in our Continuous

Media Player (cmplayer) that plays synchronized audio and video

across a network.  This system adapts to the decoding performance

of the destination machine.  A paper describing these algorithms

and the performance of the system was published at IS&T SPIE 94

(see /pub/multimedia/papers/CMMPEG-SPIE94.ps.Z).

This release fixes numerous bugs in the player including the motion

vector problem that caused problems when playing MPEGs generated

from computer-generated animations, the error in the color space

equations, some IDCT problems, and a number of minor problems with

installation on platforms with new OS releases.

New features have also been implemented, chief of which are the ability

to play system layer MPEG streams (discarding audio), gamma correction, and

frame rate control.

MPEG_ENCODE (V1.5R2)

This program generates an MPEG-1 video bitstream given a sequence

of images in an acceptable format (e.g., yuv, ppm, jpeg, etc.).

It can be run on one computer (i.e., sequential) or on several

computers (i.e., parallel).  Our goal was to produce a portable,

easy-to-use encoder that can be used to encode video material for

a variety of desktop applications (e.g., video-on-demand).  The

parallelism is done on a sequence of pictures.  In other words,

you can spawn one or more children to encode continuous runs of

pictures.  The goal is to allow you to encode using multiple

processors, think spare cycles on workstations, to speed up the

encoding time.  Although performance depends on the speed of

individual processors, the file system and network, and the P/B

frame search methods, we have encoded 3.75 frames/second on 8 HP

Snakes running in parallel as compared with 0.6 frames/second on

1 Snake when coding CIF size images.  The encoder has also been

ported to an Intel supercomputer (Paragon) on which it has encoded CCIR

601 images at 40 frames/second.

A paper describing the parallel encoder and our experiments on a

network of workstations was published at the 1994 Picture Coding

Symposium (see /pub/multimedia/papers/mpeg-encode.ps.Z).  A paper

describing the port to the Intel supercomputer and the performance

experiments on that system was presented at IS&T SPIE95 (see

/pub/multimedia/papers/intelsc-mpeg-encode.ps.Z).  This work was

done jointly with Ed Delp and his student Ke Shen from Purdue.

You can get a copy of the Intel code from /pub/dist/delp/spie95-coding

at skynet.ecn.purdue.edu.

This release fixed several bugs and added some new features.

Specifically, the encoder has been modified to: 1) accept input

images generated on the fly by another program, 2) generate constant

bitrate bitstreams, 3) be much more flexible about input formats,

and 4) allow a priori specification of motion vectors or Qscales on a

macroblock level, to avoid repetitive motion searches when reencoding.

MPEG_STAT (V2.2R2)

MPEG_STAT has been modified to gather more statistics (e.g., bit

rate, real Q-scale information, detailed motion vector/cbp information,

constrained parameter checking, etc.) and fix some bugs. The major

change (from 2.1) was to add some additional verification checks to help

determine the validty of a bitstream including illegal motion

vectors and CPB settings, and speed it up even more.

MPEG_BLOCKS (V1.0R2)

This program is a new tool that allows a user to examine how a

movie has been encoded on a picture-by-picture basis.  It shows

size statistics on the different frame types and how each macroblock

was coded.  The program also shows the decoded image so you can

see the effect of these coding parameters.

The current version of this program only works on systems that

support the X Windowing System and Tcl/Tk because it provides a

user-friendly GUI.

MPEG_BITS (V1.0R2)

This program is also new in this release.  It is based on the

MPEG_BLOCKS program, but instead of showing block encoding, it

shows how many bits were allocated to each block.  It uses the same

GUI interface.

MPEG_BITS also allows you to specify a range of blocks that should

receive more bits when recoding the sequence.  The mpeg_encoder

has not yet been modified to take this specification, but it will

in a future release.

ACKNOWLEDGEMENTS

We gratefully thank Hewlett-Packard, Fujitsu, Hitachi, and Philips who

provided financial support for this work.  We also want to thank the

following people and organizations for their help:

    Jef Poskanzer who developed the pbmplus package.

    Eiichi Kowashi of Intel and Avideh Zakhor of U.C. Berkeley who

    provided valuable suggestions on motion vector searching.

    Chad Fogg of Chromatic Research, Inc. who has helped us understand

    many issues in MPEG coding and decoding.

    Rainer Menes of the Technical University of Munich who

    ported previous versions of the Berkeley MPEG encoder and

    decoder to the Macintosh. He has provided us with many suggestions

    to improve the code.

    Robert Safranek of ATT for comments, suggestions, and most of

    the code for custom quantization tables.

    Jim Boucher of Boston University for jmovie2jpeg.

    The San Diego SuperComputing Center for providing facilities

    to develop some of the code contained within.

    Tom Lane of the Independent JPEG Group who provided us with the basic

    inverse DCT code used by our player.  (tom_lane@g.gp.cs.cmu.edu)

    Reid Judd of Sun Microsystems who provided advice and assistance.

    Todd Brunhoff of NVR who provided advice and assistance.

    Toshihiko Kawai of Sony who provided advice and assistance.