Multimedia Component Overview

This section contains the following topics:

Multimedia components list
Design Principles
Directories
Media support binaries
Media configuration files

Multimedia Components List

The multimedia package contains the following components:

Media Support Binaries

extproc.so and libextproc.so: Extproc group
libmedia.so: Common media library

Media Configuration files

/etc/config/media/mpregistry: Media player registry file
$HOME/.ph/mpsettings: Plugin settings file
libasound.so: Audio drivers and programmer interface library

Photon Media Utilities

mixer: Photon audio mixer
phplay: Photon media player
phrecord: Photon sound recorder
realplayer: RealPlayer for playing realtime audio, video and multimedia

Photon Media Player plugins

audiocd.so: Audio CD Player
mpegaudio: MPEG Audio Player
mpegsystem: MPEG Audio/Video Player
mpegvideo: MPEG Video Player
soundfile.so: Sound file Player

Command-line Media Plugins and Launchers

These plugins (typically identified with the _noph suffix) don't require Photon and are launched from the command line.

audiocd_noph.so: Play an audio CD
mpegaudio_noph.so: Play MPEG audio without Photon
soundfile_noph.so: Play a sound file without Photon

This plugin:	Is launched by this command:
`audiocd_noph.so`	`playAudioCd`
`mpegaudio_noph.so`	`plaympegaudio_noph`
`soundfile_noph.so`	`playsound_noph`

Voyager Plugin Variants

flashplayer: Macromedia Flash 4 animation plugin
mpegaudioplugin: MPEG audio player plugin
mpegsystemplugin: MPEG audio/video player
mpegvideoplugin: MPEG video player plugin
soundplugin: Sound file player plugin

Design Principles

The Multimedia Components were developed to:

accelerate OEM integration of multimedia data into their networked and/or stand-alone systems
provide basic multimedia services to Internet Appliance OEMs
provide enthusiasts with some basic media players to demonstrate the power of QNX Neutrino.

The basic design principles for the plugins are:

allow GUI-less, or optional GUIs, so OEMs have full flexibility
fast and light as possible (assembly language inserts as possible)
provide media player (phplay) source code to accelerate OEM time-to-market
create an elegant, yet powerful media API

The Photon Media Player phplay is a thin GUI application that:

identifies the right plugin to load
loads and unloads the plugins
initializes the plugins
translates the user input into plugin commands
handles plugin generated events (callbacks)
identifies minor file types (registry bypass)
supports playlists
provides the GUI for QNX plugins
provides OEM panes for custom plugins.

The Voyager plugins use the Netscape plugin interface as defined for Voyager Browser. The phplay plugins use the media API as defined in the <Mv.h> header file.

This API is NOT Photon-dependent.

The phplay plugins are DLLs with four entry points:

MvInit(): Initialize the plugin and prepare it to receive commands. The plugins also return capabilities information to the media player to allow it to adjust as needed to handle the plugin.
command(): Submit commands to the plugin (e.g. start, play, and stop).
get_item(): Allow the media player to get the plugin playlist (e.g. Audiocd.so returns the number of tracks).
terminate(): Tell the plugin to exit all threads and terminate all operations. This is the last chance for the plugin to clean-up any allocated memory.

To allow the plugins to generate events in the media player, the media player sets a callback pointer.

Directories

The media components are located in the following directories:

/lib/dll: audiocd_noph.so,
mpegaudio_noph.so,
soundfile_noph.so
/usr/lib: libextproc.so,
libmedia.so
/usr/photon/bin: mixer,
mpegaudio,
mpegsystem,
mpegvideo,
phplay,
phrecord
/usr/photon/dll: audiocd.so,
extproc.so,
soundfile.so
/usr/photon/plugins: flashplayer,
mpegaudioplugin,
mpegsystemplugin,
mpegvideoplugin,
soundplugin

Support Binaries

Here's how the binaries relate to one another.

Extproc group

The Extproc group consists of the following libraries:

extproc.so
libextproc.so

These components are symbolic links to extproc.so:

mpegaudio.so
mpegvideo.so
mpegsystem.so

In order to load the MPEG audio, MPEG video, and the MPEG system, you need to put them in separately linked executables. The media player loads extproc.so which executes a binary dynamically linked to libextproc.so. The main() for the binary is in libextproc.so.

To eliminate the need for the Extproc group, future QNX components will use position-independent modules. The Soundfile plugin (soundfile.so) and the Audio CD player (audiocd.so) don't use the Extproc Group.

Common media library (`libmedia.so`)

The common media library DLL, libmedia.so, provides developers a common interface to the media player registry file and the plugin settings file.

The header files that describe the multimedia API are:

</usr/include/photon/Mv.h>: APIs for media plugins.
</usr/include/photon/MvReg.h>: API calls associated with the registry.

The four API calls that define the registry file interface are:

MvPluginName() -- Return the associated plugin name based on an input filename
MvRegClose() -- Close the registry file
MvRegGetEntry() -- Look up which plugin goes with a specific file type
MvRegOpen() -- Open the registry file

MvRegOpen(), MvRegGetEntry() and MvRegClose() are defined in <MvReg.h>, but are for internal use only by MvPluginName().

Configuration Files

The multimedia configuration files include:

Media player registry file
Plugin settings file

Media player registry file (`mpregistry`)

When a file is selected within phplay, phplay tries to identify the plugin to load based on the media type. The registry file is used if the file media type can't be identified.

The media player registry file is located at:

/etc/config/media/mpregistry

Here's an example of its contents:

<This first line may redirect paths to find plugins (optional)>
#<TAB>so<TAB>file://*.extension or
    #TAB>so<TAB>MIME:(MIME_type) is the line format expected>
    soundfile.so    file://*.wav
    soundfile.so    file://*.au
    soundfile.so    file://*.aif
    soundfile.so    file://*.aiff
    soundfile.so    file://*.iff
    soundfile.so    MIME:audio/x-wav
    soundfile.so    MIME:audio/basic
    soundfile.so    MIME:audio/x-aiff
    mpegsystem.so   file://*.mpg
    mpegsystem.so   file://*.mpeg
    mpegsystem.so   MIME:video/mpeg
    mpegaudio.so    file://*.mpa
    mpegaudio.so    file://*.mp1
    mpegaudio.so    file://*.mp2
    mpegaudio.so    file://*.mp3
    mpegaudio.so    MIME:audio/mpeg
    mpegaudio.so    MIME:audio/mp3
    mpegaudio.so    MIME:audio/mp2
    mpegaudio.so    MIME:audio/mp1
    mpegaudio.so    MIME:audio/mpa
    mpegaudio.so    MIME:audio/x-mpeg
    mpegvideo.so    file://*.mpv
    mpegvideo.so    file://*.m2v
    mpegvideo.so    MIME:video/m2v
    mpegvideo.so    MIME:video/mpv
    audiocd.so      file://*/dev/cd?
    audiocd.so      file://*.cda
    audiocd.so      .cda:*
    playlist.so     file://*.pl
    soundfile.so=file=File
    audiocd.so=cd=Audio CD

Plugin settings file (`mpsettings`)

The mpsettings file stores your customized phplay configuration preferences. For example, you may wish to use direct digital audio for everything. Although phplay has File->Preferences, Voyager doesn't. At startup, the mpsettings file is looked for by both phplay and the Voyager plugins to obtain your user preferences.

The plugin settings file is located at:

$HOME/.ph/mpsettings

Three calls define the interface to the plugin settings file:

MvGetMpDefaultSetting() -- Get the system-calculated standard settings
MvGetMpSetting() -- Get the values stored in mpsettings
MvSetMpSetting() -- Write a new mpsettings file

`mpsettings` example

The MvSetup_t structure is defined in <Mv.h>.

#phplay settings file
WINDOW_SIZE=CUSTOM
CUSTOM_WIDTH=362
CUSTOM_HEIGHT=552
POSITION_X=128
POSITION_Y=148
DIRECT_DIGITAL_AUDIO=OFF
PLUGIN_CREATES_VIDEO=OFF
DIRECT_OVERLAY=ON
KEEP_VIDEO_ASPECT_RATIO=ON
WINDOW_ALWAYS_ON_TOP=OFF
VIDEO_MODE=VGA
TV_SCALE1_1=ON
TV_STANDARD=NTSC
TV_OUTPUT=VIDEO
CDDB=ON
PCM_A_PLAYBACK_CARD=0
PCM_A_PLAYBACK_DEVICE=0
PCM_B_PLAYBACK_CARD=0
PCM_B_PLAYBACK_DEVICE=0
PCM_RECORD_CARD=0
PCM_RECORD_DEVICE=0
SPDIF_PLAYBACK_CARD=0
SPDIF_PLAYBACK_DEVICE=2
SPDIF_RECORD_CARD=-1
SPDIF_RECORD_DEVICE=-1
MOUNT_POINT=/fs/cd0
STREAM_TYPE=MV_STREAM

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