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`mpegaudio`, `mpegaudio_noph.so`

MPEG Audio Player

Name:

/usr/photon/bin/mpegaudio (Photon)

/lib/dll/mpegaudio_noph.so

The MPEG Audio player plugins are based on the Xing DVD Player and decode MPEG Audio Layers I, II and III (MP3). They also support MPEG-2 low-bit rate streams and MPEG-2.5 Audio. An attempt is made to skip past the wrappers that sometimes accompany MP3 files.

The mpegaudio_noph.so player is launched by typing plaympegaudio_noph at the command line.

Calling MvInit() sets the value of MvPluginCtrl_t.MvPluginFlags_t pflags to 0.

Resource profile utilization and library prerequisites

See the Resource Profile Estimates and Library Dependencies appendix.

Relevant commands

Valid commands for the MPEG audio player are:

CMD_PLUGIN_CLOSE
CMD_PLUGIN_DIRECT_AUDIO
CMD_PLUGIN_GET_STATUS
CMD_PLUGIN_MUTE
CMD_PLUGIN_OPEN_URLS
CMD_PLUGIN_PAUSE
CMD_PLUGIN_SEEK_TO
CMD_PLUGIN_SET_PARAMETER
CMD_PLUGIN_START
CMD_PLUGIN_STOP

Environment variables

MPEGAUDIOBUFFERSIZE

Size of the input buffer (default is 50000 bytes).

MPEGAUDIOBUFFERSTARTPERCENT

The percent of the input buffer that needs to be filled before you begin playing (default is 30).

MPEGAUDIOCONVERTCODE

Transform the output of the MPEG audio decoder.

0: Two channel output (default).
1: Convert two channel output to mono.
2: Convert two channel output to left channel.
3: Convert two channel output to right channel.

MPEGAUDIOFREQLIMIT

Set a low pass filter on the specified frequency. Default is 24KHz. Maximum is 48KHz.

MPEGAUDIOMAXBITRATE

Set to value in Kbits-per-second. The plugin automatically sets the reduction code value to ensure the decoded data rate is kept below this specified value. For example, the following sets the reduction code to 1 for a 128Kbps MPEG audio stream.

export MPEGAUDIOMAXBITRATE=65

MPEG-1 and MPEG-2 audio bitstreams can encode at 8 to 480Kbps. Divide this in half for MPEG-2.5 extended-streams.

MPEGAUDIOREDUCTIONCODE

Tells the plugin to down-sample the MPEG audio stream by a given factor to reduce the CPU load.

0: Full sample rate output (default).
1: Half rate.
2: Quarter rate.

MPEGAUDIOREFILLONUNDERFLOW

Refill the audio input buffer to percent on underflow (default is OFF).

MPEGAUDIOTRANSFORMBITCODE

Transform the output of MPEG audio decoder.

0: Perform no transformation.
1: 16-bit linear PCM.
2: 8-bit unsigned linear PCM.
3: U-law (8-bit signed).

MPEGAUDIOTRANSFORMCHANNELCODE

Transform the output of the MPEG audio decoder.

0: Two channel output (default).
1: Convert two channel output to mono.
2: Convert two channel output to left channel.
3: Convert two channel output to right channel.

Examples:

See the callback handler example in the Soundfile player plugin and the plaympegaudio_noph.c example in the Appendix.