Encoder Menu - Omnia .9 Installation & User Manual

STREAMING PROCESSING & ENCODING MENU

Encoder Menu

The Encoder menu allows you to enable and manage each encoder belonging to a particular stream. The number of encoders
available depends on how many processing cores you have running (set in Home > System >System Configuration > Processing
Paths). 8 encoders will be available if light configurations, while an Omnia.9 classic Dual FM unit with be limited to 4 in the
heaviest configurations.
The Enable control enables or disables the stream. When enabled, the encoder will continually try to connect to the
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specified server. If Enabled, the status will be displayed above the Enable control. While connected, it will display
"Running" and the actual current bit rate of the encoded audio. If the server you are pointing to is not valid, you will see
and "Error, can't connect" message, and how many attempts have been made.
If the Server Type is set to Internal, the port number, bit rate and number of active streams is displayed above the
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Enable control. The port number is different for each individual stream, and is revealed when you enable a stream set to
server type Internal. It cannot be reassigned, but it will stay consistent. If you wish to use a different port, for external
communication, configure your router to do a port address translation.
The Codec drop down menu allows you select which type of code to use. Available codecs are MP3, MP2, AAC, HE-AAC and FLAC.
The Bit Rate menu allows you to choose encoding the available bit rates belonging to each codec. Your choice of bit rate
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settings will significantly influence the audio quality of your stream, and obviously, the lower the bit rate, the lower the
quality of the audio for each given codec. Please take use factors into consideration when selecting a bit rate, such as the
total amount of bandwidth available for the stream, the anticipated number of users, your maximum upload speed, and
the download speed limits of your intended users.
The FLAC codec has a different topology from other codes and is not set by bit rate, being a lossless codec. It deserves
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special mention since it uses bandwidth dynamically.
Lossless is 16-bit lossless, and the bit rate is variable. The average bit rate is 1200 kbps or so, but it will vary with content,
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and will be very low on silence. This can cause buffer issues downstream, and is thus not appropriate for streaming to
devices with a small internal buffer and low delay, but works fine for regular listening over the internet.
Reduced will reduce the bit depth (before the FLAC encoder) when the noise floor of the audio content is uniformly high
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across the spectrum. It sounds exactly the same, but the average bit rate is 700 kbps or so. The bit rate will be very low on
silence just like for the Lossless mode.
Lossless (Small Blocks) will use a block size of 512 instead of the default 4096. This reduces compression efficiency a bit,
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but it improves metadata timing, which may be useful for customers who use metadata to trigger commercials.
Uncompressed FLAC may sound like an oxymoron, but we did it! Because the bit rate remains constant at 1556 kbps
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(1430kbps for 44.1 KHz) regardless of program content, you can use much less buffering in the device receiving the
stream without risking buffer-related dropouts, which is important in cases where delay matters – like feeding that Barix
box connected to the lobby speakers, where one second of delay may be acceptable, but not 30.
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