PROSTREAM CONTROLS |
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AAC-LC “Low Complexity”:
Also known as aacPlus or AAC+, Advanced Audio Coding’s Low Complexity codec is a high performance
codec for excellent audio quality at lower bitrates. AAC-LC can be found in widespread use, most notably in
Apple’s iTunes. When compared side by side with MP3, the superior quality of audio encoded with AAC-LC
becomes much more apparent at lower bitrates.
HE-AAC:
High Efficiency Advanced Audio Coding is a newer AAC codec and incorporates Spectral Band Replication
(SBR) bandwidth expansion to improve audio at very low bitrates.
HE-AAC v2 applies a Parametric Stereo feature to HE-AAC codec allowing for even further reduction in
bandwidth.
Channels
Choose from mono or stereo encoding.
Bitrate
The full spectrum of ProSTREAM encoding can be anywhere from 14-320 kbps for the output data stream
bitrate. The output bitrate constraints will differ depending on which codec is selected and whether the
encode is set to mono or stereo. The range of each codec is shown in the table below:
Codec
Bitrate Range
MP3
16 to 320 kbps
AAC-LC
24 to 320 kbps
HE-AAC
24-96 kbps
HE-AAC v2
24-96 kbps
Transport
AAC audio encoding does not include a container for packaging the data stream as part of it’s format, but
instead allows for a choice of transport to define the container. The most common container for AAC data
on a personal computer is MP4. This is the technique used by iTunes for .m4a audio files. For streaming use,
a file container is not always appropriate or understood by streaming clients, so an alternative container
should be used.
ADTS:
The default transport container to use for all AAC codecs is Audio Data Transport Stream (ADTS). ADTS
encapsulates the packetized elementary streams of encoded AAC audio and metadata for transport over IP
networks.
