AJA HELO - Page 37

HELO H.264 Streaming and Recording Encoder v1.1r1 37 www.aja.com
Audio Bit Rate
Use this drop-down menu to select the audio bit rate of the encoded recording.
The available selections are:
• 32 Kbps
• 64 Kbps
• 96 Kbps
• 128 Kbps (factory default)
• 192 Kbps
• 256 Kbps
Advanced Settings
Show or hide advanced encoding settings parameters. These settings are
intended for advanced users only. Generally they should only be changed if
directed by your CDN or Streaming Service Provider.
Reset - Resets all of the advanced settings to factory default values.
Hide - Hides the advanced settings parameters (factory default).
Show - Displays the following advanced parameters for adjustment.
I-Frame [GOP] Every (Advanced Settings)
Selects how often I-frames are encoded (the Group-Of-Pictures (GOP) size). The
default value is 120 frames.
NOTE: It is important to choose a GOP size for streaming that corresponds to two
seconds or larger. The number depends on the input frame rate and the value of
the Streaming Profiles Frame Rate parameter.
For example:
Input frame rate is 30 frames per second.
Frame Rate parameter is set to "Half."
30 fps x .5 = 15 fps.
2 seconds x 15 frames per second equals 30 frames.
Therefore, for this example, the GOP size should be set to a minimum of "30."
P Interval (Advanced Settings)
Selects how often the GOP P frames appear after an I frame. This refers to the
cadence of Predictive (P) frames vs. Bidirectional (B) frames in the group of
pictures.
If set to one (factory default), all frames between I frames will be P frames; if two,
every other frame between I frames will be a P frame; if 3, every third and so on.
The remainder will be B frames.
Higher values mean more efficient encoding and potentially better video quality,
but more compute power to decode. Some decoders may not be able to decode
video with too many, or any B frames.
H.264 Encoding Profile (Advanced Settings)
Selects the encoding profile from the H.264 standard to use for this stream.
Available selections are:
• Constrained
• Baseline
• Main - (factory default)
• High