AacSettings
Required when you set Codec to the value AAC. The service accepts one of two mutually exclusive groups of AAC settings--VBR and CBR. To select one of these modes, set the value of Bitrate control mode to "VBR" or "CBR". In VBR mode, you control the audio quality with the setting VBR quality. In CBR mode, you use the setting Bitrate. Defaults and valid values depend on the rate control mode.
Types
Properties
Choose BROADCASTER_MIXED_AD when the input contains pre-mixed main audio + audio description (AD) as a stereo pair. The value for AudioType will be set to 3, which signals to downstream systems that this stream contains "broadcaster mixed AD". Note that the input received by the encoder must contain pre-mixed audio; the encoder does not perform the mixing. When you choose BROADCASTER_MIXED_AD, the encoder ignores any values you provide in AudioType and FollowInputAudioType. Choose NORMAL when the input does not contain pre-mixed audio + audio description (AD). In this case, the encoder will use any values you provide for AudioType and FollowInputAudioType.
Specify the average bitrate in bits per second. The set of valid values for this setting is: 6000, 8000, 10000, 12000, 14000, 16000, 20000, 24000, 28000, 32000, 40000, 48000, 56000, 64000, 80000, 96000, 112000, 128000, 160000, 192000, 224000, 256000, 288000, 320000, 384000, 448000, 512000, 576000, 640000, 768000, 896000, 1024000. The value you set is also constrained by the values that you choose for Profile, Bitrate control mode, and Sample rate. Default values depend on Bitrate control mode and Profile.
Specify the AAC profile. For the widest player compatibility and where higher bitrates are acceptable: Keep the default profile, LC (AAC-LC) For improved audio performance at lower bitrates: Choose HEV1 or HEV2. HEV1 (AAC-HE v1) adds spectral band replication to improve speech audio at low bitrates. HEV2 (AAC-HE v2) adds parametric stereo, which optimizes for encoding stereo audio at very low bitrates.
The Coding mode that you specify determines the number of audio channels and the audio channel layout metadata in your AAC output. Valid coding modes depend on the Rate control mode and Profile that you select. The following list shows the number of audio channels and channel layout for each coding mode. * 1.0 Audio Description (Receiver Mix): One channel, C. Includes audio description data from your stereo input. For more information see ETSI TS 101 154 Annex E. * 1.0 Mono: One channel, C. * 2.0 Stereo: Two channels, L, R. * 5.1 Surround: Six channels, C, L, R, Ls, Rs, LFE.
Choose the loudness measurement mode for your audio content. For music or advertisements: We recommend that you keep the default value, Program. For speech or other content: We recommend that you choose Anchor. When you do, MediaConvert optimizes the loudness of your output for clarify by applying speech gates.
Specify the RAP (Random Access Point) interval for your xHE-AAC audio output. A RAP allows a decoder to decode audio data mid-stream, without the need to reference previous audio frames, and perform adaptive audio bitrate switching. To specify the RAP interval: Enter an integer from 2000 to 30000, in milliseconds. Smaller values allow for better seeking and more frequent stream switching, while large values improve compression efficiency. To have MediaConvert automatically determine the RAP interval: Leave blank.
Specify the AAC rate control mode. For a constant bitrate: Choose CBR. Your AAC output bitrate will be equal to the value that you choose for Bitrate. For a variable bitrate: Choose VBR. Your AAC output bitrate will vary according to your audio content and the value that you choose for Bitrate quality.
Enables LATM/LOAS AAC output. Note that if you use LATM/LOAS AAC in an output, you must choose "No container" for the output container.
Specify the AAC sample rate in samples per second (Hz). Valid sample rates depend on the AAC profile and Coding mode that you select. For a list of supported sample rates, see: https://docs.aws.amazon.com/mediaconvert/latest/ug/aac-support.html
Use MPEG-2 AAC instead of MPEG-4 AAC audio for raw or MPEG-2 Transport Stream containers.
Specify the xHE-AAC loudness target. Enter an integer from 6 to 16, representing "loudness units". For more information, see the following specification: Supplementary information for R 128 EBU Tech 3342-2023.
Specify the quality of your variable bitrate (VBR) AAC audio. For a list of approximate VBR bitrates, see: https://docs.aws.amazon.com/mediaconvert/latest/ug/aac-support.html#aac_vbr