Encoding – Rate Control Tuning - AWS Elemental Live

This is version 2.18 of the AWS Elemental Live documentation. This is the latest version. For prior versions, see the Previous Versions section of AWS Elemental Live and AWS Elemental Statmux Documentation.

Encoding – Rate Control Tuning

Description

Following are encoding settings that can be used to provide additional tuning of video quality.

  • Lookahead: This setting indicates that AWS Elemental Live should analyze a few frames in the future of the currently encoded frame (higher values mean more frames) and allow AWS Elemental Live to take future frame data into account during rate control logic.

    For example, if future frames are more complex, AWS Elemental Live can allocate fewer bits to encode the current frame to allow those bits to be used to encode those future frames. The tradeoff is that processing and latency are increased slightly to allow those future frames to be analyzed by the encoding engine.

Recommendations

  • Use 2-pass encoding for VOD unless minimize encoding time is critical.

  • Set Lookahead to "medium" for use with 1-pass encoding unless latency is critical.

Location of Fields

Location of Field on Web Interface Location of Tag in XML
Streams – Video > Advanced > Passes

stream_assembly/video_description/codec/passes

where codec is one of the following:

  • h264_settings

  • vc1_settings

  • mpeg2_settings

  • h265_settings

Streams – Video > Advanced > Lookahead

stream_assembly/video_description/codec/look_ahead_rate_control

where codec is one of the following:

  • h264_settings

  • vc1_settings

  • mpeg2_settings

  • h265_settings