Image Processing – Scan Type – Key Controls - 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.

Image Processing – Scan Type – Key Controls

Description

You can convert the scan type of the input to a different scan type: progressive, interlaced, hard telecine, or soft telecine. You can configure to leave the scan type as is or to convert from one incoming type (or a mix of incoming scan types) to another single type. Configuring for scan type conversion involves setting fields in specific ways. The three key fields to convert the scan type of the input are Configuration - Deinterlace Mode, Configuration - Interlace Mode, and Configuration - Telecine. The following table describes how to set these three key fields to convert a given input to a given output.

Input Output Configuration - Deinterlace Mode Configuration - Interlace Mode Configuration - Telecine
Progressive Progressive Off Progressive None
Interlaced Progressive Deinterlace Progressive None
Interlaced Progressive Adaptive Progressive None
Hard telecine Progressive Inverse telecine Progressive None
Hard telecine Progressive Adaptive Progressive None
Soft telecine Progressive Off Progressive None
Mixed Progressive Adaptive Progressive None
Progressive Hard telecine Off One of the other options Hard telecine
Hard telecine Hard telecine Off One of the other options None
Soft telecine Hard telecine Off One of the other options Hard telecine
Mixed Hard telecine Off One of the other options Hard telecine
Interlaced Interlaced Off One of the other options None
Mixed Interlaced Off One of the other options None
Progressive Soft telecine Off One of the other options Soft telecine
Hard telecine Soft telecine Inverse telecine One of the other options Soft telecine
Hard telecine Soft telecine Adaptive One of the other options Soft telecine
Soft telecine Soft telecine Off One of the other options Soft telecine
Mixed Soft telecine Adaptive One of the other options Soft telecine

* Deinterlace Mode is an image processing control. Interlace Mode and Telecine are encoding controls.

Note: Converting the Scan Type to Progressive

If content is not being converted to a higher framerate, the deinterlacer outputs one frame for every two fields in the source content (i.e., 1080i30 content is converted to 1080p30). If the framerate is being doubled (e.g. 29.97 fps to 59.94 fps, 29.97 to 60, or 25 to 50), the deinterlacer converts each field into a frame.

Deinterlace Mode

This field applies an initial conversion for certain from/to conversions (as shown in the table above).

  • Deinterlace: Applies a deinterlace algorithm to content. If AWS Elemental Live detects that the source content is already progressive, no deinterlacing is applied.

  • Inverse Telecine: Converts hard telecine 29.97i to progressive 23.976p.

  • Adaptive: Analyzes source content to determine whether to apply the deinterlace or inverse telecine algorithm on source content.

Interlace Mode

This field controls video field order and how the scan type is represented in the output bitstream.

  • Progressive: Encodes output as "progressive."

  • Top Field First or Bottom Field First: Forces field polarity (top or bottom first) to the specified value, reordering fields if the source has a different order and encodes the result as interlaced.

  • Follow (Default Top) and Follow (Default Bottom): Produces interlaced output, with the output having the same field polarity as the source. Therefore:

    • If the source is "interlaced", the output is interlaced with the same polarity as the source (it follows the source). The output could therefore be a mix of “top field first” and “bottom field first.”

    • If the source is "progressive", the output is interlaced with “top field first” or “bottom field first” polarity (depending on which Follow option you chose).

Note: If the output codec is Microsoft VC-1, then the interlace mode is always set to "progressive."

Telecine

This field appears for MPEG-4 AVC and MPEG-2 only if the Streams > Advanced > framerate field is set to 29.970.

  • Hard: Produce 29.97i output from 23.976 input.

  • Soft: Produce 23.976; the player converts this output to 29.97i.

Recommendations

  • Converting to progressive output always improves output quality and should be enabled in any use case where progressive output is required or acceptable.

  • Interlace coding is inherently less efficient than progressive coding so use interlace coding only for content that has already been interlaced.

  • The choice of deinterlacing algorithm is very subjective. Motion Adaptive Interpolation is generally recommended as the sharper image quality tends to provide the best perceived quality across a broad set of users. Use the Force Mode option for deinterlacing only when the input is known to be interlaced content incorrectly flagged as "progressive."

  • Use the Force Mode option for Inverse Hard Telecine when the input is known to consist entirely of Hard Telecine content.

Location of Fields

Location of Field on Web Interface Location of Tag in XML
Streams > Advanced > Telecine

stream_assembly/video_description/codec/telecine

where codec is one of the following:

  • h264_settings

  • mpeg2_settings

  • h265_settings

  • prores_settings

Streams > Advanced > Interlace Mode

stream_assembly/video_description/codec/interlace_mode

where codec is one of the following:

  • vc1_settings

  • h264_settings

  • mpeg2_settings

  • h265_settings

  • prores_settings

Streams > Advanced >Preprocessors > Deinterlacer > Deinterlace Mode stream_assembly/video_description/video_preprocessors/deinterlacer/deinterlace_mode
Streams > Advanced >Preprocessors > Deinterlacer > Deinterlace Algorithm stream_assembly/video_description/video_preprocessors/deinterlacer/algorithm
Streams > Advanced >Preprocessors > Deinterlacer > Force Mode stream_assembly/video_description/video_preprocessors/deinterlacer/force