Configuration¶

Setting default format options¶

MADAM has several configuration options that can modify the default settings which are used to write file formats. The configuration is stored in a dictionary that can be passed to madam.core.Madam.__init__(). The structure of the dict depends on the file type category (e.g. audio, image, or video).

Image options¶

Image settings can be stored for all image formats or for a certain MIME type.

The following example shows how to set the quality factor for all images and how to enable Zopfli compression for PNG images:

>>> config = {
...     'image': {
...         'quality': 80,
...     },
...     'image/png': {
...         'zopfli': True,
...     },
... }

The following list shows all available options for file formats.

JPEG (image/jpeg)¶

progressive

A boolean value that defines whether progressive JPEG images should be written.

Defaults to True.

quality

A compression factor as an integer in the range between 0 and 100. Smaller factors produce smaller files with lower quality.

Defaults to 80.

PNG (image/png)¶

zopfli

Boolean that defines whether Zopfli should be used to further compress PNG images.

Defaults to True.

Warning

Enabling Zopfli can increase processing times dramatically depending on the input data.

zopfli_strategies

String that lists all filter strategies to try when saving PNG images:

0–4: Apply PNG filter type 0 to 4 to scanlines
m: Minimum sum
e: Entropy
p: Predefined
b: Brute force

Defaults to ‘0me’.

WebP (image/webp)¶

method

An integer in the range between 0 and 6 that defines the quality/speed trade-off when optimizing WebP images. 0 means faster compression but larger files, 6 means slower compression but smaller files.

Defaults to 6.

quality

A compression factor as an integer in the range between 0 and 100. Smaller factors produce smaller files with lower quality.

Defaults to 80.

Video options¶

Video content is split in two categories: Container options are stored by MIME type and codec options are stored in a separate MIME type category codec.

The following example shows how to set the Constant Rate Factor (CRF) for the h.264 codec (using libx265):

>>> config = {
...     'video/quicktime': {
...         'faststart': True,
...     },
...     'codec/libx265': {
...         'crf': 24,
...     },
... }

The following list shows all available options for video containers.

Quicktime/MPEG4 (video/quicktime)¶

faststart

Boolean that defines whether the video and audio files should be written in a way that allows a fast start when streaming.

Defaults to True.

The following list shows all available options for video codecs.

AVC/h.264 (libx264)¶

crf

An integer that defines the Constant Rate Factor (CRF) for quality and rate control in videos. 0 would encode slowly to lossless quality, while 51 would encode fast to the worst quality. A sane range for AVC/h.264 is between 18 and 28.

Defaults to 23.

HEVC/h.265 (libx265)¶

crf

An integer that defines the Constant Rate Factor (CRF) for quality and rate control in videos. 0 would encode slowly to lossless quality, while 51 would encode fast to the worst quality. A sane range for HEVC/h.265 is between 18 and 28.

Defaults to 28.

VP8 (libvpx)¶

crf

An integer that defines the Constant Rate Factor (CRF) for quality and rate control in videos. 0 would encode very slowly to lossless quality, while 63 would encode very fast to the worst quality. A sane range for VP8 is between 4 and 63.

Defaults to 10.

VP9 (libvpx-vp9 or vp9)¶

crf

An integer that defines the Constant Rate Factor (CRF) for quality and rate control in videos. 0 would encode very slowly to lossless quality, while 63 would encode very fast to the worst quality. A sane range for VP9 is between 4 and 63.

Defaults to 32.