mediacms-dev-exp/docs/transcoding.md

Transcoding in MediaCMS

MediaCMS uses FFmpeg for transcoding media files. Most of the transcoding settings and configurations are defined in files/helpers.py.

Configuration Options

Several transcoding parameters can be customized in cms/settings.py:

FFmpeg Preset

The default FFmpeg preset is set to "medium". This setting controls the encoding speed and compression efficiency trade-off.

# ffmpeg options
FFMPEG_DEFAULT_PRESET = "medium" # see https://trac.ffmpeg.org/wiki/Encode/H.264

Available presets include:

• ultrafast
• superfast
• veryfast
• faster
• fast
• medium (default)
• slow
• slower
• veryslow

Faster presets result in larger file sizes for the same quality, while slower presets provide better compression but take longer to encode.

Other Transcoding Settings

Additional transcoding settings in settings.py include:

• FFMPEG_COMMAND: Path to the FFmpeg executable
• FFPROBE_COMMAND: Path to the FFprobe executable
• DO_NOT_TRANSCODE_VIDEO: If set to True, only the original video is shown without transcoding
• CHUNKIZE_VIDEO_DURATION: For videos longer than this duration (in seconds), they get split into chunks and encoded independently
• VIDEO_CHUNKS_DURATION: Duration of each chunk (must be smaller than CHUNKIZE_VIDEO_DURATION)
• MINIMUM_RESOLUTIONS_TO_ENCODE: Always encode these resolutions, even if upscaling is required

Advanced Configuration

For more advanced transcoding settings, you may need to modify the following in files/helpers.py:

• Video bitrates for different codecs and resolutions
• Audio encoders and bitrates
• CRF (Constant Rate Factor) values
• Keyframe settings
• Encoding parameters for different codecs (H.264, H.265, VP9)