ffmpeg-av1-builder/README.md

ffmpeg-av1-builder

General

This repository is a simple collection of bash scripts. Scripts have only been tested using Debian/Ubuntu/Arch. If not using apt/pacman, your dependencies will need to be manually installed. With the scripts, you can:

1. Install required dependencies using ./scripts/install_deps.sh
2. Build and install ffmpeg from source using ./scripts/build.sh
3. Install an encoding script using ./scripts/recc_encode_install.sh -I
4. Install a film-grain estimation script using ./scripts/estimate_fg.sh -I
5. Benchmark the different encoders using ./scripts/benchmark.sh

Encode script

The installation of the encoding script creates a symlink to this repo's ./scripts/recc_encode.sh so do NOT remove this repo or the functionality of encode will FAIL. The encode script is a very simple way to use SvtAv1-PSY for video and Opus for audio for encoding, which are arguably the most ideal encoders as of writing this. encode does the following:

• Maps all streams except image streams (effectively no poster/image in the output)
• Sets the audio bitrate at 64kbps per channel for each audio track
• Formats the audio output channel layout correctly for Opus
• Attempts to encode with Dolby Vision and encodes without if the attempt fails
• Preset 3 and CRF 25 for for SvtAv1
• Enables sane advanced parameters
• Removes video stream title name from output
• Adds track statistics for proper output video/audio bitrate reporting Read the specifics in the actual file : ./scripts/recc_encode.sh

encode -i input_file [options] 
        [-p] print the command instead of executing it
        [-c] use cropdetect
        [-s] use same container as input, default is mkv
        [-v] Print relevant version info
        [-g NUM] set film grain for encode

        [output_file] if not set, will create at $HOME/

        [-I] Install this as /usr/local/bin/encode
        [-U] Uninstall this from /usr/local/bin/encode

Example usage:

• encode -i input.mkv output.mkv standard usage
• encode -i input.mkv -p true prints out what it will do, does not start encoding
• encode -i input.mkv no output filename will create an output video in your home folder (~/)
• encode -i input.mkv -g 20 will encode with film-grain synthesis=20 WITH denoising

Estimate film grain script

The installation of the script creates a symlink to this repo's ./scripts/estimate_fg.sh so do NOT remove this repo or the functionality of estimate-film-grain will FAIL. The estimate-film-grain script is a way to estimate the ideal film grain of a video by encoding it at different film grain values and observing at what point does a higher film grain value result in diminishing returns.

estimate-film-grain -i input_file [options]
        [-o output_file] file to output results to
        [-l NUM] low value to use as minimum film-grain
        [-s NUM] step value to use increment from low to high film-grain
        [-h NUM] high value to use as maximum film-grain
        [-p] plot bitrates using gnuplot

        [-I] Install this as /usr/local/bin/estimate-film-grain
        [-U] Uninstall this from /usr/local/bin/estimate-film-grain

Benchmark script

AV1 encode quality is tested against 5 different open source videos using libsvtav1, librav1e, and libaom. Netflix's libvmaf is used to analyze quality of the encodes against the original files.

Output after running ./scripts/benchmark.sh is in ./benchmark/results.txt which contains the following values for each encode:

• the time taken
• psnr_hvs
• cambi
• float_ms_ssim
• vmaf