Convert folders of PNG sequences to VP8 with alpha

pngsequences_to_webm_alpha.bat

@echo off
setlocal enabledelayedexpansion

rem Set default values
set "width=1920"
set "height=1080"
set "framerate=30"
set "bitrate=25000k"
set "inputdir=%CD%"
set "outputdir=%CD%"
set "codec=vp8"
set "threads=0"
set "cpu_used=0"
set "two_pass=false"

rem Parse command-line arguments
:parse_args
if "%~1"=="" goto :end_parse_args
if /i "%~1"=="-w" set "width=%~2" & shift & shift & goto :parse_args
if /i "%~1"=="-h" set "height=%~2" & shift & shift & goto :parse_args
if /i "%~1"=="-fr" set "framerate=%~2" & shift & shift & goto :parse_args
if /i "%~1"=="-fps" set "framerate=%~2" & shift & shift & goto :parse_args
if /i "%~1"=="-br" set "bitrate=%~2" & shift & shift & goto :parse_args
if /i "%~1"=="-bitrate" set "bitrate=%~2" & shift & shift & goto :parse_args
if /i "%~1"=="-input_dir" set "inputdir=%~2" & shift & shift & goto :parse_args
if /i "%~1"=="-output_dir" set "outputdir=%~2" & shift & shift & goto :parse_args
if /i "%~1"=="-threads" set "threads=%~2" & shift & shift & goto :parse_args
if /i "%~1"=="-cpu_used" set "cpu_used=%~2" & shift & shift & goto :parse_args
if /i "%~1"=="-two_pass" set "two_pass=true" & shift & goto :parse_args
shift
goto :parse_args
:end_parse_args

rem Convert input and output directories to absolute paths
for %%I in ("%inputdir%") do set "inputdir=%%~fI"
for %%O in ("%outputdir%") do set "outputdir=%%~fO"

rem Create output directory if it doesn't exist
if not exist "%outputdir%" mkdir "%outputdir%"

rem Get current date and time
for /f "tokens=2 delims==" %%I in ('wmic os get localdatetime /value') do set datetime=%%I
set datetime=%datetime:~0,8%_%datetime:~8,6%

rem Set the filter string for centered video with transparent letterboxing/pillarboxing
set "filter=scale=iw*min(%width%/iw\,%height%/ih):ih*min(%width%/iw\,%height%/ih):flags=lanczos,pad=%width%:%height%:(%width%-iw*min(%width%/iw\,%height%/ih))/2:(%height%-ih*min(%width%/iw\,%height%/ih))/2:0x00000000,format=yuva420p"

rem Process each subdirectory
for /d %%D in ("%inputdir%\*") do (
    echo Processing directory: %%D
    pushd "%%D"

    rem Create a temporary directory for numbered PNGs
    set "tempdir=%temp%\pngseq_%%~nxD"
    if exist "!tempdir!" rmdir /s /q "!tempdir!"
    mkdir "!tempdir!"

    rem Copy and rename PNG files to numbered sequence
    set "counter=0"
    for %%f in (*.png) do (
        set /a "counter+=1"
        copy "%%f" "!tempdir!\!counter!.png" > nul
    )

    if !counter! gtr 0 (
        echo Found !counter! PNG files in %%~nxD

        rem Construct output filename
        set "outfile=%%~nxD_%datetime%_%width%x%height%_%framerate%fps_%codec%_%bitrate%.webm"

        rem Construct FFmpeg command
        set "ffmpeg_cmd=ffmpeg -framerate %framerate% -i "!tempdir!\%%d.png" -c:v libvpx -b:v %bitrate% -auto-alt-ref 0 -crf 10 -deadline best -cpu-used %cpu_used% -threads %threads% -vf "!filter!" -r %framerate% -an"

        if "%two_pass%"=="true" (
            echo Performing two-pass encoding for %%~nxD
            !ffmpeg_cmd! -pass 1 -f null NUL
            !ffmpeg_cmd! -pass 2 "%outputdir%\!outfile!"
        ) else (
            !ffmpeg_cmd! "%outputdir%\!outfile!"
        )

        if !errorlevel! neq 0 (
            echo Error occurred during FFmpeg processing for %%~nxD
            echo FFmpeg command: !ffmpeg_cmd! "%outputdir%\!outfile!"
        ) else (
            echo Successfully processed %%~nxD
        )

        echo Processed !counter! frames in %%~nxD.

        rem Clean up temporary directory
        rmdir /s /q "!tempdir!"
    ) else (
        echo No PNG files found in %%~nxD
    )

    popd
)

echo All directories processed.

Usage: .\encode_all.bat -w 2112 -h 960 -fps 24 -input_dir ".\input_dir_with_subdirs\" -output_dir ".\output"