Manual

A convenient batch capture tool for both Windows and Linux. Below is an example.

Prerequisites

FFmpeg 4 or higher version should be installed. As far as I know, FFmpeg 3 lacks some APIs, causing the tool to fail.

Usage

Arguments

The arguments below are used to specify the input and output behaviors.

-p / --path (type: string, default: directory of BatchCap.py): Absolute path of a folder or a file. It specifies the video(s) to be captured.

-g / --height (type: integer, default: 270): The height of each captured image (in pixels).

-t / --tile (type: string, default value: "5x5"): Shape of the tile made up from the captured images with format "cxr" where c stands for columns and r stands for rows. "1x1" is not allowed.

-s / --seek (type: float, default: 0): Time of the first capture (in seconds).

-i / --timestamp (store true): Whether or not show present timestamp on captures. This option needs no parameters. To opt out overwriting, just omit this argument.

-o / --overwrite (store true): Whether or not overwrite the existing files. This option needs no parameters. To opt out overwriting, just omit this argument.

-f / --format (type: str, default: "png"): Output format. Should be one of the image file extensions, i.e. png, bmp, jpg and so forth.

-c / --fontcolor (type: str, default: "white"): Font color of the timestamp. For example, "red" or "0#00000000".

-r / --padratio (type: float, default: 0.01): Ratio of padding against short edge of each image.

-n / --fontratio (type: float, default: 0.08): Ratio of font size against short edge of each image.

Run the tool

You can choose to run the tool with command or with script. Usually when there is only one video to be captured, running with command is more handy, otherwise running with a script is more convenient.

Run with command

Run the following line in powershell (Windows) or bash (Linux).

On Windows, although both cmd.exe and powershell.exe can do the job, powershell is more recommended. cmd.exe does not support UNC directory, which may make the tool fail if the files to be captured are on a remote device.

# -p path   Captures screenshot(s) of file named path (or the videos under the folder named path).
# -s 1      The capture begins at second 1.0 in the video.
# -i        Embed timestamp on the captures.
# -c yellow timestamp font color is yellow.
# -n 0.08   timestamp font size is 0.08 * min(width, height).
# -g 270    The height of each image is 270 pixels (the ratio is remained the same as the source video).
# -r 0.01   padding is to be set as 0.01 * min(width, height), where width and height are the width and heigth of a frame of image.
# -t 5x4    The screenshot is made up of 20 captured images with 5 columns and 4 rows.
# -o        Overwrite existing files with the same file name with the output files.
# -f png    Output png format picture.
path_to_python path_to_batchcap.py -p path -s 1 -i -c yellow -n 0.08 -g 270 -r 0.01 -t 5x4 -o -f png

Run with script

To handle a batch of videos, especially those under a specific directory, running with script is recommended. The idea is:

(1) put the script file under the corresponding folder;

(2) run the script.

On Windows, use a powershell script (with extension ".ps1").

# Sorts the Pipeline output into several kinds of metadata.
function GetAnsVal {
    param([Parameter(Mandatory=$true, ValueFromPipeline=$true)][System.Object[]][AllowEmptyString()]$Output)
    
    $all = New-Object System.Collections.Generic.List[System.Object]
    $exception = New-Object System.Collections.Generic.List[System.Object]
    $stderr = New-Object System.Collections.Generic.List[System.Object]
    $stdout = New-Object System.Collections.Generic.List[System.Object]
    $Output | ForEach-Object {
        if ($_ -ne $null){
            if ($_.GetType().FullName -ne 'System.Management.Automation.ErrorRecord'){
                if ($null -ne $_.Exception.message){
                    $all.Add($_.Exception.message )
                    $exception.Add($_.Exception.message )
                }
                elseif ($_ -ne $null){
                    $stdout.Add($_)
                }
            } else {
                $all.Add($_.Exception.message)
                $stderr.Add($_.Exception.message)
            }   
         }
    }
    [hashtable]$return = @{}
    $return.Meta0=$all;$return.Meta1=$exception;$return.Meta2=$stderr;$return.Meta3=$stdout
    return $return
}

# Replace '\r\n' with '\n'
function Replace {
    param([Parameter(Mandatory=$true, ValueFromPipeline=$true)][hashtable]$r)

    $Meta0=""
    foreach ($el in $r.Meta0){
        $Meta0+=$el
    }
    $Meta0=($Meta0 -split "[`r`n]") -join "`n"
    $Meta0=($Meta0 -split "[`n]{2,}") -join "`n"

    return $Meta0
}

# GetAnsVal and Replace make sure powershell output correctly. 
# Replace ForEach-Object {& GetAnsVal $_ | & Replace} with ForEach-Object {"$_"} to see the difference.
& path_to_python path_to_batchcap.py -p $PSScriptRoot -s 1 -i -c yellow -n 0.08 -g 270 -r 0.01 -t 5x4 -o -f png 2>&1 | ForEach-Object {& GetAnsVal $_ | & Replace}

pause

On Linux, use a bash script (with extension ".sh").

#!/bin/bash

path_to_python path_to_batchcap.py -p $(dirname $BASH_SOURCE) -s 1 -i -c yellow -n 0.08 -g 270 -r 0.01 -t 5x4 -o -f png

or you can run it in the background

#!/bin/bash

nohup path_to_python path_to_batchcap.py -p $(dirname $BASH_SOURCE) -s 1 -i -c yellow -n 0.08 -g 270 -r 0.01 -t 5x4 -o -f png > ~/nohup.log 2>&1 &