vidterm.sh

#!/bin/bash

if [[ $# -ne 1 ]]; then
    printf "Usage: %s VIDEO_FILE\n" $0
    exit 1
fi

source_file=$1

framerate=$(ffmpeg -i "$source_file" 2>&1 | grep -oE '[0-9]+ fps' | grep -oE '^[0-9]+')

temp_dir=$(mktemp --directory)

microseconds_per_frame=$((1000000 / $framerate))
temp_frame="$temp_dir/frame.jpg"
temp_frame_ascii="$temp_dir/frame-ascii.txt"
seconds=0
minutes=0
position=0
position_in_microseconds=0

function microtime() {
    echo $(($(date +%s%N)/1000))
}

function render_frame() {
    ffmpeg -y -loglevel quiet -i "$source_file" -r "$framerate" -ss "$position" -frames: 1 -s 320x240 "$temp_frame"
    jp2a -z "$temp_frame" > "$temp_frame_ascii"
}

render_frame

# play audio in background
ffplay -hide_banner -loglevel panic -nodisp "$source_file" &

while [[ true ]]; do
    
    cat "$temp_frame_ascii"

    start_time=$(microtime)

    current_time=$(microtime)
    elapsed_time=$((current_time - start_time))

    render_frame

    while [[ elapsed_time -lt microseconds_per_frame ]]; do
        current_time=$(microtime)
        elapsed_time=$((current_time - start_time))
    done
    
    position_in_microseconds=$((position_in_microseconds + elapsed_time))

    position=$( echo "scale=2; ($position_in_microseconds) / 1000000.0" | bc -l)
    
    echo "$position" | grep -q -E "^\."

    if [[ $? -eq 0 ]]; then
        position="0$position"
    fi
done