Neat comparison commands
------------------------




this command will take a input video and transcode it for every crf value in a range

crfleveltest.sh
```
#!/bin/bash

for i in {0..63}
do
    echo da real time bro $i >> timetime
    date >> timetime
    ffmpeg -i originalencoding.mkv -c:a copy -c:v libsvtav1 -preset 8 -crf $i svtav1/crftest/svtav1_$i.mkv
    #echo \n >> timetime
done
```
this will take a specific frame out off all the videos in a folder which is useful for comparing the crf values on a specific frame
frameextractor.sh
```
#!/bin/bash

output_directory="png"

for video in *mkv; do
  filename=$(basename -- "$video")
  filename_no_ext="${filename%.*}"
  ffmpeg -ss 00:00:10 -i "$video" -vframes 1 "$output_directory/$filename_no_ext.png"
done
```
this will take all the file names of the pngs and put them into subtitles so you cam see what video (crf value typically) the current frame was from
subtitles.py
```
import os

# Assuming files are in the current directory.
# Modify this path to the location of your PNG files if needed.
files = sorted([f for f in os.listdir('.') if f.endswith('.png')])

# Start time for each subtitle in seconds
start_time = 0.0

# The duration each subtitle is displayed for in seconds
duration = 0.1

with open('subtitles.srt', 'w') as f:
    for i, filename in enumerate(files, start=1):
        # Format start and end times
        start_h = int(start_time // 3600)
        start_m = int((start_time % 3600) // 60)
        start_s = int(start_time % 60)
        start_ms = int(round((start_time % 1) * 1000))
        start = "{:02d}:{:02d}:{:02d},{:03d}".format(start_h, start_m, start_s, start_ms)

        end_time = start_time + duration
        end_h = int(end_time // 3600)
        end_m = int((end_time % 3600) // 60)
        end_s = int(end_time % 60)
        end_ms = int(round((end_time % 1) * 1000))
        end = "{:02d}:{:02d}:{:02d},{:03d}".format(end_h, end_m, end_s, end_ms)

        # Write subtitle entry
        f.write(f"{i}\n{start} --> {end}\n{filename}\n\n")

        # Update start time for next subtitle
        start_time += duration
```
this will combine all the pngs and subtitles to a video to be watched just make sure the framerates match between this command and rhe ones specified in the subtitle command
pngcombiner
```
ffmpeg -framerate 10 -i svtav1_%02d.png -i subtitles.srt -c:v libx264 -crf 10 output.mkv
```