how can i join 2 jpgs that have different sizes? and multiple jpg joining?

[sommers]

when i need to join 2 jpgs, i got this working
ffmpeg.exe -y -i %1 -i %2 -filter_complex vstack out.bmp


question 1
how can i make this work by using list.txt?

FOR %%V IN (%*) DO ( @echo file '%%~V' >> m:\LIST.TXT )
ffmpeg.exe -y -f concat -safe 0 -i m:\list.txt -filter_complex hstack out.bmp

---------------------------------------------------------------------

question 2
i need to join 2 jpgs that have different sizes.
(w1,h1) + (w2,h2) = new bmp (w1+w2, whichever is larger h1 or h2 )

[sneaker]

question 1:
You cannot use the concat demuxer to stack 2 pictures into 1 picture. It is for appending. (one shown after the other one ends)

question 2:
That's stacking horizontally, i.e. hstack filter. For inputs with same height:
ffmpeg -i "input1" -i "input2" -filter_complex "[0:v][1:v]hstack=inputs=2[out]" -map "[out]" "output.bmp"

If you want from different heights you need to scale or pad first. Whatever you want. But automating is difficult. Maybe with some scale2ref trickery.


https://trac.ffmpeg.org/wiki/FilteringGuide

[sommers]

>question 2 automating is difficult
ok i will forget it

AA=
ffmpeg -y -i "%1" -i "%2" -filter_complex "[0:v][1:v]hstack=inputs=2[out]" -map "[out]" "output.bmp"

BB=
ffmpeg.exe -y -i %1 -i %2 -filter_complex hstack out.bmp or
ffmpeg.exe -y -i %1 -i %2 -filter_complex vstack out.bmp

i can understand BB=, but i dont have energy to understand AA=, and BB= seems does the same thing as AA=
ok i resize them to a common resolution 1st then i will use hstack and vstack, one of them will be correct

---------------------------------------------
I am trying to resize an image with an aspect keep

CC= ffmpeg -i "%1" -vf scale=w=1920:h=1870:force_original_aspect_ratio=de crease out.bmp
runs but doesnt do what i want

DD=
ffmpeg -i "%1" -vf scale="'if(gt(a,4/3),1920,-1)':'if(gt(a,4/3),-1,1080)'" out.bmp
ffmpeg -i "%1" -vf scale="'if(gt(a,1.8),1920,-1)':'if(gt(a,1.8),-1,1080)'" out.bmp
ffmpeg -i "%1" -vf scale="'if(gt(a,1),1920,-1)':'if(gt(a,1),-1,2880)'" out.bmp

DD= runs but none of them does what i want.

---------------------------------------------
I am trying to resize with an aspect keep

EE=
11. ffmpeg -i "%1" -vf scale=1920:-1 out1.bmp
22. ffmpeg -i "%1" -vf scale=-1:1080 out2.bmp

EE=works nicely but the one of them (11. or 22.) will always overshoot. is there a way to find which one fits in the given resolutions?

[sneaker]

runs but doesnt do what i want
[...]
DD= runs but none of them does what i want.

What do you want?

[sommers]

i need to find which direction i need to use -1, w or h without manually looking at the input image in order to fit the final image within the resolutions.
EE= worked but i have to remove one of them manually.

[sneaker]

But what is your problem with CC or DD?

[sommers]

AA=ffmpeg -i "%1" -vf scale=w=1920:h=1080:force_original_aspect_ratio=de crease out.bmp
BB=ffmpeg -i "%1" -vf scale="'if(gt(a,4/3),1920,-1)':'if(gt(a,4/3),-1,1080)'" out.bmp
CC=ffmpeg -i "%1" -vf scale="'if(gt(a,1.8),1920,-1)':'if(gt(a,1.8),-1,1080)'" out.bmp
DD=ffmpeg -i "%1" -vf scale="'if(gt(a,1),1920,-1)':'if(gt(a,1),-1,1080)'" out.bmp

AA= works
BB=1920 x 1343 doesnt work, overshooting, but it was not so bad
CC=1920x671 works
DD=1920X1343 doesnt work, overstooting, but it was not so bad

i must have been blind.

why do BB= and DD= have the same result?

4/3= 1.33 = 640/480
1.8= 1920/1080
1 = 1000/1000

i choose AA=, thanks for making me redo this with certainty.

for BB=,CC=,DD= even if they were made to work, i couldnt find the aspect ratio manually 1.33 1.8 and etc.

in gt(a, aspect ratio), that was for the aspect ratio right?

[sneaker]

I assume "gt" means "greater than". "a" is the aspect ratio of the input. It is math.
gt(a, 1) means "is a greater than 1?"
For a=1920/1343: yes. Every time the width is bigger than the height width/height will be bigger than 1. (elementary school math)

1920/1343 is ~1,43. So it is also bigger than 4/3(~=1.3). So you get the same result.