[SOLVED] Batch process audio files and image files to create movie files by matching multiple wildcard values

Issue

I'm attempting to batch-process audio and image files to create video files using a Shell script with FFmpeg.

1. The ffmpeg script works in Terminal:

ffmpeg -loop 1 -i image.png -i audio.wav -c:v libx264 -tune stillimage -c:a aac -b:a 192k -pix_fmt yuv420p -shortest output.mp4

2. A nested for loop with wildcards works as a batch script:

#!/bin/sh
for img in *.png; do
    for wav in *.wav; do
        ffmpeg -loop 1 -i $img -i $wav -c:v libx264 -tune stillimage -c:a aac -b:a 192k -pix_fmt yuv420p -shortest ../mb/$img.mp4
    done
done

The only problem here is that it creates more combinations than I need. I'd like to be able to match wildcard values and only mix those together. I'd like to be able to prepare the filenames to match in advance to make this easier: For example, only match 1.png with 1.wav to make 1.mp4, 2.png with 2.wav to make 2.mp4 and so on. I'm able to modify the script to match the wildcards in a Regex, but I'm not sure if there is a way to then execute the logic above. Here is what I am attempting:

#!/bin/sh
img=*.png
wav=*.wav

if [[ ${img%.*} == ${wav%.*} ]];
    then
        ffmpeg -loop 1 -i $img -i $wav -c:v libx264 -tune stillimage -c:a aac -b:a 192k -pix_fmt yuv420p -shortest $img.mp4;
    else
        echo "Failure"
    fi

This begins by overwriting the image files, so it does not appear to work as planned. Is there a simpler way to do this? Perhaps looping through images {1..5} in one folder and audio files {1..5} in another?

Thanks for any insights, and happy to provide more context (very new to this, so still learning).

Solution

You can loop through *.png and derive *.wav from them like this:

for img in *.png; do
  ffmpeg -loop 1 -i "$img" -i "${img%.*}.wav" -c:v libx264 -tune stillimage -c:a aac -b:a 192k -pix_fmt yuv420p -shortest "${img%.*}.mp4"
done

Answered By - oguz ismail

Answer Checked By - Timothy Miller (WPSolving Admin)