>>147413
So the reason for the larger file size was, you exported to a higher bitrate than the source. It invents information. You pointed that out since. That one anon on 4chins mentioned converting to lossy audio, which implies spaces aren't lossy, lol. Anyway.
Make sure you're on an empty/fresh line in your command prompt.
Do the shift-rightclick thing for the ffmpeg executable and paste into the command prompt.
Now we add the trim. The command is ss, and you specify the time in hh:mm:ss, like -ss 00:05:10
Now we add the inputs. Define an input with -i and copypaste the path for the first file. Do the same for the second file.
Here's something for you to copypaste after
-filter_complex "[0:a][1:a]concat=n=2:v=0:a=1"
0:a and 1:a refer to the two input audio streams, a means audio.
n=2 means there are two inputs.
v=0 means no video output
a=1 means one audio output
next we set the codec. as you saw in the ffprobe, it's aac, we'll stay with aac
-c:a aac
-c codec, a audio, aac
now we set the bitrate, which is 95kbs
-b:a 96k
-b bitrate, a audio, 96k(bps) you can specify whatever, but numbers significantly above what you have in your source is just gonna baloon it, it can't add fidelity where there is none.
now we just set the output, you specify where the file should be put, i.e. "C:\baachaudio.m4a"
"C:\Users\Z170X-UD5\Downloads\ffmpeg-2025-04-23-git-25b0a8e295-essentials_build\bin\ffmpeg.exe" -ss 00:05:10 -i "C:\Users\Z170X-UD5\Downloads\8mb9r4.m4a" -i "C:\Users\Z170X-UD5\Downloads\jh5al9.m4a" -filter_complex "[0:a][1:a]concat=n=2:v=0:a=1" -c:a aac -b:a 96k "C:\baachaudio.m4a"
If you get stuck, lmk.