Batch File: add .srt subs to video using ffmpeg

[sambat]

Converting a bunch of avi files from 16:9 to 4:3 format with avc and aac.
That part works fine.
I have srt subs with the same names as the videos, but I don't know how to automate the command in the ffmpeg bat file.
(I want to skip using mkvmerge).

md newfiles
for %%a in (*.avi) do ffmpeg -i "%%a" -c:a aac -ac 2 -aspect 1.33 -strict -2 "newfiles\%%~na.mkv"

[jagabo]

Change this line:

for %%a in (*.avi) do ffmpeg -i "%%a" -i "%%~na.srt" -c:s copy -c:a aac -ac 2 -aspect 1.33 -strict -2

[sambat]

@jagabo
Many thanks, that was what I was missing.
Letting ffmpeg run using the default video codec reduced the size to less than one half and I don't notice a difference.