retrieve and transcode files with ffmpeg

convert.bat

@echo off

set MTS_ROOT=D:\path\to\dir
set MTS_FIXED_OPT=-f mp4 -r 29.97 -vcodec libx264 -preset slow -filter:v scale=704:384 -b:v 1000k -aspect 16:9 -flags +loop -cmp chroma -b:v 1250k -maxrate 1500k -bufsize 4M -bt 256k -refs 1 -bf 3 -coder 1 -me_method umh -me_range 16 -subq 7 -partitions +parti4x4+parti8x8+partp8x8+partb8x8 -g 250 -keyint_min 25 -level 30 -qmin 10 -qmax 51 -qcomp 0.6 -trellis 2 -sc_threshold 40 -i_qfactor 0.71 -acodec libvo_aacenc -b:a 112k -ar 48000 -ac 2

set MTS_IN_EXT=MTS
set MTS_OUT_EXT=mp4
set MTS_TMP_EXT=tmp

set FFEXE=C:\path\to\ffmpeg.exe

pushd .
cd /d %MTS_ROOT%
for /f "usebackq" %%i in (`dir /B /S *.%MTS_IN_EXT%`) do (
    if not exist "%%~ni.%MTS_OUT_EXT%" (
      "%FFEXE%" -y -i "%%~dpni.%MTS_IN_EXT%" %MTS_FIXED_OPT% "%%~dpni.%MTS_TMP_EXT%"
      ren %%~dpni.%MTS_TMP_EXT% %%~ni.%MTS_OUT_EXT%
      del "%%~dpni.%MTS_IN_EXT%"
    )
)
popd