>>150
ffmpeg.exe -codecs

抜粋
DEA.L. pcm_mulaw PCM mu-law / G.711 mu-law
DEA..S pcm_s16be PCM signed 16-bit big-endian
DEA..S pcm_s16be_planar PCM signed 16-bit big-endian planar
DEA..S pcm_s16le PCM signed 16-bit little-endian
DEA..S pcm_s16le_planar PCM signed 16-bit little-endian planar
DEA..S pcm_s24be PCM signed 24-bit big-endian
DEA..S pcm_s24daud PCM D-Cinema audio signed 24-bit
DEA..S pcm_s24le PCM signed 24-bit little-endian
DEA..S pcm_s24le_planar PCM signed 24-bit little-endian planar
DEA..S pcm_s32be PCM signed 32-bit big-endian
DEA..S pcm_s32le PCM signed 32-bit little-endian
DEA..S pcm_s32le_planar PCM signed 32-bit little-endian planar
DEA..S pcm_s64be PCM signed 64-bit big-endian
DEA..S pcm_s64le PCM signed 64-bit little-endian

よくわからないならとりあえず>>122が言ってるようにpcm_s16leを使っておけばOK。
PCMじゃなくていいならflacで可逆圧縮してもいいかもね。