[MPlayer-dev-eng] Removing ADPCM code

[Reimar Döffinger]

Hello,
unless there are objections I intend to remove our ADPCM codecs in
libmpcodecs within a few days, since they can be decoded via FFmpeg.
Except for the DK4 codec for which I could not find a sample I tested
decoding via FFmpeg and encountered no problems.
Files to be removed:
ad_dk3adpcm.c
ad_imaadpcm.c
ad_msadpcm.c

Codecs:
imaadpcm
msadpcm
dk4adpcm
dk3adpcm

Greetings,
Reimar Döffinger