freeswitch@Andrey-PC> conference 3215-192.168.88.234 record 1.mp4

+OK Record file 1.mp4 canvas 1

2018-08-03 01:09:17.511396 [WARNING] avformat.c:644 Codec [aac] is experimental
feature in libavcodec, never mind
2018-08-03 01:09:17.516396 [NOTICE] avformat.c:673 sample_rate: 32000 nb_samples
: 1024
2018-08-03 01:09:17.516396 [NOTICE] avformat.c:676 sample_fmt 8 != AV_SAMPLE_FMT
_S16, start resampler
Output #0, mp4, to '1.mp4':
    Stream #0:0: Invalid Codec type -1
2018-08-03 01:09:17.517396 [INFO] avformat.c:1817 Opening File [1.mp4] 32000hz

freeswitch@Andrey-PC>