So i did a comparison between wav recording and mp4 recording, and it seems BAD READ -1000 only occurs when using mp4.
Here is part log for mp4
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3f39d3c5-97cb-f91a-48b5-c016e82175e2 2016-04-16 21:12:10.361551 [NOTICE] mod_verto.c:2746 Hangup verto.rtc/83789 [CS_EXECUTE] [NORMAL_CLEARING]
2016-04-16 21:12:10.361551 [DEBUG] switch_core_media.c:5459 verto.rtc/83789 Video thread ended
3f39d3c5-97cb-f91a-48b5-c016e82175e2 2016-04-16 21:12:10.381543 [INFO] conference_loop.c:1400 Channel leaving conference, cause: NORMAL_CLEARING
3f39d3c5-97cb-f91a-48b5-c016e82175e2 2016-04-16 21:12:10.381543 [DEBUG] mod_conference.c:2209 verto.rtc/83789 skip receive message [UNBRIDGE] (channel is hungup already)
2016-04-16 21:12:10.381543 [DEBUG] mod_verto.c:1862 BAD READ -1000
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Here is the same bit of log with just wav recording:
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d5f7b099-e268-b149-bd5f-459b15c1a9f4 2016-04-16 22:06:57.490132 [NOTICE] mod_verto.c:2746 Hangup verto.rtc/83789 [CS_EXECUTE] [NORMAL_CLEARING]
2016-04-16 22:06:57.500121 [DEBUG] switch_core_media.c:5459 verto.rtc/83789 Video thread ended
d5f7b099-e268-b149-bd5f-459b15c1a9f4 2016-04-16 22:06:57.500121 [INFO] conference_loop.c:1400 Channel leaving conference, cause: NORMAL_CLEARING
d5f7b099-e268-b149-bd5f-459b15c1a9f4 2016-04-16 22:06:57.500121 [DEBUG] mod_conference.c:2209 verto.rtc/83789 skip receive message [UNBRIDGE] (channel is hungup already)
d5f7b099-e268-b149-bd5f-459b15c1a9f4 2016-04-16 22:06:57.500121 [DEBUG] switch_core_media.c:9147 verto.rtc/83789 skip receive message [HARD_MUTE] (channel is hungup already)
d5f7b099-e268-b149-bd5f-459b15c1a9f4 2016-04-16 22:06:57.500121 [DEBUG] switch_core_codec.c:258 Restore original codec.
d5f7b099-e268-b149-bd5f-459b15c1a9f4 2016-04-16 22:06:57.500121 [DEBUG] switch_core_session.c:2796 verto.rtc/83789 skip receive message [APPLICATION_EXEC_COMPLETE] (channel is hungup already)
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Thank you