SEGV near NULL in od_mc_get_ref_predictor

[tysmith]

Found running commit 4633b81
Built with AddressSanitizer

To reproduce run:
./dump_video test_case.ogv

==46918==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000060 (pc 0x00000053d0a7 bp 0x7ffd6536dd10 sp 0x7ffd6536dc80 T0)
    #0 0x53d0a6 in od_mc_get_ref_predictor src/mc.c:2081:31
    #1 0x4fa2dd in od_decode_mv src/decode.c:212:16
    #2 0x4f4b86 in od_dec_mv_unpack src/decode.c:899:13
    #3 0x4f4b86 in daala_decode_packet_in src/decode.c:1196
    #4 0x4ec2de in main examples/dump_video.c:426:13
    #5 0x7fe8f817d82f in __libc_start_main /build/glibc-GKVZIf/glibc-2.23/csu/../csu/libc-start.c:291
    #6 0x418f98 in _start (dump_video+0x418f98)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV src/mc.c:2081:31 in od_mc_get_ref_predictor
==46918==ABORTING

test_case.ogv.zip