diff --git a/libavformat/nutenc.c b/libavformat/nutenc.c
index a92ff55c01..6e96626ff0 100644
--- a/libavformat/nutenc.c
+++ b/libavformat/nutenc.c
@@ -1221,7 +1221,7 @@ AVOutputFormat ff_nut_muxer = {
     .priv_data_size = sizeof(NUTContext),
     .audio_codec    = CONFIG_LIBVORBIS ? AV_CODEC_ID_VORBIS :
                       CONFIG_LIBMP3LAME ? AV_CODEC_ID_MP3 : AV_CODEC_ID_MP2,
-    .video_codec    = AV_CODEC_ID_MPEG4,
+    .video_codec    = AV_CODEC_ID_FFV1,
     .write_header   = nut_write_header,
     .write_packet   = nut_write_packet,
     .write_trailer  = nut_write_trailer,
diff --git a/tests/ref/lavf/nut b/tests/ref/lavf/nut
index 1c3d7107da..ea2f89124d 100644
--- a/tests/ref/lavf/nut
+++ b/tests/ref/lavf/nut
@@ -1,3 +1,3 @@
-424e8037d7b6f3d3c09cf76bf06a63cb *./tests/data/lavf/lavf.nut
-319958 ./tests/data/lavf/lavf.nut
-./tests/data/lavf/lavf.nut CRC=0xec6c3c68
+cb603de6d9dce6eccef210f8b73980e5 *./tests/data/lavf/lavf.nut
+1353826 ./tests/data/lavf/lavf.nut
+./tests/data/lavf/lavf.nut CRC=0x233df7f5
diff --git a/tests/ref/seek/lavf-nut b/tests/ref/seek/lavf-nut
index b2da52629b..d2191a6efa 100644
--- a/tests/ref/seek/lavf-nut
+++ b/tests/ref/seek/lavf-nut
@@ -1,53 +1,53 @@
-ret: 0         st: 1 flags:1 dts: 0.000000 pts: 0.000000 pos:    395 size:   208
+ret: 0         st: 1 flags:1 dts: 0.000000 pts: 0.000000 pos:    364 size:   208
 ret: 0         st:-1 flags:0  ts:-1.000000
-ret: 0         st: 0 flags:1 dts: 0.010918 pts: 0.010918 pos:    623 size: 27837
+ret: 0         st: 0 flags:1 dts: 0.010918 pts: 0.010918 pos:    592 size: 55646
 ret: 0         st:-1 flags:1  ts: 1.894167
-ret: 0         st: 0 flags:1 dts: 0.490918 pts: 0.490918 pos: 146490 size: 27925
+ret: 0         st: 0 flags:1 dts: 0.970918 pts: 0.970918 pos:1297517 size: 55895
 ret: 0         st: 0 flags:0  ts: 0.788340
-ret: 0         st: 0 flags:1 dts: 0.490918 pts: 0.490918 pos: 146490 size: 27925
+ret: 0         st: 0 flags:1 dts: 0.970918 pts: 0.970918 pos:1297517 size: 55895
 ret: 0         st: 0 flags:1  ts:-0.317500
-ret: 0         st: 0 flags:1 dts: 0.010918 pts: 0.010918 pos:    623 size: 27837
+ret: 0         st: 0 flags:1 dts: 0.010918 pts: 0.010918 pos:    592 size: 55646
 ret: 0         st: 1 flags:0  ts: 2.576667
-ret: 0         st: 1 flags:1 dts: 0.862041 pts: 0.862041 pos: 271315 size:   209
+ret: 0         st: 1 flags:1 dts: 0.940408 pts: 0.940408 pos:1297077 size:   209
 ret: 0         st: 1 flags:1  ts: 1.470839
-ret: 0         st: 1 flags:1 dts: 0.862041 pts: 0.862041 pos: 271315 size:   209
+ret: 0         st: 1 flags:1 dts: 0.940408 pts: 0.940408 pos:1297077 size:   209
 ret: 0         st:-1 flags:0  ts: 0.365002
-ret: 0         st: 0 flags:1 dts: 0.490918 pts: 0.490918 pos: 146490 size: 27925
+ret: 0         st: 0 flags:1 dts: 0.490918 pts: 0.490918 pos: 650696 size: 54610
 ret: 0         st:-1 flags:1  ts:-0.740831
-ret: 0         st: 0 flags:1 dts: 0.010918 pts: 0.010918 pos:    623 size: 27837
+ret: 0         st: 0 flags:1 dts: 0.010918 pts: 0.010918 pos:    592 size: 55646
 ret: 0         st: 0 flags:0  ts: 2.153340
-ret: 0         st: 0 flags:1 dts: 0.490918 pts: 0.490918 pos: 146490 size: 27925
+ret: 0         st: 0 flags:1 dts: 0.970918 pts: 0.970918 pos:1297517 size: 55895
 ret: 0         st: 0 flags:1  ts: 1.047500
-ret: 0         st: 0 flags:1 dts: 0.490918 pts: 0.490918 pos: 146490 size: 27925
+ret: 0         st: 0 flags:1 dts: 0.970918 pts: 0.970918 pos:1297517 size: 55895
 ret: 0         st: 1 flags:0  ts:-0.058322
-ret: 0         st: 1 flags:1 dts: 0.000000 pts: 0.000000 pos:    395 size:   208
+ret: 0         st: 1 flags:1 dts: 0.000000 pts: 0.000000 pos:    364 size:   208
 ret: 0         st: 1 flags:1  ts: 2.835828
-ret: 0         st: 1 flags:1 dts: 0.862041 pts: 0.862041 pos: 271315 size:   209
+ret: 0         st: 1 flags:1 dts: 0.940408 pts: 0.940408 pos:1297077 size:   209
 ret: 0         st:-1 flags:0  ts: 1.730004
-ret: 0         st: 0 flags:1 dts: 0.490918 pts: 0.490918 pos: 146490 size: 27925
+ret: 0         st: 0 flags:1 dts: 0.970918 pts: 0.970918 pos:1297517 size: 55895
 ret: 0         st:-1 flags:1  ts: 0.624171
-ret: 0         st: 0 flags:1 dts: 0.490918 pts: 0.490918 pos: 146490 size: 27925
+ret: 0         st: 0 flags:1 dts: 0.490918 pts: 0.490918 pos: 650696 size: 54610
 ret: 0         st: 0 flags:0  ts:-0.481660
-ret: 0         st: 0 flags:1 dts: 0.010918 pts: 0.010918 pos:    623 size: 27837
+ret: 0         st: 0 flags:1 dts: 0.010918 pts: 0.010918 pos:    592 size: 55646
 ret: 0         st: 0 flags:1  ts: 2.412500
-ret: 0         st: 0 flags:1 dts: 0.490918 pts: 0.490918 pos: 146490 size: 27925
+ret: 0         st: 0 flags:1 dts: 0.970918 pts: 0.970918 pos:1297517 size: 55895
 ret: 0         st: 1 flags:0  ts: 1.306667
-ret: 0         st: 1 flags:1 dts: 0.862041 pts: 0.862041 pos: 271315 size:   209
+ret: 0         st: 1 flags:1 dts: 0.940408 pts: 0.940408 pos:1297077 size:   209
 ret: 0         st: 1 flags:1  ts: 0.200839
-ret: 0         st: 1 flags:1 dts: 0.182857 pts: 0.182857 pos:  71957 size:   209
+ret: 0         st: 1 flags:1 dts: 0.182857 pts: 0.182857 pos: 271744 size:   209
 ret: 0         st:-1 flags:0  ts:-0.904994
-ret: 0         st: 0 flags:1 dts: 0.010918 pts: 0.010918 pos:    623 size: 27837
+ret: 0         st: 0 flags:1 dts: 0.010918 pts: 0.010918 pos:    592 size: 55646
 ret: 0         st:-1 flags:1  ts: 1.989173
-ret: 0         st: 0 flags:1 dts: 0.490918 pts: 0.490918 pos: 146490 size: 27925
+ret: 0         st: 0 flags:1 dts: 0.970918 pts: 0.970918 pos:1297517 size: 55895
 ret: 0         st: 0 flags:0  ts: 0.883340
-ret: 0         st: 0 flags:1 dts: 0.490918 pts: 0.490918 pos: 146490 size: 27925
+ret: 0         st: 0 flags:1 dts: 0.970918 pts: 0.970918 pos:1297517 size: 55895
 ret: 0         st: 0 flags:1  ts:-0.222500
-ret: 0         st: 0 flags:1 dts: 0.010918 pts: 0.010918 pos:    623 size: 27837
+ret: 0         st: 0 flags:1 dts: 0.010918 pts: 0.010918 pos:    592 size: 55646
 ret: 0         st: 1 flags:0  ts: 2.671678
-ret: 0         st: 1 flags:1 dts: 0.862041 pts: 0.862041 pos: 271315 size:   209
+ret: 0         st: 1 flags:1 dts: 0.940408 pts: 0.940408 pos:1297077 size:   209
 ret: 0         st: 1 flags:1  ts: 1.565850
-ret: 0         st: 1 flags:1 dts: 0.862041 pts: 0.862041 pos: 271315 size:   209
+ret: 0         st: 1 flags:1 dts: 0.940408 pts: 0.940408 pos:1297077 size:   209
 ret: 0         st:-1 flags:0  ts: 0.460008
-ret: 0         st: 0 flags:1 dts: 0.490918 pts: 0.490918 pos: 146490 size: 27925
+ret: 0         st: 0 flags:1 dts: 0.490918 pts: 0.490918 pos: 650696 size: 54610
 ret: 0         st:-1 flags:1  ts:-0.645825
-ret: 0         st: 0 flags:1 dts: 0.010918 pts: 0.010918 pos:    623 size: 27837
+ret: 0         st: 0 flags:1 dts: 0.010918 pts: 0.010918 pos:    592 size: 55646
