Transcoded NUT-File has incorrect duration

[rmk]

Summary, when transcoding a file from png-mov to ffv1-nut I get a NUT file that has a duration of one frame less than the input.

Command line and output:

ffmpeg -i /Volumes/LPTest4_Mac/samples/special_content/color_frames_png_1080_50p.mov -c:v ffv1 -pix_fmt yuv422p /Volumes/LPTest4_Mac/samples/special_content/color_frames_png_1080_50p-FFV1-4-2-2-8bit-ffmpeg.nut
ffmpeg version git-2014-02-27-ee88012 Copyright (c) 2000-2014 the FFmpeg developers

built on Mar 10 2014 12:07:02 with llvm-gcc 4.2.1 (LLVM build 2336.1.00)
configuration: --enable-shared --disable-static --disable-doc --disable-avdevice --prefix=/Users/admin/repos/de.lesspain/de.lesspain.ffmpeg/ffmpeg/build/ffmpeg --extra-cflags=-I/Users/admin/repos/de.lesspain/de.lesspain.ffmpeg/ffmpeg/build/libmp3lame/include/ --extra-ldflags=-L/Users/admin/repos/de.lesspain/de.lesspain.ffmpeg/ffmpeg/build/libmp3lame/lib/ --extra-ldflags='-Wl,-rpath,@loader_path/../lib' --enable-libmp3lame
libavutil 52. 62.100 / 52. 62.100
libavcodec 55. 48.101 / 55. 48.101
libavformat 55. 24.100 / 55. 24.100
libavfilter 4. 1.100 / 4. 1.100
libswscale 2. 5.101 / 2. 5.101
libswresample 0. 17.104 / 0. 17.104

Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/Volumes/LPTest4_Mac/samples/special_content/color_frames_png_1080_50p.mov':

Metadata:

major_brand : qt
minor_version : 512
compatible_brands: qt
encoder : Lavf55.24.100

Duration: 00:00:00.12, start: 0.000000, bitrate: 3202 kb/s

Stream #0:0(eng): Video: png (png / 0x20676E70), rgb24, 1920x1080 [SAR 1:1 DAR 16:9], 3151 kb/s, 50 fps, 50 tbr, 12800 tbn, 12800 tbc (default)
Metadata:

handler_name : DataHandler

File '/Volumes/LPTest4_Mac/samples/special_content/color_frames_png_1080_50p-FFV1-4-2-2-8bit-ffmpeg.nut' already exists. Overwrite ? [y/N] y
Output #0, nut, to '/Volumes/LPTest4_Mac/samples/special_content/color_frames_png_1080_50p-FFV1-4-2-2-8bit-ffmpeg.nut':

Metadata:

major_brand : qt
minor_version : 512
compatible_brands: qt
encoder : Lavf55.24.100
Stream #0:0: Video: ffv1 (FFV1 / 0x31564646), yuv422p, 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 51200 tbn, 50 tbc (default)
Metadata:

X-Language : eng
handler_name : DataHandler

Stream mapping:

Stream #0:0 -> #0:0 (png -> ffv1)

Press [q] to stop, ? for help
frame= 6 fps=0.0 q=0.0 Lsize= 11kB time=00:00:00.12 bitrate= 777.9kbits/s
video:11kB audio:0kB subtitle:0 global headers:0kB muxing overhead 3.549561%
Roberts-MacBook-Pro:ffmpeg krueger$ ./ffmpeg -i /Volumes/LPTest4_Mac/samples/special_content/color_frames_png_1080_50p-FFV1-4-2-2-8bit-ffmpeg.nut
ffmpeg version N-62704-g92cc6d5 Copyright (c) 2000-2014 the FFmpeg developers

built on Apr 25 2014 15:47:16 with llvm-gcc 4.2.1 (LLVM build 2336.11.00)
configuration: --enable-gpl
libavutil 52. 78.100 / 52. 78.100
libavcodec 55. 59.100 / 55. 59.100
libavformat 55. 37.101 / 55. 37.101
libavdevice 55. 13.100 / 55. 13.100
libavfilter 4. 4.100 / 4. 4.100
libswscale 2. 6.100 / 2. 6.100
libswresample 0. 18.100 / 0. 18.100
libpostproc 52. 3.100 / 52. 3.100

Input #0, nut, from '/Volumes/LPTest4_Mac/samples/special_content/color_frames_png_1080_50p-FFV1-4-2-2-8bit-ffmpeg.nut':

Metadata:

major_brand : qt
minor_version : 512
compatible_brands: qt
encoder : Lavf55.24.100

Duration: 00:00:00.10, start: 0.000000, bitrate: 933 kb/s

Stream #0:0(eng): Video: ffv1 (FFV1 / 0x31564646), yuv422p, 1920x1080, SAR 1:1 DAR 16:9, 50 fps, 50 tbr, 51200 tbn, 51200 tbc (default)
Metadata:

handler_name : DataHandler

At least one output file must be specified

As you can see, the duration is reported as 0.10 but should be 0.12. I checked that the frame data for 6 frames is in the file so it only seems to be a metadata problem.

[rmk]

Input file from the example

[rmk]

Changing the container format to mov in the command line results in a file that has the correct duration (0.12).