[FFmpeg-user] How to set 3 specific metadata flags (ITU601/displayoffset) in FFmpegs IMX50 MXF-OP1a encoding?

[Christoph Gerstbauer]

Hello

I am testing with ffmpeg the IMX50 D10 encoding, and I am very close to 
my target but I have to create 3 metadata values in the MXF header which 
is standard in most IMX50 MXF ecndodings:

+ SIGNAL STANDARD = 1 (ITU 601)
+ display y offset = 32  - I am encoding 720x608 sources with included 
VBI area (32 lines high at the top) -> the offset 32 defines the active 
picture -> 720x576
+ Color siting = 4 (Rec 601)

Is it possible to encoded with ffmpeg in a way that these values can be 
written?
If yes, which syntax should I add to my used syntax?
If no, could the option be implemented in future?

My used ffmpeg syntax is:
ffmpeg -i <inputfile> -map 0:v -map 0:a  -c:v mpeg2video -r 25 -pix_fmt 
yuv422p -aspect 4:3 -minrate 50000k -maxrate 50000k -b:v 50000k -intra 
-flags +ildct+ilme+low_delay -intra_vlc 1 -non_linear_quant 1 -ps 1 
-qmin 1 -qmax 3 -top 1 -dc 10 -bufsize 2000000 -rc_init_occupancy 
2000000 -rc_buf_aggressivity 0.25 -tag:v mx5p -c:a pcm_s24le -ar 48000 
-f mxf_d10 <outpufile.mxf>

I check the MXF metadata with BMX mxf2raw.exe (BBC)
I use 2 examples:
1.) a ffmpeg encoded MXF and
2.) a MXF from the Carbon Coder (Rhozet).

The carbon Coder playout shows me the wanted values:

C:\Users\gersti>mxf2raw -i I:\IMX_tests\IMX50_CARBON.mxf
MXF File Information:
   Filename                   : I:\IMX_tests\IMX50_CARBON.mxf
   MXF version                : 1.2
   OP label                   : OP-1A (internal essence, stream file, 
multi-track)
   Wrapping type              : Frame
   Material package name      :
   Material start timecode    : 00:00:00:00 (@ 25fps)
   File src start timecode    : 00:00:00:00 (@ 25fps)
   Edit rate                  : 25/1
   Precharge                  : 0
   Duration                   : 500
   Rollout                    : 0
   Identifications            :
     Identification 0:
       Generation UID    : 10e5dae5.54663246.8c411484.8c2015e4
       Company name      : Rhozet
       Product name      : Carbon
       Product version   : (not set)
       Version string    : 1.1
       Product UID       : 842d0e07.eb104da4.b6d1c16b.bfdf797b
       Modification date : 2015-02-03 13:39:02.000
       Toolkit version   : (not set)
       Platform          : (not set)
Track 0:
   Essence kind         : Picture
   Essence type         : D10 50Mbps
   Essence label        : 060e2b34.04010101.0d010301.02010101
   Material package uid : 
060a2b34.01010105.01010d20.13000000.d403bb57.8f86e749.9a0e3118.abce6ab9
   Material track id    : 2
   Material track number: 0
   File package uid     : 
060a2b34.01010105.01010d20.13000000.09464eb5.53deb944.9566c38d.b95db9fd
   File track id        : 2
   File track number    : 0x05010100
   Edit rate            : 25/1
   Duration             : 500
   Lead filler offset   : 0
   Picture coding label : 060e2b34.04010101.04010202.01020101
   Signal standard      : 1 (ITU 601)
   Frame layout         : 1 (Separate Fields)
   Stored dimensions    : 720x608
   Display dimensions   : 720x576
   Display x offset     : 0
   Display y offset     : 32
   Aspect ratio         : 4/3
   AFD                  : (not set)
   Component depth      : 8
   Horiz subsampling    : 2
   Vert subsampling     : 1
   Color siting         : 4 (Rec 601)


The FFMPEG MXF looks like this (the 3 values are not set correctly):

C:\Users\gersti>mxf2raw -i I:\IMX_tests\IMX50_FFMPEG.mxf
MXF File Information:
   Filename                   : I:\IMX_tests\IMX50_FFMPEG.mxf
   MXF version                : 1.2
   OP label                   : OP-1A (internal essence, stream file, 
multi-track)
   Wrapping type              : Frame
   Material package name      :
   Material start timecode    : 10:00:00:00 (@ 25fps)
   File src start timecode    : 10:00:00:00 (@ 25fps)
   Edit rate                  : 25/1
   Precharge                  : 0
   Duration                   : 750
   Rollout                    : 0
   Identifications            :
     Identification 0:
       Generation UID    : adab4424.2f254dc7.92ff29bd.000b0001
       Company name      : FFmpeg
       Product name      : OP1a Muxer
       Product version   : (not set)
       Version string    : 55.48.101
       Product UID       : adab4424.2f254dc7.92ff29bd.000b0002
       Modification date : 0-00-00 00:00:00.000
       Toolkit version   : (not set)
       Platform          : (not set)
Track 0:
   Essence kind         : Picture
   Essence type         : picture essence
   Essence label        : 060e2b34.04010102.0d010301.02046001
   Material package uid : 
060a2b34.01010105.01010d00.1387b014.52947134.7187b014.00529471.34718700
   Material track id    : 2
   Material track number: 0
   File package uid     : 
060a2b34.01010105.01010d00.1387b014.52947134.7187b014.00529471.34718701
   File track id        : 2
   File track number    : 0x15010500
   Edit rate            : 25/1
   Duration             : 750
   Lead filler offset   : 0
   Picture coding label : 060e2b34.04010103.04010202.01020200
   Signal standard      : 0 (None)
   Frame layout         : 1 (Separate Fields)
   Stored dimensions    : 720x608
   Display dimensions   : 720x576
   Display x offset     : 0
   Display y offset     : 0
   Aspect ratio         : 4/3
   AFD                  : (not set)
   Component depth      : 8
   Horiz subsampling    : 2
   Vert subsampling     : 1
   Color siting         : 255 (Unknown)


Best Regards
Christoph