[HELP] Add MKV Metadata Crop and Aspect Ratio

[Selur]

Also, on a side note, the MKV transfer characteristic value of "4" seems to correspond to BT.470 System M...which would also be great to note!

Documentation says:

The transfer characteristics of the video.

Valid values and their meaning are:

0: reserved, 1: ITU-R BT.709, 2: unspecified, 3: reserved, 4: gamma 2.2 curve, 5: gamma 2.8 curve, 6: SMPTE 170M, 7: SMPTE 240M, 8: linear, 9: log, 10: log sqrt, 11: IEC 61966-2-4, 12: ITU-R BT.1361 extended color gamut, 13: IEC 61966-2-1, 14: ITU-R BT.2020 10 bit, 15: ITU-R BT.2020 12 bit, 16: SMPTE ST 2084, 17: SMPTE ST 428-1; 18: ARIB STD-B67 (HLG)

see: https://mkvtoolnix.download/doc/mkvmerge.html
-> Shouldn't SMPTE 170M be BT.470?

Would it be possible to add MKV metadata/signaling support for crop and display AR?

Looking at the documentation, there is no DAR signaling. (Hybrid does already signal the PAR through '--aspect-ratio-factor'.)
Also not sure which players support the crop signaling. (last I checked only vlc supported it,...)

I have some files with odd aspect ratios (non-1:1 PAR) and overscan that I want to preserve in the original full resolution, 4:3/16:9 capture form but I'd like to store the crop information and set the display aspect ratio for the player to interpret.

DVD, DV,... all use anamorphic aspect ratios, so it was kind of the norm until internet streaming and Blu-rays (which still use anamorphic for quite a few resolutions).

Assuming the content you have has a proper set PAR (pixel aspect ratio) and is displayed properly before conversion, just setting the crop values should be the enough.
Assuming the content you have has a wrong PAR value and thus is displayer wrongly before conversion, why would you want to keep that wrong value?

-> I'll think about adding support for the crop values.

Cu selur