You can add metadata information to the file that you encode. To do this you should add "metadata::" into your encoding configuration string.
For example, format='mov' video::codec='mpeg4' video::b='5M' audio::codec='aac' metadata::title='My Title'
Please note, that in WriterSet method (MFromats) you should set _BResetOption to 1 to be able to add new metadata to the file. With _BResetOption as 0, you can only update current properties of the Writer object.
If you are going to get the encoded metadata with PropsGet method, you should get it from "info::metadata" block for example: IMFProps.PropsGet("info::metadata::comment", ...) for MFormats and IMProps.PropsGet("file::info::metadata::comment", ...) for MPlatform.
Different file formats have a different set of possible metadata. Here is a list of possible metadata that you can encode into the output file header.
QuickTime/MOV/MP4/M4A/et al.
metadata::title
metadata::author
metadata::album_artist
metadata::album
metadata::grouping
metadata::composer
metadata::year
metadata::track
metadata::comment
metadata::genre
metadata::copyright
metadata::description
metadata::synopsis
metadata::show
metadata::episode_id
metadata::network
metadata::lyrics
ASF/WMV/WMA
metadata::title
metadata::author
metadata::copyright
metadata::comment
metadata::rating
Beyond these keys, the ASF accepts free-form key/value metadata keys to be encoded into the header
Matroska (MKV)
metadata::title
metadata::description
metadata::language
Beyond these keys, the Matroska also accepts free-form key/value metadata pairs.
AVI
metadata::IART artist
metadata::ICMT comment
metadata::ICOP copyright
metadata::ICRD date
metadata::IGNR genre
metadata::ILNG language
metadata::INAM title
metadata::IPRD album
metadata::IPRT track
metadata::ITCH encoded_by
FLV
Free-form metadata key/value pairs
MP3
metadata::title
metadata::author
metadata::album
metadata::year
metadata::comment
metadata::track
metadata::genre
MPEG Transport Streams
metadata::title
metadata::language
Metadata for individual audio/video streams
You can set the metada individually for every audio/video stream this way:
audio.1::metadata::language='eng', audio.2::metadata::language='eng'
Please note that you can not specify the first audio.0 stream directly, but you can set the default metadata without any index with f.e. audio::metadata::language and change all other streams directly.