Metadata and tags

[mpek]

Metadata won't get copied to newly generated file. Null nada empty.
You could also make a choice to user if metadata shall not be copied but it should be turned on by default.

mp4files (and subsequently mp4box) doesn't really have much metadata. Other than the basic title/etc. It does support tags but I think this would be something that is more for music than it is video muxing.

Supported tag names (name, value, type, aliases)
title (A9nam) string (alias name)
artist (A9ART) string
album_artist (aART) string (alias albumArtist)
album (A9alb) string
group (A9grp) string (alias grouping)
composer (A9com) string
writer (A9wrt) string
conductor (A9con) string
comment (A9cmt) string (alias comments)
genre (gnre) string (ID3 genre tag)
created (A9day) string (alias releaseDate)
track (A9trk) string
tracknum (trkn) fraction (syntax: A/B or A, B will be 0)
disk (disk) fraction (syntax: A/B or A, B will be 0)
tempo (tmpo) integer
compilation (cpil) bool (yes or no)
show (tvsh) string (alias tvShow)
episode_id (tven) string (alias tvEpisodeID)
season (tvsn) integer (alias tvSeason)
episode (tves) integer (alias tvEPisode)
network (tvnn) string (alias tvNetwork)
sdesc (desc) string (alias description)
ldesc (ldes) string (alias longDescription)
lyrics (A9lyr) string
sort_name (sonm) string (alias sortName)
sort_artist (soar) string (alias sortArtist)
sort_album_artist (soaa) string (alias sortAlbumArtist)
sort_album (soal) string (alias sortAlbum)
sort_composer (soco) string (alias sortComposer)
sort_show (sosn) string (alias sortShow)
cover (covr) file path (alias artwork)
copyright (cprt) string
tool (A9too) string (alias encodingTool)
encoder (A9enc) string (alias encodedBy)
pdate (purd) string (alias purchaseDate)
podcast (pcst) bool (yes or no)
url (purl) string (alias podcastURL)
keywords (kyyw) string
category (catg) string
hdvideo (hdvd) integer
media (stik) integer (alias mediaType)
rating (rtng) integer (alias contentRating)
gapless (pgap) bool (yes or no)
art_director (A9ard) string
arranger (A9arg) string
lyricist (A9aut) string
acknowledgement (A9cak) string
song_description (A9des) string
director (A9dir) string
equalizer (A9equ) string
liner (A9lnt) string
record_company (A9mak) string
original_artist (A9ope) string
phono_rights (A9phg) string
producer (A9prd) string
performer (A9prf) string
publisher (A9pub) string
sound_engineer (A9sne) string
soloist (A9sol) string
credits (A9src) string
thanks (A9thx) string
online_info (A9url) string
exec_producer (A9xpd) string
genre (A9gen) string (ID3 genre tag)
location (A9xyz) string

Originally posted by @jessielw in #33

These are also used with video files:

Supported tag names (name, value, type, aliases)
title (A9nam) string (alias name)
comment (A9cmt) string (alias comments)
genre (gnre) string (ID3 genre tag)
show (tvsh) string (alias tvShow)
episode_id (tven) string (alias tvEpisodeID)
season (tvsn) integer (alias tvSeason)
episode (tves) integer (alias tvEPisode)
network (tvnn) string (alias tvNetwork)
hdvideo (hdvd) integer
media (stik) integer (alias mediaType)
rating (rtng) integer (alias contentRating)
director (A9dir) string
genre (A9gen) string (ID3 genre tag)

[jessielw]

Are you referring to FFMPEGs metadata for files by chance? I know we can add some optional metadata via mp4box but it doesn't appear to have a direct way of including the metadata automatically/optionally.

[mpek]

If the source file has metadata, like the fields mentioned above, it should all be a choice to copy metadata when muxing a new file. FFMPEG metadata is a good comparison.

[jessielw]

If the source file has metadata, like the fields mentioned above, it should all be a choice to copy metadata when muxing a new file. FFMPEG metadata is a good comparison.

Unfortunately, there is no way to map any existing metadata from FFMPEG to MP4Box. MP4Box requires manually adding these values where FFMPEG does it's best to retain them unless specified otherwise. Considering this is just metadata supported by one or the other and they aren't necessarily the same it would be quite difficult to match this up programmatically and accurately.

[mpek]

Does that mean that mp4box cannot read already present metadata from the source file and copy it over to the new file?

[jessielw]

Does that mean that mp4box cannot read already present metadata from the source file and copy it over to the new file?

Correct, mp4box doesn't handle this at all. It adds metadata that is relevant via CLI or directly to the codecs.