Hi,
I'm trying to change the time of an MP4 video taken in the wrong time zone. The ExifTool command I use doesn't change the file, presumably because some of the tags I'm trying to change are not writable (many QuickTime tags are not writable). Other than trial and error, cross-checking my command-line options with the documentation, or carefully interpreting the output generated with the -v3 option, is there an ExifTool option that will tell me which of the tags I specified on the command line are/aren't writable?
Here's what I'm trying to do:
exiftool -P -canon:timezone=+1:00 -canon:timezonecity=Paris "-exif:offsettime*=+2:00" "-exif:*datetimeoriginal*+=6" "-exif:*modifydate*+=6" MVI_0219.MP4
0 image files updated
1 image files unchanged
I get more output with the -v3 option, but nothing that clearly indicates why the file isn't updated:
exiftool -v3 -P -canon:timezone=+1:00 -canon:timezonecity=Paris "-exif:offsettime*=+2:00" "-exif:*datetimeoriginal*+=6" "-exif:*modifydate*+=6" MVI_0219.MP4
Writing Canon:TimeZone if tag exists
Writing Canon:TimeZoneCity if tag exists
Writing ExifIFD:OffsetTime
Writing ExifIFD:OffsetTimeDigitized
Writing ExifIFD:OffsetTimeOriginal
Shifting ExifIFD:DateTimeOriginal if tag exists
Shifting IFD0:ModifyDate if tag exists
======== MVI_0219.MP4
Rewriting MVI_0219.MP4...
FileType = MP4
FileTypeExtension = MP4
MIMEType = video/mp4
Editing tags in: ExifIFD IFD0 MakerNotes
Creating tags in: ExifIFD
Rewriting Movie
Rewriting UUID-Canon
Rewriting CanonCNTH
[nothing changed in CanonCNTH]
[nothing changed in UUID-Canon]
Rewriting UserData
[nothing changed in UserData]
Rewriting MovieHeader
[nothing changed in MovieHeader]
Rewriting Track
Rewriting TrackHeader
[nothing changed in TrackHeader]
Rewriting Media
Rewriting MediaHeader
[nothing changed in MediaHeader]
Rewriting MediaInfo
Rewriting DataInfo
Rewriting DataRef
[nothing changed in DataRef]
[nothing changed in DataInfo]
Rewriting SampleTable
[nothing changed in SampleTable]
[nothing changed in MediaInfo]
[nothing changed in Media]
[nothing changed in Track]
Rewriting Track
Rewriting TrackHeader
[nothing changed in TrackHeader]
Rewriting Media
Rewriting MediaHeader
[nothing changed in MediaHeader]
Rewriting MediaInfo
Rewriting DataInfo
Rewriting DataRef
[nothing changed in DataRef]
[nothing changed in DataInfo]
Rewriting SampleTable
[nothing changed in SampleTable]
[nothing changed in MediaInfo]
[nothing changed in Media]
[nothing changed in Track]
[nothing changed in Movie]
Nothing changed in MVI_0219.MP4
0 image files updated
1 image files unchanged
I can find which time tags exist in the file with this:
exiftool -time:all -G1 -a -s MVI_0219.MP4
[System] FileModifyDate : 2024:06:30 11:18:50-04:00
[System] FileAccessDate : 2024:07:16 09:12:30-04:00
[System] FileCreateDate : 2024:07:15 20:55:23-04:00
[IFD0] ModifyDate : 2024:06:30 11:18:20
[ExifIFD] DateTimeOriginal : 2024:06:30 11:18:20
[ExifIFD] CreateDate : 2024:06:30 11:18:20
[ExifIFD] OffsetTime : -04:00
[ExifIFD] OffsetTimeOriginal : -04:00
[ExifIFD] OffsetTimeDigitized : -04:00
[Canon] TimeZone : -04:00
[Canon] TimeZoneCity : New York
[Canon] DaylightSavings : On
[ExifIFD] SubSecTime : 05
[ExifIFD] SubSecTimeOriginal : 05
[ExifIFD] SubSecTimeDigitized : 05
[QuickTime] CreateDate : 2024:06:30 15:18:20
[QuickTime] ModifyDate : 2024:06:30 15:18:20
[Track1] TrackCreateDate : 2024:06:30 15:18:20
[Track1] TrackModifyDate : 2024:06:30 15:18:20
[Track1] MediaCreateDate : 2024:06:30 15:18:20
[Track1] MediaModifyDate : 2024:06:30 15:18:20
[Track2] TrackCreateDate : 2024:06:30 15:18:20
[Track2] TrackModifyDate : 2024:06:30 15:18:20
[Track2] MediaCreateDate : 2024:06:30 15:18:20
[Track2] MediaModifyDate : 2024:06:30 15:18:20
[Composite] SubSecCreateDate : 2024:06:30 11:18:20.05-04:00
[Composite] SubSecDateTimeOriginal : 2024:06:30 11:18:20.05-04:00
[Composite] SubSecModifyDate : 2024:06:30 11:18:20.05-04:00
I'd like to find the subset of the above tags that are writable. So I tried this, which lists all writable time tags (and not just the ones I'm interested in), and seemingly all tags and their values):
exiftool -listw -time:all -G1 -a -s MVI_0219.MP4
Writable time tags:
ArtworkCircaDateCreated ArtworkDateCreated AudioModDate CameraPoseTimestamp
CaptionsDateTimeStamps CircaDateCreated ContentCreateDate CopyrightYear
CoverDate CreateDate CreationDate CreationTime Date DateAcquired DateCreated
DateDisplayFormat DateIdentified DateRecieved DateSent DateTime
DateTimeDigitized DateTimeOriginal DateTimeUTC DayOfWeek DaylightSavings
DeprecatedOn DerivedFromLastModifyDate DestinationCity DestinationDST
DigitalCreationDate DigitalCreationTime EarthPosTimestamp EmbargoDate
EncodingTime EventDate EventDay EventEarliestDate EventEndDayOfYear
EventLatestDate EventMonth EventStartDayOfYear EventTime
EventVerbatimEventDate EventYear ExclusivityEndDate ExpirationDate
ExpirationTime FileCreateDate FileModifyDate FirstPhotoDate
FirstPublicationDate GPSDateStamp GPSDateTime GPSTimeStamp HistoryWhen
HometownCity HometownDST HumanObservationDay HumanObservationEarliestDate
HumanObservationEndDayOfYear HumanObservationEventDate
HumanObservationEventTime HumanObservationLatestDate HumanObservationMonth
HumanObservationStartDayOfYear HumanObservationVerbatimEventDate
HumanObservationYear IPTCLastEdited ImageProcessingFileDateCreated
IngredientsLastModifyDate KillDateDate LastPhotoDate LicenseEndDate
LicenseStartDate LicenseTransactionDate LocationDate MDItemFSCreationDate
MachineObservationDay MachineObservationEarliestDate
MachineObservationEndDayOfYear MachineObservationEventDate
MachineObservationEventTime MachineObservationLatestDate
MachineObservationMonth MachineObservationStartDayOfYear
MachineObservationVerbatimEventDate MachineObservationYear
ManagedFromLastModifyDate ManifestReferenceLastModifyDate ManufactureDate
ManufactureDate1 ManufactureDate2 MeasurementDeterminedDate MediaCreateDate
MediaModifyDate MetadataDate MetadataLastEdited MetadataModDate MinoltaDate
MinoltaTime ModDate ModificationDate ModifyDate MonthDayCreated MoonPhase
OffSaleDateDate OffsetTime OffsetTimeDigitized OffsetTimeOriginal
OnSaleDateDate OptionEndDate OriginalCreateDateTime PanasonicDateTime
PatientBirthDate PlanePoseTimestamp PoseTimestamp PowerUpTime PreviewDate
PreviewDateTime ProductionDate PublicationDateDate PublicationDisplayDateDate
PublicationEventDate ReferenceDate RegionInfoDateRegionsValid
RelationshipEstablishedDate ReleaseDate ReleaseTime RenditionOfLastModifyDate
RicohDate SeriesDateTime ShotDate SonyDateTime SonyDateTime2 StudyDateTime
SubSecCreateDate SubSecDateTimeOriginal SubSecModifyDate SubSecTime
SubSecTimeDigitized SubSecTimeOriginal TemporalCoverageFrom
TemporalCoverageTo Time TimeCreated TimeSent TimeStamp TimeStamp1 TimeZone
TimeZoneCity TimeZoneCode TimeZoneInfo TrackCreateDate TrackModifyDate
UnknownDate VersionCreateDate VersionModifyDate VersionsEventWhen
VersionsModifyDate VideoModDate WorldTimeLocation Year YearCreated
[ExifTool] ExifToolVersion : 12.76
[System] FileName : MVI_0219.MP4
[System] Directory : .
[System] FileSize : 116 MB
[System] FileModifyDate : 2024:06:30 11:18:50-04:00
[System] FileAccessDate : 2024:07:16 09:11:04-04:00
[System] FileCreateDate : 2024:07:15 20:55:23-04:00
[System] FilePermissions : -rw-rw-rw-
[File] FileType : MP4
[File] FileTypeExtension : mp4
[File] MIMEType : video/mp4
[File] ExifByteOrder : Little-endian (Intel, II)
[File] ImageWidth : 160
[File] ImageHeight : 120
[several lines of non-time related tags edited out]
By the way, I know I can change some tags, such as this one:
exiftool -quicktime:createdate+=6 MVI_0219.MP4
1 image files updated
Thanks!
-Martin
Hi Martin,
This is a very complex issue, but the reason these particular EXIF tags aren't being updated in the video is likely because they exist within a thumbnail image in the file. ExifTool extracts thumbnail metadata, but can't currently write these tags individually. However, if you extract the thumbnail then you can edit these tags then write the thumbnail back again.
- Phil
Hi Phil,
From what I read later in other posts in this forum, I think you are right. And I understand it's because some manufacturers put EXIF data in video files, which isn't standard. See EXIF tags unchanged in mp4 files (https://exiftool.org/forum/index.php?topic=14509.0).
However, my general question still stands: is there an ExifTool option that will tell me which of the tags I specified on the command line are/aren't writable?
It feels like this information could be extracted automatically, but I cannot find how. For instance:
exiftool -v2 -canon:TimeZoneCity=Paris MVI_0219.MP4
Writing Canon:TimeZoneCity if tag exists
======== MVI_0219.MP4
Rewriting MVI_0219.MP4...
FileType = MP4
FileTypeExtension = MP4
MIMEType = video/mp4
Editing tags in: MakerNotes
Creating tags in:
Rewriting Movie
Rewriting UUID-Canon
Rewriting CanonCNTH
Rewriting UserData
Rewriting MovieHeader
Rewriting Track
Rewriting TrackHeader
Rewriting Media
Rewriting MediaHeader
Rewriting MediaInfo
Rewriting DataInfo
Rewriting DataRef
Rewriting SampleTable
Rewriting Track
Rewriting TrackHeader
Rewriting Media
Rewriting MediaHeader
Rewriting MediaInfo
Rewriting DataInfo
Rewriting DataRef
Rewriting SampleTable
Nothing changed in MVI_0219.MP4
0 image files updated
1 image files unchangedFrom the output, I can guess that Canon:TimeZoneCity cannot be written because there's no message to that effect, but it's not straightforward, especially if I specify multiple tags on the command line.
By the way, the message Writing Canon:TimeZoneCity if tag exists is misleading because this tag does exist, but cannot be written, as shown here:
exiftool -canon:TimeZoneCity MVI_0219.MP4
Time Zone City : New York
Thanks,
-Martin
Hi Martin,
Quote from: Martin B. on July 16, 2024, 10:06:05 PMis there an ExifTool option that will tell me which of the tags I specified on the command line are/aren't writable?
Absolutely not. There is no way to determine this without processing the entire file first.
Quotethe message Writing Canon:TimeZoneCity if tag exists is misleading because this tag does exist, but cannot be written
Notice that this message is sent before ExifTool starts processing the file. At this time, it is the best that ExifTool can do.
If you want to know which tags can't be written, parse the
-v2 output to see which tags
were written, and you can surmise that the rest weren't. This would be the only way that ExifTool would be able to do it.
- Phil
I understand, thanks.
I thought ExifTool had a list of tags to write, and checked off those that were done. Given that some tags may exist in multiple places, it may not be practical to keep track of what's written or not. I'll look at the -v2 output then.
- Martin