Timezone parsing fix and mov rotation extraction

[baloghf87]

Hi Drew,

I did some improvements in the library:

• I found that timezone information gets lost when extracting metadata from some images, because the library expects it to be in HH:mm format, but actually it is in HHmm.

• We needed to extract rotation angle from MOV files, so I implemented very basic handling of track headers.

Best regards,
Ferenc

[drewnoakes]

Thanks for the great contribution. Nice and clean.

[drewnoakes]

I just ran this over the test image library and found it regressed mp4/uuid540.mp4, throwing an exception. Can you take a look?

[drewnoakes]

Also, can you provide a (small) sample file that contains GPS data for regression testing? We don't have a lot of MP4/QuickTime test data.

[baloghf87]

I just checked it quickly, for me it runs without issues on uuid540.mp4. What exception do you get? I'll take a closer look at it soon...

[baloghf87]

The files I used for testing location extraction are

• MP4: 7.6 MB
• MOV: 10.5 MB

Are these considered small? :)

[Nadahar]

Are these considered small? :)

Yes, video files are often huge 😉

[drewnoakes]

I see:

java.lang.NullPointerException
	at java.util.regex.Matcher.getTextLength(Matcher.java:1283)
	at java.util.regex.Matcher.reset(Matcher.java:309)
	at java.util.regex.Matcher.<init>(Matcher.java:229)
	at java.util.regex.Pattern.matcher(Pattern.java:1093)
	at com.drew.metadata.mp4.boxes.UserDataBox.addMetadata(UserDataBox.java:64)
	at com.drew.metadata.mp4.Mp4BoxHandler.processUserData(Mp4BoxHandler.java:106)
	at com.drew.metadata.mp4.Mp4BoxHandler.processBox(Mp4BoxHandler.java:94)
	at com.drew.imaging.mp4.Mp4Reader.processBoxes(Mp4Reader.java:61)
	at com.drew.imaging.mp4.Mp4Reader.processBoxes(Mp4Reader.java:59)
	at com.drew.imaging.mp4.Mp4Reader.extract(Mp4Reader.java:45)
	at com.drew.imaging.mp4.Mp4MetadataReader.readMetadata(Mp4MetadataReader.java:57)
	at com.drew.imaging.ImageMetadataReader.readMetadata(ImageMetadataReader.java:177)
	at com.drew.imaging.ImageMetadataReader.readMetadata(ImageMetadataReader.java:124)
	at com.drew.imaging.ImageMetadataReader.readMetadata(ImageMetadataReader.java:204)
	at com.drew.imaging.ImageMetadataReader.main(ImageMetadataReader.java:253)

The code currently assumes coordinateString is non-null, which is not necessarily true.

[drewnoakes]

Are these considered small? :)

They're small, but if you're able to make them smaller somehow it'd be great. Git doesn't like large files, and the metadata is usually very small. The image library repo is already enormous. Perhaps there's some software that trims them to just a few frames of video without removing any metadata.

[Nadahar]

Perhaps there's some software that trims them to just a few frames of video without removing any metadata.

I've successfully used FFmpeg to truncate video files while retaining metadata before, using copy for all tracks and then using the -t option to control duration. I can't guarantee that the metadata will always be intact for all formats and codec combinations, but it has worked the times I've done it.

[drewnoakes]

I played around with location extraction and filed #468 which catches a few more cases.

[baloghf87]

https://drive.google.com/open?id=15WnvT9u6-B5CyghNvicFWTGaSRUShgPG

Sorry for the late reply, i had a very busy week. I could not manage to truncate MOV files retaining metadata, it only worked for MP4.

[baloghf87]

Is there anything else I can help you with?