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https://issues.apache.org/jira/browse/TIKA-4869?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18110594#comment-18110594
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ASF GitHub Bot commented on TIKA-4869:
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tballison commented on PR #3115:
URL: https://github.com/apache/tika/pull/3115#issuecomment-5508387040
On 1., I'm frankly not certain that we need to require video. If someone
sticks a PDF after an image, we should extract it. I do want to avoid the
Stackoverflow, though.
> Emit the video of a motion photo as an embedded document
> --------------------------------------------------------
>
> Key: TIKA-4869
> URL: https://issues.apache.org/jira/browse/TIKA-4869
> Project: Tika
> Issue Type: Improvement
> Reporter: Dominik Schmidt
> Priority: Major
>
> Tika exposes the Motion Photo and MicroVideo XMP of Google/Android motion
> photos, but not the video itself, although both formats say where it is and
> every byte of it is already in the file.
> The MP4 is appended after the JPEG:
> - Motion Photo (Camera:MotionPhoto): Container:Directory lists the items in
> file order, the primary image first, the rest tightly packed after it, each
> with an Item:Length and an optional Item:Padding. The video starts at
> fileLength minus the lengths of the items from the video to the end; in
> practice it is the last one, also in Ultra HDR files, where the spec puts the
> gain map before it.
> - MicroVideo (the older Camera:MicroVideo / GCamera): Camera:MicroVideoOffset
> is the number of bytes from the end of the file, so the video starts at
> fileLength minus that value.
> Proposal: the image parsers emit those bytes as an embedded document,
> ATTACHMENT, named motion-photo.<ext>. What is at the computed offset is
> detected by content, without the declared Item:Mime as a hint (a hint would
> make a wrong length pass as video/mp4 anyway), and nothing is emitted when
> detection finds no type: a wrong or hostile length then yields no embedded
> document rather than a bogus one. Extraction follows the usual embedded
> document limits; a client that does not want the video filters by type as
> usual.
> The same computation covers HEIC and AVIF motion photos, whose XMP goes
> through the same extractor: there the video sits in an mpvd box, but that box
> is last and its 8 byte header is the primary item's Padding, so the video
> still ends at the end of the file. Putting the extraction in the shared image
> parser base rather than in JpegParser therefore covers them too, untested for
> lack of a sample file.
> Apple Live Photos are a different thing and need nothing here: their video is
> a separate .MOV, paired by a content identifier, so a HEIC alone carries no
> video.
> The existing test files (testJPEG_MotionPhoto.jpg, testJPEG_MicroVideo.jpg)
> declare a video in their XMP but do not contain one; new fixtures with a
> small real MP4 appended are needed.
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