dschmidt opened a new pull request, #3114: URL: https://github.com/apache/tika/pull/3114
Tika's own fixtures show the problem: `testMP4Video.mp4` and `testMP4AudioOnly.mp4` both carry the `isom` brand, and both are detected as `video/quicktime`, because the mime magic for `video/mp4` only matches the brands `mp41` and `mp42`. Adding `isom` to that magic would type the audio-only file as video, so the brand cannot answer this; the tracks have to. `MP4TrackDetector` walks the top level boxes by their size fields, which steps over the media data rather than reading it, finds the movie box and reads the handler type of each `moov/trak/mdia/hdlr`: a video track makes it `video/mp4`, otherwise an audio track makes it `audio/mp4`, otherwise `application/mp4`, as RFC 4337 describes. Brands that name a format of their own (M4A, 3GP, HEIC, AVIF, CR3, ...) are left to their own magic, and so is a file whose movie box cannot be reached. The box primitives are shared rather than written again: `boxEnd`, `findBox` and the FourCC readers move from `Mp4SampleEntries` (TIKA-4838) into `Mp4Boxes`, which now also handles the 64 bit largesize and the size 0 form; the sample entry walker and the two sample handlers use it. Bounds, since a detector reads whatever arrives: sizes are checked as longs before any cast, the walk stops at the first box that does not fit what encloses it, the number of boxes and tracks and the size of the movie box read into memory are capped, and without a file to seek in only a movie box within the first 256 KB is found. Tests cover every truncation of a well formed file and random bytes behind a valid header. Verified on a server built from this branch: `testMP4AudioOnly.mp4` now detects as audio/mp4 and `testMP4Video.mp4` as video/mp4, where both used to be video/quicktime; HEIC, AVIF and M4A files are unchanged. This closes TIKA-3646 and, for plain MP4, the question in TIKA-2935. https://issues.apache.org/jira/browse/TIKA-3646 -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
