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https://issues.apache.org/jira/browse/TIKA-4838?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18108556#comment-18108556
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ASF GitHub Bot commented on TIKA-4838:
--------------------------------------
tballison commented on PR #3062:
URL: https://github.com/apache/tika/pull/3062#issuecomment-5431655063
From my claude:
```
Worth acting on
1. Protected entries report the wrapper fourcc, not the codec
(TikaMp4SoundHandler.java:94, same in Video). For drms/enca/encv/drmi, ISO
14496-12 puts the real codec in
the child sinf/frma box; the handler already walks child boxes for
esds/btrt, so frma is reachable. As-is a FairPlay .m4p gives audio:format=drms
— and audio:has-drm
already carries that fact. Once released, the value semantics are
frozen. (The testMP4_drm.m4a fixture's drms entry is a bare stub with no sinf,
so a real sample is
needed to test.)
2. Last-entry/last-track wins, undocumented (TikaMp4SoundHandler.java:94).
FORMAT is overwritten per stsd entry and per track, HAS_DRM is set on any
entry. [enca, mp4a]
→ has-drm=true, format=mp4a; AAC+E-AC-3 tracks → format=ec-3 while
bitrate comes from the AAC track. Pick first-entry or document it; no
multi-entry test guards it.
3. fourcc emitted verbatim with no printability check
(TikaMp4VideoHandler.java:108). Previously only compared; now a public metadata
value. Corrupt bytes 00 01 02 03
land as control chars in XML output. Gate on printable ASCII 0x20–0x7E
and trim QuickTime trailing spaces (raw , rle ).
4
> Expose the MP4 audio and video track codecs (audio:format, video:format)
> ------------------------------------------------------------------------
>
> Key: TIKA-4838
> URL: https://issues.apache.org/jira/browse/TIKA-4838
> Project: Tika
> Issue Type: New Feature
> Reporter: Dominik Schmidt
> Priority: Major
>
> The MP4/QuickTime parser does not expose the per-track codec identifiers.
> TikaMp4SoundHandler and TikaMp4VideoHandler read the sample-entry format
> fourcc but only use it for other purposes (audio: DRM detection; video:
> nothing).
> Add audio:format and video:format, each carrying the four-character codec
> identifier from the track's sample description (audio mp4a/alac/ac-3, video
> avc1/hev1). For protected streams (drms/enca, encv/drmi) the original codec
> is recovered from the nested frma box.
> The existing xmpDM:audioCompressor only fires for audio-typed files and
> carries the container major brand, and xmpDM:videoCompressor carries the
> compressor name (encoder string, e.g. "Lavc… libx264"), so neither gives the
> per-track codec fourcc for video/* files.
> Rounds out the per-track metadata added in TIKA-4779, TIKA-4800 and TIKA-4802.
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