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Sniffer.sniffFragmented() fails on MP4 files with uuid atom between ftyp and moov #3046
Description
Version
Media3 1.8.0
More version details
No response
Devices that reproduce the issue
Pixel 8 Pro, Android 16.0
Devices that do not reproduce the issue
No response
Reproducible in the demo app?
Yes
Reproduction steps
- Obtain an MP4 file with a uuid atom positioned between ftyp and moov (e.g., a video with C2PA Content Credentials metadata)
- Play the file using ProgressiveMediaSource with default extractors
- Observe playback failure
Expected result
Video plays successfully. The uuid atom is a valid extension per ISO 14496-12 and should be skipped by the sniffer.
Actual result
Sniffer fails to identify the file as fragmented MP4. ExoPlayer reports 0 tracks and throws:
ParserException: Loading finished before preparation is complete. {contentIsMalformed=true, dataType=1}
The file structure is:
ftyp @ 0, size=36
uuid @ 36, size=16776 <-- C2PA manifest (valid per ISO 14496-12)
moov @ 16812, size=1213
moof @ 18025, size=4708
mdat @ 22733, size=469611
Note: FragmentedMp4Extractor CAN parse this file correctly when forced directly (bypassing sniffing). The bug is only in the sniffing phase.
Media
Will email sample video to android-media-github@google.com.
Bug Report
- You will email the zip file produced by
adb bugreportto android-media-github@google.com after filing this issue.
Activity
icbaker commentedon Feb 3, 2026
Thanks for reporting, I've sent a change for internal review that increases the sniff limit when encountering a
uuidbox - this makes the provided video playable with the ExoPlayer demo app on the tip of themainbranch. The change will be linked here when it's submitted.MP4: Handle sniffing files with `uuid` box between `ftyp` and `moov`
icbaker commentedon Feb 5, 2026
This is fixed by the commit linked above.