This is an archived snapshot of W3C's public bugzilla bug tracker, decommissioned in April 2019. Please see the home page for more details.

Bug 18398 - MPEG-4 file can have: only one 'minf' box in a given 'mdia' box (see section 8.4.4.1 of ISO/IEC-14496-12:2012),
Summary: MPEG-4 file can have: only one 'minf' box in a given 'mdia' box (see section ...
Status: RESOLVED WORKSFORME
Alias: None
Product: WHATWG
Classification: Unclassified
Component: HTML (show other bugs)
Version: unspecified
Hardware: Other other
: P3 normal
Target Milestone: Unsorted
Assignee: Ian 'Hixie' Hickson
QA Contact: contributor
URL: http://www.whatwg.org/specs/web-apps/...
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2012-07-25 15:07 UTC by contributor
Modified: 2012-12-30 04:22 UTC (History)
3 users (show)

See Also:

Attachments

Description contributor 2012-07-25 15:07:27 UTC 
Specification: http://www.whatwg.org/specs/web-apps/current-work/multipage//the-video-element.html
Multipage: http://www.whatwg.org/C#sourcing-in-band-text-tracks
Complete: http://www.whatwg.org/c#sourcing-in-band-text-tracks

Comment:
MPEG-4 file can have: only one 'minf' box in a given 'mdia' box (see section
8.4.4.1 of ISO/IEC-14496-12:2012), 

Posted from: 2001:660:330f:2::7b
User agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.3 (KHTML, like Gecko) Chrome/22.0.1217.0 Safari/537.3
Comment 1 Cyril Concolato 2012-07-25 16:47:46 UTC 
I did not finish my previous comment:

MPEG-4 files can have: 
- exactly one 'stbl' in given 'minf' box (see 8.5.1.1 of ISO/IEC-14496-12:2012), so you can remove the word first in "first stbl"
- only one 'minf' box in a given 'mdia' box (see section
8.4.4.1), so you can remove the word first in "first mdia"
- exactly one 'mdia' box in a given 'trak' box (see section 8.4.1.1), so you can remove the word first in "first mdia"
- only one 'moov' box in a file (see 8.2.1.1), so you can remove the word first in "first moov"

Then, the whole section is about a given track "a media resource contains data that the user agent recognises and supports as being equivalent to a text track". There might be more than one text track in an MP4 file, so that section should not talk about the "first trak" but the about "the track" and the whole algorithm is applied to all tracks "that the user agent recognises and supports as being equivalent to a text track".
Comment 2 Ian 'Hixie' Hickson 2012-10-02 19:44:19 UTC 
How does the format prevent there being two stbl blocks?
Comment 3 Cyril Concolato 2012-10-05 12:16:52 UTC 
Indeed, the format doesn't prevent that. I had forgotten that you wanted to take into account invalid MP4 files. Forget the first 5 comments then. I think only the last part about having multiple tracks is still a valid comment.
Comment 4 Ian 'Hixie' Hickson 2012-12-30 04:22:03 UTC 
Looks like I fixed the "first trak" problem a while back.