GNOME Bugzilla – Bug 797321
qtmux: Add option to create a timecode trak in non-mov flavors
Last modified: 2018-11-03 15:33:44 UTC
See commit message
Created attachment 374001 [details] [review] qtmux: Add option to create a timecode trak in non-mov flavors Even if timecode trak is officially unsupported in non-mov flavors, some software still supports it, e.g. Final Cut Pro X: https://developer.apple.com/library/archive/technotes/tn2174/_index.html The user might still expect to see the timecode information in the non-mov file despite it being officially unsupported , because other software e.g. QuickTime will create a timecode trak even in mp4 files. Furthermore, software that supports timecode trak in non-mov flavors will also display the file duration in "timecode units" instead of real clock time, which is not necessarily the same for 29.97 fps and friends. This might confuse users, who see a different duration for the same framerate and amount of frames depending on whether the container is mp4 or mov.
Comment on attachment 374001 [details] [review] qtmux: Add option to create a timecode trak in non-mov flavors Seems fine to me but we should probably also research first if there's a standard for doing timecodes in MP4. If that exists we would conflict with that one here then.
Created attachment 374002 [details] [review] qtmux: Add option to create a timecode trak in non-mov flavors Even if timecode trak is officially unsupported in non-mov flavors, some software still supports it, e.g. Final Cut Pro X: https://developer.apple.com/library/archive/technotes/tn2174/_index.html The user might still expect to see the timecode information in the non-mov file despite it being officially unsupported , because other software e.g. QuickTime will create a timecode trak even in mp4 files. Furthermore, software that supports timecode trak in non-mov flavors will also display the file duration in "timecode units" instead of real clock time, which is not necessarily the same for 29.97 fps and friends. This might confuse users, who see a different duration for the same framerate and amount of frames depending on whether the container is mp4 or mov.
(In reply to Sebastian Dröge (slomo) from comment #2) > Comment on attachment 374001 [details] [review] [review] > qtmux: Add option to create a timecode trak in non-mov flavors > > Seems fine to me but we should probably also research first if there's a > standard for doing timecodes in MP4. If that exists we would conflict with > that one here then. You're right. The link in the commit message says: The timecode track in an MP4 file uses the constructs defined in the QuickTime File Format, with some minor modifications. The text formatting information to display the timecode is dropped. The Null Media Header box (nmhd) box is used instead of the Generic Media Header box (gmhd).
Created attachment 374003 [details] [review] qtmux: Add option to create a timecode trak in non-mov flavors Even if timecode trak is officially unsupported in non-mov flavors, some software still supports it, e.g. Final Cut Pro X: https://developer.apple.com/library/archive/technotes/tn2174/_index.html The user might still expect to see the timecode information in the non-mov file despite it being officially unsupported , because other software e.g. QuickTime will create a timecode trak even in mp4 files. Furthermore, software that supports timecode trak in non-mov flavors will also display the file duration in "timecode units" instead of real clock time, which is not necessarily the same for 29.97 fps and friends. This might confuse users, who see a different duration for the same framerate and amount of frames depending on whether the container is mp4 or mov.
Changed GMHD to NMHD for non-mov, please review again.
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