qtmux doesn't remove 'trak' atom when request pad is removed

Submitted by Brendan Shanks @bshankstd

Link to original bug (#780746)

Description

GStreamer 1.10.0 on my device is creating MP4 files (using qtmux) that qtdemux says are corrupt and refuses to decode.

The problem appears to be that the file contains additional streams/tracks which have timescales of 0, and I believe this is because my code requests pads from qtmux and then releases them before qtmux starts (goes to paused/playing).

gst_qt_mux_request_new_pad() creates a new trak atom and adds it to the moov with atom_moov_add_trak(), but gst_qt_mux_release_pad() never removes the trak from the moov atom.

I'll work on a patch, and I can attach a test file with the bad 'trak' atoms if anyone is interested.

Version: 1.10.0