Original commit message from CVS:
* gst/avi/gstavidemux.c: (gst_avi_demux_stream_index),
(gst_avi_demux_stream_scan), (sort), (gst_avi_demux_massage_index),
(gst_avi_demux_stream_header), (gst_avi_demux_stream_data):
Improve allocation, cutting and sorting of the index. How takes a
few seconds instead of minutes.