Auto-Detect start_time if avformat does not set any.

[GoogleCodeExporter]

Describe the issue you're having:
On some files (most notably streaming media), avformat does not properly fill 
start_time, so the start offset of the stream is not determined and the file 
will "hang" on startup.

How can the issue be reproduced? Sample File?
A lot of streaming content exhibits this issue, eg:
http://stream05.akaver.com/skyplus_hi.ogg

Original issue reported on code.google.com by h.lepp...@gmail.com on 9 Jan 2013 at 5:03

[GoogleCodeExporter]

This has been solved in other ways, by making the timestamp gap functionality 
also work at the start of the stream.

Original comment by h.lepp...@gmail.com on 31 Mar 2013 at 5:23

• Changed state: Fixed