avconv crashes after ~3 minutes – could be source regression, how do I get last stable version in git?-Collection of common programming errors

Application provided invalid, non monotonically increasing dts to muxer in stream 1: 8657 >= 8657
av_interleaved_write_frame(): Invalid argument
[pulse @ 0x2a03400] pa_simple_read failed: Bad state
Assertion 'pa_atomic_load(&(s)->_ref) >= 1' failed at pulse/stream.c:335, function pa_stream_get_state(). Aborting.

Last time this happened that last line wasn’t there, and the file was corrupted but openable.

I git cloned the source from the avconv git repo, that’s probably why it’s not working properly. How do I get the source for the last stable release in git? (My idea of version control is apt-get source)

I downloaded a “release” source and compiled it but I can’t test it as it’s giving me:

Preset lossless_ultrafast specified for stream 0:0, but could not be opened.