avconv output

[danut007ro]

This pull request is capturing avconv output (at least, don't know about ffmpeg) and is showing how much of the encoding it has done, as percentage.

Also, on my system, the aac codec is marked as experimental, so I used libfaac for aac encoding (if there is another option, that code can be removed)

[danut007ro]

The commit is ok now, I hope

[FiloSottile]

Perfect, thanks! I will merge it as soon as I'm able to check with ffmpeg.

[danut007ro]

I checked with ffmpeg and it looked ok. Can someone else also check?

[phihag]

-1. The changes in line 74 to 80 undo 65f934dc930f7996e137d61dd80ef092f9075532 without an explanation, and will therefore break Windows systems.

[FiloSottile]

A merge error, I guess, he committed it before 65f934d and rebased after...

[stolendog]

is this commit will be merged to master? It would be nice to have audio converting progress status.

[FiloSottile]

Definitively merging this, even it requires some more cleanup and testing work. Also, we would need something like that for rtmpdump, too...