ffmpeg progress message ends up in search index

While looking at my search data I noticed that the helpful temporary messages printed by ffmpeg while video processing is in progress or failed, ends up in the search index.

Precisely:
This video is currently being processed. Please wait
and...

The video conversion process has failed. You might want to submit a simpler video format like <em>mpeg</em> or <em>divx avi</em>.<br />If the problem persists please contact website administrators

Perhaps we could use drupal_set_message() for these messages instead?