Hello!
I just tried to render a project (duration: 22 min) in MPEG-4 with Kdenlive 0.8.2.1 and I got an error:

[mp3 @ 0x88bc940] Invalid size in frame , skipping the rest of tag.
[mp3 @ 0x88bc940] max_analyze_duration reached [mp3 @ 0x88bc940] Estimating duration from bitrate, this may be inaccurate
[mp3 @ 0x88ce600] Invalid size in frame , skipping the rest of tag.

and then it continues again and again. I also tried in MPEG-2 but I got the same thing. If you could help me, it would be great!