I am trying to render some videos in H.264 format using ATSC 720p 30Hz profile. The file seems to render in a timely manner, but the playback is very jerky. If I render in straight mpeg4 format, I have no issues. The source material is originally H.264, and I am importing the clip unaltered from its original state. The source material has flawless playback, so I know my problem occurs during the render. My ffmpeg version is 0.5-svn17737+3:0.svn20090303-1ubuntu6, kdenlive is version 0.7.3. Let me know if there is other information that you need.

Thanks
-Maelos

I think it may be related to this bug fixed in 0.7.4:
http://www.kdenlive.org/mantis/view.php?id=808

To fix this without upgrading and to confirm, make a custom profile from one that you want to use and remove the "crf=1" option.

Sorry for the lateness of my reply...

Upgrading to 0.7.4 did indeed solve the problem, I was unaware the Ubuntu default repos install 0.7.3. I checked my version as I was posting my problem and realized I was running a version behind.

For a better H264 support, you should upgrade to 0.7.5.

Formatted my linux drive a few days ago and I am currently running 0.7.5, so far no issues.