Very Choppy Preview of H.264

Please follow this FAQ:

https://answers.launchpad.net/openshot/+faq/983

Any "Skip the loop filter for H.264 decoding" type setting will be a configuration/compilation flag at the MLT/FFMpeg level, but I don't know if such an option even exists in either of those libraries.

My video plays back fine, just slow because of the maxed out CPU.

In VLC, if you switch to advanced view of settings, you can that the option is under the ffmpeg decoding section. After some googling, I have narrowed it down to libavcodec. http://sites.google.com/site/linuxencoding/x264-ffmpeg-mapping look at the -flags +loop part. I am assuming that Openshot or MLT uses ffmpeg to play the preview of the project.

And I agree with you, I don't know how to do this not from the commanline. (that previous link shows command line parameters.) I wonder how one could access this feature from a library.

Same issue here. I have moved some recorded TS files from my media box and converted them to m4v using handbrake default hight profile. Openshot can't preview those files whereas pitivi can. The TS files as it (h264+aac) are previewable but very choppy

Same here, although any other player or video editor I've used plays it just fine.
My system should have no problem (AMD 3.6 Ghz Quad, 8GB Ram) handling the preview.

Try changing to 'sdl_preview' output mode in the Preferences.

There has been a recent change in the MLT library which makes AVCHD files a lot more usable - you need to have > v0.9.1 of the ffmpeg libraries (not libav) and v0.7.9 of MLT.