Framerate problem when muxing

[baconharvester]

I'm trying to mux a h.264 (video file), (ogg audio file), and srt (subtitle file) into a single mkv file in mkvmerge GUI v2.10, but an error message pops up.

Error Message: You're adding an AVC/h.264 elementary stream to the output file. mkvmerge cannot determine the number of frames per second for such files itself. Therefore you have to set this parameter yourself in the "format specific options" page. If you do not do this then mkvmerge will assume 25 fps.

I've tried it on 25 fps and the file turns out to be about 5 minutes too short, desyncing the video and audio. How would I be able to determine the fps of the h.264? (I have the original mkv that I demuxed to get the h.264 as well) And if it turns out that the h.264 has a variable fps, how would I mux my file together to get an mkv that works?

[redwudz]

Since you are in the US and are likely using NTSC format, try 29.70fps. Less likely, but possible, 23.976fps.

Or MediaInfo can probably tell you the framerate, or possibly Gspot 2.70.

[jagabo]

You want a lower frame rate to make it play longer. Probalby 23.976.

[baconharvester]

Yup, setting it to 23.976 worked perfectly. Thanks for the help guys.