disk&memory video logging - why is sometimes only a single frame saved?

Dear all An application I'm developing acquires video images in real time and does some analysis. I use the memory&disk option to both save an AVI file and analyse the data. Once in a while, the generated video contains only a single frame (instead of ca. 2000-4000 frames). Any idea how this happens? A few facts: - I generate a 'videoinput' object for the acquisition, and set its loggingMode property to 'disk&memory' - At the end of acquisition, the correct number of frames appears in the 'FramesAcquired' field, even if the movie de facto contains just one - During the acquisition, the AVI file grows in size without problems; the shrinkage seems to happen just as the AVI file is closed Any input would be greatly appreciated! Gilad