This also happens with the

Luis Oscar MaymiLuis Oscar Maymi

This also happens with the Sony AX2000. Like Woody said you can use the Sony Content Management Utility to join the split files, but I also found another altermative using Premiere Pro CS5.5 (not sure if it works on lower versions). When you import the footage from the SDHC card to your computer you need to import the folder called "BDMV" located in Private > AVCHD.  After you have that file in the computer you impport the long footage to Premiere from the folder called "Stream" and it automatically joins them without lossing the 6 or so video and audio frames. With this method you will not have to convert the footage with the Sony Utlity. 

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