Advanced processing for AVCHD video

High definition video cameras often use AVCHD as a standard for video.  Camera also often use FAT32 so a deleted file looses it’s fragmentation data.  As files are long, many can be fragmented.  This CnW wizard works to overcome this problem by scanning the whole memory chip and joining all contiguous sections together.  The result is very close to the original number of files.  On a competing software product, scanning a chip produced about 500 clips, while CnW correctly recovered just the 62 original  fragmented clips.  Each of these new clips consisted of several sections, joined together.  This feature is probably unique for a data recovery package.

AVCHD stores several types of files, including a .cpi and .mpl file.  Fortunately, although CnW will recover these files, they are not totally required as a video file (.MTS) can be viewed with Windows 7 media player.

The recovery process is in three stages.  The first the complete disk is scanned to log the start of every possible .MTS cluster, and also to find and extract .cpi and .mpl files.  The second stage is to examine the database of all MTS clusters and join them into sequential runs. The joining routine checks several parameters to attempt to get a corrrect match, rather than a false positive.  It even allows for memory chips that have video recorded at different resolutions. The final stage joins the short clips into longer related runs.  The process can take maybe 1 hour for a 32GB chip, and is fastest if an image of the chip is take, and the disk image processed, rather direct reading of a memory chip.

The final result is a series of .MTS files that are contiguous, and actually the correct length.  The .CPI and .MPL files are also saved as the correct length, with the directory structure below.  However, the .cpi files will not the correct names, and so are saved for reference only.

AVCHD

BDMV

CLIPINF

.cpi files

PLAYLIST

.mpl files

STREAM

.mts files

To view the recovered files, programs such as Windows Media Viewer on Windows 7 works, or they can be copied back to the original memory chip and inserted into the camera.  The camera will then re-index the files, and they can be viewed as normal video.