Wednesday, January 29, 2014

Deleted GoPro video with high and low resolution

MP4 video is often recorded out of sequence.  This is because when the recording starts there is no knowledge of the file size.  Thus the meta data is added physically at the end of the physical file, though logically it is stored near the file start.

CnW can process this type of deleted file.  A new variation found in one version of the GoPro Hero 3+ Black camera is stored both high and low resolution video.  In this case, the video is multiplexed so physically on the disk there will be sections of high resolution, followed by low resolution.  The programming challenge is to determine which cluster is part of which video stream.  By examining the meta data this is possible and current results are very encouraging.  The next stage will be to ensure there are no glitches in the recovered streams