Total (unfiltered) depth over all samples.
While the sample-level (FORMAT) DP field describes the total depth of reads that passed the caller's internal quality control metrics (like MAPQ > 17, for example), the INFO field DP represents the unfiltered depth over all samples. Note though that the DP is affected by downsampling (-dcov), so the max value one can obtain for N samples with -dcov D is N * D
GATK version 3.1-1-g07a4bf8 built at 2014/03/18 07:00:36. GTD: NA