This is dnstap-ldns, a reference utility that can decode dnstap encoded files. It uses the ldns, fstrm, and protobuf-c libraries to perform most of the heavy lifting.
First, install the dependencies: ldns, fstrm, and protobuf-c.
Then, build and install dnstap-ldns:
./configure && make && make install
If building from a git checkout, the autotools must be installed. Run the ./autogen.sh script first to bootstrap the build system.
dnstap encoded files can be decoded and printed to stdout by running dnstap-ldns -r on the dnstap file.
The output format can be selected by passing additional command-line flags. The -q flag specifies the "quiet text" output format, which is compact (one line per dnstap frame), and excludes full DNS message details. The -y flag specifies a more verbose multi-document YAML-encoded output format that includes full DNS message details, as parsed by the ldns library.
dnstap-ldns can also read bare hex-encoded dnstap protobufs without Frame Stream encoding. The -x flag will automatically detect whether the input data is a string of hex characters (possibly with embedded whitespace), or is in the generic record data format defined by RFC 3597.