W: GPG error: download.opensuse.org  Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 5A7D1D38BEB6D886
W: Failed to fetch http://ppa.launchpad.net/mc3man/gstffmpeg-keep/ubuntu/dists/wily/main/binary-amd64/Packages  404  Not Found
W: Failed to fetch http://ppa.launchpad.net/mc3man/gstffmpeg-keep/ubuntu/dists/wily/main/binary-i386/Packages  404  Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.