public List <Match> FindMatches(SubFingerprintHash hash)
{
List <Match> matches = new List <Match>();
List <SubFingerprintLookupEntry> entries = collisionMap.GetValues(hash);
//Debug.WriteLine("Finding matches...");
// compare each track with each other
int cycle = 1;
for (int x = 0; x < entries.Count; x++)
{
SubFingerprintLookupEntry entry1 = entries[x];
for (int y = cycle; y < entries.Count; y++)
{
SubFingerprintLookupEntry entry2 = entries[y];
if (entry1.AudioTrack != entry2.AudioTrack) // don't compare tracks with themselves
//Debug.WriteLine("Comparing " + entry1.AudioTrack.Name + " with " + entry2.AudioTrack.Name + ":");
{
if (store[entry1.AudioTrack].Count - entry1.Index < fingerprintSize ||
store[entry2.AudioTrack].Count - entry2.Index < fingerprintSize)
{
// the end of at least one track has been reached and there are not enough hashes left
// to do a fingerprint comparison
continue;
}
// sum up the bit errors
List <SubFingerprintHash> track1Hashes = store[entry1.AudioTrack];
List <SubFingerprintHash> track2Hashes = store[entry2.AudioTrack];
uint bitErrors = 0;
for (int s = 0; s < fingerprintSize; s++)
{
SubFingerprintHash track1Hash = track1Hashes[entry1.Index + s];
SubFingerprintHash track2Hash = track2Hashes[entry2.Index + s];
if (track1Hash.Value == 0 || track2Hash.Value == 0)
{
bitErrors = (uint)fingerprintSize * 32;
break;
}
// skip fingerprints with hashes that are zero, since it is probably from
// a track section with silence
// by setting the bitErrors to the maximum, the match will not be added
bitErrors += track1Hash.HammingDistance(track2Hash);
}
float bitErrorRate = bitErrors / (float)(fingerprintSize * 32); // sub-fingerprints * 32 bits
//Debug.WriteLine("BER: " + bitErrorRate + " <- " + (bitErrorRate < threshold ? "MATCH!!!" : "no match"));
if (bitErrorRate < threshold)
{
matches.Add(new Match {
Similarity = 1 - bitErrorRate,
Track1 = entry1.AudioTrack,
Track1Time = SubFingerprintIndexToTimeSpan(entry1.Index),
Track2 = entry2.AudioTrack,
Track2Time = SubFingerprintIndexToTimeSpan(entry2.Index),
Source = matchSourceName
});
}
}
}
cycle++;
}
//Debug.WriteLine("finished");
return(matches);
}
