private static String buildTrackName(MediaFormat format) { if (format.adaptive) { return "auto"; } String trackName; if (MimeTypes.isVideo(format.mimeType)) { trackName = joinWithSeparator( joinWithSeparator(buildResolutionString(format), buildBitrateString(format)), buildTrackIdString(format)); } else if (MimeTypes.isAudio(format.mimeType)) { trackName = joinWithSeparator( joinWithSeparator( joinWithSeparator(buildLanguageString(format), buildAudioPropertyString(format)), buildBitrateString(format)), buildTrackIdString(format)); } else { trackName = joinWithSeparator( joinWithSeparator(buildLanguageString(format), buildBitrateString(format)), buildTrackIdString(format)); } return trackName.length() == 0 ? "unknown" : trackName; }