flac: add page (#1870)

pages/common/flac.md

@@ -0,0 +1,19 @@
+# flac
+
+> Encodes, decodes and tests flac files.
+
+- Encode a wav file to flac (this will create a flac file in the same location as the wav file):
+
+`flac {{path/to/file.wav}}`
+
+- Encode a wav file to flac, specifying the output file:
+
+`flac -o {{path/to/output.flac}} {{path/to/file.wav}}`
+
+- Decode a flac file to wav, specifying the output file:
+
+`flac -d -o {{path/to/output.wav}} {{path/to/file.flac}}`
+
+- Test a flac file for the correct encoding:
+
+`flac -t {{path/to/file.flac}}`