make_wav_header(): Add some comments.

diff --git a/wav_filter.c b/wav_filter.c
index d30b018de4f6f1a8554e1619ba7e97486d7c7b3e..f5905f1f2ec13ab2d5d220bf59ad5cd02c0b8d7e 100644 (file)
--- a/wav_filter.c
+++ b/wav_filter.c
@@ -38,15 +38,15 @@ static void make_wav_header(unsigned int channels, unsigned int samplerate,
        write_u32(headbuf + 4, size - 8);
        memcpy(headbuf + 8, "WAVE", 4);
        memcpy(headbuf + 12, "fmt ", 4);
-       write_u32(headbuf + 16, 16);
-       write_u16(headbuf + 20, 1);     /* format */
+       write_u32(headbuf + 16, 16); /* 16 + extra format bytes (zero) */
+       write_u16(headbuf + 20, 1);     /* format (1 == PCM/uncompressed) */
        write_u16(headbuf + 22, channels);
        write_u32(headbuf + 24, samplerate);
        write_u32(headbuf + 28, bytespersec);
-       write_u16(headbuf + 32, align);
-       write_u16(headbuf + 34, BITS);
-       memcpy(headbuf + 36, "data", 4);
-       write_u32(headbuf + 40, size - 44);
+       write_u16(headbuf + 32, align); /* number of bytes per sample slice */
+       write_u16(headbuf + 34, BITS); /* significant bits per sample */
+       memcpy(headbuf + 36, "data", 4); /* chunk ID */
+       write_u32(headbuf + 40, size - 44); /* chunk size */
 }
 
 static ssize_t wav_convert(char *inbuf, size_t len, struct filter_node *fn)