make_wav_header(): Add some comments.

[paraslash.git] / wav_filter.c

diff --git a/wav_filter.c b/wav_filter.c
index 242cb4bb0d1529ae3d8756083e04be04bf16d008..f5905f1f2ec13ab2d5d220bf59ad5cd02c0b8d7e 100644 (file)
--- a/wav_filter.c
+++ b/wav_filter.c
@@ -10,8 +10,10 @@
 
 #include "list.h"
 #include "sched.h"
+#include "ggo.h"
 #include "filter.h"
 #include "string.h"
+#include "portable_io.h"
 
 /** size of the output buffer */
 #define WAV_OUTBUF_SIZE 81920
@@ -20,25 +22,6 @@
 /** always write 16 bit header */
 #define BITS 16
 
-/**
- * write a 32 bit unsigned value to a buffer
- *
- * \param buf the buffer to write to
- * \param x the value to write
- */
-#define WRITE_U32(buf, x) (buf)[0] = (unsigned char)((x) & 0xff);\
-       (buf)[1] = (unsigned char)(((x) >> 8) & 0xff);\
-       (buf)[2] = (unsigned char)(((x) >> 16) & 0xff);\
-       (buf)[3] = (unsigned char)(((x) >> 24) & 0xff);
-
-/**
- * write a 16 bit unsigned value to a buffer
- *
- * \param buf the buffer to write to
- * \param x the value to write
- */
-#define WRITE_U16(buf, x) (buf)[0] = (unsigned char)((x) & 0xff);
-
 static void make_wav_header(unsigned int channels, unsigned int samplerate,
                struct filter_node *fn)
 {
@@ -52,18 +35,18 @@ static void make_wav_header(unsigned int channels, unsigned int samplerate,
        PARA_DEBUG_LOG("writing wave header: %d channels, %d KHz\n", channels, samplerate);
        memset(headbuf, 0, WAV_HEADER_LEN);
        memcpy(headbuf, "RIFF", 4);
-       WRITE_U32(headbuf + 4, size - 8);
+       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_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_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); /* 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)