stew

commit 2e12698eb0ed56f03b462a0a364079c507304b78
parent 939aaf00a856fbab7a16933e13b8c41f211ddaa4
Author: glenda <glenda@device>
Date:   Mon, 24 Oct 2022 21:00:17 +0000

add src/audio/extract

Diffstat:
A
src/audio/extract.c
 | 
20
++++++++++++++++++++
A
src/audio/mkfile
 | 
8
++++++++

2 files changed, 28 insertions(+), 0 deletions(-)
diff --git a/src/audio/extract.c b/src/audio/extract.c
@@ -0,0 +1,20 @@
+/*
+ * Extracts first channel from 16-bit stereo PCM input.
+ * Output is 16-bit mono, naturally.
+ */
+
+#include<u.h>
+#include<libc.h>
+
+void
+main(void)
+{
+	long i, n;
+	s16int buf[4096];
+	while ((n = read(0, buf, 4096 * sizeof(s16int))) > 0) {
+		for (i = 0; i <= n / sizeof(s16int) / 2; i += 1) {
+			buf[i] = buf[i * 2];
+		}
+		if (write(1, buf, n / 2) <= 0) exits("can't write");
+	}
+}
diff --git a/src/audio/mkfile b/src/audio/mkfile
@@ -0,0 +1,8 @@
+</$objtype/mkfile
+
+TARG=\
+	extract
+
+BIN=/$objtype/bin/audio
+
+</sys/src/cmd/mkmany