FFmpeg options for swaygrab

swaygrab/main.c

@@ -84,13 +84,18 @@ void grab_and_apply_movie_magic(const char *file, const char *payload,
 		sway_abort("Unknown output %s.", name);
 	}
 
-	const char *fmt = "ffmpeg -f rawvideo -framerate %d "
+	char *ffmpeg_opts = getenv("SWAYGRAB_FFMPEG_OPTS");
+	if(!ffmpeg_opts) {
+			ffmpeg_opts = "";
+	}
+
+	const char *fmt = "ffmpeg %s -f rawvideo -framerate %d "
 		"-video_size %dx%d -pixel_format argb "
 		"-i pipe:0 -r %d -vf vflip %s";
 	char *cmd = malloc(strlen(fmt) - 8 /*args*/
-			+ numlen(width) + numlen(height) + numlen(framerate) * 2
-			+ strlen(file) + 1);
-	sprintf(cmd, fmt, framerate, width, height, framerate, file);
+			+ strlen(ffmpeg_opts) + numlen(width) + numlen(height) 
+			+ numlen(framerate) * 2 + strlen(file) + 1);
+	sprintf(cmd, fmt, ffmpeg_opts, framerate, width, height, framerate, file);
 
 	long ns = (long)(1000000000 * (1.0 / framerate));
 	struct timespec start, finish, ts;

swaygrab/swaygrab.1.txt

@@ -48,6 +48,13 @@ Options
 *-f, --focused*::
 	Capture only the currently focused container.
 
+Environment Variables
+---------------------
+swaygrab reads the following environment variables.
+
+*SWAYGRAB_FFMPEG_OPTS*::
+	Pass additional arguments to FFmpeg when starting a capture.
+
 Examples
 --------
 
@@ -57,6 +64,10 @@ swaygrab output.png::
 swaygrab -c -o HDMI-A-1 output.webm::
 	Capture a webm of HDMI-A-1.
 
+SWAYGRAB_FFMPEG_OPTS="-f alsa -i pulse" swaygrab -c::
+	Capture the focused output and encode audio from the default recording
+	device.
+
 Authors
 -------