FFmpeg options for swaygrab

2 files changed, 20 insertions, 4 deletions

diff --git a/swaygrab/main.c b/swaygrab/main.c
index 413de1fa..c437653d 100644
--- a/swaygrab/main.c
+++ b/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;
diff --git a/swaygrab/swaygrab.1.txt b/swaygrab/swaygrab.1.txt
index b2c6389a..1da56db8 100644
--- a/swaygrab/swaygrab.1.txt
+++ b/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
 -------