Ticket #3192: x11grab-nonblock.diff

libavdevice/x11grab.c

@@ -319 +319 @@
     x11grab->frame_size = x11grab->width * x11grab->height * image->bits_per_pixel/8;
     x11grab->dpy = dpy;
     x11grab->time_base  = av_inv_q(x11grab->framerate);
-    x11grab->time_frame = av_gettime() / av_q2d(x11grab->time_base);
+    x11grab->time_frame = av_gettime();
     x11grab->x_off = x_off;
     x11grab->y_off = y_off;
     x11grab->image = image;
@@ -478 +478 @@
     Window root;
     int follow_mouse = s->follow_mouse;
 
-    int64_t curtime, delay;
-    struct timespec ts;
-
-    /* Calculate the time of the next frame */
-    s->time_frame += INT64_C(1000000);
+    int64_t curtime, delay, frame_dur;
 
     /* wait based on the frame rate */
-    for(;;) {
-        curtime = av_gettime();
-        delay = s->time_frame * av_q2d(s->time_base) - curtime;
-        if (delay <= 0) {
-            if (delay < INT64_C(-1000000) * av_q2d(s->time_base)) {
-                s->time_frame += INT64_C(1000000);
-            }
-            break;
-        }
-        ts.tv_sec = delay / 1000000;
-        ts.tv_nsec = (delay % 1000000) * 1000;
-        nanosleep(&ts, NULL);
-    }
+        curtime = av_gettime();
+        frame_dur = INT64_C(1000000) * av_q2d(s->time_base);
+        for (delay = s->time_frame - curtime; delay < -frame_dur; delay += frame_dur) {
+                s->time_frame += frame_dur;
+                av_log(s1, AV_LOG_DEBUG, "X11Grab: Frame skipped\n");
+        }
+        if (delay > 0) {
+                if (s1->flags & AVFMT_FLAG_NONBLOCK) {
+                        return AVERROR(EAGAIN);
+                } else {
+                        struct timespec ts;
+                        ts.tv_sec = delay / 1000000;
+                        ts.tv_nsec = (delay % 1000000) * 1000;
+                        nanosleep(&ts, NULL);
+                }
+        }
+
+        /* Calculate the time of the next frame */
+        s->time_frame += frame_dur;
 
     av_init_packet(pkt);
     pkt->data = image->data;