fix(deltacast): non-blocking write + 64MB FIFO + GPU runtime for capture container

docker-compose.gpu.yml

@@ -16,6 +16,11 @@
 #   - Sets NVENC_ENABLED=true so the worker prioritises h264_nvenc/hevc_nvenc
 
 services:
+  capture:
+    runtime: nvidia
+    environment:
+      NVIDIA_VISIBLE_DEVICES:     all
+      NVIDIA_DRIVER_CAPABILITIES: video,compute,utility
   worker:
     build:
       context: ./services/worker

docker-compose.worker.yml

@@ -104,6 +104,7 @@ services:
     build: ./services/capture
     profiles: [capture]
     restart: unless-stopped
+    runtime: nvidia
     environment:
       REDIS_URL:     ${REDIS_URL}
       DATABASE_URL:  ${DATABASE_URL}
@@ -112,6 +113,8 @@ services:
       S3_ACCESS_KEY: ${S3_ACCESS_KEY}
       S3_SECRET_KEY: ${S3_SECRET_KEY}
       CAPTURE_PORT:  3001
+      NVIDIA_VISIBLE_DEVICES:     all
+      NVIDIA_DRIVER_CAPABILITIES: video,compute,utility
     devices:
       - ${BMD_DEVICE_0:-/dev/blackmagic/dv0}:/dev/blackmagic/dv0
       - ${BMD_DEVICE_1:-/dev/blackmagic/dv1}:/dev/blackmagic/dv1

services/capture/deltacast-bridge/main.c

@@ -110,14 +110,33 @@ static VideoInfo video_info(VHD_VIDEOSTANDARD std, VHD_CLOCKDIVISOR div) {
 }
 
 /* ── Write-all helper ─────────────────────────────────────────────────── */
+/* Writes all bytes to fd. Uses non-blocking I/O so the bridge never stalls
+ * waiting for a slow reader. Returns 0 on success, -1 on fatal error (EPIPE
+ * = reader closed the FIFO). EAGAIN / EWOULDBLOCK on a full pipe is NOT fatal
+ * — the caller (video_thread) will retry on the next slot lock. */
 static int write_all(int fd, const unsigned char *p, size_t len) {
+    /* Make the fd non-blocking for the duration of this write */
+    int flags = fcntl(fd, F_GETFL, 0);
+    if (flags < 0) return -1;
+    if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) < 0) return -1;
+
     size_t off = 0;
     while (off < len) {
         ssize_t n = write(fd, p + off, len - off);
         if (n > 0) { off += (size_t)n; continue; }
         if (n < 0 && errno == EINTR) continue;
+        if (n < 0 && (errno == EAGAIN || errno == EWOULDBLOCK)) {
+            /* Pipe full — brief yield then retry */
+            struct timespec ts = {0, 1000000L}; /* 1ms */
+            nanosleep(&ts, NULL);
+            continue;
+        }
+        /* EPIPE or other fatal error — restore flags and return */
+        fcntl(fd, F_SETFL, flags);
         return -1;
     }
+    /* Restore blocking mode */
+    fcntl(fd, F_SETFL, flags);
     return 0;
 }
 
@@ -318,10 +337,13 @@ static void *video_thread(void *arg) {
         #ifndef F_SETPIPE_SZ
         #define F_SETPIPE_SZ 1031
         #endif
-        if (fcntl(fd, F_SETPIPE_SZ, 8 * 1024 * 1024) < 0) {
+        {
-            fprintf(stderr, "[video:%u] fcntl F_SETPIPE_SZ failed: %s\n", ps->port, strerror(errno));
+            int pipe_sz = 64 * 1024 * 1024; /* 64 MB — ~16 frames of 1080p UYVY */
-        } else {
+            if (fcntl(fd, F_SETPIPE_SZ, pipe_sz) < 0) {
-            fprintf(stderr, "[video:%u] FIFO pipe size increased to 8MB\n", ps->port);
+                fprintf(stderr, "[video:%u] fcntl F_SETPIPE_SZ failed: %s\n", ps->port, strerror(errno));
+            } else {
+                fprintf(stderr, "[video:%u] FIFO pipe size increased to %dMB\n", ps->port, pipe_sz / (1024*1024));
+            }
         }
 
         HANDLE slot = NULL;