v4l2: use C99 struct initializer

Remove some unneeded memsets.

libavdevice/v4l2.c

@@ -169,14 +169,11 @@ static int device_init(AVFormatContext *ctx, int *width, int *height,
 {
     struct video_data *s = ctx->priv_data;
     int fd = s->fd;
-    struct v4l2_format fmt;
+    struct v4l2_format fmt = { .type = V4L2_BUF_TYPE_VIDEO_CAPTURE };
     struct v4l2_pix_format *pix = &fmt.fmt.pix;
 
     int res;
 
-    memset(&fmt, 0, sizeof(struct v4l2_format));
-
-    fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
     pix->width = *width;
     pix->height = *height;
     pix->pixelformat = pix_fmt;
@@ -334,14 +331,14 @@ static void list_formats(AVFormatContext *ctx, int fd, int type)
 
 static int mmap_init(AVFormatContext *ctx)
 {
-    struct video_data *s = ctx->priv_data;
-    struct v4l2_requestbuffers req;
     int i, res;
+    struct video_data *s = ctx->priv_data;
+    struct v4l2_requestbuffers req = {
+        .type   = V4L2_BUF_TYPE_VIDEO_CAPTURE,
+        .count  = desired_video_buffers,
+        .memory = V4L2_MEMORY_MMAP
+    };
 
-    memset(&req, 0, sizeof(struct v4l2_requestbuffers));
-    req.count = desired_video_buffers;
-    req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
-    req.memory = V4L2_MEMORY_MMAP;
     res = ioctl(s->fd, VIDIOC_REQBUFS, &req);
     if (res < 0) {
         if (errno == EINVAL) {
@@ -374,12 +371,12 @@ static int mmap_init(AVFormatContext *ctx)
     }
 
     for (i = 0; i < req.count; i++) {
-        struct v4l2_buffer buf;
+        struct v4l2_buffer buf = {
+            .type   = V4L2_BUF_TYPE_VIDEO_CAPTURE,
+            .index  = i,
+            .memory = V4L2_MEMORY_MMAP
+        };
 
-        memset(&buf, 0, sizeof(struct v4l2_buffer));
-        buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
-        buf.memory = V4L2_MEMORY_MMAP;
-        buf.index = i;
         res = ioctl(s->fd, VIDIOC_QUERYBUF, &buf);
         if (res < 0) {
             av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYBUF)\n");
@@ -411,14 +408,13 @@ static int mmap_init(AVFormatContext *ctx)
 
 static void mmap_release_buffer(AVPacket *pkt)
 {
-    struct v4l2_buffer buf;
+    struct v4l2_buffer buf = { 0 };
     int res, fd;
     struct buff_data *buf_descriptor = pkt->priv;
 
     if (pkt->data == NULL)
         return;
 
-    memset(&buf, 0, sizeof(struct v4l2_buffer));
     buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
     buf.memory = V4L2_MEMORY_MMAP;
     buf.index = buf_descriptor->index;
@@ -437,15 +433,14 @@ static void mmap_release_buffer(AVPacket *pkt)
 static int mmap_read_frame(AVFormatContext *ctx, AVPacket *pkt)
 {
     struct video_data *s = ctx->priv_data;
-    struct v4l2_buffer buf;
+    struct v4l2_buffer buf = {
+        .type   = V4L2_BUF_TYPE_VIDEO_CAPTURE,
+        .memory = V4L2_MEMORY_MMAP
+    };
     struct buff_data *buf_descriptor;
     struct pollfd p = { .fd = s->fd, .events = POLLIN };
     int res;
 
-    memset(&buf, 0, sizeof(struct v4l2_buffer));
-    buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
-    buf.memory = V4L2_MEMORY_MMAP;
-
     res = poll(&p, 1, s->timeout);
     if (res < 0)
         return AVERROR(errno);
@@ -504,12 +499,11 @@ static int mmap_start(AVFormatContext *ctx)
     int i, res;
 
     for (i = 0; i < s->buffers; i++) {
-        struct v4l2_buffer buf;
-
-        memset(&buf, 0, sizeof(struct v4l2_buffer));
-        buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
-        buf.memory = V4L2_MEMORY_MMAP;
-        buf.index  = i;
+        struct v4l2_buffer buf = {
+            .type   = V4L2_BUF_TYPE_VIDEO_CAPTURE,
+            .index  = i,
+            .memory = V4L2_MEMORY_MMAP
+        };
 
         res = ioctl(s->fd, VIDIOC_QBUF, &buf);
         if (res < 0) {
@@ -552,12 +546,12 @@ static void mmap_close(struct video_data *s)
 static int v4l2_set_parameters(AVFormatContext *s1, AVFormatParameters *ap)
 {
     struct video_data *s = s1->priv_data;
-    struct v4l2_input input;
-    struct v4l2_standard standard;
+    struct v4l2_input input = { 0 };
+    struct v4l2_standard standard = { 0 };
     struct v4l2_streamparm streamparm = { 0 };
     struct v4l2_fract *tpf = &streamparm.parm.capture.timeperframe;
+    AVRational framerate_q = { 0 };
     int i, ret;
-    AVRational framerate_q;
 
     streamparm.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
 
@@ -569,7 +563,6 @@ static int v4l2_set_parameters(AVFormatContext *s1, AVFormatParameters *ap)
     }
 
     /* set tv video input */
-    memset (&input, 0, sizeof (input));
     input.index = s->channel;
     if (ioctl(s->fd, VIDIOC_ENUMINPUT, &input) < 0) {
         av_log(s1, AV_LOG_ERROR, "The V4L2 driver ioctl enum input failed:\n");
@@ -589,7 +582,6 @@ static int v4l2_set_parameters(AVFormatContext *s1, AVFormatParameters *ap)
         av_log(s1, AV_LOG_DEBUG, "The V4L2 driver set standard: %s\n",
                s->standard);
         /* set tv standard */
-        memset (&standard, 0, sizeof (standard));
         for(i=0;;i++) {
             standard.index = i;
             if (ioctl(s->fd, VIDIOC_ENUMSTD, &standard) < 0) {