v4l2: uniform and format options

libavdevice/v4l2.c

@@ -715,11 +715,11 @@ static int v4l2_read_close(AVFormatContext *s1)
 #define OFFSET(x) offsetof(struct video_data, x)
 #define DEC AV_OPT_FLAG_DECODING_PARAM
 static const AVOption options[] = {
-    { "standard", "", offsetof(struct video_data, standard), AV_OPT_TYPE_STRING, {.str = NULL }, 0, 0, AV_OPT_FLAG_DECODING_PARAM },
-    { "channel",  "", offsetof(struct video_data, channel),  AV_OPT_TYPE_INT,    {.dbl = 0 }, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
-    { "video_size", "A string describing frame size, such as 640x480 or hd720.", OFFSET(video_size), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },
-    { "pixel_format", "", OFFSET(pixel_format), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },
-    { "framerate", "", OFFSET(framerate), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },
+    { "standard",     "TV standard, used only by analog frame grabber",            OFFSET(standard),     AV_OPT_TYPE_STRING, {.str = NULL }, 0, 0,       DEC },
+    { "channel",      "TV channel, used only by frame grabber",                    OFFSET(channel),      AV_OPT_TYPE_INT,    {.dbl = 0 },    0, INT_MAX, DEC },
+    { "video_size",   "A string describing frame size, such as 640x480 or hd720.", OFFSET(video_size),   AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,       DEC },
+    { "pixel_format", "",                                                          OFFSET(pixel_format), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,       DEC },
+    { "framerate",    "",                                                          OFFSET(framerate),    AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,       DEC },
     { NULL },
 };