Revert "v4l2: setting device parameters early"

This reverts commit b1ad931233.

Fixes Ticket #3517

Requested-by: Giorgio Vazzana <mywing81@gmail.com>
Merged-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 6f21fb7932)

Conflicts:
	libavdevice/v4l2.c

libavdevice/v4l2.c

@@ -873,9 +873,6 @@ static int v4l2_read_header(AVFormatContext *ctx)
 
     avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
 
-    if ((res = v4l2_set_parameters(ctx)) < 0)
-        goto fail;
-
     if (s->pixel_format) {
         AVCodec *codec = avcodec_find_decoder_by_name(s->pixel_format);
 
@@ -926,6 +923,9 @@ static int v4l2_read_header(AVFormatContext *ctx)
 
     s->frame_format = desired_format;
 
+    if ((res = v4l2_set_parameters(ctx)) < 0)
+        goto fail;
+
     st->codec->pix_fmt = avpriv_fmt_v4l2ff(desired_format, codec_id);
     s->frame_size =
         avpicture_get_size(st->codec->pix_fmt, s->width, s->height);