Revert "v4l2: setting device parameters early"

This reverts commit b1ad9312.

Fixes Ticket #3517

Conflicts:

	libavdevice/v4l2.c
Requested-by: Giorgio Vazzana <mywing81@gmail.com>
Merged-by: Michael Niedermayer <michaelni@gmx.at>

libavdevice/v4l2.c

@@ -881,9 +881,6 @@ 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);
 
@@ -934,6 +931,9 @@ static int v4l2_read_header(AVFormatContext *ctx)
 
     s->pixelformat = desired_format;
 
+    if ((res = v4l2_set_parameters(ctx)) < 0)
+        goto fail;
+
     st->codec->pix_fmt = ff_fmt_v4l2ff(desired_format, codec_id);
     s->frame_size =
         avpicture_get_size(st->codec->pix_fmt, s->width, s->height);