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v4l2: get_nearest_size: Fix "Unsupported field type" errors

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Most V4L2 ioctls like try_fmt will adjust input fields to match what the
hardware can do rather then returning -EINVAL. As is docmented here:
http://linuxtv.org/downloads/v4l-dvb-apis/vidioc-g-fmt.html

EINVAL is only returned if the buffer type field is invalid or not supported.

So upon requesting V4L2_FIELD_NONE devices which can only do interlaced
mode will change the field value to e.g. V4L2_FIELD_BOTTOM as only returning
half the lines is the closest they can do to progressive modes.

In essence this means that we've failed to get a (usable) progessive mode
and should fall back to interlaced mode.

This commit adds a check for having gotten a usable field value after the first
try_fmt, to force fallback to interlaced mode even if the try_fmt succeeded,
thereby fixing get_nearest_size failing on these devices.

https://bugzilla.gnome.org/show_bug.cgi?id=735660
This commit is contained in:
Hans de Goede 2014-08-29 12:01:27 +02:00 committed by Nicolas Dufresne
parent 8ad0509a1c
commit 116649371e
1 changed files with 27 additions and 17 deletions
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44
sys/v4l2/gstv4l2object.c
View file

@ -2140,6 +2140,24 @@ default_frame_sizes:
}
}
static gboolean
gst_v4l2_object_get_interlace (int field, gboolean * interlaced)
{
switch (field) {
case V4L2_FIELD_ANY:
case V4L2_FIELD_NONE:
*interlaced = FALSE;
return TRUE;
case V4L2_FIELD_INTERLACED:
case V4L2_FIELD_INTERLACED_TB:
case V4L2_FIELD_INTERLACED_BT:
*interlaced = TRUE;
return TRUE;
default:
return FALSE;
}
}
static gboolean
gst_v4l2_object_get_nearest_size (GstV4l2Object * v4l2object,
guint32 pixelformat, gint * width, gint * height, gboolean * interlaced)
@ -2169,7 +2187,8 @@ gst_v4l2_object_get_nearest_size (GstV4l2Object * v4l2object,
fmt.fmt.pix.field = V4L2_FIELD_NONE;
r = v4l2_ioctl (fd, VIDIOC_TRY_FMT, &fmt);
if (r < 0 && errno == EINVAL) {
if ((r < 0 && errno == EINVAL) ||
!gst_v4l2_object_get_interlace (fmt.fmt.pix.field, interlaced)) {
/* try again with interlaced video */
memset (&fmt, 0, sizeof (fmt));
fmt.type = v4l2object->type;
@ -2202,7 +2221,8 @@ gst_v4l2_object_get_nearest_size (GstV4l2Object * v4l2object,
fmt.fmt.pix.field = V4L2_FIELD_NONE;
r = v4l2_ioctl (fd, VIDIOC_S_FMT, &fmt);
if (r < 0 && errno == EINVAL) {
if ((r < 0 && errno == EINVAL) ||
!gst_v4l2_object_get_interlace (fmt.fmt.pix.field, interlaced)) {
/* try again with interlaced video */
memset (&fmt, 0, sizeof (fmt));
fmt.type = v4l2object->type;
@ -2223,21 +2243,11 @@ gst_v4l2_object_get_nearest_size (GstV4l2Object * v4l2object,
*width = fmt.fmt.pix.width;
*height = fmt.fmt.pix.height;
switch (fmt.fmt.pix.field) {
case V4L2_FIELD_ANY:
case V4L2_FIELD_NONE:
*interlaced = FALSE;
break;
case V4L2_FIELD_INTERLACED:
case V4L2_FIELD_INTERLACED_TB:
case V4L2_FIELD_INTERLACED_BT:
*interlaced = TRUE;
break;
default:
GST_WARNING_OBJECT (v4l2object->element,
"Unsupported field type for %" GST_FOURCC_FORMAT "@%ux%u",
GST_FOURCC_ARGS (pixelformat), *width, *height);
goto error;
if (!gst_v4l2_object_get_interlace (fmt.fmt.pix.field, interlaced)) {
GST_WARNING_OBJECT (v4l2object->element,
"Unsupported field type for %" GST_FOURCC_FORMAT "@%ux%u: %u",
GST_FOURCC_ARGS (pixelformat), *width, *height, fmt.fmt.pix.field);
goto error;
}
ret = TRUE;