They can be both cleared however, then the buffer is in "dequeued"
state, in the application domain to say so.</entry>
</row>
+ <row>
+ <entry><constant>V4L2_BUF_FLAG_ERROR</constant></entry>
+ <entry>0x0040</entry>
+ <entry>When this flag is set, the buffer has been dequeued
+ successfully, although the data might have been corrupted.
+ This is recoverable, streaming may continue as normal and
+ the buffer may be reused normally.
+ Drivers set this flag when the <constant>VIDIOC_DQBUF</constant>
+ ioctl is called.</entry>
+ </row>
<row>
<entry><constant>V4L2_BUF_FLAG_KEYFRAME</constant></entry>
<entry>0x0008</entry>
<para>When the driver provides or accepts images field by field
rather than interleaved, it is also important applications understand
-how the fields combine to frames. We distinguish between top and
-bottom fields, the <emphasis>spatial order</emphasis>: The first line
+how the fields combine to frames. We distinguish between top (aka odd) and
+bottom (aka even) fields, the <emphasis>spatial order</emphasis>: The first line
of the top field is the first line of an interlaced frame, the first
line of the bottom field is the second line of that frame.</para>
<row>
<entry><constant>V4L2_FIELD_TOP</constant></entry>
<entry>2</entry>
- <entry>Images consist of the top field only.</entry>
+ <entry>Images consist of the top (aka odd) field only.</entry>
</row>
<row>
<entry><constant>V4L2_FIELD_BOTTOM</constant></entry>
<entry>3</entry>
- <entry>Images consist of the bottom field only.
+ <entry>Images consist of the bottom (aka even) field only.
Applications may wish to prevent a device from capturing interlaced
images because they will have "comb" or "feathering" artefacts around
moving objects.</entry>