vaapi_encode: Convert to send/receive API

This attaches the logic of picking the mode of for the next picture to
the output, which simplifies some choices by removing the concept of
the picture for which input is not yet available.  At the same time,
we allow more complex reference structures and track more reference
metadata (particularly the contents of the DPB) for use in the
codec-specific code.

It also adds flags to explicitly track the available features of the
different codecs.  The new structure also allows open-GOP support, so
that is now available for codecs which can do it.

1 files changed, 14 insertions, 5 deletions

diff --git a/doc/encoders.texi b/doc/encoders.texi
index 0a85c191e3..e86ae69cc5 100644
--- a/doc/encoders.texi
+++ b/doc/encoders.texi
@@ -2807,15 +2807,24 @@ Size / quality tradeoff: higher values are smaller / worse quality.
 @end itemize
 
 All encoders support the following options:
-@itemize
-@item
-@option{low_power}
-
+@table @option
+@item low_power
 Some drivers/platforms offer a second encoder for some codecs intended to use
 less power than the default encoder; setting this option will attempt to use
 that encoder.  Note that it may support a reduced feature set, so some other
 options may not be available in this mode.
-@end itemize
+
+@item idr_interval
+Set the number of normal intra frames between full-refresh (IDR) frames in
+open-GOP mode.  The intra frames are still IRAPs, but will not include global
+headers and may have non-decodable leading pictures.
+
+@item b_depth
+Set the B-frame reference depth.  When set to one (the default), all B-frames
+will refer only to P- or I-frames.  When set to greater values multiple layers
+of B-frames will be present, frames in each layer only referring to frames in
+higher layers.
+@end table
 
 Each encoder also has its own specific options:
 @table @option