Initialize the private class field and give the class a more
appropriate name. Add a class member to the codec context.

Most option values are simply unused or ignored and in practice the
majory of codecs only need to check whether to enable rle or not.

Add appropriate codec private options which better expose the allowed
features.
Signed-off-by: NVittorio Giovara <vittorio.giovara@gmail.com>

The rationale is that coded_frame was only used to communicate key_frame,
pict_type and quality to the caller, as well as a few other random fields,
in a non predictable, let alone consistent way.

There was agreement that there was no use case for coded_frame, as it is
a full-sized AVFrame container used for just 2-3 int-sized properties,
which shouldn't even belong into the AVCodecContext in the first place.

The appropriate AVPacket flag can be used instead of key_frame, while
quality is exported with the new AVPacketSideData quality factor.
There is no replacement for the other fields as they were unreliable,
mishandled or just not used at all.
Signed-off-by: NVittorio Giovara <vittorio.giovara@gmail.com>

Allocating coded_frame is what most encoders do anyway, so it makes
sense to always allocate and free it in a single place. Moreover a lot
of encoders freed the frame with av_freep() instead of the correct API
av_frame_free().

This bring uniformity to encoder behaviour and prevents applications
from erroneusly accessing this field when not allocated. Additionally
this helps isolating encoders that export information with coded_frame,
and heavily simplifies its deprecation.
Signed-off-by: NVittorio Giovara <vittorio.giovara@gmail.com>

Bug-Id: CID 732231

Signed-off-by: NJustin Ruggles <justin.ruggles@gmail.com>

Signed-off-by: NAnton Khirnov <anton@khirnov.net>

Signed-off-by: NJustin Ruggles <justin.ruggles@gmail.com>