There are two types of MPVPictures: Three (cur_pic, last_pic, next_pic)
that are directly part of MpegEncContext and an array of MPVPictures
that are separately allocated and are mostly accessed via pointers
(cur|last|next)_pic_ptr; they are also used to store AVFrames in the
encoder (necessary due to B-frames). As the name implies, each of the
former is directly associated with one of the _ptr pointers:
They actually share the same underlying buffers, but the ones
that are part of the context can have their data pointers offset
and their linesize doubled for field pictures.
Up until now, each of these had their own references; in particular,
there was an underlying av_frame_ref() to sync cur_pic and cur_pic_ptr
etc. This is wasteful.
This commit changes this relationship: cur_pic, last_pic and next_pic
now become MPVWorkPictures; this structure does not have an AVFrame
at all any more, but only the cached values of data and linesize.
It also contains a pointer to the corresponding MPVPicture, establishing
a more natural relationsship between the two.
This already means that creating the context-pictures from the pointers
can no longer fail.
What has not been changed is the fact that the MPVPicture* pointers
are not ownership pointers and that the MPVPictures are part of an
array of MPVPictures that is owned by a single AVCodecContext.
Doing so will be done in a latter commit.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
current_picture->cur_pic, last_picture->last_pic, similarly
for new_picture and next_picture.
Also rename the corresponding *_ptr fields.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
This commit is the AVHWAccel analogue of commit
20f9727018: It moves the private fields
of AVHWAccel to a new struct FFHWAccel extending AVHWAccel
in an internal header (namely hwaccel_internal.h).
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
With the introduction of HEVC 444 support, we technically have two
codecs that can handle 444 - HEVC and MJPEG. In the case of MJPEG,
it can decode, but can only output one of the semi-planar formats.
That means we need additional logic to decide whether to use a
444 output format or not.
This was predictably nightmarish, given how ridiculous mpeg4 is.
I had to stare at the cuvid parser output for a long time to work
out what each field was supposed to be, and even then, I still don't
fully understand some of them. Particularly:
vop_coded: If I'm reading the decoder correctly, this flag will always
be 1 as the decoder will not pass the hwaccel any frame
where it is not 1.
divx_flags: There's obviously no documentation on what the possible
flags are. I simply observed that this is '0' for a
normal bitstream and '5' for packed b-frames.
gmc_enabled: I had a number of guesses as to what this mapped to.
I picked the condition I did based on when the cuvid
parser was setting flag.
Also note that as with the vdpau hwaccel, the decoder needs to
consume the entire frame and not the slice.
