In case of IDR, any previously decoded pictures must be drained
before the IDR and POC of IDR should be zero. So we can output
IDR immediately. Also, when POC of current picture is expected to be
the next output POC, decoder can output the picture as well
without waiting.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1211>
... to prevent requesting decoding before the preparation.
For instance, baseclass should not request decoding a picture if there
is no parsed valid headers, since subclass is most likely
not ready to decoding it.
As per specification in A.3.1 h) and A.3.2 f), the maximum size of the DPB is
16. Fix the maximum in the fine and fix the formula to use MIN instead of MAX
so that we no longer always use the maximum for the profile/level.
If decoding failed because end_picture() failed, set the picture to
nonexisting, this way output_picture() will be skipped. This avoids confusing
special cases in output_picture() implementation.
See C.5.2.2 Output and removal of pictures from the DPB.
If the number of pictures in the DPB is greater than or equal to
sps_max_dec_pic_buffering_minus1[HighestTid] + 1, then the picture
should be outputted.
On new_segment, the decoder is expected to negotiate. The decoder may want to
pre-allocate the needed buffers. Pass the max_dpb_size as this is needed to
determin how many buffers should be allocated.
This introduce a library which contains a set of base classes which
handles the parsing and the state tracking for the purpose of decoding
different CODECs. Currently H264, H265 and VP9 are supported. These
bases classes are used to decode with low level decoding API like DXVA,
NVDEC, VDPAU, VAAPI and V4L2 State Less decoders. The new library is
named gstreamer-codecs-1.0 / libgstcodecs.
