The current condition can trigger in cases where it shouldn't, with
unexpected results.
Make sure that:
- container cropping is really based on the original dimensions from the
caller
- those dimenions are discarded on size change
The code is still quite hacky and eventually should be deprecated and
removed, with the decision about which cropping is used delegated to the
caller.
Calling ff_h264_field_end() when the per-field state is not properly
initialized leads to all kinds of undefined behaviour.
CC: libav-stable@libav.org
Bug-Id: 977 978 992
Since we only know whether a NAL unit corresponds to a new field after
parsing the slice header, this requires reorganizing the calls to slice
parsing, per-slice/field/frame init and actual decoding.
In the previous code, the function for slice header decoding also
immediately started a new field/frame as necessary, so any slices
already queued for decoding would no longer be decodable.
After this patch, we first parse the slice header, and if we determine
that a new field needs to be started we decode all the queued slices.
This function's purpose is not very well defined. Currently it does two
(only marginally related) things: selecting the next output frame and
calling ff_thread_finish_setup() for frame threading. The first of those
more properly belongs under field_start(), while the second can be
called directly from decode_nal_units().
Move the NAL unit types into it. This will allow to stop including the
whole decoder-specific h264dec.h in some code that is unrelated to the
decoder and only needs some enum values.
