Make the SPS/PPS parsing independent of the H264Context, to allow
decoupling the parser from the decoder. The change is modelled after the
one done earlier for HEVC.
Move the dequant buffers to the PPS to avoid complex checks whether they
changed and an expensive copy for frame threads.
According to the spec, the reference list for a slice should be
constructed by first generating an initial (what we now call "default")
reference list and then optionally applying modifications to it.
Our code has an optimization where the initial reference list is
constructed for the first inter slice and then rebuilt for other slices
if needed. This, however, adds complexity to the code, requires an extra
2.5kB array in the codec context and there is no reason to think that it
has any positive effect on performance. Therefore, simplify the code by
generating the reference list from scratch for each slice.
The container cropping is applied only when difference is within 16
pixels, and the smallest value between the two is chosen.
Bug-Id: 383
Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>
Also use the frame pixel format instead of the one from the codec
context, which is more robust.
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
It does not make sense to copy is_avc without copying this as well. This
patch should not change anything for now, but will have an effect in
later commits.
That function currently does two things -- reinitializing the DSP
contexts and setting low_delay based on the SPS values.
The former more appropriately belongs in h264_slice_header_init(), while
the latter only really makes sense in decode_slice_header().
The third call to ff_h264_set_parameter_from_sps(), done immediately
after parsing a new SPS, appears to serve no useful purpose, so it is
just dropped.
Also, drop now unneeded H264Context.cur_chroma_format_idc.
Currently, the DPB is initialized in alloc_tables() and uninitialized in
free_tables(), but those functions manage frame size-dependent
variables, so DPB management does not logically belong in there.
Since we want the init/uninit to happen exactly once per the context
lifetime, init_context()/free_context() are the proper place for this
code.
Also change the method for allocating them. Instead of two possible
alloc calls from different places, just ensure they are allocated at the
start of each slice. This should be simpler and less bug-prone than the
previous method.
Anton Khirnov
Diego Biurrun
Mark Thompson
Vittorio Giovara
Andreas Cadhalpun
Michael Niedermayer
Luca Barbato
Steve Lhomme