Currently, SPS.mb_height is actually what the spec calls
PicHeightInMapUnits, which is half the frame height when interlacing is
allowed. Calling this 'mb_height' is quite confusing, and there are at
least two associated bugs where this field is treated as the actual
frame height - in the h264 parser and in the code computing maximum
reordering buffer size for a given level.
Fix those issues (and avoid possible future ones) by exporting the real
frame height in this field.
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.
Fall back to maximum DPB size if the level is unknown.
This should be more spec-compliant and does not depend on the caller
setting has_b_frames before opening the decoder.
The old behaviour, when the delay is supplied by the caller setting
has_b_frames, can still be obtained by setting strict_std_compliance
below normal.
An invalid VUI is not considered a fatal error, so the SPS containing it
may still be used. Leaving an invalid value of num_reorder_frames there
can result in writing over the bounds of H264Context.delayed_pic.
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC:libav-stable@libav.org
There is no point in delaying the check and it avoids bugs with a
half-initialized context.
Fixes invalid reads.
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC:libav-stable@libav.org
A VUI doesn't contain anything strictly necessary for decoding.
Apparently there are many samples with truncated VUIs in the wild, this
commit should allow decoding them.
Most of the changes are just trivial are just trivial replacements of
fields from MpegEncContext with equivalent fields in H264Context.
Everything in h264* other than h264.c are those trivial changes.
The nontrivial parts are:
1) extracting a simplified version of the frame management code from
mpegvideo.c. We don't need last/next_picture anymore, since h264 uses
its own more complex system already and those were set only to appease
the mpegvideo parts.
2) some tables that need to be allocated/freed in appropriate places.
3) hwaccels -- mostly trivial replacements.
for dxva, the draw_horiz_band() call is moved from
ff_dxva2_common_end_frame() to per-codec end_frame() callbacks,
because it's now different for h264 and MpegEncContext-based
decoders.
4) svq3 -- it does not use h264 complex reference system, so I just
added some very simplistic frame management instead and dropped the
use of ff_h264_frame_start(). Because of this I also had to move some
initialization code to svq3.
Additional fixes for chroma format and bit depth changes by
Janne Grunau <janne-libav@jannau.net>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
Parsing the entire NAL as SPS fixes decoding of some AVC bitstreams
with broken escaping. Since the size of the NAL unit is known and
checked against the buffer end we can parse it entirely without buffer
overreads.
Fixes playback of
http://streams.videolan.org/streams/mp4/Mr_MrsSmith-h264_aac.mp4
Signed-off-by: Janne Grunau <janne-libav@jannau.net>
