The function is supposed to confirm that the compiler provided enough
alignment, but in practice it is only run in certain code paths and
insufficient alignment problems are restricted to legacy compilers.
Based on the aarch64 asm. CPU cycle counts on cortex-a9 compared to
gcc 4.8.2:
before: 475 decicycles in get_cabac_noinline, 67106035 runs, 2829 skips
after: 393 decicycles in get_cabac_noinline, 67106474 runs, 2390 skips
Overall speedup is above 2%. Code generated by clang 3.4 is slower on
the same hardware and the relative change is a little larger.
Based on the x86 branchless get_cabac asm. get_cabac_noinline() gets
approximately 20% faster (no cycle counts available) compared to clang
from Xcode 5.1 beta5. More than 6% faster overall. A part of the overall
speedup might be explained by additional inlining of get_cabac().
The overread avoidance fix in cbddee1cca
broke the computation for the last row since it prevented the safe
reading from the height+1-th row.
CC: libav-stable@libav.org
Some content requires an higher number of slices in order to
render properly.
Rise the number to 1024 and warn if ever it exceeds.
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
The SVQ3 decoder reuses large parts of the H.264 decoder so it
makes no sense to enable the former but not the latter.
Also drop unnecessary h263.o object from SVQ3 decoder object list.
Avoid a division by 0 in ff_mpeg4_set_one_direct_mv.
Sample-Id: 00000168-google
Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>
avcodec_flush_buffers() must release all internally held references
according to its documentation, for which all the threads need to be
flushed.
CC:libav-stable@libav.org
Bug-Id: vlc/9665
These codecs compile all of the MJPEG code anyway, so there is little
point in not enabling the MJPEG decoder directly. This also simplifies
the dependency declarations for the MJPEG codec family.
This codec compiles all of the SP5X code anyway, so there is little
point in not enabling the decoder directly. This also simplifies the
dependency declaration for the AMV decoder.
AAC LOAS can have new audio config objects in the stream itself.
Make sure the decoder reconfigures itself when the first one arrives
midstream.
Bug-Id: 644
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
The vector dequantization has a test in a loop preventing effective SIMD
implementation. By moving it out of the loop, this loop can be DSPized.
Therefore, modify the current DSP implementation. In particular, the
DSP implementation no longer has to handle null loop sizes.
The decode_hf implementations have following timings:
For x86 Arrandale:
C SSE SSE2 SSE4
win32: 260 162 119 104
win64: 242 N/A 89 72
The arm NEON optimizations follow in a later patch as external asm. The
now unused check for the y modifier in arm inline asm is removed from
configure.
Based on a patch from Christophe Gisquet.
Unrolling of the m == 0 case avoids a possible use of the uninitilized
value sum when s->predictor_history is not set. I failed to find a
sample for it. It also reduced the cycle count from 220 to 150 on
sandy bridge, x86_64 linux, gcc 4.8.2 compared to his patch.
Timings for Arrandale:
C SSE
win32: 2108 334
win64: 1152 322
Factorizing the inner loop with a call/jmp is a >15 cycles cost, even with
the jmp destination being aligned.
Unrolling for ARCH_X86_64 is a 20 cycles gain.
Signed-off-by: Janne Grunau <janne-libav@jannau.net>
Diego Biurrun
Janne Grunau
Vittorio Giovara
Luca Barbato
Michael Niedermayer
Keiji Costantini
Derek Buitenhuis
Rainer Hochecker
Rémi Denis-Courmont
Anton Khirnov
Hendrik Leppkes
Christophe Gisquet