wm4 [Tue, 10 Nov 2015 12:47:01 +0000 (13:47 +0100)]
mmaldec: send only a single EOS packet on flushing
Fixes apparent mmal_port_disable() freezes in ffmmal_stop_decoder() when
calling ffmmal_decode() with flush semantics a large number of times in
a row.
Somewhat ironic that this "safe" interface is actually being used
unsafely here. This fixes the usage preventing potential null pointer
dereference, where the old code was doubly broken: ctime can return
NULL, and ctime can return an arbitrarily long buffer.
Reviewed-by: Mark Harris <mark.hsj@gmail.com> Reviewed-by: Michael Niedermayer <michael@niedermayer.cc> Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>
swresample/resample: speed up Blackman Nuttall filter
This may be a slightly surprising optimization, but is actually based on
an understanding of how math libraries compute trigonometric functions.
Explanation is given here so that future development uses libm more effectively
across the codebase.
All libm's essentially compute transcendental functions via some kind of
polynomial approximation, be it Taylor-Maclaurin or Chebyshev.
Correction terms are added via polynomial correction factors when needed
to squeeze out the last bits of accuracy. Lookup tables are also
inserted strategically.
In the case of trigonometric functions, periodicity is exploited via
first doing a range reduction to an interval around zero, and then using
some polynomial approximation.
This range reduction is the most natural way of doing things - else one
would need polynomials for ranges in different periods which makes no
sense whatsoever.
To avoid the need for the range reduction, it is helpful to feed in
arguments as close to the origin as possible for the trigonometric
functions. In fact, this also makes sense from an accuracy point of view:
IEEE floating point has far more resolution for small numbers than big ones.
This patch does this for the Blackman-Nuttall filter, and yields a
non-negligible speedup.
swresample/resample: speed up upsampling by precomputing sines
When upsampling, factor is set to 1 and sines need to be evaluated only
once for each phase, and the complexity should not depend on the number
of filter taps. This does the desired precomputation, yielding
significant speedups. Hard guarantees on the gain are not possible, but gains
themselves are obvious and are illustrated below.
Note that this does not statically allocate the sin lookup table. This
may be done for the default 1024 phases, yielding a 512*8 = 4kB array
which should be small enough.
This should yield a small improvement. Nevertheless, this is separate from
this patch, is more ambiguous due to the binary increase, and requires a
lut to be generated offline.
Reviewed-by: Michael Niedermayer <michael@niedermayer.cc> Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>
Bryan Huh [Mon, 9 Nov 2015 00:35:01 +0000 (16:35 -0800)]
avformat/cache: Avoid int-overflow in cache compare function
cache protocol indexes its cache using AVTreeNodes which require a cmp
function for inserting and searching new cache-entries. This cmp
function expects a 32-bit int return value (negative, zero, or positive)
but the cache cmp function returns an int64_t which can overflow the
int, giving negative numbers for when it should be positive, vice versa.
This manifests itself only for very large files (e.g. 4GB+)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
swresample/resample: improve bessel function accuracy and speed
This improves accuracy for the bessel function at large arguments, and this in turn
should improve the quality of the Kaiser window. It also improves the
performance of the bessel function and hence build_filter by ~ 20%.
Details are given below.
Algorithm: taken from the Boost project, who have done a detailed
investigation of the accuracy of their method, as compared with e.g the
GNU Scientific Library (GSL):
http://www.boost.org/doc/libs/1_52_0/libs/math/doc/sf_and_dist/html/math_toolkit/special/bessel/mbessel.html.
Boost source code (also cited and licensed in the code):
https://searchcode.com/codesearch/view/14918379/.
Accuracy: sample values may be obtained as follows. i0 denotes the old bessel code,
i0_boost the approach here, and i0_real an arbitrary precision result (truncated) from Wolfram Alpha:
type "bessel i0(6.0)" to reproduce. These are evaluation points that occur for
the default kaiser_beta = 9.
Reason for accuracy: Main accuracy benefits come at larger bessel arguments, where the
Taylor-Maclaurin method is not that good: 23+ iterations
(at large arguments, since the series is about 0) can cause
significant floating point error accumulation.
Benchmarks: Obtained on x86-64, Haswell, GNU/Linux via a loop calling
build_filter 1000 times:
test: fate-swr-resample-dblp-44100-2626
new: 995894468 decicycles in build_filter(loop 1000), 256 runs, 0 skips 1029719302 decicycles in build_filter(loop 1000), 512 runs, 0 skips 984101131 decicycles in build_filter(loop 1000), 1024 runs, 0 skips
old: 1250020763 decicycles in build_filter(loop 1000), 256 runs, 0 skips 1246353282 decicycles in build_filter(loop 1000), 512 runs, 0 skips 1220017565 decicycles in build_filter(loop 1000), 1024 runs, 0 skips
A further ~ 5% may be squeezed by enabling -ftree-vectorize. However,
this is a separate issue from this patch.
Reviewed-by: Michael Niedermayer <michael@niedermayer.cc> Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>
swresample: allow double precision beta value for the Kaiser window
Kaiser windows inherently don't require beta to be an integer. This was
an arbitrary restriction. Moreover, soxr does not require it, and in
fact often estimates beta to a non-integral value.
Thus, this patch allows greater flexibility for swresample clients.
Micro version is updated.
wm4 [Fri, 6 Nov 2015 12:02:16 +0000 (13:02 +0100)]
mmaldec: correct package buffering accounting
The assert in ffmmal_stop_decoder() could trigger sometimes. The
packets_buffered counter was indeed not correctly maintained, and
packets were not subtracted from it if they were still in the waiting
queue.
For some reason, this happened especially with VC-1.
Nicolas George [Mon, 26 Oct 2015 20:07:33 +0000 (21:07 +0100)]
lavu/opt: enhance printing durations.
Trim unneeded leading components and trailing zeros.
Move the formating code in a separate function.
Use the function also to format the default value, it was currently
printed as plain integer, inconsistent to the way it is parsed.
Nicolas George [Sun, 25 Oct 2015 15:31:00 +0000 (16:31 +0100)]
lavfi: add testsrc2 test source.
Similar to testsrc, but using drawutils and therefore
supporting a lot of pixel formats instead of just rgb24.
This allows using it as input for other tests without
requiring a format conversion.
It is also slightly faster than testsrc for some reason.
The buffer needs s->bpp bytes, at maximum currently 10.
Assert that s->bpp is not larger.
This fixes a stack buffer overflow.
Reviewed-by: wm4 <nfxjfg@googlemail.com> Reviewed-by: Paul B Mahol <onemda@gmail.com> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
The return type of strlen is size_t, i.e. unsigned, so if pd->buf_size
is 3, the right side overflows leading to a wrong result of the
comparison and subsequently a heap buffer overflow.
Reviewed-by: Paul B Mahol <onemda@gmail.com> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
Fixes out of array access Fixes: b877a6b788a25c70e8b1d014f8628549/asan_heap-oob_1da2c3f_2324_5a1b329b0b3c4bb6b1d775660ac56717.r3d Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
avcodec/microdvddec: Check for string end in 'P' case
Fixes out of array read Fixes: a9502b60f4cecc19475382aee255f73c/asan_heap-oob_1e87fba_2548_a8ad47f6dde36644fe9cdc444d4632d0.sub Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This seems not to do anything any more since a long time, and removing
it avoids using uninitialized memory. Also change the error value
forwarding as done everywhere else.
John Stebbins [Sun, 25 Oct 2015 18:36:10 +0000 (11:36 -0700)]
vf_pad: fix x, y option expression evaluation
Calculation of x an y based on width and height did not work when
width == 0 or height == 0. "0" substitutes the input width and
height, but did so too late for x, y expression evaluation.
projects / ffmpeg / log