Mans Rullgard
8b0de73464
g723.1: deobfuscate "(x << 4) - x" to "15 * x"
...
The compiler performs this optimisation.
Signed-off-by: Mans Rullgard <mans@mansr.com>
2012-08-13 01:03:25 +01:00
Mans Rullgard
05c36e0e5f
g723.1: fix addition overflow
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This addition must be done as 64-bit to avoid overflow and for
the subsequent clipping to be meaningful.
Signed-off-by: Mans Rullgard <mans@mansr.com>
2012-08-10 12:18:38 +01:00
Mans Rullgard
52aa3015a3
g723.1: simplify and fix multiplication overflow
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In 16-bit arithmetic, x * 0xffffc is simply x * -4 with extra overflows,
(and the constant was probably meant to be 0xfffc). Combined with the
shift, this simplifies to -x >> 1. Finally, clearing the low two bits
with a 32-bit mask and switching to a 32-bit type allows more efficient
code on 32-bit machines.
Signed-off-by: Mans Rullgard <mans@mansr.com>
2012-08-10 12:18:38 +01:00
Mans Rullgard
e141cf2c57
g723.1: deobfuscate an expression
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(x << 2) - x is just an optimisation of 3 * x the compiler is
perfectly capable of doing on its own.
Signed-off-by: Mans Rullgard <mans@mansr.com>
2012-08-10 12:18:38 +01:00
Mans Rullgard
e2b7c5783d
g723.1: remove unused #includes
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Signed-off-by: Mans Rullgard <mans@mansr.com>
2012-08-10 12:18:38 +01:00
Kostya Shishkov
e78e6c37ef
g723_1: clip argument for 15-bit version of normalize_bits()
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It expects maximum value to be 32767 but calculations in scale_vector()
which uses this function can give it ABS(-32768) which leads to wrong
result and thus clipping is needed.
2012-08-08 13:24:19 +02:00
Kostya Shishkov
f86b2f3661
g723_1: use all LPC vectors in formant postfilter
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Due to some mistake LPC vector for the first subframe was used for all
subframes instead of their own LPC vectors.
2012-08-08 13:23:22 +02:00
Anton Khirnov
36ef5369ee
Replace all CODEC_ID_* with AV_CODEC_ID_*
2012-08-07 16:00:24 +02:00
Kostya Shishkov
d3e0766fc0
g723_1: scale output as supposed for the case with postfilter disabled
2012-08-03 07:07:07 +02:00
Kostya Shishkov
94bfdfd6f0
g723_1: increase excitation storage by 4
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Fixed codebook mode in 5300 rate may write up to SUBFRAME_LEN + 4 and
that is considered normal by the reference decoder. Without that additional
padding it might overwrite first elements of LPC history.
2012-08-03 07:07:07 +02:00
Kostya Shishkov
802bcdcb2f
g723_1: fix upper bound parameter from inverse maximum autocorrelation
2012-08-03 07:07:07 +02:00
Kostya Shishkov
8ddadea171
g723_1: make scale_vector() behave like the reference
2012-08-03 07:07:07 +02:00
Kostya Shishkov
8772d2511a
g723_1: fix off-by-one error in normalize_bits()
2012-08-03 07:07:07 +02:00
Kostya Shishkov
7f92db14f9
g723_1: save/restore excitation with offset to store LPC history
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The same buffer with saved data is used later in LPC reconstruction, so
it should have some head space for LPC history.
2012-08-03 07:07:06 +02:00
Mohamed Naufal Basheer
55c3a4f617
G.723.1 demuxer and decoder
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Signed-off-by: Kostya Shishkov <kostya.shishkov@gmail.com>
2012-07-22 07:58:54 +02:00