Displaying 10 results from an estimated 10 matches for "flac__max_extra_residual_bps".
2014 Jun 19
7
[PATCH] stream_encoder : Improve selection of residual accumulator width
...libFLAC/include/private/stream_encoder.h
+++ b/src/libFLAC/include/private/stream_encoder.h
@@ -37,6 +37,12 @@
#include <config.h>
#endif
+/*
+ * This is used to avoid overflow with unusual signals in 32-bit
+ * accumulator in the *precompute_partition_info_sums_* functions.
+ */
+#define FLAC__MAX_EXTRA_RESIDUAL_BPS 4
+
#if (defined FLAC__CPU_IA32 || defined FLAC__CPU_X86_64) && defined FLAC__HAS_X86INTRIN
#include "private/cpu.h"
#include "FLAC/format.h"
diff --git a/src/libFLAC/stream_encoder.c b/src/libFLAC/stream_encoder.c
index e64ece2..8928a39 100644
--- a/src/libFLAC/strea...
2014 Jun 19
1
[PATCH] stream_encoder : Improve selection of residual accumulator width
...l_from_qlp_coefficients_16bit(...);
> else
> encoder->private_->local_lpc_compute_residual_from_qlp_coefficients(...);
> else
> encoder->private_->local_lpc_compute_residual_from_qlp_coefficients_64bit(...);
Yes, it's the same check. Assuming residual can be at most
FLAC__MAX_EXTRA_RESIDUAL_BPS bits wider than subframe_bps, I think it
should be:
if(subframe_bps + qlp_coeff_precision + FLAC__bitmath_ilog2(order) + FLAC__MAX_EXTRA_RESIDUAL_BPS - 1 <= 32)
if(subframe_bps + FLAC__MAX_EXTRA_RESIDUAL_BPS <= 16 && qlp_coeff_precision <= 16)
> vs. read_subframe_lpc_():
>...
2014 Jun 20
2
[PATCH] stream_encoder : Improve selection of residual accumulator width
On Fri, Jun 20, 2014 at 01:21:03PM +0400, lvqcl wrote:
> Miroslav Lichvar ?????:
>
> > +/*
> > + * This is used to avoid overflow with unusual signals in 32-bit
> > + * accumulator in the *precompute_partition_info_sums_* functions.
> > + */
> > +#define FLAC__MAX_EXTRA_RESIDUAL_BPS 4
>
> > + /* WATCHOUT: "+ bps + FLAC__MAX_EXTRA_RESIDUAL_BPS" is the maximum
> > + * assumed size of the average residual magnitude */
> > + if(FLAC__bitmath_ilog2(default_partition_samples) + bps + FLAC__MAX_EXTRA_RESIDUAL_BPS < 32) {
>
> From FLAC__f...
2014 Jun 29
4
[PATCH] stream_encoder : Improve selection of residual accumulator width
...order, residual[]) function.
And indeed, max. possible residual value is 16 times bigger than max. value
in data[] array:
residual[i] = data[i] - 4*data[i-1] + 6*data[i-2] - 4*data[i-3] + data[i-4]
16 == 2^4, so max. bps value for residual[] is equal to max. bps for data[] + 4.
The value of FLAC__MAX_EXTRA_RESIDUAL_BPS == 4 is enough to fix this problem
with FLAC__fixed_compute_residual().
2015 May 23
2
A patch for precompute_partition_info_sums_()
...h a preliminary version of a patch for precompute_partition_info_sums_()
function that should accelerate encoding of 24-bit input data.
1) SSE2, SSSE3 and AVX2 versions of this function should be updated, too
2) the patch also changes
if(FLAC__bitmath_ilog2(default_partition_samples) + bps + FLAC__MAX_EXTRA_RESIDUAL_BPS < 32)
into (in effect)
if(FLAC__bitmath_ilog2(default_partition_samples) + bps + FLAC__MAX_EXTRA_RESIDUAL_BPS <= 32)
So, should the value of FLAC__MAX_EXTRA_RESIDUAL_BPS be increased (to 5? or to 6?)
3) any comments?
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2014 Jun 29
0
[PATCH] stream_encoder : Improve selection of residual accumulator width
...; And indeed, max. possible residual value is 16 times bigger than max. value
> in data[] array:
>
> residual[i] = data[i] - 4*data[i-1] + 6*data[i-2] - 4*data[i-3] + data[i-4]
>
> 16 == 2^4, so max. bps value for residual[] is equal to max. bps for data[] + 4.
> The value of FLAC__MAX_EXTRA_RESIDUAL_BPS == 4 is enough to fix this problem
> with FLAC__fixed_compute_residual().
On the other hand, it is possible to set FLAC__MAX_EXTRA_RESIDUAL_BPS
to 0, and change evaluate_fixed_subframe_() function instead: in the call
of find_best_partition_order_() function, replace subframe_bps
with subframe...
2015 May 18
1
A condition in precompute_partition_info_sums_()
...31 Mar 2007) adds the following conditional:
if(FLAC__bitmath_ilog2(default_partition_samples) + bps < 32)
And the commit http://git.xiph.org/?p=flac.git;a=commitdiff;h=f081524c19eeafd08f4db6ee5d52a9634c60f475
has this:
if(FLAC__bitmath_ilog2(default_partition_samples) + bps + FLAC__MAX_EXTRA_RESIDUAL_BPS < 32)
The question is: why ... < 32, not ... <= 32 ?
Basically we want to know the number of bits that is necessary to represent
the value of (default_partition_samples * max_value_of_residual) product.
Let's assume that the bitness of the residual signal is N. The minimum value
is...
2014 Jun 30
2
[PATCH] stream_encoder : Improve selection of residual accumulator width
...sidual value is 16 times bigger than max. value
> > in data[] array:
> >
> > residual[i] = data[i] - 4*data[i-1] + 6*data[i-2] - 4*data[i-3] + data[i-4]
> >
> > 16 == 2^4, so max. bps value for residual[] is equal to max. bps for data[] + 4.
> > The value of FLAC__MAX_EXTRA_RESIDUAL_BPS == 4 is enough to fix this problem
> > with FLAC__fixed_compute_residual().
>
>
> On the other hand, it is possible to set FLAC__MAX_EXTRA_RESIDUAL_BPS
> to 0, and change evaluate_fixed_subframe_() function instead: in the call
> of find_best_partition_order_() function, repl...
2014 Jun 19
5
[PATCH] stream_encoder : Improve selection of residual accumulator width
On Thu, Jun 19, 2014 at 03:30:22PM +0400, lvqcl wrote:
> BTW, what can you say about the following place in stream_decoder.c
> in read_subframe_lpc_() function:
>
> /*@@@@@@ technically not pessimistic enough, should be more like
> if( (FLAC__uint64)order * ((((FLAC__uint64)1)<<bps)-1) * ((1<<subframe->qlp_coeff_precision)-1) < (((FLAC__uint64)-1)
2015 Sep 26
9
Supporting 32 bit data
Hi all,
I just noticed this:
https://sourceforge.net/p/flac/feature-requests/91/
a request for support of 32 bit audio data. The request has been around
since 2008.
Had two inial impressions:
* Would adding this break brackwards compatibility too badly? Obviously
decoding of 32 bit encoded data would not work with older versions of
flac.
* This is nuts. 24 bits has a dynamic range of