As suggested in https://github.com/xiph/opus/pull/83

We now try not to fold below band 17 since that produces a lot of harshness.
This mostly helps around 32-40 kb/s.

As reported by Giovanni Rovatti, this should fix some TI C55 issues.

Avoids accidental name collisions

Newer versions of MSVC are unhappy with the strategy of the build
 environment redefining "inline" (even though they don't support the
 actual keyword). Instead we define OPUS_INLINE to the right thing
 in opus_defines.h.

This is the same approach we use for restrict.

This fixes a SWB hybrid issue where band 18 isn't folded and cannot even
be folded because it's wider than band 17. This was causing noise to
be injected instead.

This reverts commit 9f407afa.

Also added 3rd clause to "master" COPYING file

Ralph Giles authored 13 years ago and Jean-Marc Valin committed 13 years ago

C reserves identifiers of the from _[A-Z]+ and we have a number of
those in the code. This patch renames the various function arguments,
MACROS and preprocessor symbols to avoid the reserved form.

It also removes the CHANNELS() macro altogether. This was a
minor optimization for TI DSP to force a mono-only build,
as were the associated local 'const' versions. Since stereo
support is manditory, it wasn't worth keeping.

Thanks to John Ridges for raising the issue, and Jean-Marc Valin
and Greg Maxwell for reviewing the changes.

Gregory Maxwell authored 13 years ago and Jean-Marc Valin committed 13 years ago

As of commit 44203907 all celt bands N>1 are even, including custom modes. In light of this, remove some pointless tests.

Gregory Maxwell authored 13 years ago and Jean-Marc Valin committed 13 years ago

The object code is unchanged (except ectest). Also reenables -Wparentheses, -Wsign-compare,
and the MSVC warnings.

The object code is unchanged.

Gregory Maxwell authored 13 years ago and Jean-Marc Valin committed 13 years ago

non-ascii characters from the source.

Got authorization from all copyright holders

Timothy B. Terriberry authored 14 years ago and Jean-Marc Valin committed 14 years ago

This fixes a number of issues for platforms with a 16-bit int, but
 by no means all of them.
The type change for ec_window (for platforms where sizeof(size_t)==2)
 will break ABI (but not API) compatibility with libsilk and libopus,
 and reduce speed on x86-64, but allows the code to work in real-mode
 DOS without using the huge memory model, which is useful for testing
 16-bit int compliance.

Timothy B. Terriberry authored 14 years ago and Jean-Marc Valin committed 14 years ago

This unifies the byte buffer, encoder, and decoder into a single
 struct.
The common encoder and decoder functions (such as ec_tell()) can
 operate on either one, simplifying code which uses both.
The precision argument to ec_tell() has been removed.
It now comes in two precisions:
  ec_tell() gives 1 bit precision in two operations, and
  ec_tell_frac() gives 1/8th bit precision in... somewhat more.
ec_{enc|dec}_bit_prob() were removed (they are no longer needed).
Some of the byte buffer access functions were made static and
 removed from the cross-module API.
All of the code in rangeenc.c and rangedec.c was merged into
 entenc.c and entdec.c, respectively, as we are no longer
 considering alternative backends.
rangeenc.c and rangede.c have been removed entirely.

This passes make check, after disabling the modes that we removed
 support for in cf5d3a8c.

Timothy B. Terriberry authored 14 years ago and Jean-Marc Valin committed 14 years ago

This stores the caps array in 32nd bits/sample instead of 1/2 bits
 scaled by LM and the channel count, which is slightly less
 less accurate for the last two bands, and much more accurate for
 all the other bands.
A constant offset is subtracted to allow it to represent values
 larger than 255 in 8 bits (the range of unoffset values is
 77...304).
In addition, this replaces the last modeline in the allocation table
 with the caps array, allowing the initial interpolation to
 allocate 8 bits/sample or more, which was otherwise impossible.

Timothy B. Terriberry authored 14 years ago and Jean-Marc Valin committed 14 years ago

9b34bd83 caused serious regressions for 240-sample frame stereo,
 because the previous qb limit was _always_ hit for two-phase
 stereo.
Two-phase stereo really does operate with a different model (for
 example, the single bit allocated to the side should really
 probably be thought of as a sign bit for qtheta, but we don't
 count it as part of qtheta's allocation).
The old code was equivalent to a separate two-phase offset of 12,
 however Greg Maxwell's testing demonstrates that 16 performs
 best.

Timothy B. Terriberry authored 14 years ago and Jean-Marc Valin committed 14 years ago

Previously, we would only split a band if it was allocated more than
 32 bits.
However, the N=4 codebook can only produce about 22.5 bits, and two
 N=2 bands combined can only produce 26 bits, including 8 bits for
 qtheta, so if we wait until we allocate 32, we're guaranteed to fall
 short.
Several of the larger bands come pretty far from filling 32 bits as
 well, though their split versions will.

Greg Maxwell also suggested adding an offset to the threshold to
 account for the inefficiency of using qtheta compared to another
 VQ dimension.
This patch uses 1 bit as a placeholder, as it's a clear
 improvement, but we may adjust this later after collecting data on
 more possibilities over more files.