Koen Vos authored 13 years ago and Jean-Marc Valin committed 13 years ago

Also adds the encoder part of commit ee8adbe7 as well as a few
minor cleanups.

This is not strictly necessary because the only streams that cause these
already sound horrible, but it helps the testing process.

- Safer gain clamping for PLC
- Makes opus_decoder_get_nb_samples() report an error on invalid ToC
- Giving a free license to the text ofthe draft (not just the code)

Koen Vos authored 13 years ago and Jean-Marc Valin committed 13 years ago

Also clamps the gain to avoid forcing a float decoder to emulate the
state rescaling.

Koen Vos authored 13 years ago and Jean-Marc Valin committed 13 years ago

decoder:
- fixed incorrect scaling of filter states for the smallest quantization
  step sizes
- NLSF2A now limits the prediction gain of LPC filters

encoder:
- increased damping of LTP coefficients in LTP analysis
- increased white noise fraction in noise shaping LPC analysis
- introduced maximum total prediction gain.  Used by Burg's method to
  exit early if prediction gain is exceeded.  This improves packet
  loss robustness and numerical robustness in Burg's method
- Prefiltered signal is now in int32 Q10 domain, from int16 Q0
- Increased max number of iterations in CBR gain control loop from 5 to 6
- Removed useless code from LTP scaling control
- Optimization: smarter LPC loop unrolling
- Switched default win32 compile mode to be floating-point

resampler:
- made resampler have constant delay of 0.75 ms; removed delay
  compensation from silk code.
- removed obsolete table entries (~850 Bytes)
- increased downsampling filter order from 16 to 18/24/36 (depending on
  frequency ratio)
- reoptimized filter coefficients

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.

These fix corner cases discovered during the latest fuzzing tests.

Koen Vos authored 13 years ago and Jean-Marc Valin committed 13 years ago

- Calling the decoder for FEC when there's no LBRR should no longer crash
- There should no longer be an issue with the PLC on frame size switching

When FEC is enabled in the decoder but not included in the bit-stream
we could end up applying the PLC on a non-existant side.

Koen Vos authored 13 years ago and Jean-Marc Valin committed 13 years ago

Also some comment/warning fixes

Only encoder changes were necessary because this uses the same
"redundant frames" mechanism as SILK<->CELT switching.
This also fixes a regression introduced in 78291b27 that was
causing the encoder to go back and forth between bandwidths when
SILK wasn't ready to change.

Fix stack corruption with high rate SILK encoding added by the recent CBR changes and enable -fstack-protector-all on gcc autotools builds.

This fixes an overflow that was caused by having a huge gain

This is achieved by running the encoding process in a loop and
padding when we don't reach the exact rate. It also implements
VBR-with-cap, which means we no longer need to artificially decrease
the SILK bandwidth when it's close to the cap.

Correct encoder/decoder state mismatch and spurious state resetting in the encoder when side is reset.

Patch from Tim which corrects a glitch during mode switching tests.

Timothy B. Terriberry authored 13 years ago and Gregory Maxwell committed 13 years ago

If there is activity in a regular, side SILK frame, then it must
 be coded, so we don't need to send a mid-only flag.

Timothy B. Terriberry authored 13 years ago and Jean-Marc Valin committed 13 years ago

Neither the encoder nor decoder were incrementing the side-channel
 index for a mid-only frame.
Unfortunately, they used that index to index the VAD flags and LBRR
 flags.
This made the VAD flags for the side channel particularly useless,
 as you couldn't tell which frame a flag belonged to without
 decoding most of the packet.
It also desynched the LBRR information, as look at the wrong LBRR
 flags to decide when it had to code a mid-only flag.
If some frames were skipped in the side channel, then the last few
 VAD flags and LBRR flags would be garbage, but still get encoded.

This patch fixes this by continuing to increment nFramesDecoded or
 nFramesEncoded, even when skipping a frame in the side channel.
This makes the side-channel VAD and LBRR flags correspond to the
 correct time periods for frames greater than 20 ms.
It also fixes a bug where if DTX was not used on the packet where
 the side channel got turned off, it would never get used again
 until the encoder attempted to encode something in the side
 channel again.

Timothy B. Terriberry authored 13 years ago and Jean-Marc Valin committed 13 years ago

b24e5746 introduced changes to LastGainIndex which broke
 conditional coding for side frames after a mid-only frame (i.e.,
 in a 60 ms frame where the side is coded, not coded, then coded
 again).
These rules were a mess in general, however, because the side
 channel state kept a different nFramesDecoded count from the mid
 channel state, and had no way to tell if the prior side frame was
 coded.

This patch attempts to rationalize them by moving the conditional
 coding decision up to the top level, where all this information is
 available.
The first coded side frame after an uncoded side frame now always
 uses independent coding.
If such a frame is also not the first side frame in an Opus frame,
 then it doesn't include an LTP scaling parameter (because the LTP
 state is well-defined).

Koen Vos authored 13 years ago and Jean-Marc Valin committed 13 years ago

Input that caused the problem was:
a_Q16[] = [129763 -49346 -42032 5488 28014 -1549 -2384 -8568
3154 -5104 -1605 6291 11861 -1843 -17715 7361]

The energy "sliding window" was using double accumulation with
float multiplications. This forces the multiplications to be
double as well.

The previous commit introduced some cross-talk for the case of SILK
with one channel muted.