The previous src/libs/g722 was spandsp's G.722 offered only under GPL-2 or
LGPL-2.1. That blocks shipping rtphone statically linked in a closed binary
(the freeware VQ for Asterisk engine) without a relink offer. Asterisk's
codecs/g722 is the same code: Steve Underwood placed his contributions in the
public domain there, and the CMU 1993 code under it is "completely
unrestricted" for any use. src/libs/g722/README.md records the provenance and
both statements.
It also fixes the decoded level. Asterisk's copy halves the encoder input and
doubles the decoder output, so streams from Asterisk and ffmpeg decode at
their original level. The old copy decoded them 6 dB too quiet (ITU-convention
streams from pjmedia 12 dB), and its encoder clipped input above -6 dBFS.
Local changes to Asterisk's files:
- the decoder saturates its output instead of casting. Asterisk's cast wraps:
259 samples in 11 s of speech peaking at -0.2 dBFS came out with the
opposite sign;
- g722.h includes <stdint.h> and maps __inline__ for MSVC (the removed
g722_inttypes.h used to).
Dropped: g722_bitstream.*, g722codec.c and three helper headers, none used.
The API is unchanged (g722_encode_init / g722_decode, same options).
Measured in vq-core (16 simultaneous replayed calls, NISQA speech):
- G.711 control calls score identically;
- normal-level G.722: SilentCall -0.09..-0.14, DeadAir-01 -0.06..-0.09, MOS
unchanged;
- loud G.722 with a clipped source now shows AmpClipping 0.02-0.03 and MOS
3.89/4.28 instead of 4.45: the codec overshoots on the clipped peaks at the
correct level, which the old -6 dB hid;
- results are identical across runs (the old decoder varied by up to 0.30 MOS).
G.722 still loses about 44% of its packets in AudioReceiver because
G722Codec::info() reports an 8 kHz sample rate for 16 kHz audio. That is fixed
separately.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Lets a host inject e.g. NullInputDevice before start() so the default
platform microphone is not constructed, avoiding the RECORD_AUDIO
permission on Android while leaving the real speaker output in place.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Dmytro Bogovych
dmytro.bogovych