FreeCalypso > hg > gsm-codec-lib
view amrconv/bitmanip.c @ 477:4c9222d95647
libtwamr encoder: always emit frame->mode = mode;
In the original implementation of amr_encode_frame(), the 'mode' member
of the output struct was set to 0xFF if the output frame type is TX_NO_DATA.
This design was made to mimic the mode field (16-bit word) being set to
0xFFFF (or -1) in 3GPP test sequence format - but nothing actually depends
on this struct member being set in any way, and amr_frame_to_tseq()
generates the needed 0xFFFF on its own, based on frame->type being equal
to TX_NO_DATA.
It is simpler and more efficient to always set frame->mode to the actual
encoding mode in amr_encode_frame(), and this new behavior has already
been documented in doc/AMR-library-API description in anticipation of
the present change.
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Sat, 18 May 2024 22:30:42 +0000 |
parents | b092a510141e |
children |
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/* * This module provides two utility functions that serve as building blocks * for frame bit reordering operations. */ #include <stdint.h> msb_get_bit(buf, bn) uint8_t *buf; { int pos_byte = bn >> 3; int pos_bit = 7 - (bn & 7); return (buf[pos_byte] >> pos_bit) & 1; } msb_set_bit(buf, bn, bit) uint8_t *buf; { int pos_byte = bn >> 3; int pos_bit = 7 - (bn & 7); if (bit) buf[pos_byte] |= (1 << pos_bit); else buf[pos_byte] &= ~(1 << pos_bit); }