FreeCalypso > hg > gsm-codec-lib
view libtwamr/if1_pack.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 | ebe499058c63 |
children |
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line source
/* * In this module we implement our function for packing AMR codec bits * from an array containing them in the codec's natural bit order * into the octet form of AMR IF1 and RFC 4867. */ #include <stdint.h> #include "tw_amr.h" #include "typedef.h" #include "namespace.h" #include "int_defs.h" #include "if1_func.h" static inline void msb_set_bit(uint8_t *buf, Word16 bn, Word16 bit) { Word16 pos_byte = bn >> 3; Word16 pos_bit = 7 - (bn & 7); if (bit) buf[pos_byte] |= (1 << pos_bit); else buf[pos_byte] &= ~(1 << pos_bit); } static void pack_bits(uint8_t *if1_bytes, const Word16 *src_bits, Word16 nbits, const uint8_t *table) { Word16 n, nb; for (n = 0; n < nbits; n++) { if (table) nb = table[n]; else nb = n; msb_set_bit(if1_bytes, n, src_bits[nb]); } } void if1_pack_bytes(enum Mode mode, const Word16 *serial_bits, uint8_t *if1_bytes) { switch (mode) { case MR475: pack_bits(if1_bytes, serial_bits, AMR_NBITS_475, sort_475); if1_bytes[11] &= 0xFE; return; case MR515: pack_bits(if1_bytes, serial_bits, AMR_NBITS_515, sort_515); if1_bytes[12] &= 0xFE; return; case MR59: pack_bits(if1_bytes, serial_bits, AMR_NBITS_59, sort_59); if1_bytes[14] &= 0xFC; return; case MR67: pack_bits(if1_bytes, serial_bits, AMR_NBITS_67, sort_67); if1_bytes[16] &= 0xFC; return; case MR74: pack_bits(if1_bytes, serial_bits, AMR_NBITS_74, sort_74); if1_bytes[18] &= 0xF0; return; case MR795: pack_bits(if1_bytes, serial_bits, AMR_NBITS_795, sort_795); if1_bytes[19] &= 0xFE; return; case MR102: pack_bits(if1_bytes, serial_bits, AMR_NBITS_102, sort_102); if1_bytes[25] &= 0xF0; return; case MR122: pack_bits(if1_bytes, serial_bits, AMR_NBITS_122, sort_122); if1_bytes[30] &= 0xF0; return; case MRDTX: pack_bits(if1_bytes, serial_bits, AMR_NBITS_SID, (const uint8_t *) 0); if1_bytes[4] &= 0xE0; return; } }