FreeCalypso > hg > gsm-codec-lib
view libgsmefr/enc_state.h @ 242:f081a6850fb5
libgsmfrp: new refined implementation
The previous implementation exhibited the following defects,
which are now fixed:
1) The last received valid SID was cached forever for the purpose of
handling future invalid SIDs - we could have received some valid
SID ages ago, then lots of speech or NO_DATA, and if we then get
an invalid SID, we would resurrect the last valid SID from ancient
history - a bad design. In our new design, we handle invalid SID
based on the current state, much like BFI.
2) GSM 06.11 spec says clearly that after the second lost SID
(received BFI=1 && TAF=1 in CN state) we need to gradually decrease
the output level, rather than jump directly to emitting silence
frames - we previously failed to implement such logic.
3) Per GSM 06.12 section 5.2, Xmaxc should be the same in all 4 subframes
in a SID frame. What should we do if we receive an otherwise valid
SID frame with different Xmaxc? Our previous approach would
replicate this Xmaxc oddity in every subsequent generated CN frame,
which is rather bad. In our new design, the very first CN frame
(which can be seen as a transformation of the SID frame itself)
retains the original 4 distinct Xmaxc, but all subsequent CN frames
are based on the Xmaxc from the last subframe of the most recent SID.
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Tue, 09 May 2023 05:16:31 +0000 |
parents | 77803ce2cc22 |
children |
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/* * In this header file we define our encoder state structure. * This encoder state structure is internal to libgsmefr, * NOT part of our external public interface! */ struct EFR_encoder_state { /* from coder.c */ Word16 dtx_mode; /* from cod_12k2.c */ Word16 old_speech[L_TOTAL]; Word16 old_wsp[L_FRAME + PIT_MAX]; Word16 old_exc[L_FRAME + PIT_MAX + L_INTERPOL]; Word16 ai_zero[L_SUBFR + MP1]; Word16 hvec[L_SUBFR * 2]; Word16 lsp_old[M]; Word16 lsp_old_q[M]; Word16 mem_syn[M]; Word16 mem_w0[M]; Word16 mem_w[M]; Word16 mem_err[M + L_SUBFR]; /* from levinson.c */ Word16 old_A[M + 1]; /* from pre_proc.c */ struct preproc_state { Word16 y2_hi; Word16 y2_lo; Word16 y1_hi; Word16 y1_lo; Word16 x0; Word16 x1; } pre_proc; /* from q_plsf_5.c */ Word16 past_r2_q[M]; Word16 lsf_p_CN[M]; /* from q_gains.c */ Word16 past_qua_en[4]; Word16 pred[4]; Word16 gcode0_CN; /* from dtx.c */ Word16 txdtx_ctrl; Word16 CN_excitation_gain; Word32 L_pn_seed_tx; Word16 txdtx_hangover; Word16 txdtx_N_elapsed; Word16 old_CN_mem_tx[6]; Word16 buf_p_tx; Word16 lsf_old_tx[DTX_HANGOVER][M]; Word16 gain_code_old_tx[4 * DTX_HANGOVER]; /* from vad.c */ struct vad_state { Word16 rvad[9]; Word16 scal_rvad; Pfloat thvad; Word32 L_sacf[27]; Word32 L_sav0[36]; Word16 pt_sacf; Word16 pt_sav0; Word32 L_lastdm; Word16 adaptcount; Word16 burstcount; Word16 hangcount; Word16 oldlagcount; Word16 veryoldlagcount; Word16 oldlag; } vad; Word16 ptch; };