FreeCalypso > hg > gsm-codec-lib
view frtest/max-out.c @ 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 | a5ffec18e4cd |
children |
line wrap: on
line source
/* * This program reads an extended-libgsm binary file (which must be in FR * codec format, not EFR) and performs the following processing, in this * order: * * 1) dumps every frame in human-readable form just like gsmrec-dump; * 2) passes the frame stream through our DTX Rx preprocessor; * 3) dumps the output from the preprocessor; * 4) feeds this output to the standard 06.10 decoder (libgsm); * 5) finds the highest-magnitude PCM sample in the decoder output and * reports this maximum output magnitude. * * This program is intended to serve as a debug aid, for troubleshooting * of our libgsmfrp+libgsm stack. */ #include <stdio.h> #include <stdint.h> #include <stdlib.h> #include <gsm.h> #include "../libgsmfrp/gsm_fr_preproc.h" #include "../libtest/binreader.h" main(argc, argv) char **argv; { FILE *binf; gsm dec_state; struct gsmfr_preproc_state *pp_state; unsigned frame_index; uint8_t frame[BINFILE_MAX_FRAME]; int16_t pcm[160]; gsm_signal fr_params[76]; int rc, bfi, taf; int i, j, n; unsigned samp_abs, samp_max; if (argc != 2) { fprintf(stderr, "usage: %s bin-stream-file\n", argv[0]); exit(1); } binf = fopen(argv[1], "r"); if (!binf) { perror(argv[1]); exit(1); } dec_state = gsm_create(); if (!dec_state) { fprintf(stderr, "gsm_create() failed!\n"); exit(1); } pp_state = gsmfr_preproc_create(); if (!pp_state) { fprintf(stderr, "gsmfr_preproc_create() failed!\n"); exit(1); } for (frame_index = 0; ; frame_index++) { rc = binfile_read_frame(binf, frame); if (rc < 0) { fprintf(stderr, "error: garbage in %s\n", argv[1]); exit(1); } if (!rc) break; printf("#%u: ", frame_index); switch (frame[0] & 0xF0) { case 0xB0: bfi = 1; taf = frame[1] & 1; printf("BFI TAF=%u\n", taf); break; case 0xD0: bfi = 0; fputs("FR", stdout); gsm_explode(dec_state, frame, fr_params); n = 0; for (i = 0; i < 8; i++) printf(" %d", fr_params[n++]); putchar('\n'); for (i = 0; i < 4; i++) { putchar(' '); for (j = 0; j < 17; j++) printf(" %d", fr_params[n++]); putchar('\n'); } break; default: fprintf(stderr, "error: %s is not in FR codec format\n", argv[1]); exit(1); } if (bfi) gsmfr_preproc_bfi(pp_state, taf, frame); else gsmfr_preproc_good_frame(pp_state, frame); fputs("Xform:", stdout); gsm_explode(dec_state, frame, fr_params); n = 0; for (i = 0; i < 8; i++) printf(" %d", fr_params[n++]); putchar('\n'); for (i = 0; i < 4; i++) { putchar(' '); for (j = 0; j < 17; j++) printf(" %d", fr_params[n++]); putchar('\n'); } gsm_decode(dec_state, frame, pcm); samp_max = 0; for (i = 0; i < 160; i++) { if (pcm[i] >= 0) samp_abs = pcm[i]; else samp_abs = -pcm[i]; if (samp_abs > samp_max) samp_max = samp_abs; } printf(" MAX=%u\n", samp_max); } exit(0); }