116 lines
3.0 KiB
C
116 lines
3.0 KiB
C
/* G726decode.c
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* G.726 codec
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* SPDX-License-Identifier: GPL-2.0-or-later*/
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#include "config.h"
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#include <glib.h>
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#ifdef HAVE_SPANDSP
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#include "spandsp.h"
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#include "G726decode.h"
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#include "ws_attributes.h"
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typedef struct _g726_codec_ctx {
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g726_state_t *state;
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int bit_rate;
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} g726_codec_ctx;
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static inline void *
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codec_g726_init(int bit_rate, int packing)
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{
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g726_state_t *decoder = g726_init(NULL, bit_rate, G726_ENCODING_LINEAR, packing);
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if (!decoder) {
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return NULL; /* out-of-memory; */
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}
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g726_codec_ctx *state = g_new(g726_codec_ctx, 1);
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state->state = decoder;
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state->bit_rate = bit_rate;
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return state;
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}
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void *codec_g726_16_init(void) { return codec_g726_init(16000, G726_PACKING_RIGHT); }
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void *codec_g726_24_init(void) { return codec_g726_init(24000, G726_PACKING_RIGHT); }
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void *codec_g726_32_init(void) { return codec_g726_init(32000, G726_PACKING_RIGHT); }
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void *codec_g726_40_init(void) { return codec_g726_init(40000, G726_PACKING_RIGHT); }
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void *codec_aal2_g726_16_init(void) { return codec_g726_init(16000, G726_PACKING_LEFT); }
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void *codec_aal2_g726_24_init(void) { return codec_g726_init(24000, G726_PACKING_LEFT); }
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void *codec_aal2_g726_32_init(void) { return codec_g726_init(32000, G726_PACKING_LEFT); }
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void *codec_aal2_g726_40_init(void) { return codec_g726_init(40000, G726_PACKING_LEFT); }
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void
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codec_g726_release(void *ctx)
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{
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g726_codec_ctx *state = (g726_codec_ctx *)ctx;
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if (!state) {
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return; /* out-of-memory; */
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}
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/* Note: replaces g726_release since SpanDSP 20090211 */
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g726_free(state->state);
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g_free(state);
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}
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unsigned
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codec_g726_get_channels(void *ctx _U_)
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{
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return 1;
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}
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unsigned
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codec_g726_get_frequency(void *ctx _U_)
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{
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return 8000;
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}
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size_t
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codec_g726_decode(void *ctx, const void *input, size_t inputSizeBytes, void *output,
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size_t *outputSizeBytes)
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{
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g726_codec_ctx *state = (g726_codec_ctx *)ctx;
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if (!state) {
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return 0; /* out-of-memory; */
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}
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if (!output || !outputSizeBytes) {
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/*
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* sample rate 8kHz, for bitrate 16kHz we have 16/8 = 2 bits/sample, so
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* 1 input byte (8 bits) will expand to four 16-bit samples. Likewise,
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* for bitrate 40kHz we have 40/8 = 5 bits/sample. Alternatively:
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* bitsPerSample = bitRate / sampleRate (8kHz).
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* outputBytes = (inputBits / bitsPerSample) * sizeof(sample)
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*/
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return inputSizeBytes * 8 / (state->bit_rate / 8000) * 2;
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}
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/* g726_decode returns the number of 16-bit samples. */
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*outputSizeBytes = 2 * g726_decode(state->state, (int16_t *)output, (const uint8_t *) input, (int)inputSizeBytes);
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return *outputSizeBytes;
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}
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#endif
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/*
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* Editor modelines - http://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 4
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* tab-width: 8
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* indent-tabs-mode: nil
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* End:
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*
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* vi: set shiftwidth=4 tabstop=8 expandtab:
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* :indentSize=4:tabSize=8:noTabs=true:
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*/
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