plugins/codecs/G722/G722decode.c

   1 /* G722decode.c
   2  * G.722 codec
   3  *
   4  * Wireshark - Network traffic analyzer
   5  * By Gerald Combs <gerald@wireshark.org>
   6  * Copyright 1998 Gerald Combs
   7  *
   8  * SPDX-License-Identifier: GPL-2.0-or-later
   9  */
  10
  11 #include "config.h"
  12
  13 #include <glib.h>
  14
  15 #include "spandsp.h"
  16 #include "wsutil/codecs.h"
  17 #include "ws_attributes.h"
  18
  19 void codec_register_g722(void);
  20
  21 static void *
  22 codec_g722_init(codec_context_t *ctx _U_)
  23 {
  24     g722_decode_state_t *state;
  25
  26     /* Valid values for bit_rate for G.722 are 48000, 56000, 64000, but RTP/AVP
  27      * profile requires 64kbps, aligned at octets. */
  28     state = g722_decode_init(NULL, 64000, 0);
  29
  30     return state;
  31 }
  32
  33 static void
  34 codec_g722_release(codec_context_t *ctx)
  35 {
  36     g722_decode_state_t *state = (g722_decode_state_t *)ctx->priv;
  37
  38     if (!state) {
  39         return;  /* out-of-memory; */
  40     }
  41
  42     /* Note: replaces g722_decode_release since SpanDSP 20090211 */
  43     g722_decode_free(state);
  44 }
  45
  46 static unsigned
  47 codec_g722_get_channels(codec_context_t *ctx _U_)
  48 {
  49     /* G.722 has only one channel. */
  50     return 1;
  51 }
  52
  53 static unsigned
  54 codec_g722_get_frequency(codec_context_t *ctx _U_)
  55 {
  56     /* Note: RTP Clock rate is 8kHz due to a historic error, but actual sampling
  57      * rate is 16kHz (RFC 3551, section 4.5.2). */
  58     return 16000;
  59 }
  60
  61 static size_t
  62 codec_g722_decode(codec_context_t *ctx, const void *inputBytes,
  63         size_t inputBytesSize, void *outputSamples, size_t *outputSamplesSize)
  64 {
  65     g722_decode_state_t *state = (g722_decode_state_t *)ctx->priv;
  66
  67     if (!state) {
  68         return 0;  /* out-of-memory; */
  69     }
  70
  71     if (!outputSamples || !outputSamplesSize) {
  72         return 4 * inputBytesSize;
  73     }
  74
  75     /* g722_decode returns the number of 16-bit samples. */
  76     *outputSamplesSize = 2 * g722_decode(state, (int16_t *)outputSamples,
  77         (const uint8_t *)inputBytes, (int)inputBytesSize);
  78     return *outputSamplesSize;
  79 }
  80
  81 void
  82 codec_register_g722(void)
  83 {
  84     register_codec("g722", codec_g722_init, codec_g722_release,
  85             codec_g722_get_channels, codec_g722_get_frequency, codec_g722_decode);
  86 }
  87
  88 /*
  89  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
  90  *
  91  * Local variables:
  92  * c-basic-offset: 4
  93  * tab-width: 8
  94  * indent-tabs-mode: nil
  95  * End:
  96  *
  97  * vi: set shiftwidth=4 tabstop=8 expandtab:
  98  * :indentSize=4:tabSize=8:noTabs=true:
  99  */