codecs: Add support for G.722 and G.726

Integrate the Spandsp library for G.722 and G.726 support. Adds support
for G.722 and all eight variants of G.726.

Note: this also fixes a crash in Qt (buffer overrun, reading too much
data) caused by confusion of the larger output buffer (resample_buff)
with the smaller input buffer (decode_buff). It was not triggered before
because the sample rate was always 8k, but with the addition of the new
codecs, a different sample rate became possible (16k).

Fix also a crash which occurs when the RTP_STREAM_DEBUG macro is enabled
and the VOIP Calls dialog is opened (the begin frame, start_fd, is not
yet known and therfore a NULL dereference could occur).

Passes testing (plays normally without bad RTP timing errors) with
SampleCaptures files: sip-rtp-g722.pcap and sip-rtp-g726.pcap. Tested
with cmake (Qt), autotools (Qt and GTK+) with ASAN enabled.

Bug: 5619
Change-Id: I5661908d193927bba50901079119eeff0c04991f
Reviewed-on: https://code.wireshark.org/review/18939
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Alexis La Goutte <alexis.lagoutte@gmail.com>
Reviewed-by: Peter Wu <peter@lekensteyn.nl>

2 files changed, 43 insertions, 22 deletions

diff --git a/codecs/G722/G722decode.c b/codecs/G722/G722decode.c
index af45520d08..fae16c0626 100644
--- a/codecs/G722/G722decode.c
+++ b/codecs/G722/G722decode.c
@@ -1,5 +1,5 @@
 /* G722decode.c
- * A-law G.711 codec
+ * G.722 codec
  *
  * Wireshark - Network traffic analyzer
  * By Gerald Combs <gerald@wireshark.org>
@@ -25,45 +25,66 @@
 #include <glib.h>
 
 #ifdef HAVE_SPANDSP
-#include "telephony.h"
-#include "g722.h"
+#include "spandsp.h"
 #include "G722decode.h"
 
-static g722_decode_state_t state;
-
 void *
 codec_g722_init(void)
 {
-    memset (&state, 0, sizeof (state));
-    g722_decode_init(&state, 64000, 0);
+    g722_decode_state_t *state;
+
+    /* Valid values for bit_rate for G.722 are 48000, 56000, 64000, but RTP/AVP
+     * profile requires 64kbps, aligned at octets. */
+    state = g722_decode_init(NULL, 64000, 0);
 
-    return NULL;
+    return state;
 }
 
 void
-codec_g722_release(void *ctx _U_)
+codec_g722_release(void *ctx)
 {
+    g722_decode_state_t *state = (g722_decode_state_t *)ctx;
+
+    if (!state) {
+        return;  /* out-of-memory; */
+    }
 
+    /* Note: replaces g722_decode_release since spandsp 20090211 */
+    g722_decode_free(state);
 }
 
-int
+unsigned
 codec_g722_get_channels(void *ctx _U_)
 {
+    /* G.722 has only one channel. */
     return 1;
 }
 
-int
+unsigned
 codec_g722_get_frequency(void *ctx _U_)
 {
-    return 64000;
+    /* Note: RTP Clock rate is 8kHz due to a historic error, but actual sampling
+     * rate is 16kHz (RFC 3551, section 4.5.2). */
+    return 16000;
 }
 
-int
-codec_g722_decode(void *ctx _U_, const void *input, int inputSizeBytes, void *output,
-        int *outputSizeBytes)
+size_t
+codec_g722_decode(void *ctx, const void *input, size_t inputSizeBytes, void *output,
+        size_t *outputSizeBytes)
 {
-    *outputSizeBytes = g722_decode(&state, output, input, inputSizeBytes);
-    return 0;
+    g722_decode_state_t *state = (g722_decode_state_t *)ctx;
+
+    if (!state) {
+        return 0;  /* out-of-memory; */
+    }
+
+    if (!output || !outputSizeBytes) {
+        return 4 * inputSizeBytes;
+    }
+
+    /* g722_decode returns the number of 16-bit samples. */
+    *outputSizeBytes = 2 * g722_decode(state, (int16_t *)output, (const uint8_t *)input, (int)inputSizeBytes);
+    return *outputSizeBytes;
 }
 
 #endif
diff --git a/codecs/G722/G722decode.h b/codecs/G722/G722decode.h
index fa30a092c0..46502632a7 100644
--- a/codecs/G722/G722decode.h
+++ b/codecs/G722/G722decode.h
@@ -1,5 +1,5 @@
 /* G722decode.h
- * Definitions for A-law G.722 codec
+ * Definitions for G.722 codec
  *
  * Wireshark - Network traffic analyzer
  * By Gerald Combs <gerald@wireshark.org>
@@ -25,10 +25,10 @@
 
 void *codec_g722_init(void);
 void  codec_g722_release(void *ctx);
-int   codec_g722_get_channels(void *ctx);
-int   codec_g722_get_frequency(void *ctx);
-int   codec_g722_decode(void *ctx, const void *input, int inputSizeBytes, void *output,
-        int *outputSizeBytes);
+unsigned codec_g722_get_channels(void *ctx);
+unsigned codec_g722_get_frequency(void *ctx);
+size_t codec_g722_decode(void *ctx, const void *input, size_t inputSizeBytes, void *output,
+        size_t *outputSizeBytes);
 
 #endif /* G722decode.h */