[Asterisk-code-review] audiohook.c: Substitute silence for unavailable audio frames (...asterisk[16])
George Joseph
asteriskteam at digium.com
Wed Aug 21 06:59:06 CDT 2019
George Joseph has submitted this change and it was merged. ( https://gerrit.asterisk.org/c/asterisk/+/12736 )
Change subject: audiohook.c: Substitute silence for unavailable audio frames
......................................................................
audiohook.c: Substitute silence for unavailable audio frames
There are 4 scenarios to consider when capturing audio from a channel
with an audiohook:
1. There is no rx and no tx audio, so return nothing.
2. There is rx but no tx audio, so return rx.
3. There is tx but no rx audio, so return tx.
4. There is rx and tx audio, so mix them and return.
The file passed as the primary argument to MixMonitor will be written to
in scenarios 2, 3, and 4. However, if you pass the r() and t() options
to MixMonitor, a frame will only be written to the r() file if there was
rx audio and a frame will only be written to the t() file if there was
tx audio.
If you subsequently take the r() and t() files and try to mix them, the
sides of the conversation will 'drift' and be non-representative of the
user experience.
This patch adds a new 'S' option to MixMonitor that injects a frame of
silence on either the r() side or the t() side of the channel so that
when later mixed, there is no such drift.
Change-Id: Ibf5ed73a811087727bd561a89a59f4447b4ee20e
---
M apps/app_mixmonitor.c
A doc/CHANGES-staging/mixmonitor-s-option.txt
M include/asterisk/audiohook.h
M main/audiohook.c
4 files changed, 32 insertions(+), 1 deletion(-)
Approvals:
Benjamin Keith Ford: Looks good to me, but someone else must approve
George Joseph: Looks good to me, approved; Approved for Submit
diff --git a/apps/app_mixmonitor.c b/apps/app_mixmonitor.c
index af29492..6746c47 100644
--- a/apps/app_mixmonitor.c
+++ b/apps/app_mixmonitor.c
@@ -115,6 +115,11 @@
Like with the basic filename argument, if an absolute path isn't given, it will create
the file in the configured monitoring directory.</para>
</option>
+ <option name="S">
+ <para>When combined with the <replaceable>r</replaceable> or <replaceable>t</replaceable>
+ option, inserts silence when necessary to maintain synchronization between the receive
+ and transmit audio streams.</para>
+ </option>
<option name="i">
<argument name="chanvar" required="true" />
<para>Stores the MixMonitor's ID on this channel variable.</para>
@@ -347,7 +352,8 @@
MUXFLAG_VMRECIPIENTS = (1 << 10),
MUXFLAG_BEEP = (1 << 11),
MUXFLAG_BEEP_START = (1 << 12),
- MUXFLAG_BEEP_STOP = (1 << 13)
+ MUXFLAG_BEEP_STOP = (1 << 13),
+ MUXFLAG_RWSYNC = (1 << 14),
};
enum mixmonitor_args {
@@ -359,6 +365,7 @@
OPT_ARG_UID,
OPT_ARG_VMRECIPIENTS,
OPT_ARG_BEEP_INTERVAL,
+ OPT_ARG_RWSYNC,
OPT_ARG_ARRAY_SIZE, /* Always last element of the enum */
};
@@ -375,6 +382,7 @@
AST_APP_OPTION_ARG('t', MUXFLAG_WRITE, OPT_ARG_WRITENAME),
AST_APP_OPTION_ARG('i', MUXFLAG_UID, OPT_ARG_UID),
AST_APP_OPTION_ARG('m', MUXFLAG_VMRECIPIENTS, OPT_ARG_VMRECIPIENTS),
+ AST_APP_OPTION_ARG('S', MUXFLAG_RWSYNC, OPT_ARG_RWSYNC),
});
struct mixmonitor_ds {
@@ -962,6 +970,9 @@
}
ast_set_flag(&mixmonitor->audiohook, AST_AUDIOHOOK_TRIGGER_SYNC);
+ if ((ast_test_flag(mixmonitor, MUXFLAG_RWSYNC))) {
+ ast_set_flag(&mixmonitor->audiohook, AST_AUDIOHOOK_SUBSTITUTE_SILENCE);
+ }
if (readvol)
mixmonitor->audiohook.options.read_volume = readvol;
diff --git a/doc/CHANGES-staging/mixmonitor-s-option.txt b/doc/CHANGES-staging/mixmonitor-s-option.txt
new file mode 100644
index 0000000..d08b86d
--- /dev/null
+++ b/doc/CHANGES-staging/mixmonitor-s-option.txt
@@ -0,0 +1,7 @@
+Subject: app_mixmonitor
+
+An option 'S' has been added to MixMonitor. If used in combination with
+the r() and/or t() options, if a frame is available to write to one of
+those files but not the other, a frame of silence if written to the file
+that does not have an audio frame. This should prevent the two files
+from "drifting" when mixed after the fact.
diff --git a/include/asterisk/audiohook.h b/include/asterisk/audiohook.h
index cae8cc0..1252e36 100644
--- a/include/asterisk/audiohook.h
+++ b/include/asterisk/audiohook.h
@@ -64,6 +64,8 @@
AST_AUDIOHOOK_MUTE_READ = (1 << 5), /*!< audiohook should be mute frames read */
AST_AUDIOHOOK_MUTE_WRITE = (1 << 6), /*!< audiohook should be mute frames written */
AST_AUDIOHOOK_COMPATIBLE = (1 << 7), /*!< is the audiohook native slin compatible */
+
+ AST_AUDIOHOOK_SUBSTITUTE_SILENCE = (1 << 8), /*!< Substitute silence for missing audio */
};
enum ast_audiohook_init_flags {
diff --git a/main/audiohook.c b/main/audiohook.c
index 04a379f..4db32ea 100644
--- a/main/audiohook.c
+++ b/main/audiohook.c
@@ -338,6 +338,17 @@
frame.subclass.format = ast_format_cache_get_slin_by_rate(audiohook->hook_internal_samp_rate);
+ /* Should we substitute silence if one side lacks audio? */
+ if ((ast_test_flag(audiohook, AST_AUDIOHOOK_SUBSTITUTE_SILENCE))) {
+ if (read_reference && !read_buf && write_buf) {
+ read_buf = buf1;
+ memset(buf1, 0, sizeof(buf1));
+ } else if (write_reference && read_buf && !write_buf) {
+ write_buf = buf2;
+ memset(buf2, 0, sizeof(buf2));
+ }
+ }
+
/* Basically we figure out which buffer to use... and if mixing can be done here */
if (read_buf && read_reference) {
frame.data.ptr = read_buf;
--
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Gerrit-Project: asterisk
Gerrit-Branch: 16
Gerrit-Change-Id: Ibf5ed73a811087727bd561a89a59f4447b4ee20e
Gerrit-Change-Number: 12736
Gerrit-PatchSet: 4
Gerrit-Owner: Sean Bright <sean.bright at gmail.com>
Gerrit-Reviewer: Benjamin Keith Ford <bford at digium.com>
Gerrit-Reviewer: Friendly Automation
Gerrit-Reviewer: George Joseph <gjoseph at digium.com>
Gerrit-Reviewer: Joshua Colp <jcolp at digium.com>
Gerrit-MessageType: merged
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