MDL-83570 tiny_recordrtc: Turn the audio bitrate input to Select field

The current code may have a bug. If users set the audio bit rate to
a non-supported value, such as 1000,
Firefox will display an error in the console,
while Chrome will create the recorded audio file successfully,
but it will have no sound. I tested this on Ubuntu 24.04.

The minimum bit rate threshold varies depending on the audio format.
During my tests with Firefox version 131.0.3, which uses
the audio/Ogg format, I found that the minimum supported value
is 24000. In Chrome 129.0.6668.70, which uses the audio/MP4 format,
the minimum supported value is 2400.

Due to these differences, I decided to change the input from
a text field to a select field, offering options that support both
Ogg and MP4 audio formats.

The database conversion for the old value has been provided in
the lib/db/upgrade.php. The script will find the closest match to
the current data and update it accordingly.

lib/editor/tiny/plugins/recordrtc/classes/constants.php

@@ -39,4 +39,7 @@ class constants {
 
     /** @var string TINYRECORDRTC_SCREEN_FHD The Full-HD screen-sharing resolution. */
     public const TINYRECORDRTC_SCREEN_FHD = '1920,1080';
+
+    /** @var array TINYRECORDRTC_AUDIO_BITRATES The audio bitrate options. */
+    public const TINYRECORDRTC_AUDIO_BITRATES = [24000, 32000, 48000, 64000, 96000, 128000, 160000, 192000, 256000, 320000];
 }

lib/editor/tiny/plugins/recordrtc/db/upgrade.php

@@ -45,6 +45,24 @@ function xmldb_tiny_recordrtc_upgrade($oldversion) {
         upgrade_plugin_savepoint(true, 2024042400, 'tiny', 'recordrtc');
     }
 
+    if ($oldversion < 2024112000) {
+        // The input bitrate to be converted.
+        $currentbitrate = get_config('tiny_recordrtc', 'audiobitrate');
+
+        // Supported bitrates.
+        $supportedbitrates = \tiny_recordrtc\constants::TINYRECORDRTC_AUDIO_BITRATES;
+
+        // Find the nearest value.
+        usort($supportedbitrates, fn($a, $b) => abs($currentbitrate - $a) <=> abs($currentbitrate - $b));
+        $nearestbitrate = $supportedbitrates[0];
+
+        // Update the bitrate setting with the nearest supported bitrate.
+        set_config('audiobitrate', $nearestbitrate, 'tiny_recordrtc');
+
+        // Main savepoint reached.
+        upgrade_main_savepoint(true, 2024112000);
+    }
+
     // Automatically generated Moodle v4.5.0 release upgrade line.
     // Put any upgrade step following this.
 

lib/editor/tiny/plugins/recordrtc/lang/en/tiny_recordrtc.php

@@ -54,6 +54,7 @@ $string['gumtype'] = 'Tried to get stream from the webcam/microphone/screen, but
 $string['gumtype_title'] = 'No constraints specified';
 $string['insecurealert'] = 'Your browser might not allow this plugin to work unless it is used either over HTTPS or from localhost.';
 $string['insecurealert_title'] = 'Insecure connection!';
+$string['kbrate'] = '{$a} kb/s';
 $string['maxfilesizehit'] = 'You have reached the maximum size limit for file uploads.';
 $string['maxfilesizehit_title'] = 'Recording stopped';
 $string['norecordingfound'] = 'Something has gone wrong. Nothing has been recorded.';

lib/editor/tiny/plugins/recordrtc/settings.php

@@ -61,8 +61,18 @@ if ($ADMIN->fulltree) {
     // Audio bitrate.
     $name = get_string('audiobitrate', 'tiny_recordrtc');
     $desc = get_string('audiobitrate_desc', 'tiny_recordrtc');
-    $default = '128000';
-    $setting = new admin_setting_configtext('tiny_recordrtc/audiobitrate', $name, $desc, $default, PARAM_INT, 8);
+    $options = [];
+    foreach (\tiny_recordrtc\constants::TINYRECORDRTC_AUDIO_BITRATES as $rate) {
+        $kbrate = $rate / 1000;
+        $options[$rate] = get_string('kbrate', 'tiny_recordrtc', $kbrate);
+    }
+    $setting = new admin_setting_configselect(
+        name: 'tiny_recordrtc/audiobitrate',
+        visiblename: $name,
+        description: $desc,
+        defaultsetting: \tiny_recordrtc\constants::TINYRECORDRTC_AUDIO_BITRATES[5],
+        choices: $options,
+    );
     $settings->add($setting);
 
     // Video bitrate.

lib/editor/tiny/plugins/recordrtc/version.php

@@ -24,6 +24,6 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$plugin->version   = 2024100700;
+$plugin->version   = 2024112000;
 $plugin->requires  = 2024100100;
 $plugin->component = 'tiny_recordrtc';