From 1f535826a296556252d5c0c8da5cb6aaa8fec656 Mon Sep 17 00:00:00 2001
From: jade <101148768+jadeddelta@users.noreply.github.com>
Date: Fri, 31 Jan 2025 17:29:37 -0500
Subject: [PATCH] add default `mimeType` if none is specified

---
 .changeset/sixty-ears-tan.md                        | 5 +++++
 docs/reference/jspsych-pluginAPI.md                 | 3 +--
 examples/extension-record-video.html                | 5 ++++-
 packages/jspsych/src/modules/plugin-api/MediaAPI.ts | 6 ++++++
 4 files changed, 16 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/sixty-ears-tan.md

diff --git a/.changeset/sixty-ears-tan.md b/.changeset/sixty-ears-tan.md
new file mode 100644
index 00000000..0404a468
--- /dev/null
+++ b/.changeset/sixty-ears-tan.md
@@ -0,0 +1,5 @@
+---
+"jspsych": patch
+---
+
+add a default `mimeType` of `"video/webm" to `initializeCameraRecorder()`
diff --git a/docs/reference/jspsych-pluginAPI.md b/docs/reference/jspsych-pluginAPI.md
index b7fa6005..81b036ef 100644
--- a/docs/reference/jspsych-pluginAPI.md
+++ b/docs/reference/jspsych-pluginAPI.md
@@ -507,8 +507,7 @@ None.
 
 #### Description
 
-Generates a `MediaRecorder` object from provided `MediaStream` and stores this for access via [`getCameraRecorder()`](#getcamerarecorder).
-
+Generates a `MediaRecorder` object from provided `MediaStream` and stores this for access via [`getCameraRecorder()`](#getcamerarecorder). By default, `mimeType` is set to `"video/webm"`.
 #### Example
 
 ```javascript
diff --git a/examples/extension-record-video.html b/examples/extension-record-video.html
index 29cf9ee5..5008fd0e 100644
--- a/examples/extension-record-video.html
+++ b/examples/extension-record-video.html
@@ -13,7 +13,10 @@
     const jsPsych = initJsPsych({
         extensions: [
             {type: jsPsychExtensionRecordVideo}
-        ]
+        ],
+        on_finish: function() {
+          jsPsych.data.displayData();
+        }
     });
 
     const initCamera = {
diff --git a/packages/jspsych/src/modules/plugin-api/MediaAPI.ts b/packages/jspsych/src/modules/plugin-api/MediaAPI.ts
index 6dabb447..de50e0af 100644
--- a/packages/jspsych/src/modules/plugin-api/MediaAPI.ts
+++ b/packages/jspsych/src/modules/plugin-api/MediaAPI.ts
@@ -284,6 +284,12 @@ export class MediaAPI {
   private camera_recorder: MediaRecorder = null;
 
   initializeCameraRecorder(stream: MediaStream, opts?: MediaRecorderOptions) {
+    if (!opts) {
+      opts = { mimeType: "video/webm" };
+    } else if (!opts.mimeType) {
+      opts.mimeType = "video/webm";
+    }
+
     this.camera_stream = stream;
     const recorder = new MediaRecorder(stream, opts);
     this.camera_recorder = recorder;