Video compression in composer (#4638)

Co-authored-by: Samuel Newman <10959775+mozzius@users.noreply.github.com>
Co-authored-by: Hailey <me@haileyok.com>

src/lib/media/video/compress.web.ts

@@ -0,0 +1,28 @@
+import {VideoTooLargeError} from 'lib/media/video/errors'
+
+const MAX_VIDEO_SIZE = 1024 * 1024 * 100 // 100MB
+
+export type CompressedVideo = {
+  uri: string
+  size: number
+}
+
+// doesn't actually compress, but throws if >100MB
+export async function compressVideo(
+  file: string,
+  _callbacks?: {
+    onProgress: (progress: number) => void
+  },
+): Promise<CompressedVideo> {
+  const blob = await fetch(file).then(res => res.blob())
+  const video = URL.createObjectURL(blob)
+
+  if (blob.size > MAX_VIDEO_SIZE) {
+    throw new VideoTooLargeError()
+  }
+
+  return {
+    size: blob.size,
+    uri: video,
+  }
+}