Function describeRecordingCodecs

packages/recorder-core/src/recorder-utils.ts:223–253

(
	mimeType: string,
	hasAudio: boolean,
)

// Chromebooks) would otherwise be mislabelled, and an mp4 fallback carries aac,
// not opus.
export const describeRecordingCodecs = (
	mimeType: string,
	hasAudio: boolean,
): { videoCodec: string; audioCodec: string | undefined } => {
	const lowerType = mimeType.toLowerCase();
	const codecsMatch = lowerType.match(/codecs\s*=\s*"?([^"]+)"?/);
	const codecs = (codecsMatch?.[1] ?? "")
		.split(",")
		.map((codec) => codec.trim())
		.filter(Boolean);
	const isWebm = lowerType.includes("webm");
	const hasCodec = (prefix: string) =>
		codecs.some((codec) => codec.startsWith(prefix));

	let videoCodec: string;
	if (hasCodec("vp9")) videoCodec = "vp9";
	else if (hasCodec("vp8")) videoCodec = "vp8";
	else if (hasCodec("avc1") || hasCodec("h264")) videoCodec = "h264";
	else videoCodec = isWebm ? "vp8" : "h264";

	if (!hasAudio) {
		return { videoCodec, audioCodec: undefined };
	}

	let audioCodec: string;
	if (hasCodec("opus")) audioCodec = "opus";
	else if (hasCodec("mp4a") || hasCodec("aac")) audioCodec = "aac";
	else audioCodec = isWebm ? "opus" : "aac";

	return { videoCodec, audioCodec };
};

export const isUserCancellationError = (error: unknown): boolean => {
	if (!(error instanceof DOMException)) return false;