obs-ffmpeg: Add YUV alpha formats for completeness

plugins/obs-ffmpeg/obs-ffmpeg-formats.h

@@ -37,6 +37,12 @@ obs_to_ffmpeg_video_format(enum video_format format)
 		return AV_PIX_FMT_BGR24;
 	case VIDEO_FORMAT_I422:
 		return AV_PIX_FMT_YUV422P;
+	case VIDEO_FORMAT_I40A:
+		return AV_PIX_FMT_YUVA420P;
+	case VIDEO_FORMAT_I42A:
+		return AV_PIX_FMT_YUVA422P;
+	case VIDEO_FORMAT_YUVA:
+		return AV_PIX_FMT_YUVA444P;
 	}
 
 	return AV_PIX_FMT_NONE;
@@ -66,6 +72,12 @@ ffmpeg_to_obs_video_format(enum AVPixelFormat format)
 		return VIDEO_FORMAT_BGR3;
 	case AV_PIX_FMT_YUV422P:
 		return VIDEO_FORMAT_I422;
+	case AV_PIX_FMT_YUVA420P:
+		return VIDEO_FORMAT_I40A;
+	case AV_PIX_FMT_YUVA422P:
+		return VIDEO_FORMAT_I42A;
+	case AV_PIX_FMT_YUVA444P:
+		return VIDEO_FORMAT_YUVA;
 	case AV_PIX_FMT_NONE:
 	default:
 		return VIDEO_FORMAT_NONE;