diff --git a/pkg/connector/handlematrix.go b/pkg/connector/handlematrix.go
index 988e8b4..434e299 100644
--- a/pkg/connector/handlematrix.go
+++ b/pkg/connector/handlematrix.go
@@ -244,13 +244,16 @@ func (gc *GMClient) uploadMatrixMedia(ctx context.Context, content *event.Messag
 	case event.MsgVideo, event.MsgAudio:
 		var extension string
 		mimeType, extension = mediaUploadType(content, mimeType)
-		var groupID, recipientID string
+		req := groupmeext.UploadRequest{SenderId: gc.Meta.GMID, Extension: extension}
 		if portalType == PortalTypeDM {
-			recipientID = string(gmid)
+			req.RecipientId = string(gmid)
 		} else {
-			groupID = string(gmid)
+			req.GroupId = string(gmid)
 		}
-		uploaded, err := groupmeext.UploadMedia(ctx, gc.Meta.Token, gc.Meta.GMID, groupID, recipientID, data, extension, mimeType)
+		if content.MsgType == event.MsgVideo && content.Info != nil {
+			req.Width, req.Height = content.Info.Width, content.Info.Height
+		}
+		uploaded, err := groupmeext.UploadMedia(ctx, gc.Meta.Token, req, data, mimeType)
 		if err != nil {
 			return nil, wrapGroupMeError(err, "failed to upload media").WithIsCertain(true)
 		}
diff --git a/pkg/groupmeext/message.go b/pkg/groupmeext/message.go
index 8c0cf0a..8eca085 100644
--- a/pkg/groupmeext/message.go
+++ b/pkg/groupmeext/message.go
@@ -115,12 +115,15 @@ func GetFileMetadata(ctx context.Context, groupID groupme.ID, fileID, token stri
 }
 
 // Upload sessions require a group ID or recipient ID, plus size and extension.
-type createUploadRequest struct {
+// GroupMe's clients also send the dimensions of videos.
+type UploadRequest struct {
 	FileSize    int64  `json:"FileSize"`
 	SenderId    string `json:"SenderId"`
 	Extension   string `json:"Extension"`
 	GroupId     string `json:"groupId,omitempty"`
 	RecipientId string `json:"recipientId,omitempty"`
+	Width       int    `json:"width,omitempty"`
+	Height      int    `json:"height,omitempty"`
 }
 
 // UploadURL is a temporary signed upload destination. The other URLs are
@@ -133,16 +136,10 @@ type UploadedMedia struct {
 }
 
 // UploadMedia uploads a video or voice note: it creates a session, then PUTs
-// bytes to its signed URL without GroupMe credentials. Exactly one of groupID
-// and recipientID must be set.
-func UploadMedia(ctx context.Context, token, senderID, groupID, recipientID string, data []byte, extension, mimeType string) (*UploadedMedia, error) {
-	reqBody, err := json.Marshal(createUploadRequest{
-		FileSize:    int64(len(data)),
-		SenderId:    senderID,
-		Extension:   extension,
-		GroupId:     groupID,
-		RecipientId: recipientID,
-	})
+// bytes to its signed URL without GroupMe credentials.
+func UploadMedia(ctx context.Context, token string, req UploadRequest, data []byte, mimeType string) (*UploadedMedia, error) {
+	req.FileSize = int64(len(data))
+	reqBody, err := json.Marshal(req)
 	if err != nil {
 		return nil, fmt.Errorf("failed to build upload session request: %w", err)
 	}