diff --git a/src/zm_image.cpp b/src/zm_image.cpp
index 49cf4ac0a7..ce76392efb 100644
--- a/src/zm_image.cpp
+++ b/src/zm_image.cpp
@@ -1617,7 +1617,7 @@ bool Image::EncodeJpeg(JOCTET *outbuffer, int *outbuffer_size, AVCodecContext *p
   av_frame_ptr frame = av_frame_ptr{zm_av_frame_alloc()};
   AVPacket *pkt;
 
-  if (av_image_get_buffer_size(AV_PIX_FMT_YUVJ420P, width, height, 32) > Size()) {
+  if (av_image_get_buffer_size(AV_PIX_FMT_YUVJ420P, width, height, 32) > static_cast<int>(Size())) {
     Error("Output buffer not large enough");
     return false;
   }
@@ -1639,6 +1639,12 @@ bool Image::EncodeJpeg(JOCTET *outbuffer, int *outbuffer_size, AVCodecContext *p
     PopulateFrame(frame.get());
   }
 
+  if (frame.get()->format != AV_PIX_FMT_YUV420P) {
+    Error("Jpeg frame format incorrect, got %d", frame.get()->format);
+    av_frame_unref(frame.get());
+    return false;
+  }
+
   pkt = av_packet_alloc();
 
   avcodec_send_frame(p_jpegcodeccontext, frame.get());
@@ -5460,7 +5466,9 @@ __attribute__((noinline)) void std_deinterlace_4field_abgr(uint8_t* col1, uint8_
 }
 
 AVPixelFormat Image::AVPixFormat() const {
-  if ( colours == ZM_COLOUR_RGB32 ) {
+  if ( subpixelorder == ZM_SUBPIX_ORDER_YUV420P) {
+    return AV_PIX_FMT_YUV420P;
+  } else if ( colours == ZM_COLOUR_RGB32 ) {
     return AV_PIX_FMT_RGBA;
   } else if ( colours == ZM_COLOUR_RGB24 ) {
     if ( subpixelorder == ZM_SUBPIX_ORDER_BGR) {
diff --git a/src/zm_monitor.cpp b/src/zm_monitor.cpp
index 5eeb035a3f..8c23dc49bc 100644
--- a/src/zm_monitor.cpp
+++ b/src/zm_monitor.cpp
@@ -2932,7 +2932,8 @@ bool Monitor::Decode() {
       int ret = packet->decode(camera->getVideoCodecContext());
       if (ret > 0 and !zm_terminate) {
         if (packet->in_frame and !packet->image) {
-          packet->image = new Image(camera_width, camera_height, camera->Colours(), camera->SubpixelOrder());
+          unsigned int subpix = packet->in_frame->format == AV_PIX_FMT_YUV420P ? ZM_SUBPIX_ORDER_YUV420P : camera->SubpixelOrder();
+          packet->image = new Image(camera_width, camera_height, camera->Colours(), subpix);
 
           if (convert_context || this->setupConvertContext(packet->in_frame.get(), packet->image)) {
             if (!packet->image->Assign(packet->in_frame.get(), convert_context, dest_frame.get())) {