diff --git a/spa/include/spa/param/audio/format-utils.h b/spa/include/spa/param/audio/format-utils.h
index 6b63e31a0..dc7a2b9f5 100644
--- a/spa/include/spa/param/audio/format-utils.h
+++ b/spa/include/spa/param/audio/format-utils.h
@@ -72,15 +72,21 @@ spa_format_audio_raw_build(struct spa_pod_builder *builder, uint32_t id, struct
 	spa_pod_builder_add(builder,
 			SPA_FORMAT_mediaType,		SPA_POD_Id(SPA_MEDIA_TYPE_audio),
 			SPA_FORMAT_mediaSubtype,	SPA_POD_Id(SPA_MEDIA_SUBTYPE_raw),
-			SPA_FORMAT_AUDIO_format,	SPA_POD_Id(info->format),
-			SPA_FORMAT_AUDIO_rate,		SPA_POD_Int(info->rate),
-			SPA_FORMAT_AUDIO_channels,	SPA_POD_Int(info->channels),
 			0);
-
-	if (!SPA_FLAG_IS_SET(info->flags, SPA_AUDIO_FLAG_UNPOSITIONED)) {
-		spa_pod_builder_prop(builder, SPA_FORMAT_AUDIO_position, 0);
-		spa_pod_builder_array(builder, sizeof(uint32_t), SPA_TYPE_Id,
-				info->channels, info->position);
+	if (info->format != SPA_AUDIO_FORMAT_UNKNOWN)
+		spa_pod_builder_add(builder,
+			SPA_FORMAT_AUDIO_format,	SPA_POD_Id(info->format), 0);
+	if (info->rate != 0)
+		spa_pod_builder_add(builder,
+			SPA_FORMAT_AUDIO_rate,		SPA_POD_Int(info->rate), 0);
+	if (info->channels != 0) {
+		spa_pod_builder_add(builder,
+			SPA_FORMAT_AUDIO_channels,	SPA_POD_Int(info->channels), 0);
+		if (!SPA_FLAG_IS_SET(info->flags, SPA_AUDIO_FLAG_UNPOSITIONED)) {
+			spa_pod_builder_add(builder, SPA_FORMAT_AUDIO_position,
+				SPA_POD_Array(sizeof(uint32_t), SPA_TYPE_Id,
+					info->channels, info->position), 0);
+		}
 	}
 	return (struct spa_pod*)spa_pod_builder_pop(builder, &f);
 }
@@ -93,8 +99,10 @@ spa_format_audio_dsp_build(struct spa_pod_builder *builder, uint32_t id, struct
 	spa_pod_builder_add(builder,
 			SPA_FORMAT_mediaType,		SPA_POD_Id(SPA_MEDIA_TYPE_audio),
 			SPA_FORMAT_mediaSubtype,	SPA_POD_Id(SPA_MEDIA_SUBTYPE_dsp),
-			SPA_FORMAT_AUDIO_format,	SPA_POD_Id(info->format),
 			0);
+	if (info->format != SPA_AUDIO_FORMAT_UNKNOWN)
+		spa_pod_builder_add(builder,
+			SPA_FORMAT_AUDIO_format,	SPA_POD_Id(info->format), 0);
 	return (struct spa_pod*)spa_pod_builder_pop(builder, &f);
 }
 
diff --git a/spa/include/spa/param/video/format-utils.h b/spa/include/spa/param/video/format-utils.h
index 19964973b..321ff5a2f 100644
--- a/spa/include/spa/param/video/format-utils.h
+++ b/spa/include/spa/param/video/format-utils.h
@@ -76,10 +76,16 @@ spa_format_video_raw_build(struct spa_pod_builder *builder, uint32_t id,
 	spa_pod_builder_add(builder,
 			SPA_FORMAT_mediaType,		SPA_POD_Id(SPA_MEDIA_TYPE_video),
 			SPA_FORMAT_mediaSubtype,	SPA_POD_Id(SPA_MEDIA_SUBTYPE_raw),
-			SPA_FORMAT_VIDEO_format,	SPA_POD_Id(info->format),
-			SPA_FORMAT_VIDEO_size,		SPA_POD_Rectangle(&info->size),
-			SPA_FORMAT_VIDEO_framerate,	SPA_POD_Fraction(&info->framerate),
 			0);
+	if (info->format != SPA_VIDEO_FORMAT_UNKNOWN)
+		spa_pod_builder_add(builder,
+			SPA_FORMAT_VIDEO_format,	SPA_POD_Id(info->format), 0);
+	if (info->size.width != 0 && info->size.height != 0)
+		spa_pod_builder_add(builder,
+			SPA_FORMAT_VIDEO_size,		SPA_POD_Rectangle(&info->size), 0);
+	if (info->framerate.denom != 0)
+		spa_pod_builder_add(builder,
+			SPA_FORMAT_VIDEO_framerate,	SPA_POD_Fraction(&info->framerate), 0);
 	if (info->modifier != 0)
 		spa_pod_builder_add(builder,
 			SPA_FORMAT_VIDEO_modifier,	SPA_POD_Long(info->modifier), 0);
@@ -128,8 +134,10 @@ spa_format_video_dsp_build(struct spa_pod_builder *builder, uint32_t id,
 	spa_pod_builder_add(builder,
 			SPA_FORMAT_mediaType,		SPA_POD_Id(SPA_MEDIA_TYPE_video),
 			SPA_FORMAT_mediaSubtype,	SPA_POD_Id(SPA_MEDIA_SUBTYPE_dsp),
-			SPA_FORMAT_VIDEO_format,	SPA_POD_Id(info->format),
 			0);
+	if (info->format != SPA_VIDEO_FORMAT_UNKNOWN)
+		spa_pod_builder_add(builder,
+			SPA_FORMAT_VIDEO_format,	SPA_POD_Id(info->format), 0);
 	if (info->modifier)
 		spa_pod_builder_add(builder,
 			SPA_FORMAT_VIDEO_modifier,	SPA_POD_Long(info->modifier), 0);