diff --git a/subprojects/gst-docs/markdown/additional/design/dmabuf.md b/subprojects/gst-docs/markdown/additional/design/dmabuf.md
index eb197da1c3..e713d7dc72 100644
--- a/subprojects/gst-docs/markdown/additional/design/dmabuf.md
+++ b/subprojects/gst-docs/markdown/additional/design/dmabuf.md
@@ -139,17 +139,19 @@ Unlike other type of video buffers, DMABuf frames might not be mappable and
 its internal format is opaque to the user. Then, unless the modifier is
 linear (0x0000000000000000) or some other well known tiled format such as
 NV12_4L4, NV12_16L16, NV12_64Z32, NV12_16L32S, etc. (which are defined in
-video-format.h), we always use `GST_VIDEO_FORMAT_ENCODED` in
+video-format.h), we always use `GST_VIDEO_FORMAT_DMA_DRM` in
 `GstVideoFormat` enum to represent its video format.
 
 In order to not misuse this new format with the common video format, **in**
-*memory:DMABuf* feature, *drm-format* field in caps will replace the
-traditional *format* field.
+*memory:DMABuf* feature, the traditional *format* should be set to DMA_DRM.
+And a new *drm-format* field in caps is introduced to represent the video
+format in details(the composing of fourcc:modifier).
 
 So a DMABuf-backed video caps may look like:
 
 ```
      video/x-raw(memory:DMABuf), \
+                format=(string)DMA_DRM, \
                 drm-format=(string)NV12:0x0x0100000000000001, \
                 width=(int)1920, \
                 height=(int)1080, \
@@ -162,7 +164,7 @@ So a DMABuf-backed video caps may look like:
 ```
 
 And when we call a video info API such as `gst_video_info_from_caps()` with
-this caps, it should return an video format as `GST_VIDEO_FORMAT_ENCODED`,
+this caps, it should return an video format as `GST_VIDEO_FORMAT_DMA_DRM`,
 leaving other fields unchanged as normal video caps.
 
 In addition, a new structure
@@ -235,6 +237,7 @@ SRC template: 'src'
         video/x-raw(memory:DMABuf)
           width:  [ 16, 16384 ]
           height: [ 16, 16384 ]
+          format: DMA_DRM
           drm-format: { (string)NV12:0x0100000000000001, \
                         (string)YU12, (string)YV12, \
                         (string)YUYV:0x0100000000000002, \
@@ -284,6 +287,7 @@ SRC template: 'src'
         video/x-raw(memory:DMABuf)
           width:  [ 16, 16384 ]
           height: [ 16, 16384 ]
+          format: DMA_DRM
           drm-format: { (string)NV12:0x0100000000000001, \
                         (string)NV12, (string)I420, (string)YV12, \
                         (string)BGRA:0x0100000000000002 }
@@ -300,6 +304,7 @@ SINK template: 'sink'
         video/x-raw(memory:DMABuf)
           width:  [ 1, 2147483647 ]
           height: [ 1, 2147483647 ]
+          format: DMA_DRM
 ```
 
 At runtime, when the `vapostproc` wants to decide its src caps, it first