Extend SDS schema to support video streams

schema/README.md

@@ -3,6 +3,7 @@
 The **SDS Framework** uses a binary data file format to store the individual data streams. It supports the recording and playback of multiple data streams that may have jitters.  Therefore each stream contains timestamp information that allows to correlate the data streams as it is for example required in a sensor fusion application.
 
 The binary data format (stored in `*.<n>.sds` data files) has a record structure with a variable size. Each record has the following format:
+
 1. **timestamp**: record timestamp in tick-frequency (32-bit unsigned integer, little endian)
 2. **data size**: number of data bytes in the record (32-bit unsigned integer, little endian)
 3. **binary data**: SDS stream (little endian, no padding) as described with the `*.sds.yml` file.
@@ -28,8 +29,28 @@ The following section defines the YAML format of this metadata file. The file `s
 &nbsp;&nbsp;&nbsp; `offset:`         | Offset of the value (optional); default: 0
 &nbsp;&nbsp;&nbsp; `scale:`          | Scale factor of the value (optional); default: 1.0
 &nbsp;&nbsp;&nbsp; `unit:`           | Physical unit of the value (optional); default: no units
+&nbsp;&nbsp;&nbsp; `image:`          | Image format metadata (optional)
+
+### Image Format Metadata Fields
+
+The `image` fields provide metadata for image data captured in the SDS stream. When a content item represents image data, `image` describes the format, dimensions, and memory layout.
+
+`image:`                             | Image stream metadata (all fields required except where noted)
+:------------------------------------|---------------------------------------------------
+&nbsp;&nbsp;&nbsp; `pixel_format:`   | Pixel format identifier (enum)
+&nbsp;&nbsp;&nbsp; `width:`          | Number of pixels per row (integer, minimum: 1)
+&nbsp;&nbsp;&nbsp; `height:`         | Number of rows (integer, minimum: 1)
+&nbsp;&nbsp;&nbsp; `stride_bytes:`   | Bytes per row for single-plane formats (required for single-plane)
+&nbsp;&nbsp;&nbsp; `planes:`         | Per-plane stride array for multi-plane formats (required for multi-plane)
+
+The `pixel_format` field accepts the following identifiers:
+
+- **Single-plane formats**: `RAW8`, `RAW10`, `RGB565`, `RGB888`, `YUYV`, `UYVY`
+- **Multi-plane formats**: `NV12`, `NV21`, `I420`, `NV16`, `NV61`, `YUV422P`, `YUV444`, `YUV444P`
 
-## Example
+## Examples
+
+### Sensor Data Stream
 
 This example defines a data stream with the name "sensorX" that contains the values of a gyroscope, temperature sensor, and additional raw data (that are not further described).
 
@@ -69,3 +90,22 @@ sds:                   # describes a synchronous data stream
   - value: flag
     type: uint32_t:1   # a single bit stored in a 32-bit int
 ```
+
+### Video Frame Stream
+
+This example shows a video stream capturing RGB888 frames at 30 Hz. Each frame is 640x480 pixels with 3 bytes per pixel (RGB), requiring a stride of 1920 bytes per row.
+
+```yml
+sds:
+  name: Camera stream
+  description: RGB888 video capture at 30 fps
+  frequency: 30
+  content:
+  - value: frame
+    type: uint8_t
+    image:
+      pixel_format: RGB888
+      width: 640
+      height: 480
+      stride_bytes: 1920   # 640 pixels * 3 bytes/pixel
+```

schema/sds.schema.json

@@ -1,5 +1,5 @@
 {
-  "$schema": "http://json-schema.org/draft-07/schema#",
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
   "type": "object",
   "properties": {
     "sds": {
@@ -19,7 +19,8 @@
         },
         "tick-frequency": {
           "type": "number",
-          "description": "Tick frequency of the timestamp value (optional); default: 1000 for 1 milli-second interval"
+          "description": "Tick frequency of the timestamp value (optional); default: 1000 for 1 milli-second interval",
+          "default": 1000
         },
         "content": {
           "type": "array",
@@ -37,15 +38,86 @@
               },
               "offset": {
                 "type": "number",
-                "description": "Offset of the value (optional); default: 0"
+                "description": "Offset of the value (optional); default: 0",
+                "default": 0
               },
               "scale": {
                 "type": "number",
-                "description": "Scale factor of the value (optional); default: 1.0"
+                "description": "Scale factor of the value (optional); default: 1.0",
+                "default": 1.0
               },
               "unit": {
                 "type": "string",
                 "description": "Physical unit of the value (optional); default: no units"
+              },
+              "image": {
+                "type": "object",
+                "description": "Image stream metadata, applicable when the value represents an image frame",
+                "properties": {
+                  "pixel_format": {
+                    "type": "string",
+                    "description": "Pixel format identifier.",
+                    "enum": [
+                      "RAW8",
+                      "RAW10",
+                      "RGB565",
+                      "RGB888",
+                      "NV12",
+                      "NV21",
+                      "I420",
+                      "NV16",
+                      "NV61",
+                      "YUYV",
+                      "UYVY",
+                      "YUV422P",
+                      "YUV444",
+                      "YUV444P"
+                    ]
+                  },
+                  "width": {
+                    "type": "integer",
+                    "minimum": 1,
+                    "description": "Number of pixels per row."
+                  },
+                  "height": {
+                    "type": "integer",
+                    "minimum": 1,
+                    "description": "Number of rows."
+                  },
+                  "stride_bytes": {
+                    "type": "integer",
+                    "minimum": 1,
+                    "description": "Bytes per row for single-plane formats."
+                  },
+                  "planes": {
+                    "type": "array",
+                    "description": "Per-plane stride (for multi-plane formats).",
+                    "minItems": 2,
+                    "maxItems": 3,
+                    "items": {
+                      "type": "object",
+                      "properties": {
+                        "stride_bytes": {
+                          "type": "integer",
+                          "minimum": 1,
+                          "description": "Bytes per row for this plane."
+                        }
+                      },
+                      "required": ["stride_bytes"]
+                    }
+                  }
+                },
+                "required": ["pixel_format", "width", "height"],
+                "oneOf": [
+                  {
+                    "required": ["stride_bytes"],
+                    "not": { "required": ["planes"] }
+                  },
+                  {
+                    "required": ["planes"],
+                    "not": { "required": ["stride_bytes"] }
+                  }
+                ]
               }
             },
             "required": ["value", "type"]