Add data stream sending support

README.md

@@ -26,7 +26,7 @@ Use this SDK to add realtime video, audio and data features to your ESP32 projec
 - **Bidirectional audio**: Opus encoding, acoustic echo cancellation (AEC)
 - **Video publishing**: H.264 encoding, subscribing coming soon
 - **AI Agents**: interact with agents in the cloud built with [LiveKit Agents](https://docs.livekit.io/agents/)
-- **Real-time data**: data streams (receiving), data packets, remote method calls (RPC)
+- **Real-time data**: data streams, data packets, remote method calls (RPC)
 
 ## Getting Started
 
@@ -173,17 +173,16 @@ livekit_room_rpc_register(room_handle, "get_cpu_temp", get_cpu_temp);
 
 #### Data streams
 
-Data streams deliver ordered sequences of chunks (Header → Chunks → Trailer) over the reliable data channel. Currently, only receiving data streams is supported. There are two kinds:
+Data streams deliver ordered sequences of chunks (Header → Chunks → Trailer) over the reliable data channel. There are two kinds:
 
-- **Text streams**: Each chunk is independently valid UTF-8 and can be used directly as a string. Used for chat messages, transcriptions, etc.
+- **Text streams**: Each chunk is independently valid UTF-8 and can be used directly as a string. When sending, data is automatically chunked at UTF-8 character boundaries so multi-byte characters are never split. Used for chat messages, transcriptions, etc.
 - **Byte streams**: Chunks are raw binary fragments of a larger payload, split without delimiters. Chunks must be aggregated by the application to reconstruct the original data. Used for file transfers, binary payloads, etc.
 
-Register a handler to receive text stream chunks on a topic:
+**Receiving** — register a handler for a topic:
 
 ```c
 static void on_text_chunk(const livekit_data_stream_chunk_t* chunk, void* ctx)
 {
-    // Each chunk is valid UTF-8, safe to use as a string directly
     ESP_LOGI(TAG, "%.*s", (int)chunk->content_size, (const char*)chunk->content);
 }
 
@@ -195,6 +194,34 @@ livekit_room_data_stream_topic_register(room_handle, "lk.chat", &handler);
 
 The optional `on_open` and `on_close` callbacks in the handler can be set for additional behavior such as logging stream metadata or detecting abnormal closure.
 
+**Sending a text stream:**
+
+```c
+livekit_data_stream_options_t opts = { .topic = "lk.chat", .is_text = true };
+livekit_data_stream_handle_t stream;
+livekit_room_data_stream_open(room_handle, &opts, &stream);
+livekit_room_data_stream_write(room_handle, stream, (const uint8_t*)"hello world", 11);
+livekit_room_data_stream_close(room_handle, stream);
+```
+
+**Sending a byte stream:**
+
+```c
+uint8_t image_data[4096];
+size_t image_size = read_image(image_data, sizeof(image_data));
+
+livekit_data_stream_options_t opts = {
+    .topic = "image",
+    .is_text = false,
+    .total_length = image_size,
+    .has_total_length = true,
+};
+livekit_data_stream_handle_t stream;
+livekit_room_data_stream_open(room_handle, &opts, &stream);
+livekit_room_data_stream_write(room_handle, stream, image_data, image_size);
+livekit_room_data_stream_close(room_handle, stream);
+```
+
 #### User packets
 
 Publish a user packet containing a raw data payload under a specific topic:

components/livekit/Kconfig

@@ -24,8 +24,12 @@ menu "LiveKit"
     config LK_PUB_VIDEO_TRACK_NAME
         string "Name of the published video track"
         default "Video"
-    config LK_MAX_DATA_STREAMS
+    config LK_MAX_DATA_STREAM_READERS
         int "Maximum concurrent incoming data streams"
         range 1 32
         default 4
+    config LK_MAX_DATA_STREAM_WRITERS
+        int "Maximum concurrent outgoing data streams"
+        range 1 32
+        default 4
 endmenu

components/livekit/README.md

@@ -12,4 +12,4 @@ Use this SDK to add realtime video, audio and data features to your ESP32 projec
 - **Bidirectional audio**: Opus encoding, acoustic echo cancellation (AEC)
 - **Video publishing**: H.264 encoding, subscribing coming soon
 - **AI Agents**: interact with agents in the cloud built with [LiveKit Agents](https://docs.livekit.io/agents/)
-- **Real-time data**: data packets, remote method calls (RPC)
+- **Real-time data**: data streams, data packets, remote method calls (RPC)