2 files changed, 90 insertions, 0 deletions
diff --git a/include/uvcgadget/meson.build b/include/uvcgadget/meson.build
index a9e4384..af795c4 100644
--- a/include/uvcgadget/meson.build
+++ b/include/uvcgadget/meson.build
@@ -9,6 +9,7 @@ uvcgadget_public_headers = files([
   'timer.h',
   'v4l2-source.h',
   'video-source.h',
+  'mjpeg_encoder.hpp',
   ])
 
 
diff --git a/include/uvcgadget/mjpeg_encoder.hpp b/include/uvcgadget/mjpeg_encoder.hpp
new file mode 100644
index 0000000..a3e92fc
--- /dev/null
+++ b/include/uvcgadget/mjpeg_encoder.hpp
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (C) 2020, Raspberry Pi (Trading) Ltd.
+ *
+ * mjpeg_encoder.hpp - mjpeg video encoder.
+ */
+
+#pragma once
+
+#include <condition_variable>
+#include <mutex>
+#include <queue>
+#include <thread>
+#include <functional>
+
+struct jpeg_compress_struct;
+typedef std::function<void(void *, size_t, int64_t, unsigned int)> OutputReadyCallback;
+
+struct StreamInfo
+{
+	StreamInfo() : width(0), height(0), stride(0) {}
+	unsigned int width;
+	unsigned int height;
+	unsigned int stride;
+	libcamera::PixelFormat pixel_format;
+	std::optional<libcamera::ColorSpace> colour_space;
+};
+
+class MjpegEncoder
+{
+public:
+	MjpegEncoder();
+	~MjpegEncoder();
+
+	void EncodeBuffer(void *mem, void *dest, unsigned int size,
+			  StreamInfo const &info, int64_t timestamp_us,
+			  unsigned int cookie);
+	StreamInfo getStreamInfo(libcamera::Stream *stream);
+	void SetOutputReadyCallback(OutputReadyCallback callback) { output_ready_callback_ = callback; }
+
+private:
+	static const int NUM_ENC_THREADS = 4;
+
+	void encodeThread(int num);
+
+	/*
+	 * Handle the output buffers in another thread so as not to block the
+	 * encoders. The application can take its time, after which we return
+	 * this buffer to the encoder for re-use.
+	 */
+	void outputThread();
+
+	bool abortEncode_;
+	bool abortOutput_;
+	uint64_t index_;
+
+	struct EncodeItem
+	{
+		void *mem;
+		void *dest;
+		unsigned int size;
+		StreamInfo info;
+		int64_t timestamp_us;
+		uint64_t index;
+		unsigned int cookie;
+	};
+
+	std::queue<EncodeItem> encode_queue_;
+	std::mutex encode_mutex_;
+	std::condition_variable encode_cond_var_;
+	std::thread encode_thread_[NUM_ENC_THREADS];
+	void encodeJPEG(struct jpeg_compress_struct &cinfo, EncodeItem &item,
+			uint8_t *&encoded_buffer, size_t &buffer_len);
+
+	struct OutputItem
+	{
+		void *mem;
+		size_t bytes_used;
+		int64_t timestamp_us;
+		uint64_t index;
+		unsigned int cookie;
+	};
+
+	std::queue<OutputItem> output_queue_[NUM_ENC_THREADS];
+	std::mutex output_mutex_;
+	std::condition_variable output_cond_var_;
+	std::thread output_thread_;
+	OutputReadyCallback output_ready_callback_ ;
+};