TAD: arbitrary steps with bitplanes

video_encoder/range_coder.h

@@ -0,0 +1,42 @@
+#ifndef RANGE_CODER_H
+#define RANGE_CODER_H
+
+#include <stdint.h>
+#include <stddef.h>
+
+// Simple range coder for signed 16-bit integers
+// Uses adaptive frequency model for better compression
+
+typedef struct {
+    uint32_t low;
+    uint32_t range;
+    uint8_t *buffer;
+    size_t buffer_pos;
+    size_t buffer_capacity;
+} RangeEncoder;
+
+typedef struct {
+    uint32_t low;
+    uint32_t range;
+    uint32_t code;
+    const uint8_t *buffer;
+    size_t buffer_pos;
+    size_t buffer_size;
+} RangeDecoder;
+
+// Initialize encoder
+void range_encoder_init(RangeEncoder *enc, uint8_t *buffer, size_t capacity);
+
+// Encode a signed 16-bit value with Laplacian distribution (λ=5.0, μ=0)
+void range_encode_int16_laplacian(RangeEncoder *enc, int16_t value, int16_t max_abs_value, float lambda);
+
+// Finalize encoding and return bytes written
+size_t range_encoder_finish(RangeEncoder *enc);
+
+// Initialize decoder
+void range_decoder_init(RangeDecoder *dec, const uint8_t *buffer, size_t size);
+
+// Decode a signed 16-bit value with Laplacian distribution (λ=5.0, μ=0)
+int16_t range_decode_int16_laplacian(RangeDecoder *dec, int16_t max_abs_value, float lambda);
+
+#endif // RANGE_CODER_H