tav: librarying

video_encoder/include/entropy_coder.h

@@ -0,0 +1,74 @@
+// TEV Entropy Coder - Specialised for DCT coefficients
+// Replaces gzip with video-optimized compression
+#ifndef ENTROPY_CODER_H
+#define ENTROPY_CODER_H
+
+#include <stdint.h>
+#include <stdio.h>
+
+// Bit writer for variable-length codes
+typedef struct {
+    uint8_t *buffer;
+    size_t buffer_size;
+    size_t byte_pos;
+    int bit_pos;  // 0-7, next bit to write
+} bit_writer_t;
+
+// Bit reader for decoding
+typedef struct {
+    const uint8_t *buffer;
+    size_t buffer_size;
+    size_t byte_pos;
+    int bit_pos;  // 0-7, next bit to read
+} bit_reader_t;
+
+// Huffman table entry
+typedef struct {
+    uint16_t code;    // Huffman code
+    uint8_t bits;     // Code length in bits
+} huffman_entry_t;
+
+// Video entropy coder optimized for TEV coefficients
+typedef struct {
+    // Huffman tables for different coefficient types
+    huffman_entry_t y_dc_table[512];      // Y DC coefficients (-255 to +255)
+    huffman_entry_t y_ac_table[512];      // Y AC coefficients
+    huffman_entry_t c_dc_table[512];      // Chroma DC coefficients  
+    huffman_entry_t c_ac_table[512];      // Chroma AC coefficients
+    huffman_entry_t run_table[256];       // Zero run lengths (0-255)
+    
+    // Motion vector Huffman tables
+    huffman_entry_t mv_table[65];         // Motion vectors (-32 to +32)
+    
+    // Bit writer/reader
+    bit_writer_t writer;
+    bit_reader_t reader;
+} entropy_coder_t;
+
+static const huffman_entry_t BLOCK_MODE_HUFFMAN[16];
+
+void write_bits(bit_writer_t *writer, uint32_t value, int bits);
+uint32_t read_bits(bit_reader_t *reader, int bits);
+
+// Initialise entropy coder
+entropy_coder_t* entropy_coder_create(uint8_t *buffer, size_t buffer_size);
+void entropy_coder_destroy(entropy_coder_t *coder);
+
+// Encoding functions
+int encode_y_block(entropy_coder_t *coder, int16_t *y_coeffs);
+int encode_chroma_block(entropy_coder_t *coder, int16_t *chroma_coeffs, int is_cg);
+int encode_motion_vector(entropy_coder_t *coder, int16_t mv_x, int16_t mv_y);
+int encode_block_mode(entropy_coder_t *coder, uint8_t mode);
+
+// Decoding functions  
+void entropy_coder_init_reader(entropy_coder_t *coder, const uint8_t *buffer, size_t buffer_size);
+int decode_y_block(entropy_coder_t *coder, int16_t *y_coeffs);
+int decode_chroma_block(entropy_coder_t *coder, int16_t *chroma_coeffs, int is_cg);
+int decode_motion_vector(entropy_coder_t *coder, int16_t *mv_x, int16_t *mv_y);
+int decode_block_mode(entropy_coder_t *coder, uint8_t *mode);
+
+// Get compressed size
+size_t entropy_coder_get_size(entropy_coder_t *coder);
+void entropy_coder_reset(entropy_coder_t *coder);
+
+#endif // ENTROPY_CODER_H