/*******************************************************************
   MPEG Video sequance header reading routine
 *******************************************************************/

#include "scan.h"

#define SEQUENCE_HEADER_C
#include "sequence_header.h"

int read_sequence_header(VIDEO_STREAM *in, SEQUENCE_HEADER *out);
int sequence_header_to_bgr_conversion_parameter(SEQUENCE_HEADER *in, BGR_CONVERSION_PARAMETER *out, int remap);
int sequence_header_to_read_picture_header_option(SEQUENCE_HEADER *in, READ_PICTURE_HEADER_OPTION *out);
int sequence_header_to_read_slice_header_option(SEQUENCE_HEADER *in, READ_SLICE_HEADER_OPTION *out);
int sequence_header_to_read_macroblock_option(SEQUENCE_HEADER *in, READ_MACROBLOCK_OPTION *out);
int sequence_header_to_read_block_option(SEQUENCE_HEADER *in, READ_BLOCK_OPTION *out);
int sequence_header_to_mc_parameter(SEQUENCE_HEADER *in, MC_PARAMETER *out);

int read_sequence_header(VIDEO_STREAM *in, SEQUENCE_HEADER *out)
{
	int i;
	int code;
	
	out->orig_h_size = vs_get_bits(in, 12);
	out->orig_v_size = vs_get_bits(in, 12);
	out->aspect_ratio = vs_get_bits(in, 4);
	out->picture_rate = vs_get_bits(in, 4);
	out->bit_rate = vs_get_bits(in, 18);
	vs_get_bits(in, 1); /* marker bit */
	out->vbv_buffer_size = vs_get_bits(in, 10);
	out->mpeg1 = vs_get_bits(in, 1);
	out->has_intra_quantizer_matrix = vs_get_bits(in, 1);
	if(out->has_intra_quantizer_matrix){
		for(i=0;i<64;i++){
			out->iqm[i] = vs_get_bits(in, 8);
		}
	}
	out->has_nonintra_quantizer_matrix = vs_get_bits(in, 1);
	if(out->has_nonintra_quantizer_matrix){
		for(i=0;i<64;i++){
			out->nqm[i] = vs_get_bits(in, 8);
		}
	}

	while(vs_next_start_code(in)){
		code = vs_read_bits(in, 32);
		if(code != 0x1b5){
			break;
		}
		vs_erase_bits(in, 32);

		code = vs_get_bits(in, 4);
		switch(code){
		case 1:
			out->has_sequence_extension = 1;
			out->se.profile_and_level = vs_get_bits(in, 8);
			out->se.progressive = vs_get_bits(in, 1);
			out->se.chroma_format = vs_get_bits(in, 2);
			out->orig_h_size += vs_get_bits(in, 2) << 12;
			out->orig_v_size += vs_get_bits(in, 2) << 12;
			out->bit_rate += vs_get_bits(in, 12) << 18;
			vs_erase_bits(in, 1); /* marker bits */
			out->vbv_buffer_size += vs_get_bits(in, 8) << 10;
			out->se.low_delay = vs_get_bits(in, 1);
			out->se.frame_rate_ext_n = vs_get_bits(in, 2);			
			out->se.frame_rate_ext_d = vs_get_bits(in, 2);
			break;
		case 2:
			out->has_sequence_display_extension = 1;
			out->sd.video_format = vs_get_bits(in, 3);
			out->sd.has_color_description = vs_get_bits(in, 1);
			if(out->sd.has_color_description){
				out->sd.color_primaries = vs_get_bits(in, 8);
				out->sd.transfer_characteristics = vs_get_bits(in, 8);
				out->sd.matrix_coefficients = vs_get_bits(in, 8);
			}
			out->sd.display_h_size = vs_get_bits(in, 14);
			vs_erase_bits(in, 1);
			out->sd.display_v_size = vs_get_bits(in, 14);
			break;
		case 5:
			out->has_sequence_scalable_extension = 1;
			out->ss.scalable_mode = vs_get_bits(in, 2);
			out->ss.layer = vs_get_bits(in, 4);
			if(out->ss.scalable_mode == 1){
				out->ss.lower_layer_prediction_h_size = vs_get_bits(in, 14);
				out->ss.lower_layer_prediction_v_size = vs_get_bits(in, 14);
				out->ss.h_subsampling_facter_m = vs_get_bits(in, 5);
				out->ss.h_subsampling_facter_n = vs_get_bits(in, 5);
				out->ss.v_subsampling_facter_m = vs_get_bits(in, 5);	
				out->ss.v_subsampling_facter_n = vs_get_bits(in, 5);
			}else if(out->ss.scalable_mode == 3){
				out->ss.picture_mux_enable = vs_get_bits(in, 1);
				out->ss.mux_to_progressive_sequence = vs_get_bits(in, 1);
				out->ss.pixture_mux_order = vs_get_bits(in, 3);
				out->ss.pixture_mux_facter = vs_get_bits(in, 3);
			}
			break;
		default:
			break;
		}
	}

	out->h_size = out->orig_h_size + 15;
	out->h_size >>= 4;
	out->h_size <<= 4;

	if(out->has_sequence_extension && (out->se.progressive == 0)){
		out->v_size = out->orig_v_size + 31;
		out->v_size >>= 5;
		out->v_size <<= 5;
	}else{
		out->v_size = out->orig_v_size + 15;
		out->v_size >>= 4;
		out->v_size <<= 4;
	}

	return 1;
}

int sequence_header_to_bgr_conversion_parameter(SEQUENCE_HEADER *in, BGR_CONVERSION_PARAMETER *out, int remap)
{
	static const int table[8][2][5] = {
		{
			{  /*   RV      GU      GV      BU  */     
				103219, -12257, -30659, 121621,
			}, /* straight conversion */
	

			{  /*   RV      GU      GV      BU  */     
				117504, -13954, -34903, 138453,
			}, /* re-map conversion */
		
		}, /* no sequence_display_extension */

		{
			{  /*   RV      GU      GV      BU  */     
				103219, -12257, -30659, 121621,
			}, /* straight conversion */
	

			{  /*   RV      GU      GV      BU  */     
				117504, -13954, -34903, 138453,
			}, /* re-map conversion */
		
		}, /* ITU-R Rec. 709 */

		{
			{  /*   RV      GU      GV      BU  */     
				 91881, -22553, -46801, 116129,
			}, /* straight conversion */
	
			{  /*   RV      GU      GV      BU  */     
				104597, -25675, -53279, 132201,
			}, /* re-map conversion */
		
		}, /* unspecified video */

		{
			{  /*   RV      GU      GV      BU  */     
				 91881, -22553, -46801, 116129,
			}, /* straight conversion */
	
			{  /*   RV      GU      GV      BU  */     
				104597, -25675, -53279, 132201,
			}, /* re-map conversion */
		
		}, /* reserved */

		{
			{  /*   RV      GU      GV      BU  */     
				 91750, -21749, -46652, 116654,
			}, /* straight conversion */
	
			{  /*   RV      GU      GV      BU  */     
				104448, -24759, -53109, 132798,
			}, /* re-map conversion */
		
		}, /* FCC */

		{
			{  /*   RV      GU      GV      BU  */     
				 91881, -22553, -46801, 116129,
			}, /* straight conversion */
	
			{  /*   RV      GU      GV      BU  */     
				104597, -25675, -53279, 132201,
			}, /* re-map conversion */
		
		}, /* ITU-R Rec. 624-4 System B, G */

		{
			{  /*   RV      GU      GV      BU  */     
				 91881, -22553, -46801, 116129,
			}, /* straight conversion */
	
			{  /*   RV      GU      GV      BU  */     
				104597, -25675, -53279, 132201,
			}, /* re-map conversion */
		
		}, /* SMPTE 170M */

		{
			{  /*   RV      GU      GV      BU  */     
				103284, -14851, -31235, 119668,
			}, /* straight conversion */
	
			{  /*   RV      GU      GV      BU  */     
				117579, -16907, -35559, 136230,
			}, /* re-map conversion */
		
		}, /* SMPTE 240 */
	};

	static const int y_offset[2] = {
		0, 16,
	};

	static const int y_gain[2] = {
		65536, 76309,
	};

	if(in->has_sequence_extension){
		out->chroma_format = in->se.chroma_format;
		out->progressive = in->se.progressive;
	}else{
		out->chroma_format = 1;
		out->progressive = 1;
	}

	if(in->has_sequence_display_extension){
		out->yo = y_offset[remap];
		out->yg = y_gain[remap];

		out->rv = table[in->sd.matrix_coefficients][remap][0];

		out->gu = table[in->sd.matrix_coefficients][remap][1];
		out->gv = table[in->sd.matrix_coefficients][remap][2];

		out->bu = table[in->sd.matrix_coefficients][remap][3];
	}else{
		out->yo = y_offset[remap];
		out->yg = y_gain[remap];
		
		out->rv = table[0][remap][0];

		out->gu = table[0][remap][1];
		out->gv = table[0][remap][2];

		out->bu = table[0][remap][3];
	}

    return 1;		
}
int sequence_header_to_read_picture_header_option(SEQUENCE_HEADER *in, READ_PICTURE_HEADER_OPTION *out)
{
	if(in->has_sequence_extension){
		out->progressive_sequence = in->se.progressive;
	}else{
		out->progressive_sequence = 1;
	}
	
	return 1;
}

int sequence_header_to_read_slice_header_option(SEQUENCE_HEADER *in, READ_SLICE_HEADER_OPTION *out)
{
	out->v_size = in->v_size;

	if(in->has_sequence_scalable_extension){
		out->scalable_mode = in->ss.scalable_mode;
	}else{
		out->scalable_mode = -1;
	}

	return 1;
}

int sequence_header_to_read_macroblock_option(SEQUENCE_HEADER *in, READ_MACROBLOCK_OPTION *out)
{
	if(in->has_sequence_extension){
		out->chroma_format = in->se.chroma_format;
	}else{
		out->chroma_format = 1;
	}
	
	if(in->has_sequence_scalable_extension){
		out->scalable_mode = in->ss.scalable_mode;
	}else{
		out->scalable_mode = -1;
	}

	return 1;
}

int sequence_header_to_read_block_option(SEQUENCE_HEADER *in, READ_BLOCK_OPTION *out)
{
	int i;

	if(in->has_sequence_extension){
		out->chroma_format = in->se.chroma_format;
	}else{
		out->chroma_format = 1;
	}
		
	if(in->has_intra_quantizer_matrix){
		for(i=0;i<64;i++){
			out->quantizer_weight[0][scan_table[0][i]] = in->iqm[i];
			out->quantizer_weight[2][scan_table[0][i]] = in->iqm[i];
		}
	}else{
		memcpy(out->quantizer_weight[0], default_intra_quantizer_matrix, 64);
		memcpy(out->quantizer_weight[2], default_intra_quantizer_matrix, 64);
	}

	if(in->has_nonintra_quantizer_matrix){
		for(i=0;i<64;i++){
			out->quantizer_weight[1][scan_table[0][i]] = in->nqm[i];
			out->quantizer_weight[3][scan_table[0][i]] = in->nqm[i];
		}
	}else{
		memset(out->quantizer_weight[1], 16, 64);
		memset(out->quantizer_weight[3], 16, 64);
	}

	return 1;
}

int sequence_header_to_mc_parameter(SEQUENCE_HEADER *in, MC_PARAMETER *out)
{
	if(in->has_sequence_extension){
		out->chroma_format = in->se.chroma_format;
	}else{
		out->chroma_format = 1;
	}
	
	return 1;
}