/* puthdr.c, generation of headers                                          */

/* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */

/*
 * Disclaimer of Warranty
 *
 * These software programs are available to the user without any license fee or
 * royalty on an "as is" basis.  The MPEG Software Simulation Group disclaims
 * any and all warranties, whether express, implied, or statuary, including any
 * implied warranties or merchantability or of fitness for a particular
 * purpose.  In no event shall the copyright-holder be liable for any
 * incidental, punitive, or consequential damages of any kind whatsoever
 * arising from the use of these programs.
 *
 * This disclaimer of warranty extends to the user of these programs and user's
 * customers, employees, agents, transferees, successors, and assigns.
 *
 * The MPEG Software Simulation Group does not represent or warrant that the
 * programs furnished hereunder are free of infringement of any third-party
 * patents.
 *
 * Commercial implementations of MPEG-1 and MPEG-2 video, including shareware,
 * are subject to royalty fees to patent holders.  Many of these patents are
 * general enough such that they are unavoidable regardless of implementation
 * design.
 *
 */

#include <stdio.h>
#include <math.h>
#include "config.h"
#include "global.h"

/* private prototypes */
static int frametotc _ANSI_ARGS_((int frame));

/* generate sequence header (6.2.2.1, 6.3.3)
 *
 * matrix download not implemented
 */
void putseqhdr()
{
    int i;

    alignbits();
    putbits(SEQ_START_CODE, 32);	/* sequence_header_code */
    putbits(horizontal_size, 12);	/* horizontal_size_value */
    putbits(vertical_size, 12);	/* vertical_size_value */
    putbits(aspectratio, 4);	/* aspect_ratio_information */
    putbits(frame_rate_code, 4);	/* frame_rate_code */
    putbits((int) ceil(bit_rate / 400.0), 18);	/* bit_rate_value */
    putbits(1, 1);		/* marker_bit */
    putbits(vbv_buffer_size, 10);	/* vbv_buffer_size_value */
    putbits(constrparms, 1);	/* constrained_parameters_flag */

    putbits(load_iquant, 1);	/* load_intra_quantizer_matrix */
    if (load_iquant)
	for (i = 0; i < 64; i++)	/* matrices are always downloaded in zig-zag order */
	    putbits(intra_q[zig_zag_scan[i]], 8);	/* intra_quantizer_matrix */

    putbits(load_niquant, 1);	/* load_non_intra_quantizer_matrix */
    if (load_niquant)
	for (i = 0; i < 64; i++)
	    putbits(inter_q[zig_zag_scan[i]], 8);	/* non_intra_quantizer_matrix */
}

/* generate sequence extension (6.2.2.3, 6.3.5) header (MPEG-2 only) */
void putseqext()
{
    alignbits();
    putbits(EXT_START_CODE, 32);	/* extension_start_code */
    putbits(SEQ_ID, 4);		/* extension_start_code_identifier */
    putbits((profile << 4) | level, 8);	/* profile_and_level_indication */
    putbits(prog_seq, 1);	/* progressive sequence */
    putbits(chroma_format, 2);	/* chroma_format */
    putbits(horizontal_size >> 12, 2);	/* horizontal_size_extension */
    putbits(vertical_size >> 12, 2);	/* vertical_size_extension */
    putbits(((int) ceil(bit_rate / 400.0)) >> 18, 12);	/* bit_rate_extension */
    putbits(1, 1);		/* marker_bit */
    putbits(vbv_buffer_size >> 10, 8);	/* vbv_buffer_size_extension */
    putbits(0, 1);		/* low_delay  -- currently not implemented */
    putbits(0, 2);		/* frame_rate_extension_n */
    putbits(0, 5);		/* frame_rate_extension_d */
}

/* generate sequence display extension (6.2.2.4, 6.3.6)
 *
 * content not yet user setable
 */
void putseqdispext()
{
    alignbits();
    putbits(EXT_START_CODE, 32);	/* extension_start_code */
    putbits(DISP_ID, 4);	/* extension_start_code_identifier */
    putbits(video_format, 3);	/* video_format */
    putbits(1, 1);		/* colour_description */
    putbits(color_primaries, 8);	/* colour_primaries */
    putbits(transfer_characteristics, 8);	/* transfer_characteristics */
    putbits(matrix_coefficients, 8);	/* matrix_coefficients */
    putbits(display_horizontal_size, 14);	/* display_horizontal_size */
    putbits(1, 1);		/* marker_bit */
    putbits(display_vertical_size, 14);	/* display_vertical_size */
}

/* output a zero terminated string as user data (6.2.2.2.2, 6.3.4.1)
 *
 * string must not emulate start codes
 */
void putuserdata(userdata)
char *userdata;
{
    alignbits();
    putbits(USER_START_CODE, 32);	/* user_data_start_code */
    while (*userdata)
	putbits(*userdata++, 8);
}

/* generate group of pictures header (6.2.2.6, 6.3.9)
 *
 * uses tc0 (timecode of first frame) and frame0 (number of first frame)
 */
void putgophdr(frame, closed_gop)
int frame, closed_gop;
{
    int tc;


    alignbits();
    putbits(GOP_START_CODE, 32);	/* group_start_code */
    tc = frametotc(tc0 + frame);
    putbits(tc, 25);		/* time_code */
    putbits(closed_gop, 1);	/* closed_gop */
    putbits(0, 1);		/* broken_link */
}

/* convert frame number to time_code
 *
 * drop_frame not implemented
 */
static int frametotc(frame)
int frame;
{
    int fps, pict, sec, minute, hour, tc;

    fps = (int) (frame_rate + 0.5);
    pict = frame % fps;
    frame = (frame - pict) / fps;
    sec = frame % 60;
    frame = (frame - sec) / 60;
    minute = frame % 60;
    frame = (frame - minute) / 60;
    hour = frame % 24;
    tc = (hour << 19) | (minute << 13) | (1 << 12) | (sec << 6) | pict;

    return tc;
}

/* generate picture header (6.2.3, 6.3.10) */
void putpicthdr()
{
    alignbits();
    putbits(PICTURE_START_CODE, 32);	/* picture_start_code */
    calc_vbv_delay();
    putbits(temp_ref, 10);	/* temporal_reference */
    putbits(pict_type, 3);	/* picture_coding_type */
    putbits(vbv_delay, 16);	/* vbv_delay */

    if (pict_type == P_TYPE || pict_type == B_TYPE) {
	putbits(0, 1);		/* full_pel_forward_vector */
	if (mpeg1)
	    putbits(forw_hor_f_code, 3);
	else
	    putbits(7, 3);	/* forward_f_code */
    }

    if (pict_type == B_TYPE) {
	putbits(0, 1);		/* full_pel_backward_vector */
	if (mpeg1)
	    putbits(back_hor_f_code, 3);
	else
	    putbits(7, 3);	/* backward_f_code */
    }

    putbits(0, 1);		/* extra_bit_picture */
}

/* generate picture coding extension (6.2.3.1, 6.3.11)
 *
 * composite display information (v_axis etc.) not implemented
 */
void putpictcodext()
{
    alignbits();
    putbits(EXT_START_CODE, 32);	/* extension_start_code */
    putbits(CODING_ID, 4);	/* extension_start_code_identifier */
    putbits(forw_hor_f_code, 4);	/* forward_horizontal_f_code */
    putbits(forw_vert_f_code, 4);	/* forward_vertical_f_code */
    putbits(back_hor_f_code, 4);	/* backward_horizontal_f_code */
    putbits(back_vert_f_code, 4);	/* backward_vertical_f_code */
    putbits(dc_prec, 2);	/* intra_dc_precision */
    putbits(pict_struct, 2);	/* picture_structure */
    putbits((pict_struct == FRAME_PICTURE) ? topfirst : 0, 1);	/* top_field_first */
    putbits(frame_pred_dct, 1);	/* frame_pred_frame_dct */
    putbits(0, 1);		/* concealment_motion_vectors  -- currently not implemented */
    putbits(q_scale_type, 1);	/* q_scale_type */
    putbits(intravlc, 1);	/* intra_vlc_format */
    putbits(altscan, 1);	/* alternate_scan */
    putbits(repeatfirst, 1);	/* repeat_first_field */
    putbits(prog_frame, 1);	/* chroma_420_type */
    putbits(prog_frame, 1);	/* progressive_frame */
    putbits(0, 1);		/* composite_display_flag */
}

/* generate sequence_end_code (6.2.2) */
void putseqend()
{
    alignbits();
    putbits(SEQ_END_CODE, 32);
}