/*
    gcc -O1 -o ${HBIN:-.}/grey8_to_h264 Grey8_to_H264.c -lx264
    dd if=/dev/random count=100 bs=15000  |  grey8_to_h264 10 150 100 > random.h264
*/

#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <x264.h>

static int EncodeFrame (FILE *out, x264_t *h, x264_picture_t *pic)
{
    x264_picture_t  pic_out;
    x264_nal_t     *p_nal;
    int             i_nal, i_frame_size;

    i_frame_size = x264_encoder_encode (h, &p_nal, &i_nal, pic, &pic_out);
    if (i_frame_size < 0)
	fprintf (stderr, "EncodeFrame(): x264_encoder_encode() failed.\n");
    if (i_frame_size > 0)
	i_frame_size = fwrite (p_nal[0].p_payload, i_frame_size, 1, out);
    return i_frame_size;
}

static int Grey8_to_H264 (FILE *in, FILE *out, int fps, int width, int height)
{
    int c = 1;
    x264_t *h;
    x264_picture_t pic;
    x264_param_t param;
    x264_param_default (&param);
#if 1
    x264_param_parse (&param, "threads", "1"); /* <-- avoid endless loop*/
    x264_param_parse (&param, "crf", "0");     /* <-- enforce lossless encoding*/
#endif
    param.i_width = width;
    param.i_height = height;
    param.i_fps_num = fps;
    param.i_fps_den = 1;

    h = x264_encoder_open (&param);
    if (h != (x264_t*)(0)) {
	if (x264_picture_alloc (&pic, param.i_csp, param.i_width, param.i_height) == 0) {
	    x264_nal_t *p_nal;
	    int i_nal;
	    if (x264_encoder_headers (h, &p_nal, &i_nal) >= 0) {
		if (fwrite (p_nal[0].p_payload, (p_nal[0].i_payload + p_nal[1].i_payload + p_nal[2].i_payload), 1, out) > 0)
		{
		    int cnt = 0;
		    memset (pic.img.plane[1], /*u*/ 128, (param.i_width/2)*(param.i_height/2)); /*have no color*/
		    memset (pic.img.plane[2], /*v*/ 128, (param.i_width/2)*(param.i_height/2)); /*have no color*/

		    /*encode sequence*/
		    while (feof(in) == 0)
		    {
			for (c = 0; c < param.i_width*param.i_height && feof(in) == 0; ++c) /*read frame, i.e. 'y'*/
			    ((unsigned char*)(pic.img.plane[0]))[c] = (unsigned char)(fgetc(in));

			pic.i_pts = cnt++;           /* <-- what is this?*/
			pic.i_type = X264_TYPE_AUTO; /* <-- what is this?*/
			pic.i_qpplus1 = 0;           /* <-- what is this?*/
			if (EncodeFrame (out, h, &pic) < 0)
			    break;
		    }

		    /*flush*/
		    while (x264_encoder_delayed_frames (h) > 0)
			if (EncodeFrame (out, h, &pic) < 0)
			    break;
		    c = 0;
		}
	    }
	    x264_picture_clean (&pic);
	}
	x264_encoder_close (h);
    }
    return c;
}

int main (int argc, char *argv[])
{
    int fps, width, height;
    if (argc >= 4
	    && sscanf (argv[1], " %d", &fps) == 1 && fps > 0
	    && sscanf (argv[2], " %d", &width) == 1 && width > 0
	    && sscanf (argv[3], " %d", &height) == 1 && height > 0)
	return Grey8_to_H264 (stdin, stdout, fps, width, height);
    fprintf (stderr, "Usage:  %s  framerate  framewidth  frameheight  < grey8stream.data  > stream.h264\n", argv[0]);
    return 1;
}