common/y4menc.c

/*
 * Copyright (c) 2021, Alliance for Open Media. All rights reserved
 *
 * This source code is subject to the terms of the BSD 3-Clause Clear License
 * and the Alliance for Open Media Patent License 1.0. If the BSD 3-Clause Clear
 * License was not distributed with this source code in the LICENSE file, you
 * can obtain it at aomedia.org/license/software-license/bsd-3-c-c/.  If the
 * Alliance for Open Media Patent License 1.0 was not distributed with this
 * source code in the PATENTS file, you can obtain it at
 * aomedia.org/license/patent-license/.
 */

#include <assert.h>

#include "common/rawenc.h"
#include "common/y4menc.h"

// Returns the Y4M name associated with the monochrome colorspace.
static const char *monochrome_colorspace(unsigned int bit_depth) {
  switch (bit_depth) {
    case 8: return "Cmono";
    case 9: return "Cmono9";
    case 10: return "Cmono10";
    case 12: return "Cmono12";
    case 16: return "Cmono16";
    default: assert(0); return NULL;
  }
}

// Return the Y4M name of the 8-bit colorspace, given the chroma position and
// image format.
const char *colorspace8(aom_chroma_sample_position_t csp, aom_img_fmt_t fmt) {
  switch (fmt) {
    case AOM_IMG_FMT_I444: return "C444";
    case AOM_IMG_FMT_I422: return "C422";
    default:
      if (csp == AOM_CSP_VERTICAL) {
        return "C420mpeg2 XYSCSS=420MPEG2";
      } else if (csp == AOM_CSP_COLOCATED) {
        // Note that Y4M does not have a dedicated header for colocated chroma,
        // and that FFMPEG interprets C420 as C420jpeg.
        return "C420";
      } else {
        return "C420jpeg";
      }
  }
}

// Return the Y4M name of the colorspace, given the bit depth and image format.
static const char *colorspace(unsigned int bit_depth,
                              aom_chroma_sample_position_t csp,
                              aom_img_fmt_t fmt) {
  switch (bit_depth) {
    case 8: return colorspace8(csp, fmt);
    case 9:
      return fmt == AOM_IMG_FMT_I44416   ? "C444p9 XYSCSS=444P9"
             : fmt == AOM_IMG_FMT_I42216 ? "C422p9 XYSCSS=422P9"
                                         : "C420p9 XYSCSS=420P9";
    case 10:
      return fmt == AOM_IMG_FMT_I44416   ? "C444p10 XYSCSS=444P10"
             : fmt == AOM_IMG_FMT_I42216 ? "C422p10 XYSCSS=422P10"
                                         : "C420p10 XYSCSS=420P10";
    case 12:
      return fmt == AOM_IMG_FMT_I44416   ? "C444p12 XYSCSS=444P12"
             : fmt == AOM_IMG_FMT_I42216 ? "C422p12 XYSCSS=422P12"
                                         : "C420p12 XYSCSS=420P12";
    case 14:
      return fmt == AOM_IMG_FMT_I44416   ? "C444p14 XYSCSS=444P14"
             : fmt == AOM_IMG_FMT_I42216 ? "C422p14 XYSCSS=422P14"
                                         : "C420p14 XYSCSS=420P14";
    case 16:
      return fmt == AOM_IMG_FMT_I44416   ? "C444p16 XYSCSS=444P16"
             : fmt == AOM_IMG_FMT_I42216 ? "C422p16 XYSCSS=422P16"
                                         : "C420p16 XYSCSS=420P16";
    default: assert(0); return NULL;
  }
}

int y4m_write_file_header(char *buf, size_t len, int width, int height,
                          const struct AvxRational *framerate, int monochrome,
                          aom_chroma_sample_position_t csp, aom_img_fmt_t fmt,
                          unsigned int bit_depth) {
  const char *color = monochrome ? monochrome_colorspace(bit_depth)
                                 : colorspace(bit_depth, csp, fmt);
  return snprintf(buf, len, "YUV4MPEG2 W%d H%d F%d:%d I%c %s\n", width, height,
                  framerate->numerator, framerate->denominator, 'p', color);
}

int y4m_write_frame_header(char *buf, size_t len) {
  return snprintf(buf, len, "FRAME\n");
}

void y4m_write_image_file(const aom_image_t *img, const int *planes,
                          FILE *file) {
  int num_planes = img->monochrome ? 1 : 3;
  raw_write_image_file(img, planes, num_planes, file);
}

void y4m_update_image_md5(const aom_image_t *img, const int *planes,
                          MD5Context *md5) {
  int num_planes = img->monochrome ? 1 : 3;
  raw_update_image_md5(img, planes, num_planes, md5);
}