Move pixdesc.{h,c} from libavcodec to libavutil.

This way pixdescs can be used without requiring a dependency on
libavcodec.

Originally committed as revision 20389 to svn://svn.ffmpeg.org/ffmpeg/trunk

2 files changed, 803 insertions, 0 deletions

diff --git a/libavutil/pixdesc.c b/libavutil/pixdesc.c
new file mode 100644
index 0000000000..7e8cea76c6
--- /dev/null
+++ b/libavutil/pixdesc.c
@@ -0,0 +1,596 @@
+/*
+ * pixel format descriptor
+ * Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "pixfmt.h"
+#include "pixdesc.h"
+
+const AVPixFmtDescriptor av_pix_fmt_descriptors[PIX_FMT_NB] = {
+    [PIX_FMT_YUV420P] = {
+        .name = "yuv420p",
+        .nb_channels  = 3,
+        .log2_chroma_w= 1,
+        .log2_chroma_h= 1,
+        .comp = {
+            {0,0,1,0,7},        /* Y */
+            {1,0,1,0,7},        /* U */
+            {2,0,1,0,7},        /* V */
+        },
+    },
+    [PIX_FMT_YUYV422] = {
+        .name = "yuyv422",
+        .nb_channels  = 3,
+        .log2_chroma_w= 1,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,1,1,0,7},        /* Y */
+            {0,3,2,0,7},        /* U */
+            {0,3,4,0,7},        /* V */
+        },
+    },
+    [PIX_FMT_RGB24] = {
+        .name = "rgb24",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,2,1,0,7},        /* R */
+            {0,2,2,0,7},        /* G */
+            {0,2,3,0,7},        /* B */
+        },
+    },
+    [PIX_FMT_BGR24] = {
+        .name = "bgr24",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,2,1,0,7},        /* B */
+            {0,2,2,0,7},        /* G */
+            {0,2,3,0,7},        /* R */
+        },
+    },
+    [PIX_FMT_YUV422P] = {
+        .name = "yuv422p",
+        .nb_channels  = 3,
+        .log2_chroma_w= 1,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,0,1,0,7},        /* Y */
+            {1,0,1,0,7},        /* U */
+            {2,0,1,0,7},        /* V */
+        },
+    },
+    [PIX_FMT_YUV444P] = {
+        .name = "yuv444p",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,0,1,0,7},        /* Y */
+            {1,0,1,0,7},        /* U */
+            {2,0,1,0,7},        /* V */
+        },
+    },
+    [PIX_FMT_YUV410P] = {
+        .name = "yuv410p",
+        .nb_channels  = 3,
+        .log2_chroma_w= 2,
+        .log2_chroma_h= 2,
+        .comp = {
+            {0,0,1,0,7},        /* Y */
+            {1,0,1,0,7},        /* U */
+            {2,0,1,0,7},        /* V */
+        },
+    },
+    [PIX_FMT_YUV411P] = {
+        .name = "yuv411p",
+        .nb_channels  = 3,
+        .log2_chroma_w= 2,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,0,1,0,7},        /* Y */
+            {1,0,1,0,7},        /* U */
+            {2,0,1,0,7},        /* V */
+        },
+    },
+    [PIX_FMT_GRAY8] = {
+        .name = "gray8",
+        .nb_channels  = 1,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,0,1,0,7},        /* Y */
+        },
+    },
+    [PIX_FMT_MONOWHITE] = {
+        .name = "monowhite",
+        .nb_channels  = 1,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,0,1,0,0},        /* Y */
+        },
+        .flags = PIX_FMT_BITSTREAM,
+    },
+    [PIX_FMT_MONOBLACK] = {
+        .name = "monoblack",
+        .nb_channels  = 1,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,0,1,7,0},        /* Y */
+        },
+        .flags = PIX_FMT_BITSTREAM,
+    },
+    [PIX_FMT_PAL8] = {
+        .name = "pal8",
+        .nb_channels  = 1,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,0,1,0,7},
+        },
+        .flags = PIX_FMT_PAL,
+    },
+    [PIX_FMT_YUVJ420P] = {
+        .name = "yuvj420p",
+        .nb_channels  = 3,
+        .log2_chroma_w= 1,
+        .log2_chroma_h= 1,
+        .comp = {
+            {0,0,1,0,7},        /* Y */
+            {1,0,1,0,7},        /* U */
+            {2,0,1,0,7},        /* V */
+        },
+    },
+    [PIX_FMT_YUVJ422P] = {
+        .name = "yuvj422p",
+        .nb_channels  = 3,
+        .log2_chroma_w= 1,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,0,1,0,7},        /* Y */
+            {1,0,1,0,7},        /* U */
+            {2,0,1,0,7},        /* V */
+        },
+    },
+    [PIX_FMT_YUVJ444P] = {
+        .name = "yuvj444p",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,0,1,0,7},        /* Y */
+            {1,0,1,0,7},        /* U */
+            {2,0,1,0,7},        /* V */
+        },
+    },
+    [PIX_FMT_UYVY422] = {
+        .name = "uyvy422",
+        .nb_channels  = 3,
+        .log2_chroma_w= 1,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,1,2,0,7},        /* Y */
+            {0,3,1,0,7},        /* U */
+            {0,3,3,0,7},        /* V */
+        },
+    },
+    [PIX_FMT_UYYVYY411] = {
+        .name = "uyyvyy411",
+        .nb_channels  = 3,
+        .log2_chroma_w= 2,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,3,2,0,7},        /* Y */
+            {0,5,1,0,7},        /* U */
+            {0,5,4,0,7},        /* V */
+        },
+    },
+    [PIX_FMT_BGR8] = {
+        .name = "bgr8",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,0,1,6,1},        /* B */
+            {0,0,1,3,2},        /* G */
+            {0,0,1,0,2},        /* R */
+        },
+    },
+    [PIX_FMT_BGR4] = {
+        .name = "bgr4",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,3,1,0,0},        /* B */
+            {0,3,2,0,1},        /* G */
+            {0,3,4,0,0},        /* R */
+        },
+        .flags = PIX_FMT_BITSTREAM,
+    },
+    [PIX_FMT_BGR4_BYTE] = {
+        .name = "bgr4_byte",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,0,1,3,0},        /* B */
+            {0,0,1,1,1},        /* G */
+            {0,0,1,0,0},        /* R */
+        },
+    },
+    [PIX_FMT_RGB8] = {
+        .name = "rgb8",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,0,1,6,1},        /* R */
+            {0,0,1,3,2},        /* G */
+            {0,0,1,0,2},        /* B */
+        },
+    },
+    [PIX_FMT_RGB4] = {
+        .name = "rgb4",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,3,1,0,0},       /* R */
+            {0,3,2,0,1},       /* G */
+            {0,3,4,0,0},       /* B */
+        },
+        .flags = PIX_FMT_BITSTREAM,
+    },
+    [PIX_FMT_RGB4_BYTE] = {
+        .name = "rgb4_byte",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,0,1,3,0},        /* R */
+            {0,0,1,1,1},        /* G */
+            {0,0,1,0,0},        /* B */
+        },
+    },
+    [PIX_FMT_NV12] = {
+        .name = "nv12",
+        .nb_channels  = 3,
+        .log2_chroma_w= 1,
+        .log2_chroma_h= 1,
+        .comp = {
+            {0,0,1,0,7},        /* Y */
+            {1,1,1,0,7},        /* U */
+            {1,1,2,0,7},        /* V */
+        },
+    },
+    [PIX_FMT_NV21] = {
+        .name = "nv21",
+        .nb_channels  = 3,
+        .log2_chroma_w= 1,
+        .log2_chroma_h= 1,
+        .comp = {
+            {0,0,1,0,7},        /* Y */
+            {1,1,1,0,7},        /* V */
+            {1,1,2,0,7},        /* U */
+        },
+    },
+    [PIX_FMT_ARGB] = {
+        .name = "argb",
+        .nb_channels  = 4,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,3,1,0,7},        /* A */
+            {0,3,2,0,7},        /* R */
+            {0,3,3,0,7},        /* G */
+            {0,3,4,0,7},        /* B */
+        },
+    },
+    [PIX_FMT_RGBA] = {
+        .name = "rgba",
+        .nb_channels  = 4,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,3,1,0,7},        /* R */
+            {0,3,2,0,7},        /* G */
+            {0,3,3,0,7},        /* B */
+            {0,3,4,0,7},        /* A */
+        },
+    },
+    [PIX_FMT_ABGR] = {
+        .name = "abgr",
+        .nb_channels  = 4,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,3,1,0,7},        /* A */
+            {0,3,2,0,7},        /* B */
+            {0,3,3,0,7},        /* G */
+            {0,3,4,0,7},        /* R */
+        },
+    },
+    [PIX_FMT_BGRA] = {
+        .name = "bgra",
+        .nb_channels  = 4,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,3,1,0,7},        /* B */
+            {0,3,2,0,7},        /* G */
+            {0,3,3,0,7},        /* R */
+            {0,3,4,0,7},        /* A */
+        },
+    },
+    [PIX_FMT_GRAY16BE] = {
+        .name = "gray16be",
+        .nb_channels  = 1,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,1,1,0,15},       /* Y */
+        },
+        .flags = PIX_FMT_BE,
+    },
+    [PIX_FMT_GRAY16LE] = {
+        .name = "gray16le",
+        .nb_channels  = 1,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,1,1,0,15},       /* Y */
+        },
+    },
+    [PIX_FMT_YUV440P] = {
+        .name = "yuv440p",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 1,
+        .comp = {
+            {0,0,1,0,7},        /* Y */
+            {1,0,1,0,7},        /* U */
+            {2,0,1,0,7},        /* V */
+        },
+    },
+    [PIX_FMT_YUVJ440P] = {
+        .name = "yuvj440p",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 1,
+        .comp = {
+            {0,0,1,0,7},        /* Y */
+            {1,0,1,0,7},        /* U */
+            {2,0,1,0,7},        /* V */
+        },
+    },
+    [PIX_FMT_YUVA420P] = {
+        .name = "yuva420p",
+        .nb_channels  = 4,
+        .log2_chroma_w= 1,
+        .log2_chroma_h= 1,
+        .comp = {
+            {0,0,1,0,7},        /* Y */
+            {1,0,1,0,7},        /* U */
+            {2,0,1,0,7},        /* V */
+            {3,0,1,0,7},        /* A */
+        },
+    },
+    [PIX_FMT_RGB48BE] = {
+        .name = "rgb48be",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,5,1,0,15},       /* R */
+            {0,5,3,0,15},       /* G */
+            {0,5,5,0,15},       /* B */
+        },
+        .flags = PIX_FMT_BE,
+    },
+    [PIX_FMT_RGB48LE] = {
+        .name = "rgb48le",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,5,1,0,15},       /* R */
+            {0,5,3,0,15},       /* G */
+            {0,5,5,0,15},       /* B */
+        },
+    },
+    [PIX_FMT_RGB565BE] = {
+        .name = "rgb565be",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,1,0,3,4},        /* R */
+            {0,1,1,5,5},        /* G */
+            {0,1,1,0,4},        /* B */
+        },
+        .flags = PIX_FMT_BE,
+    },
+    [PIX_FMT_RGB565LE] = {
+        .name = "rgb565le",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,1,2,3,4},        /* R */
+            {0,1,1,5,5},        /* G */
+            {0,1,1,0,4},        /* B */
+        },
+    },
+    [PIX_FMT_RGB555BE] = {
+        .name = "rgb555be",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,1,0,2,4},        /* R */
+            {0,1,1,5,4},        /* G */
+            {0,1,1,0,4},        /* B */
+        },
+        .flags = PIX_FMT_BE,
+    },
+    [PIX_FMT_RGB555LE] = {
+        .name = "rgb555le",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,1,2,2,4},        /* R */
+            {0,1,1,5,4},        /* G */
+            {0,1,1,0,4},        /* B */
+        },
+    },
+    [PIX_FMT_BGR565BE] = {
+        .name = "bgr565be",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,1,0,3,4},        /* B */
+            {0,1,1,5,5},        /* G */
+            {0,1,1,0,4},        /* R */
+        },
+        .flags = PIX_FMT_BE,
+    },
+    [PIX_FMT_BGR565LE] = {
+        .name = "bgr565le",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,1,2,3,4},        /* B */
+            {0,1,1,5,5},        /* G */
+            {0,1,1,0,4},        /* R */
+        },
+    },
+    [PIX_FMT_BGR555BE] = {
+        .name = "bgr555be",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,1,0,2,4},       /* B */
+            {0,1,1,5,4},       /* G */
+            {0,1,1,0,4},       /* R */
+        },
+        .flags = PIX_FMT_BE,
+     },
+    [PIX_FMT_BGR555LE] = {
+        .name = "bgr555le",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,1,2,2,4},        /* B */
+            {0,1,1,5,4},        /* G */
+            {0,1,1,0,4},        /* R */
+        },
+    },
+    [PIX_FMT_YUV420P16LE] = {
+        .name = "yuv420p16le",
+        .nb_channels  = 3,
+        .log2_chroma_w= 1,
+        .log2_chroma_h= 1,
+        .comp = {
+            {0,1,1,0,15},        /* Y */
+            {1,1,1,0,15},        /* U */
+            {2,1,1,0,15},        /* V */
+        },
+    },
+    [PIX_FMT_YUV420P16BE] = {
+        .name = "yuv420p16be",
+        .nb_channels  = 3,
+        .log2_chroma_w= 1,
+        .log2_chroma_h= 1,
+        .comp = {
+            {0,1,1,0,15},        /* Y */
+            {1,1,1,0,15},        /* U */
+            {2,1,1,0,15},        /* V */
+        },
+        .flags = PIX_FMT_BE,
+    },
+    [PIX_FMT_YUV422P16LE] = {
+        .name = "yuv422p16le",
+        .nb_channels  = 3,
+        .log2_chroma_w= 1,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,1,1,0,15},        /* Y */
+            {1,1,1,0,15},        /* U */
+            {2,1,1,0,15},        /* V */
+        },
+    },
+    [PIX_FMT_YUV422P16BE] = {
+        .name = "yuv422p16be",
+        .nb_channels  = 3,
+        .log2_chroma_w= 1,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,1,1,0,15},        /* Y */
+            {1,1,1,0,15},        /* U */
+            {2,1,1,0,15},        /* V */
+        },
+        .flags = PIX_FMT_BE,
+    },
+    [PIX_FMT_YUV444P16LE] = {
+        .name = "yuv444p16le",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,1,1,0,15},        /* Y */
+            {1,1,1,0,15},        /* U */
+            {2,1,1,0,15},        /* V */
+        },
+    },
+    [PIX_FMT_YUV444P16BE] = {
+        .name = "yuv444p16be",
+        .nb_channels  = 3,
+        .log2_chroma_w= 0,
+        .log2_chroma_h= 0,
+        .comp = {
+            {0,1,1,0,15},        /* Y */
+            {1,1,1,0,15},        /* U */
+            {2,1,1,0,15},        /* V */
+        },
+        .flags = PIX_FMT_BE,
+    },
+};
+
+int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc)
+{
+    int c, bits = 0;
+    int log2_pixels = pixdesc->log2_chroma_w + pixdesc->log2_chroma_h;
+
+    for (c = 0; c < pixdesc->nb_channels; c++) {
+        int s = c==1 || c==2 ? 0 : log2_pixels;
+        bits += (pixdesc->comp[c].depth_minus1+1) << s;
+    }
+
+    return bits >> log2_pixels;
+}
diff --git a/libavutil/pixdesc.h b/libavutil/pixdesc.h
new file mode 100644
index 0000000000..fd1428fd81
--- /dev/null
+++ b/libavutil/pixdesc.h
@@ -0,0 +1,207 @@
+/*
+ * pixel format descriptor
+ * Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVUTIL_PIXDESC_H
+#define AVUTIL_PIXDESC_H
+
+#include <inttypes.h>
+
+#include "intreadwrite.h"
+
+typedef struct AVComponentDescriptor{
+    uint16_t plane        :2;            ///< which of the 4 planes contains the component
+
+    /**
+     * Number of elements between 2 horizontally consecutive pixels minus 1.
+     * Elements are bits for bitstream formats, bytes otherwise.
+     */
+    uint16_t step_minus1  :3;
+
+    /**
+     * Number of elements before the component of the first pixel plus 1.
+     * Elements are bits for bitstream formats, bytes otherwise.
+     */
+    uint16_t offset_plus1 :3;
+    uint16_t shift        :3;            ///< number of least significant bits that must be shifted away to get the value
+    uint16_t depth_minus1 :4;            ///< number of bits in the component minus 1
+}AVComponentDescriptor;
+
+/**
+ * Descriptor that unambiguously describes how the bits of a pixel are
+ * stored in the up to 4 data planes of an image. It also stores the
+ * subsampling factors and number of components.
+ *
+ * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV
+ *       and all the YUV variants) AVPixFmtDescriptor just stores how values
+ *       are stored not what these values represent.
+ */
+typedef struct AVPixFmtDescriptor{
+    const char *name;
+    uint8_t nb_channels;        ///< The number of components each pixel has, (1-4)
+
+    /**
+     * Amount to shift the luma width right to find the chroma width.
+     * For YV12 this is 1 for example.
+     * chroma_width = -((-luma_width) >> log2_chroma_w)
+     * The note above is needed to ensure rounding up.
+     */
+    uint8_t log2_chroma_w;      ///< chroma_width = -((-luma_width )>>log2_chroma_w)
+
+    /**
+     * Amount to shift the luma height right to find the chroma height.
+     * For YV12 this is 1 for example.
+     * chroma_height= -((-luma_height) >> log2_chroma_h)
+     * The note above is needed to ensure rounding up.
+     */
+    uint8_t log2_chroma_h;
+    uint8_t flags;
+    AVComponentDescriptor comp[4]; ///< parameters that describe how pixels are packed
+}AVPixFmtDescriptor;
+
+#define PIX_FMT_BE        1 ///< big-endian
+#define PIX_FMT_PAL       2 ///< Pixel format has a palette in data[1], values are indexes in this palette.
+#define PIX_FMT_BITSTREAM 4 ///< All values of a component are bit-wise packed end to end.
+#define PIX_FMT_HWACCEL   8 ///< Pixel format is an HW accelerated format.
+
+/**
+ * The array of all the pixel format descriptors.
+ */
+extern const AVPixFmtDescriptor av_pix_fmt_descriptors[];
+
+/**
+ * Reads a line from an image, and writes to dst the values of the
+ * pixel format component c.
+ *
+ * @param data the array containing the pointers to the planes of the image
+ * @param linesizes the array containing the linesizes of the image
+ * @param desc the pixel format descriptor for the image
+ * @param x the horizontal coordinate of the first pixel to read
+ * @param y the vertical coordinate of the first pixel to read
+ * @param w the width of the line to read, that is the number of
+ * values to write to dst
+ * @param read_pal_component if not zero and the format is a paletted
+ * format writes to dst the values corresponding to the palette
+ * component c in data[1], rather than the palette indexes in
+ * data[0]. The behavior is undefined if the format is not paletted.
+ */
+static inline void read_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4],
+                             const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int read_pal_component)
+{
+    AVComponentDescriptor comp= desc->comp[c];
+    int plane= comp.plane;
+    int depth= comp.depth_minus1+1;
+    int mask = (1<<depth)-1;
+    int shift= comp.shift;
+    int step = comp.step_minus1+1;
+    int flags= desc->flags;
+
+    if (flags & PIX_FMT_BITSTREAM){
+        int skip = x*step + comp.offset_plus1-1;
+        const uint8_t *p = data[plane] + y*linesize[plane] + (skip>>3);
+        int shift = 8 - depth - (skip&7);
+
+        while(w--){
+            int val = (*p >> shift) & mask;
+            if(read_pal_component)
+                val= data[1][4*val + c];
+            shift -= step;
+            p -= shift>>3;
+            shift &= 7;
+            *dst++= val;
+        }
+    } else {
+        const uint8_t *p = data[plane]+ y*linesize[plane] + x*step + comp.offset_plus1-1;
+
+        while(w--){
+            int val;
+            if(flags & PIX_FMT_BE) val= AV_RB16(p);
+            else                   val= AV_RL16(p);
+            val = (val>>shift) & mask;
+            if(read_pal_component)
+                val= data[1][4*val + c];
+            p+= step;
+            *dst++= val;
+        }
+    }
+}
+
+/**
+ * Writes the values from src to the pixel format component c of an
+ * image line.
+ *
+ * @param src array containing the values to write
+ * @param data the array containing the pointers to the planes of the
+ * image to write into. It is supposed to be zeroed.
+ * @param linesizes the array containing the linesizes of the image
+ * @param desc the pixel format descriptor for the image
+ * @param x the horizontal coordinate of the first pixel to write
+ * @param y the vertical coordinate of the first pixel to write
+ * @param w the width of the line to write, that is the number of
+ * values to write to the image line
+ */
+static inline void write_line(const uint16_t *src, uint8_t *data[4], const int linesize[4],
+                              const AVPixFmtDescriptor *desc, int x, int y, int c, int w)
+{
+    AVComponentDescriptor comp = desc->comp[c];
+    int plane = comp.plane;
+    int depth = comp.depth_minus1+1;
+    int step  = comp.step_minus1+1;
+    int flags = desc->flags;
+
+    if (flags & PIX_FMT_BITSTREAM) {
+        int skip = x*step + comp.offset_plus1-1;
+        uint8_t *p = data[plane] + y*linesize[plane] + (skip>>3);
+        int shift = 8 - depth - (skip&7);
+
+        while (w--) {
+            *p |= *src++ << shift;
+            shift -= step;
+            p -= shift>>3;
+            shift &= 7;
+        }
+    } else {
+        int shift = comp.shift;
+        uint8_t *p = data[plane]+ y*linesize[plane] + x*step + comp.offset_plus1-1;
+
+        while (w--) {
+            if (flags & PIX_FMT_BE) {
+                uint16_t val = AV_RB16(p) | (*src++<<shift);
+                AV_WB16(p, val);
+            } else {
+                uint16_t val = AV_RL16(p) | (*src++<<shift);
+                AV_WL16(p, val);
+            }
+            p+= step;
+        }
+    }
+}
+
+/**
+ * Returns the number of bits per pixel used by the pixel format
+ * described by pixdesc.
+ *
+ * The returned number of bits refers to the number of bits actually
+ * used for storing the pixel information, that is padding bits are
+ * not counted.
+ */
+int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
+
+#endif /* AVUTIL_PIXDESC_H */