avformat: factor ff_get_qtpalette() out of mov.c

This consists mainly of moving the palette handling from
the mov_parse_stsd_video() function to a new ff_get_qtpalette() function
in the new file qtpalette.c, which will be shared by both matroskadec.c and
mov.c.

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

1 files changed, 121 insertions, 0 deletions

diff --git a/libavformat/qtpalette.c b/libavformat/qtpalette.c
new file mode 100644
index 0000000000..2901122875
--- /dev/null
+++ b/libavformat/qtpalette.c
@@ -0,0 +1,121 @@
+/*
+ * QuickTime palette handling
+ * Copyright (c) 2001 Fabrice Bellard
+ * Copyright (c) 2009 Baptiste Coudurier <baptiste dot coudurier at gmail dot com>
+ * Copyright (c) 2015 Mats Peterson
+ *
+ * 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 <stdio.h>
+#include <stdint.h>
+
+#include "avformat.h"
+#include "libavutil/intreadwrite.h"
+#include "qtpalette.h"
+
+/**
+ * Retrieve the palette (or "color table" in QuickTime terms), either
+ * from the video sample description, or from the default Macintosh
+ * palette.
+ *
+ * The file offset of the AVIOContext pointed to by the 'pb' variable
+ * should be the start of the video sample description (the sample
+ * description size and the data format).
+ */
+int ff_get_qtpalette(int codec_id, AVIOContext *pb, uint32_t *palette)
+{
+    int tmp, bit_depth, color_table_id, greyscale, i;
+
+    avio_seek(pb, 82, SEEK_CUR);
+
+    /* Get the bit depth and greyscale state */
+    tmp = avio_rb16(pb);
+    bit_depth = tmp & 0x1F;
+    greyscale = tmp & 0x20;
+
+    /* Get the color table ID */
+    color_table_id = avio_rb16(pb);
+
+    /* Do not create a greyscale palette for Cinepak */
+    if (greyscale && codec_id == AV_CODEC_ID_CINEPAK)
+        return 0;
+
+    /* If the depth is 2, 4, or 8 bpp, file is palettized. */
+    if ((bit_depth == 2 || bit_depth == 4 || bit_depth == 8)) {
+        int color_count, color_start, color_end;
+        uint32_t a, r, g, b;
+
+        if (greyscale) {
+            int color_index, color_dec;
+            /* compute the greyscale palette */
+            color_count = 1 << bit_depth;
+            color_index = 255;
+            color_dec   = 256 / (color_count - 1);
+            for (i = 0; i < color_count; i++) {
+                r = g = b = color_index;
+                palette[i] = (0xFFU << 24) | (r << 16) | (g << 8) | (b);
+                color_index -= color_dec;
+                if (color_index < 0)
+                    color_index = 0;
+            }
+        } else if (color_table_id) {
+            /* The color table ID is non-zero. Interpret this as
+             * being -1, which means use the default Macintosh
+             * color table */
+            const uint8_t *color_table;
+            color_count = 1 << bit_depth;
+            if (bit_depth == 2)
+                color_table = ff_qt_default_palette_4;
+            else if (bit_depth == 4)
+                color_table = ff_qt_default_palette_16;
+            else
+                color_table = ff_qt_default_palette_256;
+            for (i = 0; i < color_count; i++) {
+                r = color_table[i * 3 + 0];
+                g = color_table[i * 3 + 1];
+                b = color_table[i * 3 + 2];
+                palette[i] = (0xFFU << 24) | (r << 16) | (g << 8) | (b);
+            }
+        } else {
+            /* The color table ID is 0; the color table is in the sample
+             * description */
+            color_start = avio_rb32(pb);
+            avio_rb16(pb); /* color table flags */
+            color_end = avio_rb16(pb);
+            if ((color_start <= 255) && (color_end <= 255)) {
+                for (i = color_start; i <= color_end; i++) {
+                    /* each A, R, G, or B component is 16 bits;
+                     * only use the top 8 bits */
+                    a = avio_r8(pb);
+                    avio_r8(pb);
+                    r = avio_r8(pb);
+                    avio_r8(pb);
+                    g = avio_r8(pb);
+                    avio_r8(pb);
+                    b = avio_r8(pb);
+                    avio_r8(pb);
+                    palette[i] = (a << 24 ) | (r << 16) | (g << 8) | (b);
+                }
+            }
+        }
+
+        return 1;
+    }
+
+    return 0;
+}