[FFmpeg-devel] [PATCH] libavformat: add DVD subtitle palette (CLUT) utilities

[Marth64 <marth64@proxyid.net>]

DVD subtitle palettes, which are natively YUV, are currently carried as
a hex string in their respective subtitle streams and have
no concept of colorspace tagging. In fact, the convention is to convert
them to RGB prior to storage. Common players will only render
the palettes properly if they are stored as RGB. Even ffmpeg itself
expects this, and already does -in libavformat- the YUV-RGB conversions,
specifically in mov.c and movenc.c.

The point of this patch is to provide a consolidation of the code
that deals with creating the extradata as well as the RGB conversion.
That can then (1) enable usable palette support for DVD demuxer if it is merged
and (2) start the process of consolidating the related conversions in
MOV muxer/demuxer and eventually find a way to properly tag
the colorspace.

Signed-off-by: Marth64 <marth64@proxyid.net>
---
 libavformat/dvdclut.c | 104 ++++++++++++++++++++++++++++++++++++++++++
 libavformat/dvdclut.h |  37 +++++++++++++++
 2 files changed, 141 insertions(+)
 create mode 100644 libavformat/dvdclut.c
 create mode 100644 libavformat/dvdclut.h

diff --git a/libavformat/dvdclut.c b/libavformat/dvdclut.c
new file mode 100644
index 0000000000..71fdda7925
--- /dev/null
+++ b/libavformat/dvdclut.c
@@ -0,0 +1,104 @@
+/*
+ * DVD-Video subpicture CLUT (Color Lookup Table) utilities
+ *
+ * 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 "libavutil/bprint.h"
+#include "libavutil/colorspace.h"
+#include "libavutil/intreadwrite.h"
+
+#include "avformat.h"
+#include "dvdclut.h"
+#include "internal.h"
+
+/* crop table for YUV to RGB subpicture palette conversion */
+#define FF_DVDCLUT_YUV_NEG_CROP_MAX    1024
+#define times4(x)                      x, x, x, x
+#define times256(x)                    times4(times4(times4(times4(times4(x)))))
+
+const uint8_t ff_dvdclut_yuv_crop_tab[256 + 2 * FF_DVDCLUT_YUV_NEG_CROP_MAX] = {
+times256(0x00),
+0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E,0x0F,
+0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,0x18,0x19,0x1A,0x1B,0x1C,0x1D,0x1E,0x1F,
+0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27,0x28,0x29,0x2A,0x2B,0x2C,0x2D,0x2E,0x2F,
+0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39,0x3A,0x3B,0x3C,0x3D,0x3E,0x3F,
+0x40,0x41,0x42,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0x4A,0x4B,0x4C,0x4D,0x4E,0x4F,
+0x50,0x51,0x52,0x53,0x54,0x55,0x56,0x57,0x58,0x59,0x5A,0x5B,0x5C,0x5D,0x5E,0x5F,
+0x60,0x61,0x62,0x63,0x64,0x65,0x66,0x67,0x68,0x69,0x6A,0x6B,0x6C,0x6D,0x6E,0x6F,
+0x70,0x71,0x72,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7A,0x7B,0x7C,0x7D,0x7E,0x7F,
+0x80,0x81,0x82,0x83,0x84,0x85,0x86,0x87,0x88,0x89,0x8A,0x8B,0x8C,0x8D,0x8E,0x8F,
+0x90,0x91,0x92,0x93,0x94,0x95,0x96,0x97,0x98,0x99,0x9A,0x9B,0x9C,0x9D,0x9E,0x9F,
+0xA0,0xA1,0xA2,0xA3,0xA4,0xA5,0xA6,0xA7,0xA8,0xA9,0xAA,0xAB,0xAC,0xAD,0xAE,0xAF,
+0xB0,0xB1,0xB2,0xB3,0xB4,0xB5,0xB6,0xB7,0xB8,0xB9,0xBA,0xBB,0xBC,0xBD,0xBE,0xBF,
+0xC0,0xC1,0xC2,0xC3,0xC4,0xC5,0xC6,0xC7,0xC8,0xC9,0xCA,0xCB,0xCC,0xCD,0xCE,0xCF,
+0xD0,0xD1,0xD2,0xD3,0xD4,0xD5,0xD6,0xD7,0xD8,0xD9,0xDA,0xDB,0xDC,0xDD,0xDE,0xDF,
+0xE0,0xE1,0xE2,0xE3,0xE4,0xE5,0xE6,0xE7,0xE8,0xE9,0xEA,0xEB,0xEC,0xED,0xEE,0xEF,
+0xF0,0xF1,0xF2,0xF3,0xF4,0xF5,0xF6,0xF7,0xF8,0xF9,0xFA,0xFB,0xFC,0xFD,0xFE,0xFF,
+times256(0xFF)
+};
+
+int ff_dvdclut_palette_extradata_cat(const uint32_t *clut,
+                                     const size_t clut_size,
+                                     AVCodecParameters *par)
+{
+    int ret = 0;
+    AVBPrint bp;
+
+    if (clut_size != FF_DVDCLUT_CLUT_SIZE)
+        return AVERROR(EINVAL);
+
+    av_bprint_init(&bp, 0, FF_DVDCLUT_EXTRADATA_SIZE);
+
+    av_bprintf(&bp, "palette: ");
+
+    for (int i = 0; i < FF_DVDCLUT_CLUT_LEN; i++)
+        av_bprintf(&bp, "%06"PRIx32"%s", clut[i], i != 15 ? ", " : "");
+
+    av_bprintf(&bp, "\n");
+
+    ret = ff_bprint_to_codecpar_extradata(par, &bp);
+
+    av_bprint_finalize(&bp, NULL);
+
+    return ret;
+}
+
+int ff_dvdclut_yuv_to_rgb(uint32_t *clut, const size_t clut_size)
+{
+    const uint8_t *cm = ff_dvdclut_yuv_crop_tab + FF_DVDCLUT_YUV_NEG_CROP_MAX;
+
+    int i, y, cb, cr;
+    uint8_t r, g, b;
+    int r_add, g_add, b_add;
+
+    if (clut_size != FF_DVDCLUT_CLUT_SIZE)
+        return AVERROR(EINVAL);
+
+    for (i = 0; i < FF_DVDCLUT_CLUT_LEN; i++) {
+        y  = (clut[i] >> 16) & 0xFF;
+        cr = (clut[i] >> 8)  & 0xFF;
+        cb = clut[i]         & 0xFF;
+
+        YUV_TO_RGB1_CCIR(cb, cr);
+        YUV_TO_RGB2_CCIR(r, g, b, y);
+
+        clut[i] = (r << 16) | (g << 8) | b;
+    }
+
+    return 0;
+}
diff --git a/libavformat/dvdclut.h b/libavformat/dvdclut.h
new file mode 100644
index 0000000000..40eff6de34
--- /dev/null
+++ b/libavformat/dvdclut.h
@@ -0,0 +1,37 @@
+/*
+ * DVD-Video subpicture CLUT (Color Lookup Table) utilities
+ *
+ * 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 AVFORMAT_DVDCLUT_H
+#define AVFORMAT_DVDCLUT_H
+
+#include "avformat.h"
+
+/* ("palette: ") + ("rrggbb, "*15) + ("rrggbb") + \n + \0 */
+#define FF_DVDCLUT_EXTRADATA_SIZE        (9 + (8 * 15) + 6 + 1 + 1)
+#define FF_DVDCLUT_CLUT_LEN              16
+#define FF_DVDCLUT_CLUT_SIZE             FF_DVDCLUT_CLUT_LEN * sizeof(uint32_t)
+
+int ff_dvdclut_palette_extradata_cat(const uint32_t *clut,
+                                     const size_t clut_size,
+                                     AVCodecParameters *par);
+
+int ff_dvdclut_yuv_to_rgb(uint32_t *clut, const size_t clut_size);
+
+#endif /* AVFORMAT_DVDCLUT_H */
-- 
2.34.1

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".