mirror of
https://git.ffmpeg.org/ffmpeg.git
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511 lines
15 KiB
C
511 lines
15 KiB
C
/*
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* DVD subtitle decoding for ffmpeg
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* Copyright (c) 2005 Fabrice Bellard.
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "avcodec.h"
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#include "bitstream.h"
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#include "colorspace.h"
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#include "dsputil.h"
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//#define DEBUG
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static void yuv_a_to_rgba(const uint8_t *ycbcr, const uint8_t *alpha, uint32_t *rgba, int num_values)
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{
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uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
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uint8_t r, g, b;
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int i, y, cb, cr;
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int r_add, g_add, b_add;
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for (i = num_values; i > 0; i--) {
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y = *ycbcr++;
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cb = *ycbcr++;
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cr = *ycbcr++;
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YUV_TO_RGB1_CCIR(cb, cr);
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YUV_TO_RGB2_CCIR(r, g, b, y);
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*rgba++ = (*alpha++ << 24) | (r << 16) | (g << 8) | b;
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}
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}
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static int decode_run_2bit(GetBitContext *gb, int *color)
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{
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unsigned int v, t;
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v = 0;
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for (t = 1; v < t && t <= 0x40; t <<= 2)
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v = (v << 4) | get_bits(gb, 4);
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*color = v & 3;
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if (v < 4) { /* Code for fill rest of line */
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return INT_MAX;
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}
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return v >> 2;
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}
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static int decode_run_8bit(GetBitContext *gb, int *color)
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{
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int len;
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int has_run = get_bits1(gb);
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if (get_bits1(gb))
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*color = get_bits(gb, 8);
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else
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*color = get_bits(gb, 2);
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if (has_run) {
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if (get_bits1(gb)) {
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len = get_bits(gb, 7);
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if (len == 0)
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len = INT_MAX;
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else
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len += 9;
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} else
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len = get_bits(gb, 3) + 2;
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} else
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len = 1;
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return len;
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}
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static int decode_rle(uint8_t *bitmap, int linesize, int w, int h,
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const uint8_t *buf, int start, int buf_size, int is_8bit)
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{
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GetBitContext gb;
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int bit_len;
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int x, y, len, color;
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uint8_t *d;
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bit_len = (buf_size - start) * 8;
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init_get_bits(&gb, buf + start, bit_len);
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x = 0;
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y = 0;
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d = bitmap;
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for(;;) {
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if (get_bits_count(&gb) > bit_len)
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return -1;
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if (is_8bit)
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len = decode_run_8bit(&gb, &color);
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else
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len = decode_run_2bit(&gb, &color);
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len = FFMIN(len, w - x);
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memset(d + x, color, len);
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x += len;
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if (x >= w) {
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y++;
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if (y >= h)
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break;
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d += linesize;
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x = 0;
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/* byte align */
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align_get_bits(&gb);
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}
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}
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return 0;
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}
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static void guess_palette(uint32_t *rgba_palette,
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uint8_t *colormap,
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uint8_t *alpha,
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uint32_t subtitle_color)
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{
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uint8_t color_used[16];
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int nb_opaque_colors, i, level, j, r, g, b;
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for(i = 0; i < 4; i++)
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rgba_palette[i] = 0;
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memset(color_used, 0, 16);
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nb_opaque_colors = 0;
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for(i = 0; i < 4; i++) {
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if (alpha[i] != 0 && !color_used[colormap[i]]) {
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color_used[colormap[i]] = 1;
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nb_opaque_colors++;
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}
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}
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if (nb_opaque_colors == 0)
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return;
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j = nb_opaque_colors;
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memset(color_used, 0, 16);
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for(i = 0; i < 4; i++) {
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if (alpha[i] != 0) {
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if (!color_used[colormap[i]]) {
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level = (0xff * j) / nb_opaque_colors;
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r = (((subtitle_color >> 16) & 0xff) * level) >> 8;
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g = (((subtitle_color >> 8) & 0xff) * level) >> 8;
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b = (((subtitle_color >> 0) & 0xff) * level) >> 8;
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rgba_palette[i] = b | (g << 8) | (r << 16) | ((alpha[i] * 17) << 24);
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color_used[colormap[i]] = (i + 1);
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j--;
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} else {
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rgba_palette[i] = (rgba_palette[color_used[colormap[i]] - 1] & 0x00ffffff) |
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((alpha[i] * 17) << 24);
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}
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}
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}
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}
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#define READ_OFFSET(a) (big_offsets ? AV_RB32(a) : AV_RB16(a))
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static int decode_dvd_subtitles(AVSubtitle *sub_header,
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const uint8_t *buf, int buf_size)
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{
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int cmd_pos, pos, cmd, x1, y1, x2, y2, offset1, offset2, next_cmd_pos;
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int big_offsets, offset_size, is_8bit = 0;
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const uint8_t *yuv_palette = 0;
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uint8_t colormap[4], alpha[256];
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int date;
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int i;
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int is_menu = 0;
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if (buf_size < 10)
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return -1;
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sub_header->rects = NULL;
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sub_header->num_rects = 0;
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sub_header->start_display_time = 0;
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sub_header->end_display_time = 0;
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if (AV_RB16(buf) == 0) { /* HD subpicture with 4-byte offsets */
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big_offsets = 1;
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offset_size = 4;
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cmd_pos = 6;
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} else {
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big_offsets = 0;
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offset_size = 2;
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cmd_pos = 2;
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}
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cmd_pos = READ_OFFSET(buf + cmd_pos);
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while ((cmd_pos + 2 + offset_size) < buf_size) {
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date = AV_RB16(buf + cmd_pos);
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next_cmd_pos = READ_OFFSET(buf + cmd_pos + 2);
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#ifdef DEBUG
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av_log(NULL, AV_LOG_INFO, "cmd_pos=0x%04x next=0x%04x date=%d\n",
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cmd_pos, next_cmd_pos, date);
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#endif
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pos = cmd_pos + 2 + offset_size;
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offset1 = -1;
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offset2 = -1;
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x1 = y1 = x2 = y2 = 0;
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while (pos < buf_size) {
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cmd = buf[pos++];
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#ifdef DEBUG
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av_log(NULL, AV_LOG_INFO, "cmd=%02x\n", cmd);
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#endif
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switch(cmd) {
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case 0x00:
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/* menu subpicture */
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is_menu = 1;
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break;
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case 0x01:
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/* set start date */
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sub_header->start_display_time = (date << 10) / 90;
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break;
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case 0x02:
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/* set end date */
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sub_header->end_display_time = (date << 10) / 90;
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break;
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case 0x03:
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/* set colormap */
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if ((buf_size - pos) < 2)
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goto fail;
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colormap[3] = buf[pos] >> 4;
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colormap[2] = buf[pos] & 0x0f;
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colormap[1] = buf[pos + 1] >> 4;
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colormap[0] = buf[pos + 1] & 0x0f;
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pos += 2;
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break;
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case 0x04:
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/* set alpha */
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if ((buf_size - pos) < 2)
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goto fail;
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alpha[3] = buf[pos] >> 4;
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alpha[2] = buf[pos] & 0x0f;
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alpha[1] = buf[pos + 1] >> 4;
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alpha[0] = buf[pos + 1] & 0x0f;
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pos += 2;
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#ifdef DEBUG
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av_log(NULL, AV_LOG_INFO, "alpha=%x%x%x%x\n", alpha[0],alpha[1],alpha[2],alpha[3]);
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#endif
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break;
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case 0x05:
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case 0x85:
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if ((buf_size - pos) < 6)
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goto fail;
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x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4);
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x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2];
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y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4);
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y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5];
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if (cmd & 0x80)
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is_8bit = 1;
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#ifdef DEBUG
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av_log(NULL, AV_LOG_INFO, "x1=%d x2=%d y1=%d y2=%d\n",
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x1, x2, y1, y2);
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#endif
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pos += 6;
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break;
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case 0x06:
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if ((buf_size - pos) < 4)
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goto fail;
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offset1 = AV_RB16(buf + pos);
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offset2 = AV_RB16(buf + pos + 2);
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#ifdef DEBUG
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av_log(NULL, AV_LOG_INFO, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
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#endif
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pos += 4;
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break;
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case 0x86:
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if ((buf_size - pos) < 8)
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goto fail;
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offset1 = AV_RB32(buf + pos);
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offset2 = AV_RB32(buf + pos + 4);
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#ifdef DEBUG
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av_log(NULL, AV_LOG_INFO, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
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#endif
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pos += 8;
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break;
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case 0x83:
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/* HD set palette */
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if ((buf_size - pos) < 768)
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goto fail;
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yuv_palette = buf + pos;
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pos += 768;
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break;
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case 0x84:
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/* HD set contrast (alpha) */
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if ((buf_size - pos) < 256)
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goto fail;
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for (i = 0; i < 256; i++)
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alpha[i] = 0xFF - buf[pos+i];
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pos += 256;
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break;
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case 0xff:
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goto the_end;
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default:
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#ifdef DEBUG
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av_log(NULL, AV_LOG_INFO, "unrecognised subpicture command 0x%x\n", cmd);
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#endif
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goto the_end;
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}
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}
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the_end:
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if (offset1 >= 0) {
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int w, h;
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uint8_t *bitmap;
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/* decode the bitmap */
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w = x2 - x1 + 1;
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if (w < 0)
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w = 0;
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h = y2 - y1;
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if (h < 0)
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h = 0;
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if (w > 0 && h > 0) {
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if (sub_header->rects != NULL) {
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for (i = 0; i < sub_header->num_rects; i++) {
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av_free(sub_header->rects[i].bitmap);
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av_free(sub_header->rects[i].rgba_palette);
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}
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av_freep(&sub_header->rects);
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sub_header->num_rects = 0;
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}
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bitmap = av_malloc(w * h);
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sub_header->rects = av_mallocz(sizeof(AVSubtitleRect));
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sub_header->num_rects = 1;
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sub_header->rects[0].bitmap = bitmap;
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decode_rle(bitmap, w * 2, w, (h + 1) / 2,
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buf, offset1, buf_size, is_8bit);
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decode_rle(bitmap + w, w * 2, w, h / 2,
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buf, offset2, buf_size, is_8bit);
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if (is_8bit) {
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if (yuv_palette == 0)
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goto fail;
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sub_header->rects[0].rgba_palette = av_malloc(256 * 4);
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sub_header->rects[0].nb_colors = 256;
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yuv_a_to_rgba(yuv_palette, alpha, sub_header->rects[0].rgba_palette, 256);
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} else {
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sub_header->rects[0].rgba_palette = av_malloc(4 * 4);
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sub_header->rects[0].nb_colors = 4;
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guess_palette(sub_header->rects[0].rgba_palette,
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colormap, alpha, 0xffff00);
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}
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sub_header->rects[0].x = x1;
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sub_header->rects[0].y = y1;
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sub_header->rects[0].w = w;
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sub_header->rects[0].h = h;
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sub_header->rects[0].linesize = w;
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}
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}
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if (next_cmd_pos == cmd_pos)
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break;
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cmd_pos = next_cmd_pos;
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}
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if (sub_header->num_rects > 0)
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return is_menu;
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fail:
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if (sub_header->rects != NULL) {
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for (i = 0; i < sub_header->num_rects; i++) {
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av_free(sub_header->rects[i].bitmap);
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av_free(sub_header->rects[i].rgba_palette);
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}
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av_freep(&sub_header->rects);
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sub_header->num_rects = 0;
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}
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return -1;
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}
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static int is_transp(const uint8_t *buf, int pitch, int n,
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const uint8_t *transp_color)
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{
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int i;
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for(i = 0; i < n; i++) {
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if (!transp_color[*buf])
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return 0;
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buf += pitch;
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}
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return 1;
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}
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/* return 0 if empty rectangle, 1 if non empty */
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static int find_smallest_bounding_rectangle(AVSubtitle *s)
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{
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uint8_t transp_color[256];
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int y1, y2, x1, x2, y, w, h, i;
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uint8_t *bitmap;
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if (s->num_rects == 0 || s->rects == NULL || s->rects[0].w <= 0 || s->rects[0].h <= 0)
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return 0;
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memset(transp_color, 0, 256);
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for(i = 0; i < s->rects[0].nb_colors; i++) {
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if ((s->rects[0].rgba_palette[i] >> 24) == 0)
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transp_color[i] = 1;
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}
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y1 = 0;
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while (y1 < s->rects[0].h && is_transp(s->rects[0].bitmap + y1 * s->rects[0].linesize,
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1, s->rects[0].w, transp_color))
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y1++;
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if (y1 == s->rects[0].h) {
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av_freep(&s->rects[0].bitmap);
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s->rects[0].w = s->rects[0].h = 0;
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return 0;
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}
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y2 = s->rects[0].h - 1;
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while (y2 > 0 && is_transp(s->rects[0].bitmap + y2 * s->rects[0].linesize, 1,
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s->rects[0].w, transp_color))
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y2--;
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x1 = 0;
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while (x1 < (s->rects[0].w - 1) && is_transp(s->rects[0].bitmap + x1, s->rects[0].linesize,
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s->rects[0].h, transp_color))
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x1++;
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x2 = s->rects[0].w - 1;
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while (x2 > 0 && is_transp(s->rects[0].bitmap + x2, s->rects[0].linesize, s->rects[0].h,
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transp_color))
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x2--;
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w = x2 - x1 + 1;
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h = y2 - y1 + 1;
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bitmap = av_malloc(w * h);
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if (!bitmap)
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return 1;
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for(y = 0; y < h; y++) {
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memcpy(bitmap + w * y, s->rects[0].bitmap + x1 + (y1 + y) * s->rects[0].linesize, w);
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}
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av_freep(&s->rects[0].bitmap);
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s->rects[0].bitmap = bitmap;
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s->rects[0].linesize = w;
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s->rects[0].w = w;
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s->rects[0].h = h;
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s->rects[0].x += x1;
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s->rects[0].y += y1;
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return 1;
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}
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#ifdef DEBUG
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#undef fprintf
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static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,
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uint32_t *rgba_palette)
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{
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int x, y, v;
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FILE *f;
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f = fopen(filename, "w");
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if (!f) {
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perror(filename);
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exit(1);
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}
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fprintf(f, "P6\n"
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"%d %d\n"
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"%d\n",
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w, h, 255);
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for(y = 0; y < h; y++) {
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for(x = 0; x < w; x++) {
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v = rgba_palette[bitmap[y * w + x]];
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putc((v >> 16) & 0xff, f);
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putc((v >> 8) & 0xff, f);
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putc((v >> 0) & 0xff, f);
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}
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}
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fclose(f);
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}
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#endif
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static int dvdsub_decode(AVCodecContext *avctx,
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void *data, int *data_size,
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const uint8_t *buf, int buf_size)
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{
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AVSubtitle *sub = (void *)data;
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int is_menu;
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is_menu = decode_dvd_subtitles(sub, buf, buf_size);
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|
|
if (is_menu < 0) {
|
|
no_subtitle:
|
|
*data_size = 0;
|
|
|
|
return buf_size;
|
|
}
|
|
if (!is_menu && find_smallest_bounding_rectangle(sub) == 0)
|
|
goto no_subtitle;
|
|
|
|
#if defined(DEBUG)
|
|
av_log(NULL, AV_LOG_INFO, "start=%d ms end =%d ms\n",
|
|
sub->start_display_time,
|
|
sub->end_display_time);
|
|
ppm_save("/tmp/a.ppm", sub->rects[0].bitmap,
|
|
sub->rects[0].w, sub->rects[0].h, sub->rects[0].rgba_palette);
|
|
#endif
|
|
|
|
*data_size = 1;
|
|
return buf_size;
|
|
}
|
|
|
|
AVCodec dvdsub_decoder = {
|
|
"dvdsub",
|
|
CODEC_TYPE_SUBTITLE,
|
|
CODEC_ID_DVD_SUBTITLE,
|
|
0,
|
|
NULL,
|
|
NULL,
|
|
NULL,
|
|
dvdsub_decode,
|
|
.long_name = NULL_IF_CONFIG_SMALL("DVD subtitles"),
|
|
};
|