444 lines
14 KiB
C
444 lines
14 KiB
C
/*
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* DVD subtitle encoding
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* Copyright (c) 2005 Wolfram Gloger
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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 "bytestream.h"
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#include "internal.h"
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#include "libavutil/avassert.h"
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#include "libavutil/bprint.h"
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#include "libavutil/imgutils.h"
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typedef struct {
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uint32_t global_palette[16];
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} DVDSubtitleContext;
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// ncnt is the nibble counter
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#define PUTNIBBLE(val)\
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do {\
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if (ncnt++ & 1)\
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*q++ = bitbuf | ((val) & 0x0f);\
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else\
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bitbuf = (val) << 4;\
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} while(0)
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static void dvd_encode_rle(uint8_t **pq,
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const uint8_t *bitmap, int linesize,
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int w, int h,
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const int cmap[256])
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{
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uint8_t *q;
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unsigned int bitbuf = 0;
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int ncnt;
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int x, y, len, color;
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q = *pq;
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for (y = 0; y < h; ++y) {
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ncnt = 0;
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for(x = 0; x < w; x += len) {
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color = bitmap[x];
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for (len=1; x+len < w; ++len)
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if (bitmap[x+len] != color)
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break;
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color = cmap[color];
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av_assert0(color < 4);
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if (len < 0x04) {
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PUTNIBBLE((len << 2)|color);
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} else if (len < 0x10) {
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PUTNIBBLE(len >> 2);
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PUTNIBBLE((len << 2)|color);
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} else if (len < 0x40) {
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PUTNIBBLE(0);
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PUTNIBBLE(len >> 2);
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PUTNIBBLE((len << 2)|color);
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} else if (x+len == w) {
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PUTNIBBLE(0);
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PUTNIBBLE(0);
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PUTNIBBLE(0);
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PUTNIBBLE(color);
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} else {
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if (len > 0xff)
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len = 0xff;
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PUTNIBBLE(0);
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PUTNIBBLE(len >> 6);
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PUTNIBBLE(len >> 2);
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PUTNIBBLE((len << 2)|color);
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}
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}
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/* end of line */
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if (ncnt & 1)
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PUTNIBBLE(0);
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bitmap += linesize;
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}
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*pq = q;
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}
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static int color_distance(uint32_t a, uint32_t b)
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{
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int r = 0, d, i;
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int alpha_a = 8, alpha_b = 8;
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for (i = 24; i >= 0; i -= 8) {
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d = alpha_a * (int)((a >> i) & 0xFF) -
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alpha_b * (int)((b >> i) & 0xFF);
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r += d * d;
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alpha_a = a >> 28;
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alpha_b = b >> 28;
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}
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return r;
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}
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/**
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* Count colors used in a rectangle, quantizing alpha and grouping by
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* nearest global palette entry.
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*/
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static void count_colors(AVCodecContext *avctx, unsigned hits[33],
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const AVSubtitleRect *r)
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{
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DVDSubtitleContext *dvdc = avctx->priv_data;
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unsigned count[256] = { 0 };
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uint32_t *palette = (uint32_t *)r->pict.data[1];
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uint32_t color;
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int x, y, i, j, match, d, best_d, av_uninit(best_j);
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uint8_t *p = r->pict.data[0];
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for (y = 0; y < r->h; y++) {
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for (x = 0; x < r->w; x++)
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count[*(p++)]++;
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p += r->pict.linesize[0] - r->w;
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}
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for (i = 0; i < 256; i++) {
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if (!count[i]) /* avoid useless search */
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continue;
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color = palette[i];
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/* 0: transparent, 1-16: semi-transparent, 17-33 opaque */
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match = color < 0x33000000 ? 0 : color < 0xCC000000 ? 1 : 17;
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if (match) {
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best_d = INT_MAX;
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for (j = 0; j < 16; j++) {
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d = color_distance(0xFF000000 | color,
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0xFF000000 | dvdc->global_palette[j]);
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if (d < best_d) {
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best_d = d;
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best_j = j;
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}
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}
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match += best_j;
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}
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hits[match] += count[i];
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}
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}
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static void select_palette(AVCodecContext *avctx, int out_palette[4],
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int out_alpha[4], unsigned hits[33])
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{
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DVDSubtitleContext *dvdc = avctx->priv_data;
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int i, j, bright, mult;
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uint32_t color;
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int selected[4] = { 0 };
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uint32_t pseudopal[33] = { 0 };
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uint32_t refcolor[3] = { 0x00000000, 0xFFFFFFFF, 0xFF000000 };
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/* Bonus for transparent: if the rectangle fits tightly the text, the
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background color can be quite rare, but it would be ugly without it */
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hits[0] *= 16;
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/* Bonus for bright colors */
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for (i = 0; i < 16; i++) {
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if (!(hits[1 + i] + hits[17 + i]))
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continue; /* skip unused colors to gain time */
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color = dvdc->global_palette[i];
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bright = 0;
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for (j = 0; j < 3; j++, color >>= 8)
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bright += (color & 0xFF) < 0x40 || (color & 0xFF) >= 0xC0;
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mult = 2 + FFMIN(bright, 2);
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hits[ 1 + i] *= mult;
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hits[17 + i] *= mult;
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}
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/* Select four most frequent colors */
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for (i = 0; i < 4; i++) {
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for (j = 0; j < 33; j++)
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if (hits[j] > hits[selected[i]])
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selected[i] = j;
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hits[selected[i]] = 0;
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}
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/* Order the colors like in most DVDs:
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0: background, 1: foreground, 2: outline */
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for (i = 0; i < 16; i++) {
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pseudopal[ 1 + i] = 0x80000000 | dvdc->global_palette[i];
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pseudopal[17 + i] = 0xFF000000 | dvdc->global_palette[i];
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}
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for (i = 0; i < 3; i++) {
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int best_d = color_distance(refcolor[i], pseudopal[selected[i]]);
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for (j = i + 1; j < 4; j++) {
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int d = color_distance(refcolor[i], pseudopal[selected[j]]);
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if (d < best_d) {
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FFSWAP(int, selected[i], selected[j]);
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best_d = d;
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}
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}
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}
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/* Output */
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for (i = 0; i < 4; i++) {
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out_palette[i] = selected[i] ? (selected[i] - 1) & 0xF : 0;
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out_alpha [i] = !selected[i] ? 0 : selected[i] < 17 ? 0x80 : 0xFF;
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}
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}
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static void build_color_map(AVCodecContext *avctx, int cmap[],
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const uint32_t palette[],
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const int out_palette[], unsigned int const out_alpha[])
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{
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DVDSubtitleContext *dvdc = avctx->priv_data;
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int i, j, d, best_d;
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uint32_t pseudopal[4];
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for (i = 0; i < 4; i++)
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pseudopal[i] = (out_alpha[i] << 24) |
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dvdc->global_palette[out_palette[i]];
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for (i = 0; i < 256; i++) {
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best_d = INT_MAX;
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for (j = 0; j < 4; j++) {
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d = color_distance(pseudopal[j], palette[i]);
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if (d < best_d) {
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cmap[i] = j;
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best_d = d;
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}
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}
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}
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}
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static void copy_rectangle(AVSubtitleRect *dst, AVSubtitleRect *src, int cmap[])
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{
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int x, y;
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uint8_t *p, *q;
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p = src->pict.data[0];
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q = dst->pict.data[0] + (src->x - dst->x) +
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(src->y - dst->y) * dst->pict.linesize[0];
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for (y = 0; y < src->h; y++) {
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for (x = 0; x < src->w; x++)
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*(q++) = cmap[*(p++)];
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p += src->pict.linesize[0] - src->w;
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q += dst->pict.linesize[0] - src->w;
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}
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}
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static int encode_dvd_subtitles(AVCodecContext *avctx,
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uint8_t *outbuf, int outbuf_size,
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const AVSubtitle *h)
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{
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DVDSubtitleContext *dvdc = avctx->priv_data;
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uint8_t *q, *qq;
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int offset1, offset2;
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int i, rects = h->num_rects, ret;
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unsigned global_palette_hits[33] = { 0 };
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int cmap[256];
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int out_palette[4];
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int out_alpha[4];
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AVSubtitleRect vrect;
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uint8_t *vrect_data = NULL;
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int x2, y2;
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if (rects == 0 || h->rects == NULL)
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return AVERROR(EINVAL);
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for (i = 0; i < rects; i++)
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if (h->rects[i]->type != SUBTITLE_BITMAP) {
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av_log(avctx, AV_LOG_ERROR, "Bitmap subtitle required\n");
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return AVERROR(EINVAL);
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}
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vrect = *h->rects[0];
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if (rects > 1) {
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/* DVD subtitles can have only one rectangle: build a virtual
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rectangle containing all actual rectangles.
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The data of the rectangles will be copied later, when the palette
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is decided, because the rectangles may have different palettes. */
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int xmin = h->rects[0]->x, xmax = xmin + h->rects[0]->w;
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int ymin = h->rects[0]->y, ymax = ymin + h->rects[0]->h;
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for (i = 1; i < rects; i++) {
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xmin = FFMIN(xmin, h->rects[i]->x);
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ymin = FFMIN(ymin, h->rects[i]->y);
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xmax = FFMAX(xmax, h->rects[i]->x + h->rects[i]->w);
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ymax = FFMAX(ymax, h->rects[i]->y + h->rects[i]->h);
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}
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vrect.x = xmin;
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vrect.y = ymin;
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vrect.w = xmax - xmin;
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vrect.h = ymax - ymin;
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if ((ret = av_image_check_size(vrect.w, vrect.h, 0, avctx)) < 0)
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return ret;
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/* Count pixels outside the virtual rectangle as transparent */
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global_palette_hits[0] = vrect.w * vrect.h;
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for (i = 0; i < rects; i++)
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global_palette_hits[0] -= h->rects[i]->w * h->rects[i]->h;
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}
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for (i = 0; i < rects; i++)
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count_colors(avctx, global_palette_hits, h->rects[i]);
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select_palette(avctx, out_palette, out_alpha, global_palette_hits);
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if (rects > 1) {
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if (!(vrect_data = av_calloc(vrect.w, vrect.h)))
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return AVERROR(ENOMEM);
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vrect.pict.data [0] = vrect_data;
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vrect.pict.linesize[0] = vrect.w;
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for (i = 0; i < rects; i++) {
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build_color_map(avctx, cmap, (uint32_t *)h->rects[i]->pict.data[1],
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out_palette, out_alpha);
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copy_rectangle(&vrect, h->rects[i], cmap);
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}
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for (i = 0; i < 4; i++)
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cmap[i] = i;
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} else {
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build_color_map(avctx, cmap, (uint32_t *)h->rects[0]->pict.data[1],
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out_palette, out_alpha);
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}
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av_log(avctx, AV_LOG_DEBUG, "Selected palette:");
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for (i = 0; i < 4; i++)
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av_log(avctx, AV_LOG_DEBUG, " 0x%06x@@%02x (0x%x,0x%x)",
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dvdc->global_palette[out_palette[i]], out_alpha[i],
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out_palette[i], out_alpha[i] >> 4);
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av_log(avctx, AV_LOG_DEBUG, "\n");
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// encode data block
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q = outbuf + 4;
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offset1 = q - outbuf;
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// worst case memory requirement: 1 nibble per pixel..
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if ((q - outbuf) + vrect.w * vrect.h / 2 + 17 + 21 > outbuf_size) {
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av_log(NULL, AV_LOG_ERROR, "dvd_subtitle too big\n");
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ret = AVERROR_BUFFER_TOO_SMALL;
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goto fail;
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}
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dvd_encode_rle(&q, vrect.pict.data[0], vrect.w * 2,
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vrect.w, (vrect.h + 1) >> 1, cmap);
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offset2 = q - outbuf;
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dvd_encode_rle(&q, vrect.pict.data[0] + vrect.w, vrect.w * 2,
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vrect.w, vrect.h >> 1, cmap);
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// set data packet size
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qq = outbuf + 2;
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bytestream_put_be16(&qq, q - outbuf);
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// send start display command
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bytestream_put_be16(&q, (h->start_display_time*90) >> 10);
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bytestream_put_be16(&q, (q - outbuf) /*- 2 */ + 8 + 12 + 2);
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*q++ = 0x03; // palette - 4 nibbles
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*q++ = (out_palette[3] << 4) | out_palette[2];
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*q++ = (out_palette[1] << 4) | out_palette[0];
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*q++ = 0x04; // alpha - 4 nibbles
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*q++ = (out_alpha[3] & 0xF0) | (out_alpha[2] >> 4);
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*q++ = (out_alpha[1] & 0xF0) | (out_alpha[0] >> 4);
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// 12 bytes per rect
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x2 = vrect.x + vrect.w - 1;
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y2 = vrect.y + vrect.h - 1;
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*q++ = 0x05;
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// x1 x2 -> 6 nibbles
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*q++ = vrect.x >> 4;
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*q++ = (vrect.x << 4) | ((x2 >> 8) & 0xf);
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*q++ = x2;
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// y1 y2 -> 6 nibbles
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*q++ = vrect.y >> 4;
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*q++ = (vrect.y << 4) | ((y2 >> 8) & 0xf);
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*q++ = y2;
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*q++ = 0x06;
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// offset1, offset2
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bytestream_put_be16(&q, offset1);
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bytestream_put_be16(&q, offset2);
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*q++ = 0x01; // start command
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*q++ = 0xff; // terminating command
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// send stop display command last
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bytestream_put_be16(&q, (h->end_display_time*90) >> 10);
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bytestream_put_be16(&q, (q - outbuf) - 2 /*+ 4*/);
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*q++ = 0x02; // set end
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*q++ = 0xff; // terminating command
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qq = outbuf;
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bytestream_put_be16(&qq, q - outbuf);
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av_log(NULL, AV_LOG_DEBUG, "subtitle_packet size=%td\n", q - outbuf);
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ret = q - outbuf;
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fail:
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av_free(vrect_data);
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return ret;
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}
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static int dvdsub_init(AVCodecContext *avctx)
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{
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DVDSubtitleContext *dvdc = avctx->priv_data;
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static const uint32_t default_palette[16] = {
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0x000000, 0x0000FF, 0x00FF00, 0xFF0000,
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0xFFFF00, 0xFF00FF, 0x00FFFF, 0xFFFFFF,
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0x808000, 0x8080FF, 0x800080, 0x80FF80,
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0x008080, 0xFF8080, 0x555555, 0xAAAAAA,
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};
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AVBPrint extradata;
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int i, ret;
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av_assert0(sizeof(dvdc->global_palette) == sizeof(default_palette));
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memcpy(dvdc->global_palette, default_palette, sizeof(dvdc->global_palette));
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av_bprint_init(&extradata, 0, 1);
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if (avctx->width && avctx->height)
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av_bprintf(&extradata, "size: %dx%d\n", avctx->width, avctx->height);
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av_bprintf(&extradata, "palette:");
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for (i = 0; i < 16; i++)
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av_bprintf(&extradata, " %06"PRIx32"%c",
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dvdc->global_palette[i] & 0xFFFFFF, i < 15 ? ',' : '\n');
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ret = avpriv_bprint_to_extradata(avctx, &extradata);
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if (ret < 0)
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return ret;
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return 0;
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}
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static int dvdsub_encode(AVCodecContext *avctx,
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unsigned char *buf, int buf_size,
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const AVSubtitle *sub)
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{
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//DVDSubtitleContext *s = avctx->priv_data;
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int ret;
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ret = encode_dvd_subtitles(avctx, buf, buf_size, sub);
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return ret;
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}
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AVCodec ff_dvdsub_encoder = {
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.name = "dvdsub",
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.long_name = NULL_IF_CONFIG_SMALL("DVD subtitles"),
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.type = AVMEDIA_TYPE_SUBTITLE,
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.id = AV_CODEC_ID_DVD_SUBTITLE,
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.init = dvdsub_init,
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.encode_sub = dvdsub_encode,
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.priv_data_size = sizeof(DVDSubtitleContext),
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};
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