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ffmpeg / libavcodec / dvbsub.c @ 2912e87a

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/*
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 * DVB subtitle encoding for ffmpeg
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 * Copyright (c) 2005 Fabrice Bellard
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 *
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 * This file is part of Libav.
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 *
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 * Libav 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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 * Libav 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 Libav; 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 "libavutil/colorspace.h"
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typedef struct DVBSubtitleContext {
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    int hide_state;
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    int object_version;
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} DVBSubtitleContext;
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#define PUTBITS2(val)\
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{\
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    bitbuf |= (val) << bitcnt;\
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    bitcnt -= 2;\
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    if (bitcnt < 0) {\
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        bitcnt = 6;\
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        *q++ = bitbuf;\
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        bitbuf = 0;\
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    }\
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}
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static void dvb_encode_rle2(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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{
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    uint8_t *q;
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    unsigned int bitbuf;
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    int bitcnt;
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    int x, y, len, x1, v, color;
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    q = *pq;
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    for(y = 0; y < h; y++) {
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        *q++ = 0x10;
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        bitbuf = 0;
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        bitcnt = 6;
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        x = 0;
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        while (x < w) {
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            x1 = x;
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            color = bitmap[x1++];
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            while (x1 < w && bitmap[x1] == color)
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                x1++;
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            len = x1 - x;
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            if (color == 0 && len == 2) {
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                PUTBITS2(0);
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                PUTBITS2(0);
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                PUTBITS2(1);
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            } else if (len >= 3 && len <= 10) {
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                v = len - 3;
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                PUTBITS2(0);
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                PUTBITS2((v >> 2) | 2);
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                PUTBITS2(v & 3);
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                PUTBITS2(color);
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            } else if (len >= 12 && len <= 27) {
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                v = len - 12;
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                PUTBITS2(0);
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                PUTBITS2(0);
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                PUTBITS2(2);
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                PUTBITS2(v >> 2);
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                PUTBITS2(v & 3);
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                PUTBITS2(color);
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            } else if (len >= 29) {
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                /* length = 29 ... 284 */
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                if (len > 284)
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                    len = 284;
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                v = len - 29;
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                PUTBITS2(0);
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                PUTBITS2(0);
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                PUTBITS2(3);
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                PUTBITS2((v >> 6));
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                PUTBITS2((v >> 4) & 3);
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                PUTBITS2((v >> 2) & 3);
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                PUTBITS2(v & 3);
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                PUTBITS2(color);
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            } else {
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                PUTBITS2(color);
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                if (color == 0) {
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                    PUTBITS2(1);
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                }
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                len = 1;
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            }
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            x += len;
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        }
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        /* end of line */
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        PUTBITS2(0);
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        PUTBITS2(0);
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        PUTBITS2(0);
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        if (bitcnt != 6) {
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            *q++ = bitbuf;
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        }
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        *q++ = 0xf0;
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        bitmap += linesize;
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    }
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    *pq = q;
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}
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#define PUTBITS4(val)\
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{\
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    bitbuf |= (val) << bitcnt;\
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    bitcnt -= 4;\
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    if (bitcnt < 0) {\
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        bitcnt = 4;\
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        *q++ = bitbuf;\
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        bitbuf = 0;\
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    }\
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}
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/* some DVB decoders only implement 4 bits/pixel */
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static void dvb_encode_rle4(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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{
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    uint8_t *q;
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    unsigned int bitbuf;
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    int bitcnt;
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    int x, y, len, x1, v, color;
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    q = *pq;
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    for(y = 0; y < h; y++) {
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        *q++ = 0x11;
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        bitbuf = 0;
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        bitcnt = 4;
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        x = 0;
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        while (x < w) {
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            x1 = x;
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            color = bitmap[x1++];
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            while (x1 < w && bitmap[x1] == color)
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                x1++;
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            len = x1 - x;
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            if (color == 0 && len == 2) {
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                PUTBITS4(0);
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                PUTBITS4(0xd);
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            } else if (color == 0 && (len >= 3 && len <= 9)) {
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                PUTBITS4(0);
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                PUTBITS4(len - 2);
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            } else if (len >= 4 && len <= 7) {
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                PUTBITS4(0);
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                PUTBITS4(8 + len - 4);
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                PUTBITS4(color);
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            } else if (len >= 9 && len <= 24) {
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                PUTBITS4(0);
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                PUTBITS4(0xe);
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                PUTBITS4(len - 9);
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                PUTBITS4(color);
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            } else if (len >= 25) {
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                if (len > 280)
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                    len = 280;
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                v = len - 25;
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                PUTBITS4(0);
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                PUTBITS4(0xf);
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                PUTBITS4(v >> 4);
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                PUTBITS4(v & 0xf);
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                PUTBITS4(color);
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            } else {
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                PUTBITS4(color);
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                if (color == 0) {
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                    PUTBITS4(0xc);
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                }
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                len = 1;
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            }
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            x += len;
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        }
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        /* end of line */
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        PUTBITS4(0);
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        PUTBITS4(0);
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        if (bitcnt != 4) {
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            *q++ = bitbuf;
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        }
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        *q++ = 0xf0;
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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 encode_dvb_subtitles(DVBSubtitleContext *s,
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                                uint8_t *outbuf, AVSubtitle *h)
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{
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    uint8_t *q, *pseg_len;
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    int page_id, region_id, clut_id, object_id, i, bpp_index, page_state;
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    q = outbuf;
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    page_id = 1;
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    if (h->num_rects == 0 || h->rects == NULL)
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        return -1;
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    *q++ = 0x00; /* subtitle_stream_id */
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    /* page composition segment */
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    *q++ = 0x0f; /* sync_byte */
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    *q++ = 0x10; /* segment_type */
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    bytestream_put_be16(&q, page_id);
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    pseg_len = q;
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    q += 2; /* segment length */
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    *q++ = 30; /* page_timeout (seconds) */
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    if (s->hide_state)
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        page_state = 0; /* normal case */
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    else
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        page_state = 2; /* mode change */
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    /* page_version = 0 + page_state */
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    *q++ = (s->object_version << 4) | (page_state << 2) | 3;
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    for (region_id = 0; region_id < h->num_rects; region_id++) {
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        *q++ = region_id;
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        *q++ = 0xff; /* reserved */
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        bytestream_put_be16(&q, h->rects[region_id]->x); /* left pos */
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        bytestream_put_be16(&q, h->rects[region_id]->y); /* top pos */
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    }
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    bytestream_put_be16(&pseg_len, q - pseg_len - 2);
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    if (!s->hide_state) {
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        for (clut_id = 0; clut_id < h->num_rects; clut_id++) {
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            /* CLUT segment */
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            if (h->rects[clut_id]->nb_colors <= 4) {
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                /* 2 bpp, some decoders do not support it correctly */
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                bpp_index = 0;
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            } else if (h->rects[clut_id]->nb_colors <= 16) {
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                /* 4 bpp, standard encoding */
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                bpp_index = 1;
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            } else {
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                return -1;
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            }
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            *q++ = 0x0f; /* sync byte */
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            *q++ = 0x12; /* CLUT definition segment */
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            bytestream_put_be16(&q, page_id);
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            pseg_len = q;
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            q += 2; /* segment length */
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            *q++ = clut_id;
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            *q++ = (0 << 4) | 0xf; /* version = 0 */
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            for(i = 0; i < h->rects[clut_id]->nb_colors; i++) {
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                *q++ = i; /* clut_entry_id */
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                *q++ = (1 << (7 - bpp_index)) | (0xf << 1) | 1; /* 2 bits/pixel full range */
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                {
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                    int a, r, g, b;
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                    uint32_t x= ((uint32_t*)h->rects[clut_id]->pict.data[1])[i];
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                    a = (x >> 24) & 0xff;
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                    r = (x >> 16) & 0xff;
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                    g = (x >>  8) & 0xff;
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                    b = (x >>  0) & 0xff;
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                    *q++ = RGB_TO_Y_CCIR(r, g, b);
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                    *q++ = RGB_TO_V_CCIR(r, g, b, 0);
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                    *q++ = RGB_TO_U_CCIR(r, g, b, 0);
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                    *q++ = 255 - a;
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                }
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            }
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            bytestream_put_be16(&pseg_len, q - pseg_len - 2);
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        }
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    }
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    for (region_id = 0; region_id < h->num_rects; region_id++) {
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        /* region composition segment */
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        if (h->rects[region_id]->nb_colors <= 4) {
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            /* 2 bpp, some decoders do not support it correctly */
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            bpp_index = 0;
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        } else if (h->rects[region_id]->nb_colors <= 16) {
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            /* 4 bpp, standard encoding */
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            bpp_index = 1;
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        } else {
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            return -1;
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        }
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        *q++ = 0x0f; /* sync_byte */
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        *q++ = 0x11; /* segment_type */
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        bytestream_put_be16(&q, page_id);
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        pseg_len = q;
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        q += 2; /* segment length */
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        *q++ = region_id;
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        *q++ = (s->object_version << 4) | (0 << 3) | 0x07; /* version , no fill */
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        bytestream_put_be16(&q, h->rects[region_id]->w); /* region width */
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        bytestream_put_be16(&q, h->rects[region_id]->h); /* region height */
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        *q++ = ((1 + bpp_index) << 5) | ((1 + bpp_index) << 2) | 0x03;
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        *q++ = region_id; /* clut_id == region_id */
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        *q++ = 0; /* 8 bit fill colors */
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        *q++ = 0x03; /* 4 bit and 2 bit fill colors */
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        if (!s->hide_state) {
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            bytestream_put_be16(&q, region_id); /* object_id == region_id */
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            *q++ = (0 << 6) | (0 << 4);
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            *q++ = 0;
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            *q++ = 0xf0;
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            *q++ = 0;
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        }
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        bytestream_put_be16(&pseg_len, q - pseg_len - 2);
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    }
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    if (!s->hide_state) {
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        for (object_id = 0; object_id < h->num_rects; object_id++) {
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            /* Object Data segment */
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            if (h->rects[object_id]->nb_colors <= 4) {
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                /* 2 bpp, some decoders do not support it correctly */
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                bpp_index = 0;
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            } else if (h->rects[object_id]->nb_colors <= 16) {
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                /* 4 bpp, standard encoding */
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                bpp_index = 1;
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            } else {
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                return -1;
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            }
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            *q++ = 0x0f; /* sync byte */
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            *q++ = 0x13;
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            bytestream_put_be16(&q, page_id);
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            pseg_len = q;
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            q += 2; /* segment length */
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            bytestream_put_be16(&q, object_id);
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            *q++ = (s->object_version << 4) | (0 << 2) | (0 << 1) | 1; /* version = 0,
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                                                                       onject_coding_method,
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                                                                       non_modifying_color_flag */
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            {
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                uint8_t *ptop_field_len, *pbottom_field_len, *top_ptr, *bottom_ptr;
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                void (*dvb_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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                ptop_field_len = q;
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                q += 2;
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                pbottom_field_len = q;
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                q += 2;
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                if (bpp_index == 0)
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                    dvb_encode_rle = dvb_encode_rle2;
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                else
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                    dvb_encode_rle = dvb_encode_rle4;
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                top_ptr = q;
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                dvb_encode_rle(&q, h->rects[object_id]->pict.data[0], h->rects[object_id]->w * 2,
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                                    h->rects[object_id]->w, h->rects[object_id]->h >> 1);
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                bottom_ptr = q;
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                dvb_encode_rle(&q, h->rects[object_id]->pict.data[0] + h->rects[object_id]->w,
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                                    h->rects[object_id]->w * 2, h->rects[object_id]->w,
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                                    h->rects[object_id]->h >> 1);
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                bytestream_put_be16(&ptop_field_len, bottom_ptr - top_ptr);
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                bytestream_put_be16(&pbottom_field_len, q - bottom_ptr);
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            }
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            bytestream_put_be16(&pseg_len, q - pseg_len - 2);
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        }
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    }
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    /* end of display set segment */
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    *q++ = 0x0f; /* sync_byte */
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    *q++ = 0x80; /* segment_type */
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    bytestream_put_be16(&q, page_id);
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    pseg_len = q;
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    q += 2; /* segment length */
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    bytestream_put_be16(&pseg_len, q - pseg_len - 2);
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    *q++ = 0xff; /* end of PES data */
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    s->object_version = (s->object_version + 1) & 0xf;
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    s->hide_state = !s->hide_state;
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    return q - outbuf;
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}
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static int dvbsub_encode(AVCodecContext *avctx,
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                       unsigned char *buf, int buf_size, void *data)
396
{
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    DVBSubtitleContext *s = avctx->priv_data;
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    AVSubtitle *sub = data;
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    int ret;
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    ret = encode_dvb_subtitles(s, buf, sub);
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    return ret;
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}
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AVCodec ff_dvbsub_encoder = {
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    "dvbsub",
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    AVMEDIA_TYPE_SUBTITLE,
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    CODEC_ID_DVB_SUBTITLE,
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    sizeof(DVBSubtitleContext),
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    NULL,
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    dvbsub_encode,
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    .long_name = NULL_IF_CONFIG_SMALL("DVB subtitles"),
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};