mirror of
https://git.ffmpeg.org/ffmpeg.git
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237 lines
6.9 KiB
C
237 lines
6.9 KiB
C
/*
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* DVD subtitle encoding for ffmpeg
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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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#undef NDEBUG
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#include <assert.h>
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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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assert(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 encode_dvd_subtitles(uint8_t *outbuf, int outbuf_size,
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const AVSubtitle *h)
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{
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uint8_t *q, *qq;
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int object_id;
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int offset1[20], offset2[20];
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int i, imax, color, alpha, rects = h->num_rects;
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unsigned long hmax;
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unsigned long hist[256];
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int cmap[256];
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if (rects == 0 || h->rects == NULL)
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return -1;
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if (rects > 20)
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rects = 20;
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// analyze bitmaps, compress to 4 colors
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for (i=0; i<256; ++i) {
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hist[i] = 0;
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cmap[i] = 0;
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}
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for (object_id = 0; object_id < rects; object_id++)
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for (i=0; i<h->rects[object_id].w*h->rects[object_id].h; ++i) {
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color = h->rects[object_id].bitmap[i];
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// only count non-transparent pixels
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alpha = h->rects[object_id].rgba_palette[color] >> 24;
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hist[color] += alpha;
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}
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for (color=3;; --color) {
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hmax = 0;
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imax = 0;
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for (i=0; i<256; ++i)
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if (hist[i] > hmax) {
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imax = i;
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hmax = hist[i];
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}
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if (hmax == 0)
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break;
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if (color == 0)
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color = 3;
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av_log(NULL, AV_LOG_DEBUG, "dvd_subtitle hist[%d]=%ld -> col %d\n",
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imax, hist[imax], color);
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cmap[imax] = color;
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hist[imax] = 0;
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}
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// encode data block
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q = outbuf + 4;
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for (object_id = 0; object_id < rects; object_id++) {
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offset1[object_id] = q - outbuf;
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// worst case memory requirement: 1 nibble per pixel..
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if ((q - outbuf) + h->rects[object_id].w*h->rects[object_id].h/2
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+ 17*rects + 21 > outbuf_size) {
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av_log(NULL, AV_LOG_ERROR, "dvd_subtitle too big\n");
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return -1;
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}
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dvd_encode_rle(&q, h->rects[object_id].bitmap,
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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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cmap);
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offset2[object_id] = q - outbuf;
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dvd_encode_rle(&q, h->rects[object_id].bitmap + h->rects[object_id].w,
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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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cmap);
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}
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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*rects + 2);
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*q++ = 0x03; // palette - 4 nibbles
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*q++ = 0x03; *q++ = 0x7f;
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*q++ = 0x04; // alpha - 4 nibbles
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*q++ = 0xf0; *q++ = 0x00;
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//*q++ = 0x0f; *q++ = 0xff;
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// XXX not sure if more than one rect can really be encoded..
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// 12 bytes per rect
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for (object_id = 0; object_id < rects; object_id++) {
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int x2 = h->rects[object_id].x + h->rects[object_id].w - 1;
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int y2 = h->rects[object_id].y + h->rects[object_id].h - 1;
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*q++ = 0x05;
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// x1 x2 -> 6 nibbles
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*q++ = h->rects[object_id].x >> 4;
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*q++ = (h->rects[object_id].x << 4) | ((x2 >> 8) & 0xf);
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*q++ = x2;
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// y1 y2 -> 6 nibbles
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*q++ = h->rects[object_id].y >> 4;
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*q++ = (h->rects[object_id].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[object_id]);
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bytestream_put_be16(&q, offset2[object_id]);
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}
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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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return q - outbuf;
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}
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static int dvdsub_init_encoder(AVCodecContext *avctx)
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{
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return 0;
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}
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static int dvdsub_close_encoder(AVCodecContext *avctx)
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{
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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, void *data)
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{
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//DVDSubtitleContext *s = avctx->priv_data;
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AVSubtitle *sub = data;
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int ret;
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ret = encode_dvd_subtitles(buf, buf_size, sub);
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return ret;
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}
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AVCodec dvdsub_encoder = {
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"dvdsub",
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CODEC_TYPE_SUBTITLE,
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CODEC_ID_DVD_SUBTITLE,
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0,
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dvdsub_init_encoder,
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dvdsub_encode,
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dvdsub_close_encoder,
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};
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