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FFmpeg/libavcodec/dvdsub.c
Ian Caulfield bf01fb696d subs.diff fixes a couple of minor bugs in my DVB subtitle decoder, and also fixes a few
problems in the DVD decoder (the palette entries were being read
back-to-front, and the timing conversions were slighly off)
patch by (Ian Caulfield: imc25, cam ac uk)

Originally committed as revision 4520 to svn://svn.ffmpeg.org/ffmpeg/trunk
2005-08-14 01:15:27 +00:00

479 lines
14 KiB
C

/*
* DVD subtitle decoding for ffmpeg
* Copyright (c) 2005 Fabrice Bellard.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "avcodec.h"
//#define DEBUG
typedef struct DVDSubContext {
} DVDSubContext;
static int dvdsub_init_decoder(AVCodecContext *avctx)
{
return 0;
}
uint16_t getbe16(const uint8_t *p)
{
return (p[0] << 8) | p[1];
}
int get_nibble(const uint8_t *buf, int nibble_offset)
{
return (buf[nibble_offset >> 1] >> ((1 - (nibble_offset & 1)) << 2)) & 0xf;
}
static int decode_rle(uint8_t *bitmap, int linesize, int w, int h,
const uint8_t *buf, int nibble_offset, int buf_size)
{
unsigned int v;
int x, y, len, color, nibble_end;
uint8_t *d;
nibble_end = buf_size * 2;
x = 0;
y = 0;
d = bitmap;
for(;;) {
if (nibble_offset >= nibble_end)
return -1;
v = get_nibble(buf, nibble_offset++);
if (v < 0x4) {
v = (v << 4) | get_nibble(buf, nibble_offset++);
if (v < 0x10) {
v = (v << 4) | get_nibble(buf, nibble_offset++);
if (v < 0x040) {
v = (v << 4) | get_nibble(buf, nibble_offset++);
if (v < 4) {
v |= (w - x) << 2;
}
}
}
}
len = v >> 2;
if (len > (w - x))
len = (w - x);
color = v & 0x03;
memset(d + x, color, len);
x += len;
if (x >= w) {
y++;
if (y >= h)
break;
d += linesize;
x = 0;
/* byte align */
nibble_offset += (nibble_offset & 1);
}
}
return 0;
}
static void guess_palette(uint32_t *rgba_palette,
uint8_t *palette,
uint8_t *alpha,
uint32_t subtitle_color)
{
uint8_t color_used[16];
int nb_opaque_colors, i, level, j, r, g, b;
for(i = 0; i < 4; i++)
rgba_palette[i] = 0;
memset(color_used, 0, 16);
nb_opaque_colors = 0;
for(i = 0; i < 4; i++) {
if (alpha[i] != 0 && !color_used[palette[i]]) {
color_used[palette[i]] = 1;
nb_opaque_colors++;
}
}
if (nb_opaque_colors == 0)
return;
j = nb_opaque_colors;
memset(color_used, 0, 16);
for(i = 0; i < 4; i++) {
if (alpha[i] != 0) {
if (!color_used[palette[i]]) {
level = (0xff * j) / nb_opaque_colors;
r = (((subtitle_color >> 16) & 0xff) * level) >> 8;
g = (((subtitle_color >> 8) & 0xff) * level) >> 8;
b = (((subtitle_color >> 0) & 0xff) * level) >> 8;
rgba_palette[i] = b | (g << 8) | (r << 16) | ((alpha[i] * 17) << 24);
color_used[palette[i]] = (i + 1);
j--;
} else {
rgba_palette[i] = (rgba_palette[color_used[palette[i]] - 1] & 0x00ffffff) |
((alpha[i] * 17) << 24);
}
}
}
}
static int decode_dvd_subtitles(AVSubtitle *sub_header,
const uint8_t *buf, int buf_size)
{
int cmd_pos, pos, cmd, x1, y1, x2, y2, offset1, offset2, next_cmd_pos;
uint8_t palette[4], alpha[4];
int date;
int i;
int is_menu = 0;
if (buf_size < 4)
return -1;
sub_header->rects = NULL;
sub_header->num_rects = 0;
sub_header->start_display_time = 0;
sub_header->end_display_time = 0;
cmd_pos = getbe16(buf + 2);
while ((cmd_pos + 4) < buf_size) {
date = getbe16(buf + cmd_pos);
next_cmd_pos = getbe16(buf + cmd_pos + 2);
#ifdef DEBUG
av_log(NULL, AV_LOG_INFO, "cmd_pos=0x%04x next=0x%04x date=%d\n",
cmd_pos, next_cmd_pos, date);
#endif
pos = cmd_pos + 4;
offset1 = -1;
offset2 = -1;
x1 = y1 = x2 = y2 = 0;
while (pos < buf_size) {
cmd = buf[pos++];
#ifdef DEBUG
av_log(NULL, AV_LOG_INFO, "cmd=%02x\n", cmd);
#endif
switch(cmd) {
case 0x00:
/* menu subpicture */
is_menu = 1;
break;
case 0x01:
/* set start date */
sub_header->start_display_time = (date << 10) / 90;
break;
case 0x02:
/* set end date */
sub_header->end_display_time = (date << 10) / 90;
break;
case 0x03:
/* set palette */
if ((buf_size - pos) < 2)
goto fail;
palette[3] = buf[pos] >> 4;
palette[2] = buf[pos] & 0x0f;
palette[1] = buf[pos + 1] >> 4;
palette[0] = buf[pos + 1] & 0x0f;
pos += 2;
break;
case 0x04:
/* set alpha */
if ((buf_size - pos) < 2)
goto fail;
alpha[3] = buf[pos] >> 4;
alpha[2] = buf[pos] & 0x0f;
alpha[1] = buf[pos + 1] >> 4;
alpha[0] = buf[pos + 1] & 0x0f;
pos += 2;
#ifdef DEBUG
av_log(NULL, AV_LOG_INFO, "alpha=%x%x%x%x\n", alpha[0],alpha[1],alpha[2],alpha[3]);
#endif
break;
case 0x05:
if ((buf_size - pos) < 6)
goto fail;
x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4);
x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2];
y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4);
y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5];
#ifdef DEBUG
av_log(NULL, AV_LOG_INFO, "x1=%d x2=%d y1=%d y2=%d\n",
x1, x2, y1, y2);
#endif
pos += 6;
break;
case 0x06:
if ((buf_size - pos) < 4)
goto fail;
offset1 = getbe16(buf + pos);
offset2 = getbe16(buf + pos + 2);
#ifdef DEBUG
av_log(NULL, AV_LOG_INFO, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
#endif
pos += 4;
break;
case 0xff:
default:
goto the_end;
}
}
the_end:
if (offset1 >= 0) {
int w, h;
uint8_t *bitmap;
/* decode the bitmap */
w = x2 - x1 + 1;
if (w < 0)
w = 0;
h = y2 - y1;
if (h < 0)
h = 0;
if (w > 0 && h > 0) {
if (sub_header->rects != NULL) {
for (i = 0; i < sub_header->num_rects; i++) {
av_free(sub_header->rects[i].bitmap);
av_free(sub_header->rects[i].rgba_palette);
}
av_freep(&sub_header->rects);
sub_header->num_rects = 0;
}
bitmap = av_malloc(w * h);
sub_header->rects = av_mallocz(sizeof(AVSubtitleRect));
sub_header->num_rects = 1;
sub_header->rects[0].rgba_palette = av_malloc(4 * 4);
decode_rle(bitmap, w * 2, w, h / 2,
buf, offset1 * 2, buf_size);
decode_rle(bitmap + w, w * 2, w, h / 2,
buf, offset2 * 2, buf_size);
guess_palette(sub_header->rects[0].rgba_palette,
palette, alpha, 0xffff00);
sub_header->rects[0].x = x1;
sub_header->rects[0].y = y1;
sub_header->rects[0].w = w;
sub_header->rects[0].h = h;
sub_header->rects[0].nb_colors = 4;
sub_header->rects[0].linesize = w;
sub_header->rects[0].bitmap = bitmap;
}
}
if (next_cmd_pos == cmd_pos)
break;
cmd_pos = next_cmd_pos;
}
if (sub_header->num_rects > 0)
return is_menu;
fail:
return -1;
}
static int is_transp(const uint8_t *buf, int pitch, int n,
const uint8_t *transp_color)
{
int i;
for(i = 0; i < n; i++) {
if (!transp_color[*buf])
return 0;
buf += pitch;
}
return 1;
}
/* return 0 if empty rectangle, 1 if non empty */
static int find_smallest_bounding_rectangle(AVSubtitle *s)
{
uint8_t transp_color[256];
int y1, y2, x1, x2, y, w, h, i;
uint8_t *bitmap;
if (s->num_rects == 0 || s->rects == NULL || s->rects[0].w <= 0 || s->rects[0].h <= 0)
return 0;
memset(transp_color, 0, 256);
for(i = 0; i < s->rects[0].nb_colors; i++) {
if ((s->rects[0].rgba_palette[i] >> 24) == 0)
transp_color[i] = 1;
}
y1 = 0;
while (y1 < s->rects[0].h && is_transp(s->rects[0].bitmap + y1 * s->rects[0].linesize,
1, s->rects[0].w, transp_color))
y1++;
if (y1 == s->rects[0].h) {
av_freep(&s->rects[0].bitmap);
s->rects[0].w = s->rects[0].h = 0;
return 0;
}
y2 = s->rects[0].h - 1;
while (y2 > 0 && is_transp(s->rects[0].bitmap + y2 * s->rects[0].linesize, 1,
s->rects[0].w, transp_color))
y2--;
x1 = 0;
while (x1 < (s->rects[0].w - 1) && is_transp(s->rects[0].bitmap + x1, s->rects[0].linesize,
s->rects[0].h, transp_color))
x1++;
x2 = s->rects[0].w - 1;
while (x2 > 0 && is_transp(s->rects[0].bitmap + x2, s->rects[0].linesize, s->rects[0].h,
transp_color))
x2--;
w = x2 - x1 + 1;
h = y2 - y1 + 1;
bitmap = av_malloc(w * h);
if (!bitmap)
return 1;
for(y = 0; y < h; y++) {
memcpy(bitmap + w * y, s->rects[0].bitmap + x1 + (y1 + y) * s->rects[0].linesize, w);
}
av_freep(&s->rects[0].bitmap);
s->rects[0].bitmap = bitmap;
s->rects[0].linesize = w;
s->rects[0].w = w;
s->rects[0].h = h;
s->rects[0].x += x1;
s->rects[0].y += y1;
return 1;
}
static int dvdsub_close_decoder(AVCodecContext *avctx)
{
return 0;
}
#ifdef DEBUG
#undef fprintf
static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,
uint32_t *rgba_palette)
{
int x, y, v;
FILE *f;
f = fopen(filename, "w");
if (!f) {
perror(filename);
exit(1);
}
fprintf(f, "P6\n"
"%d %d\n"
"%d\n",
w, h, 255);
for(y = 0; y < h; y++) {
for(x = 0; x < w; x++) {
v = rgba_palette[bitmap[y * w + x]];
putc((v >> 16) & 0xff, f);
putc((v >> 8) & 0xff, f);
putc((v >> 0) & 0xff, f);
}
}
fclose(f);
}
#endif
static int dvdsub_decode(AVCodecContext *avctx,
void *data, int *data_size,
uint8_t *buf, int buf_size)
{
AVSubtitle *sub = (void *)data;
int is_menu;
is_menu = decode_dvd_subtitles(sub, buf, buf_size);
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,
sizeof(DVDSubContext),
dvdsub_init_decoder,
NULL,
dvdsub_close_decoder,
dvdsub_decode,
};
/* parser definition */
typedef struct DVDSubParseContext {
uint8_t *packet;
int packet_len;
int packet_index;
} DVDSubParseContext;
static int dvdsub_parse_init(AVCodecParserContext *s)
{
return 0;
}
static int dvdsub_parse(AVCodecParserContext *s,
AVCodecContext *avctx,
uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size)
{
DVDSubParseContext *pc = s->priv_data;
if (pc->packet_index == 0) {
if (buf_size < 2)
return 0;
pc->packet_len = (buf[0] << 8) | buf[1];
av_freep(&pc->packet);
pc->packet = av_malloc(pc->packet_len);
}
if (pc->packet) {
if (pc->packet_index + buf_size <= pc->packet_len) {
memcpy(pc->packet + pc->packet_index, buf, buf_size);
pc->packet_index += buf_size;
if (pc->packet_index >= pc->packet_len) {
*poutbuf = pc->packet;
*poutbuf_size = pc->packet_len;
pc->packet_index = 0;
return buf_size;
}
} else {
/* erroneous size */
pc->packet_index = 0;
}
}
*poutbuf = NULL;
*poutbuf_size = 0;
return buf_size;
}
static void dvdsub_parse_close(AVCodecParserContext *s)
{
DVDSubParseContext *pc = s->priv_data;
av_freep(&pc->packet);
}
AVCodecParser dvdsub_parser = {
{ CODEC_ID_DVD_SUBTITLE },
sizeof(DVDSubParseContext),
dvdsub_parse_init,
dvdsub_parse,
dvdsub_parse_close,
};