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ffmpeg/libavcodec/dvbsub.c
Jernej Fijacko f86f213a6d avcodec/dvbsub: add support for Display Definition Segment to DVB Subtitle encoder 
Current version of dvbsub encoder doesn't support HD DVB subtitles. The high
resolution bitmaps are muxed into the stream but without the DDS (display definition
segment) the players asume that the DVB subtitles are in SD (720x576) resolution
which causes them to either render the subtitles too large and misplaced or don't
render them at all. By including the DDS as defined in section 7.7.1 of ETSI EN 300
743 (V1.3.1) this problem is fixed.

7.2.1 Display definition segment The display definition for a subtitle service may
be defined by the display definition segment if present in the stream. Absence of a
DDS implies that the stream is coded in accordance with EN 300 743 (V1.2.1) [5] and
that a display width of 720 pixels and a display height of 576 lines may be assumed.

https://www.etsi.org/deliver/etsi_en/300700_300799/300743/01.03.01_60/en_300743v010301p.pdf

Signed-off-by: Jernej Fijacko <mikrohard@gmail.com>
Signed-off-by: Marton Balint <cus@passwd.hu>
2019-07-13 19:34:15 +02:00

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/*
* DVB subtitle encoding
* Copyright (c) 2005 Fabrice Bellard
*
* This file is part of FFmpeg.
*
* FFmpeg 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 2.1 of the License, or (at your option) any later version.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avcodec.h"
#include "bytestream.h"
#include "libavutil/colorspace.h"
typedef struct DVBSubtitleContext {
int object_version;
} DVBSubtitleContext;
#define PUTBITS2(val)\
{\
bitbuf |= (val) << bitcnt;\
bitcnt -= 2;\
if (bitcnt < 0) {\
bitcnt = 6;\
*q++ = bitbuf;\
bitbuf = 0;\
}\
}
static void dvb_encode_rle2(uint8_t **pq,
const uint8_t *bitmap, int linesize,
int w, int h)
{
uint8_t *q;
unsigned int bitbuf;
int bitcnt;
int x, y, len, x1, v, color;
q = *pq;
for(y = 0; y < h; y++) {
*q++ = 0x10;
bitbuf = 0;
bitcnt = 6;
x = 0;
while (x < w) {
x1 = x;
color = bitmap[x1++];
while (x1 < w && bitmap[x1] == color)
x1++;
len = x1 - x;
if (color == 0 && len == 2) {
PUTBITS2(0);
PUTBITS2(0);
PUTBITS2(1);
} else if (len >= 3 && len <= 10) {
v = len - 3;
PUTBITS2(0);
PUTBITS2((v >> 2) | 2);
PUTBITS2(v & 3);
PUTBITS2(color);
} else if (len >= 12 && len <= 27) {
v = len - 12;
PUTBITS2(0);
PUTBITS2(0);
PUTBITS2(2);
PUTBITS2(v >> 2);
PUTBITS2(v & 3);
PUTBITS2(color);
} else if (len >= 29) {
/* length = 29 ... 284 */
if (len > 284)
len = 284;
v = len - 29;
PUTBITS2(0);
PUTBITS2(0);
PUTBITS2(3);
PUTBITS2((v >> 6));
PUTBITS2((v >> 4) & 3);
PUTBITS2((v >> 2) & 3);
PUTBITS2(v & 3);
PUTBITS2(color);
} else {
PUTBITS2(color);
if (color == 0) {
PUTBITS2(1);
}
len = 1;
}
x += len;
}
/* end of line */
PUTBITS2(0);
PUTBITS2(0);
PUTBITS2(0);
if (bitcnt != 6) {
*q++ = bitbuf;
}
*q++ = 0xf0;
bitmap += linesize;
}
*pq = q;
}
#define PUTBITS4(val)\
{\
bitbuf |= (val) << bitcnt;\
bitcnt -= 4;\
if (bitcnt < 0) {\
bitcnt = 4;\
*q++ = bitbuf;\
bitbuf = 0;\
}\
}
/* some DVB decoders only implement 4 bits/pixel */
static void dvb_encode_rle4(uint8_t **pq,
const uint8_t *bitmap, int linesize,
int w, int h)
{
uint8_t *q;
unsigned int bitbuf;
int bitcnt;
int x, y, len, x1, v, color;
q = *pq;
for(y = 0; y < h; y++) {
*q++ = 0x11;
bitbuf = 0;
bitcnt = 4;
x = 0;
while (x < w) {
x1 = x;
color = bitmap[x1++];
while (x1 < w && bitmap[x1] == color)
x1++;
len = x1 - x;
if (color == 0 && len == 2) {
PUTBITS4(0);
PUTBITS4(0xd);
} else if (color == 0 && (len >= 3 && len <= 9)) {
PUTBITS4(0);
PUTBITS4(len - 2);
} else if (len >= 4 && len <= 7) {
PUTBITS4(0);
PUTBITS4(8 + len - 4);
PUTBITS4(color);
} else if (len >= 9 && len <= 24) {
PUTBITS4(0);
PUTBITS4(0xe);
PUTBITS4(len - 9);
PUTBITS4(color);
} else if (len >= 25) {
if (len > 280)
len = 280;
v = len - 25;
PUTBITS4(0);
PUTBITS4(0xf);
PUTBITS4(v >> 4);
PUTBITS4(v & 0xf);
PUTBITS4(color);
} else {
PUTBITS4(color);
if (color == 0) {
PUTBITS4(0xc);
}
len = 1;
}
x += len;
}
/* end of line */
PUTBITS4(0);
PUTBITS4(0);
if (bitcnt != 4) {
*q++ = bitbuf;
}
*q++ = 0xf0;
bitmap += linesize;
}
*pq = q;
}
static void dvb_encode_rle8(uint8_t **pq,
const uint8_t *bitmap, int linesize,
int w, int h)
{
uint8_t *q;
int x, y, len, x1, color;
q = *pq;
for (y = 0; y < h; y++) {
*q++ = 0x12;
x = 0;
while (x < w) {
x1 = x;
color = bitmap[x1++];
while (x1 < w && bitmap[x1] == color)
x1++;
len = x1 - x;
if (len == 1 && color) {
// 00000001 to 11111111 1 pixel in colour x
*q++ = color;
} else {
if (color == 0x00) {
// 00000000 0LLLLLLL L pixels (1-127) in colour 0 (L > 0)
len = FFMIN(len, 127);
*q++ = 0x00;
*q++ = len;
} else if (len > 2) {
// 00000000 1LLLLLLL CCCCCCCC L pixels (3-127) in colour C (L > 2)
len = FFMIN(len, 127);
*q++ = 0x00;
*q++ = 0x80+len;
*q++ = color;
}
else if (len == 2) {
*q++ = color;
*q++ = color;
} else {
*q++ = color;
len = 1;
}
}
x += len;
}
/* end of line */
// 00000000 end of 8-bit/pixel_code_string
*q++ = 0x00;
*q++ = 0xf0;
bitmap += linesize;
}
*pq = q;
}
static int encode_dvb_subtitles(AVCodecContext *avctx,
uint8_t *outbuf, const AVSubtitle *h)
{
DVBSubtitleContext *s = avctx->priv_data;
uint8_t *q, *pseg_len;
int page_id, region_id, clut_id, object_id, i, bpp_index, page_state;
q = outbuf;
page_id = 1;
if (h->num_rects && !h->rects)
return -1;
if (avctx->width > 0 && avctx->height > 0) {
/* display definition segment */
*q++ = 0x0f; /* sync_byte */
*q++ = 0x14; /* segment_type */
bytestream_put_be16(&q, page_id);
pseg_len = q;
q += 2; /* segment length */
*q++ = 0x00; /* dds version number & display window flag */
bytestream_put_be16(&q, avctx->width - 1); /* display width */
bytestream_put_be16(&q, avctx->height - 1); /* display height */
bytestream_put_be16(&pseg_len, q - pseg_len - 2);
}
/* page composition segment */
*q++ = 0x0f; /* sync_byte */
*q++ = 0x10; /* segment_type */
bytestream_put_be16(&q, page_id);
pseg_len = q;
q += 2; /* segment length */
*q++ = 30; /* page_timeout (seconds) */
page_state = 2; /* mode change */
/* page_version = 0 + page_state */
*q++ = (s->object_version << 4) | (page_state << 2) | 3;
for (region_id = 0; region_id < h->num_rects; region_id++) {
*q++ = region_id;
*q++ = 0xff; /* reserved */
bytestream_put_be16(&q, h->rects[region_id]->x); /* left pos */
bytestream_put_be16(&q, h->rects[region_id]->y); /* top pos */
}
bytestream_put_be16(&pseg_len, q - pseg_len - 2);
if (h->num_rects) {
for (clut_id = 0; clut_id < h->num_rects; clut_id++) {
/* CLUT segment */
if (h->rects[clut_id]->nb_colors <= 4) {
/* 2 bpp, some decoders do not support it correctly */
bpp_index = 0;
} else if (h->rects[clut_id]->nb_colors <= 16) {
/* 4 bpp, standard encoding */
bpp_index = 1;
} else if (h->rects[clut_id]->nb_colors <= 256) {
/* 8 bpp, standard encoding */
bpp_index = 2;
} else {
return -1;
}
/* CLUT segment */
*q++ = 0x0f; /* sync byte */
*q++ = 0x12; /* CLUT definition segment */
bytestream_put_be16(&q, page_id);
pseg_len = q;
q += 2; /* segment length */
*q++ = clut_id;
*q++ = (0 << 4) | 0xf; /* version = 0 */
for(i = 0; i < h->rects[clut_id]->nb_colors; i++) {
*q++ = i; /* clut_entry_id */
*q++ = (1 << (7 - bpp_index)) | (0xf << 1) | 1; /* 2 bits/pixel full range */
{
int a, r, g, b;
uint32_t x= ((uint32_t*)h->rects[clut_id]->data[1])[i];
a = (x >> 24) & 0xff;
r = (x >> 16) & 0xff;
g = (x >> 8) & 0xff;
b = (x >> 0) & 0xff;
*q++ = RGB_TO_Y_CCIR(r, g, b);
*q++ = RGB_TO_V_CCIR(r, g, b, 0);
*q++ = RGB_TO_U_CCIR(r, g, b, 0);
*q++ = 255 - a;
}
}
bytestream_put_be16(&pseg_len, q - pseg_len - 2);
}
}
for (region_id = 0; region_id < h->num_rects; region_id++) {
/* region composition segment */
if (h->rects[region_id]->nb_colors <= 4) {
/* 2 bpp, some decoders do not support it correctly */
bpp_index = 0;
} else if (h->rects[region_id]->nb_colors <= 16) {
/* 4 bpp, standard encoding */
bpp_index = 1;
} else if (h->rects[region_id]->nb_colors <= 256) {
/* 8 bpp, standard encoding */
bpp_index = 2;
} else {
return -1;
}
*q++ = 0x0f; /* sync_byte */
*q++ = 0x11; /* segment_type */
bytestream_put_be16(&q, page_id);
pseg_len = q;
q += 2; /* segment length */
*q++ = region_id;
*q++ = (s->object_version << 4) | (0 << 3) | 0x07; /* version , no fill */
bytestream_put_be16(&q, h->rects[region_id]->w); /* region width */
bytestream_put_be16(&q, h->rects[region_id]->h); /* region height */
*q++ = ((1 + bpp_index) << 5) | ((1 + bpp_index) << 2) | 0x03;
*q++ = region_id; /* clut_id == region_id */
*q++ = 0; /* 8 bit fill colors */
*q++ = 0x03; /* 4 bit and 2 bit fill colors */
bytestream_put_be16(&q, region_id); /* object_id == region_id */
*q++ = (0 << 6) | (0 << 4);
*q++ = 0;
*q++ = 0xf0;
*q++ = 0;
bytestream_put_be16(&pseg_len, q - pseg_len - 2);
}
if (h->num_rects) {
for (object_id = 0; object_id < h->num_rects; object_id++) {
void (*dvb_encode_rle)(uint8_t **pq,
const uint8_t *bitmap, int linesize,
int w, int h);
/* bpp_index maths */
if (h->rects[object_id]->nb_colors <= 4) {
/* 2 bpp, some decoders do not support it correctly */
dvb_encode_rle = dvb_encode_rle2;
} else if (h->rects[object_id]->nb_colors <= 16) {
/* 4 bpp, standard encoding */
dvb_encode_rle = dvb_encode_rle4;
} else if (h->rects[object_id]->nb_colors <= 256) {
/* 8 bpp, standard encoding */
dvb_encode_rle = dvb_encode_rle8;
} else {
return -1;
}
/* Object Data segment */
*q++ = 0x0f; /* sync byte */
*q++ = 0x13;
bytestream_put_be16(&q, page_id);
pseg_len = q;
q += 2; /* segment length */
bytestream_put_be16(&q, object_id);
*q++ = (s->object_version << 4) | (0 << 2) | (0 << 1) | 1; /* version = 0,
onject_coding_method,
non_modifying_color_flag */
{
uint8_t *ptop_field_len, *pbottom_field_len, *top_ptr, *bottom_ptr;
ptop_field_len = q;
q += 2;
pbottom_field_len = q;
q += 2;
top_ptr = q;
dvb_encode_rle(&q, h->rects[object_id]->data[0], h->rects[object_id]->w * 2,
h->rects[object_id]->w, h->rects[object_id]->h >> 1);
bottom_ptr = q;
dvb_encode_rle(&q, h->rects[object_id]->data[0] + h->rects[object_id]->w,
h->rects[object_id]->w * 2, h->rects[object_id]->w,
h->rects[object_id]->h >> 1);
bytestream_put_be16(&ptop_field_len, bottom_ptr - top_ptr);
bytestream_put_be16(&pbottom_field_len, q - bottom_ptr);
}
bytestream_put_be16(&pseg_len, q - pseg_len - 2);
}
}
/* end of display set segment */
*q++ = 0x0f; /* sync_byte */
*q++ = 0x80; /* segment_type */
bytestream_put_be16(&q, page_id);
pseg_len = q;
q += 2; /* segment length */
bytestream_put_be16(&pseg_len, q - pseg_len - 2);
s->object_version = (s->object_version + 1) & 0xf;
return q - outbuf;
}
static int dvbsub_encode(AVCodecContext *avctx,
unsigned char *buf, int buf_size,
const AVSubtitle *sub)
{
int ret;
ret = encode_dvb_subtitles(avctx, buf, sub);
return ret;
}
AVCodec ff_dvbsub_encoder = {
.name = "dvbsub",
.long_name = NULL_IF_CONFIG_SMALL("DVB subtitles"),
.type = AVMEDIA_TYPE_SUBTITLE,
.id = AV_CODEC_ID_DVB_SUBTITLE,
.priv_data_size = sizeof(DVBSubtitleContext),
.encode_sub = dvbsub_encode,
};
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