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FFmpeg/libavcodec/libzvbi-teletextdec.c
Andreas Rheinhardt 6ed0d95fa2 avcodec/codec_internal: Constify AVPacket in decode_sub cb 
No subtitle decoder ever modifies the AVPacket given to it.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2022-04-05 20:02:47 +02:00

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/*
* Teletext decoding for ffmpeg
* Copyright (c) 2005-2010, 2012 Wolfram Gloger
* Copyright (c) 2013 Marton Balint
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avcodec.h"
#include "libavcodec/ass.h"
#include "codec_internal.h"
#include "libavcodec/dvbtxt.h"
#include "libavutil/opt.h"
#include "libavutil/bprint.h"
#include "libavutil/internal.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/log.h"
#include "libavutil/common.h"
#include <libzvbi.h>
#define TEXT_MAXSZ (25 * (56 + 1) * 4 + 2)
#define VBI_NB_COLORS 40
#define VBI_TRANSPARENT_BLACK 8
#define RGBA(r,g,b,a) (((a) << 24) | ((r) << 16) | ((g) << 8) | (b))
#define VBI_R(rgba) (((rgba) >> 0) & 0xFF)
#define VBI_G(rgba) (((rgba) >> 8) & 0xFF)
#define VBI_B(rgba) (((rgba) >> 16) & 0xFF)
#define VBI_A(rgba) (((rgba) >> 24) & 0xFF)
#define MAX_BUFFERED_PAGES 25
#define BITMAP_CHAR_WIDTH 12
#define BITMAP_CHAR_HEIGHT 10
#define MAX_SLICES 64
typedef struct TeletextPage
{
AVSubtitleRect *sub_rect;
int pgno;
int subno;
int64_t pts;
} TeletextPage;
typedef struct TeletextContext
{
AVClass *class;
char *pgno;
int default_region;
int x_offset;
int y_offset;
int format_id; /* 0 = bitmap, 1 = text/ass, 2 = ass */
int chop_top;
int sub_duration; /* in msec */
int transparent_bg;
int opacity;
int chop_spaces;
int lines_processed;
TeletextPage *pages;
int nb_pages;
int64_t pts;
int handler_ret;
vbi_decoder * vbi;
vbi_sliced sliced[MAX_SLICES];
int readorder;
uint8_t subtitle_map[2048];
int last_pgno;
int last_p5;
int last_ass_alignment;
} TeletextContext;
static int my_ass_subtitle_header(AVCodecContext *avctx)
{
int ret = ff_ass_subtitle_header_default(avctx);
char *new_header;
uint8_t *event_pos;
if (ret < 0)
return ret;
event_pos = strstr(avctx->subtitle_header, "\r\n[Events]\r\n");
if (!event_pos)
return AVERROR_BUG;
new_header = av_asprintf("%.*s%s%s",
(int)(event_pos - avctx->subtitle_header), avctx->subtitle_header,
"Style: "
"Teletext," /* Name */
"Monospace,11," /* Font{name,size} */
"&Hffffff,&Hffffff,&H0,&H0," /* {Primary,Secondary,Outline,Back}Colour */
"0,0,0,0," /* Bold, Italic, Underline, StrikeOut */
"160,100," /* Scale{X,Y} */
"0,0," /* Spacing, Angle */
"3,0.1,0," /* BorderStyle, Outline, Shadow */
"5,1,1,1," /* Alignment, Margin[LRV] */
"0\r\n" /* Encoding */
"Style: "
"Subtitle," /* Name */
"Monospace,16," /* Font{name,size} */
"&Hffffff,&Hffffff,&H0,&H0," /* {Primary,Secondary,Outline,Back}Colour */
"0,0,0,0," /* Bold, Italic, Underline, StrikeOut */
"100,100," /* Scale{X,Y} */
"0,0," /* Spacing, Angle */
"1,1,1," /* BorderStyle, Outline, Shadow */
"8,48,48,20," /* Alignment, Margin[LRV] */
"0\r\n" /* Encoding */
, event_pos);
if (!new_header)
return AVERROR(ENOMEM);
av_free(avctx->subtitle_header);
avctx->subtitle_header = new_header;
avctx->subtitle_header_size = strlen(new_header);
return 0;
}
static int chop_spaces_utf8(const unsigned char* t, int len)
{
t += len;
while (len > 0) {
if (*--t != ' ' || (len-1 > 0 && *(t-1) & 0x80))
break;
--len;
}
return len;
}
static void subtitle_rect_free(AVSubtitleRect **sub_rect)
{
av_freep(&(*sub_rect)->data[0]);
av_freep(&(*sub_rect)->data[1]);
av_freep(&(*sub_rect)->ass);
av_freep(sub_rect);
}
static char *create_ass_text(TeletextContext *ctx, const char *text)
{
char *dialog;
AVBPrint buf;
av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
ff_ass_bprint_text_event(&buf, text, strlen(text), "", 0);
if (!av_bprint_is_complete(&buf)) {
av_bprint_finalize(&buf, NULL);
return NULL;
}
dialog = ff_ass_get_dialog(ctx->readorder++, 0, NULL, NULL, buf.str);
av_bprint_finalize(&buf, NULL);
return dialog;
}
/* Draw a page as text */
static int gen_sub_text(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top)
{
const char *in;
AVBPrint buf;
char *vbi_text = av_malloc(TEXT_MAXSZ);
int sz;
if (!vbi_text)
return AVERROR(ENOMEM);
sz = vbi_print_page_region(page, vbi_text, TEXT_MAXSZ-1, "UTF-8",
/*table mode*/ TRUE, FALSE,
0, chop_top,
page->columns, page->rows-chop_top);
if (sz <= 0) {
av_log(ctx, AV_LOG_ERROR, "vbi_print error\n");
av_free(vbi_text);
return AVERROR_EXTERNAL;
}
vbi_text[sz] = '\0';
in = vbi_text;
av_bprint_init(&buf, 0, TEXT_MAXSZ);
if (ctx->chop_spaces) {
for (;;) {
int nl, sz;
// skip leading spaces and newlines
in += strspn(in, " \n");
// compute end of row
for (nl = 0; in[nl]; ++nl)
if (in[nl] == '\n' && (nl==0 || !(in[nl-1] & 0x80)))
break;
if (!in[nl])
break;
// skip trailing spaces
sz = chop_spaces_utf8(in, nl);
av_bprint_append_data(&buf, in, sz);
av_bprintf(&buf, "\n");
in += nl;
}
} else {
av_bprintf(&buf, "%s\n", vbi_text);
}
av_free(vbi_text);
if (!av_bprint_is_complete(&buf)) {
av_bprint_finalize(&buf, NULL);
return AVERROR(ENOMEM);
}
if (buf.len) {
sub_rect->type = SUBTITLE_ASS;
sub_rect->ass = create_ass_text(ctx, buf.str);
if (!sub_rect->ass) {
av_bprint_finalize(&buf, NULL);
return AVERROR(ENOMEM);
}
av_log(ctx, AV_LOG_DEBUG, "subtext:%s:txetbus\n", sub_rect->ass);
} else {
sub_rect->type = SUBTITLE_NONE;
}
av_bprint_finalize(&buf, NULL);
return 0;
}
static void bprint_color(const char *type, AVBPrint *buf, vbi_page *page, unsigned ci)
{
int r = VBI_R(page->color_map[ci]);
int g = VBI_G(page->color_map[ci]);
int b = VBI_B(page->color_map[ci]);
av_bprintf(buf, "{\\%s&H%02X%02X%02X&}", type, b, g, r);
}
#define IS_TXT_SPACE(ch) ((ch).unicode < 0x0020 || (ch).unicode >= 0xe000 || (ch).unicode == 0x00a0 ||\
(ch).size > VBI_DOUBLE_SIZE || (ch).opacity == VBI_TRANSPARENT_SPACE)
static void get_trim_info(vbi_page *page, vbi_char *row, int *leading, int *trailing, int *olen)
{
int i, len = 0;
int char_seen = 0;
*leading = 0;
for (i = 0; i < page->columns; i++) {
uint16_t out = IS_TXT_SPACE(row[i]) ? 32 : row[i].unicode;
if (out == 32 && !char_seen)
(*leading)++;
else if (out != 32)
char_seen = 1, len = i - (*leading) + 1;
}
*olen = len;
*trailing = len > 0 ? page->columns - *leading - len : page->columns;
}
static void decode_string(vbi_page *page, vbi_char *row, AVBPrint *buf,
int start, int end, vbi_color *cur_color, vbi_color *cur_back_color)
{
int i;
for (i = start; i < end; i++) {
uint16_t out = IS_TXT_SPACE(row[i]) ? 32 : row[i].unicode;
if (*cur_color != row[i].foreground) {
bprint_color("c", buf, page, row[i].foreground);
*cur_color = row[i].foreground;
}
if (*cur_back_color != row[i].background) {
bprint_color("3c", buf, page, row[i].background);
*cur_back_color = row[i].background;
}
if (out == 32) {
av_bprintf(buf, "\\h");
} else if (out == '\\' || out == '{' || out == '}') {
av_bprintf(buf, "\\%c", (char)out);
} else {
char tmp;
/* convert to utf-8 */
PUT_UTF8(out, tmp, av_bprint_chars(buf, tmp, 1););
}
}
}
/* Draw a page as ass formatted text */
static int gen_sub_ass(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top)
{
int i;
int leading, trailing, len;
int last_trailing = -1, last_leading = -1;
int min_trailing = page->columns, min_leading = page->columns;
int alignment = 2;
int vertical_align = -1;
int can_align_left = 1, can_align_right = 1, can_align_center = 1;
int is_subtitle_page = ctx->subtitle_map[page->pgno & 0x7ff];
int empty_lines = 0;
vbi_color cur_color = VBI_WHITE;
vbi_color cur_back_color = VBI_BLACK;
AVBPrint buf;
av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
for (i = chop_top; i < page->rows; i++) {
vbi_char *row = page->text + i * page->columns;
get_trim_info(page, row, &leading, &trailing, &len);
if (len) {
if (last_leading != -1 && last_leading != leading || leading > 5)
can_align_left = 0;
if (last_trailing != -1 && last_trailing != trailing || trailing > 2)
can_align_right = 0;
if (last_trailing != -1 && (FFABS((trailing - leading) - (last_trailing - last_leading)) > 1) || trailing - leading > 4)
can_align_center = 0;
last_leading = leading;
last_trailing = trailing;
min_leading = FFMIN(leading, min_leading);
min_trailing = FFMIN(trailing, min_trailing);
}
}
if (!can_align_right && can_align_left && !can_align_center) {
ctx->last_ass_alignment = alignment = 1;
} else if (!can_align_right && !can_align_left && can_align_center) {
ctx->last_ass_alignment = alignment = 2;
} else if (can_align_right && !can_align_left && !can_align_center) {
ctx->last_ass_alignment = alignment = 3;
} else {
if (ctx->last_ass_alignment == 1 && can_align_left ||
ctx->last_ass_alignment == 2 && can_align_center ||
ctx->last_ass_alignment == 3 && can_align_right)
alignment = ctx->last_ass_alignment;
}
for (i = chop_top; i < page->rows; i++) {
int j;
vbi_char *row = page->text + i * page->columns;
int is_transparent_line;
for (j = 0; j < page->columns; j++)
if (row[j].opacity != VBI_TRANSPARENT_SPACE)
break;
is_transparent_line = (j == page->columns);
len = is_transparent_line ? 0 : page->columns;
leading = trailing = is_transparent_line ? page->columns : 0;
if (is_subtitle_page) {
if (!is_transparent_line)
get_trim_info(page, row, &leading, &trailing, &len);
if (vertical_align == -1 && len) {
vertical_align = (2 - (av_clip(i + 1, 0, 23) / 8));
av_bprintf(&buf, "{\\an%d}", alignment + vertical_align * 3);
if (vertical_align != 2)
empty_lines = 0;
}
if (len && empty_lines > 1)
for (empty_lines /= 2; empty_lines > 0; empty_lines--)
av_bprintf(&buf, " \\N");
if (alignment == 1 || alignment == 2 && !can_align_center)
leading = min_leading;
if (alignment == 3 || alignment == 2 && !can_align_center)
trailing = min_trailing;
}
if (len || !is_subtitle_page) {
decode_string(page, row, &buf, leading, page->columns - trailing, &cur_color, &cur_back_color);
av_bprintf(&buf, " \\N");
empty_lines = 0;
} else {
empty_lines++;
}
}
if (vertical_align == 0)
for (empty_lines = (empty_lines - 1) / 2; empty_lines > 0; empty_lines--)
av_bprintf(&buf, " \\N");
if (!av_bprint_is_complete(&buf)) {
av_bprint_finalize(&buf, NULL);
return AVERROR(ENOMEM);
}
if (buf.len) {
sub_rect->type = SUBTITLE_ASS;
sub_rect->ass = ff_ass_get_dialog(ctx->readorder++, 0, is_subtitle_page ? "Subtitle" : "Teletext", NULL, buf.str);
if (!sub_rect->ass) {
av_bprint_finalize(&buf, NULL);
return AVERROR(ENOMEM);
}
av_log(ctx, AV_LOG_DEBUG, "subtext:%s:txetbus\n", sub_rect->ass);
} else {
sub_rect->type = SUBTITLE_NONE;
}
av_bprint_finalize(&buf, NULL);
return 0;
}
static void fix_transparency(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page,
int chop_top, int resx, int resy)
{
int iy;
// Hack for transparency, inspired by VLC code...
for (iy = 0; iy < resy; iy++) {
uint8_t *pixel = sub_rect->data[0] + iy * sub_rect->linesize[0];
vbi_char *vc = page->text + (iy / BITMAP_CHAR_HEIGHT + chop_top) * page->columns;
vbi_char *vcnext = vc + page->columns;
for (; vc < vcnext; vc++) {
uint8_t *pixelnext = pixel + BITMAP_CHAR_WIDTH;
switch (vc->opacity) {
case VBI_TRANSPARENT_SPACE:
memset(pixel, VBI_TRANSPARENT_BLACK, BITMAP_CHAR_WIDTH);
break;
case VBI_OPAQUE:
if (!ctx->transparent_bg)
break;
case VBI_SEMI_TRANSPARENT:
if (ctx->opacity > 0) {
if (ctx->opacity < 255)
for(; pixel < pixelnext; pixel++)
if (*pixel == vc->background)
*pixel += VBI_NB_COLORS;
break;
}
case VBI_TRANSPARENT_FULL:
for(; pixel < pixelnext; pixel++)
if (*pixel == vc->background)
*pixel = VBI_TRANSPARENT_BLACK;
break;
}
pixel = pixelnext;
}
}
}
/* Draw a page as bitmap */
static int gen_sub_bitmap(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top)
{
int resx = page->columns * BITMAP_CHAR_WIDTH;
int resy = (page->rows - chop_top) * BITMAP_CHAR_HEIGHT;
uint8_t ci;
vbi_char *vc = page->text + (chop_top * page->columns);
vbi_char *vcend = page->text + (page->rows * page->columns);
for (; vc < vcend; vc++) {
if (vc->opacity != VBI_TRANSPARENT_SPACE)
break;
}
if (vc >= vcend) {
av_log(ctx, AV_LOG_DEBUG, "dropping empty page %3x\n", page->pgno);
sub_rect->type = SUBTITLE_NONE;
return 0;
}
sub_rect->data[0] = av_mallocz(resx * resy);
sub_rect->linesize[0] = resx;
if (!sub_rect->data[0])
return AVERROR(ENOMEM);
vbi_draw_vt_page_region(page, VBI_PIXFMT_PAL8,
sub_rect->data[0], sub_rect->linesize[0],
0, chop_top, page->columns, page->rows - chop_top,
/*reveal*/ 1, /*flash*/ 1);
fix_transparency(ctx, sub_rect, page, chop_top, resx, resy);
sub_rect->x = ctx->x_offset;
sub_rect->y = ctx->y_offset + chop_top * BITMAP_CHAR_HEIGHT;
sub_rect->w = resx;
sub_rect->h = resy;
sub_rect->nb_colors = ctx->opacity > 0 && ctx->opacity < 255 ? 2 * VBI_NB_COLORS : VBI_NB_COLORS;
sub_rect->data[1] = av_mallocz(AVPALETTE_SIZE);
if (!sub_rect->data[1]) {
av_freep(&sub_rect->data[0]);
return AVERROR(ENOMEM);
}
for (ci = 0; ci < VBI_NB_COLORS; ci++) {
int r, g, b, a;
r = VBI_R(page->color_map[ci]);
g = VBI_G(page->color_map[ci]);
b = VBI_B(page->color_map[ci]);
a = VBI_A(page->color_map[ci]);
((uint32_t *)sub_rect->data[1])[ci] = RGBA(r, g, b, a);
((uint32_t *)sub_rect->data[1])[ci + VBI_NB_COLORS] = RGBA(r, g, b, ctx->opacity);
ff_dlog(ctx, "palette %0x\n", ((uint32_t *)sub_rect->data[1])[ci]);
}
((uint32_t *)sub_rect->data[1])[VBI_TRANSPARENT_BLACK] = RGBA(0, 0, 0, 0);
((uint32_t *)sub_rect->data[1])[VBI_TRANSPARENT_BLACK + VBI_NB_COLORS] = RGBA(0, 0, 0, 0);
sub_rect->type = SUBTITLE_BITMAP;
return 0;
}
static void handler(vbi_event *ev, void *user_data)
{
TeletextContext *ctx = user_data;
TeletextPage *new_pages;
vbi_page page;
int res;
char pgno_str[12];
int chop_top;
int is_subtitle_page = ctx->subtitle_map[ev->ev.ttx_page.pgno & 0x7ff];
snprintf(pgno_str, sizeof pgno_str, "%03x", ev->ev.ttx_page.pgno);
av_log(ctx, AV_LOG_DEBUG, "decoded page %s.%02x\n",
pgno_str, ev->ev.ttx_page.subno & 0xFF);
if (strcmp(ctx->pgno, "*") && (strcmp(ctx->pgno, "subtitle") || !is_subtitle_page) && !strstr(ctx->pgno, pgno_str))
return;
if (ctx->handler_ret < 0)
return;
res = vbi_fetch_vt_page(ctx->vbi, &page,
ev->ev.ttx_page.pgno,
ev->ev.ttx_page.subno,
VBI_WST_LEVEL_3p5, 25, TRUE);
if (!res)
return;
chop_top = ctx->chop_top || ((page.rows > 1) && is_subtitle_page);
av_log(ctx, AV_LOG_DEBUG, "%d x %d page chop:%d\n",
page.columns, page.rows, chop_top);
if (ctx->nb_pages < MAX_BUFFERED_PAGES) {
if ((new_pages = av_realloc_array(ctx->pages, ctx->nb_pages + 1, sizeof(TeletextPage)))) {
TeletextPage *cur_page = new_pages + ctx->nb_pages;
ctx->pages = new_pages;
cur_page->sub_rect = av_mallocz(sizeof(*cur_page->sub_rect));
cur_page->pts = ctx->pts;
cur_page->pgno = ev->ev.ttx_page.pgno;
cur_page->subno = ev->ev.ttx_page.subno;
if (cur_page->sub_rect) {
switch (ctx->format_id) {
case 0:
res = gen_sub_bitmap(ctx, cur_page->sub_rect, &page, chop_top);
break;
case 1:
res = gen_sub_text(ctx, cur_page->sub_rect, &page, chop_top);
break;
case 2:
res = gen_sub_ass(ctx, cur_page->sub_rect, &page, chop_top);
break;
default:
res = AVERROR_BUG;
break;
}
if (res < 0) {
av_freep(&cur_page->sub_rect);
ctx->handler_ret = res;
} else {
ctx->pages[ctx->nb_pages++] = *cur_page;
}
} else {
ctx->handler_ret = AVERROR(ENOMEM);
}
} else {
ctx->handler_ret = AVERROR(ENOMEM);
}
} else {
//TODO: If multiple packets contain more than one page, pages may got queued up, and this may happen...
av_log(ctx, AV_LOG_ERROR, "Buffered too many pages, dropping page %s.\n", pgno_str);
ctx->handler_ret = AVERROR(ENOSYS);
}
vbi_unref_page(&page);
}
static int slice_to_vbi_lines(TeletextContext *ctx, uint8_t* buf, int size)
{
int lines = 0;
while (size >= 2 && lines < MAX_SLICES) {
int data_unit_id = buf[0];
int data_unit_length = buf[1];
if (data_unit_length + 2 > size)
return AVERROR_INVALIDDATA;
if (ff_data_unit_id_is_teletext(data_unit_id)) {
if (data_unit_length != 0x2c)
return AVERROR_INVALIDDATA;
else {
int line_offset = buf[2] & 0x1f;
int field_parity = buf[2] & 0x20;
uint8_t *p = ctx->sliced[lines].data;
int i, pmag;
ctx->sliced[lines].id = VBI_SLICED_TELETEXT_B;
ctx->sliced[lines].line = (line_offset > 0 ? (line_offset + (field_parity ? 0 : 313)) : 0);
for (i = 0; i < 42; i++)
p[i] = vbi_rev8(buf[4 + i]);
/* Unfortunately libzvbi does not expose page flags, and
* vbi_classify_page only checks MIP, so we have to manually
* decode the page flags and store the results. */
pmag = vbi_unham16p(p);
if (pmag >= 0 && pmag >> 3 == 0) { // We found a row 0 header
int page = vbi_unham16p(p + 2);
int flags1 = vbi_unham16p(p + 6);
int flags2 = vbi_unham16p(p + 8);
if (page >= 0 && flags1 >= 0 && flags2 >= 0) {
int pgno = ((pmag & 7) << 8) + page;
// Check for disabled NEWSFLASH flag and enabled SUBTITLE and SUPRESS_HEADER flags
ctx->subtitle_map[pgno] = (!(flags1 & 0x40) && flags1 & 0x80 && flags2 & 0x01);
// Propagate ERASE_PAGE flag for repeated page headers to work around a libzvbi bug
if (ctx->subtitle_map[pgno] && pgno == ctx->last_pgno) {
int last_byte9 = vbi_unham8(ctx->last_p5);
if (last_byte9 >= 0 && last_byte9 & 0x8) {
int byte9 = vbi_unham8(p[5]);
if (byte9 >= 0)
p[5] = vbi_ham8(byte9 | 0x8);
}
}
ctx->last_pgno = pgno;
ctx->last_p5 = p[5];
}
}
lines++;
}
}
size -= data_unit_length + 2;
buf += data_unit_length + 2;
}
if (size)
av_log(ctx, AV_LOG_WARNING, "%d bytes remained after slicing data\n", size);
return lines;
}
static int teletext_decode_frame(AVCodecContext *avctx, AVSubtitle *sub,
int *got_sub_ptr, const AVPacket *pkt)
{
TeletextContext *ctx = avctx->priv_data;
int ret = 0;
if (!ctx->vbi) {
if (!(ctx->vbi = vbi_decoder_new()))
return AVERROR(ENOMEM);
if (ctx->default_region != -1) {
av_log(avctx, AV_LOG_INFO, "Setting default zvbi region to %i\n", ctx->default_region);
vbi_teletext_set_default_region(ctx->vbi, ctx->default_region);
}
if (!vbi_event_handler_register(ctx->vbi, VBI_EVENT_TTX_PAGE, handler, ctx)) {
vbi_decoder_delete(ctx->vbi);
ctx->vbi = NULL;
return AVERROR(ENOMEM);
}
}
if (avctx->pkt_timebase.num && pkt->pts != AV_NOPTS_VALUE)
ctx->pts = av_rescale_q(pkt->pts, avctx->pkt_timebase, AV_TIME_BASE_Q);
if (pkt->size) {
int lines;
const int full_pes_size = pkt->size + 45; /* PES header is 45 bytes */
// We allow unreasonably big packets, even if the standard only allows a max size of 1472
if (full_pes_size < 184 || full_pes_size > 65504 || full_pes_size % 184 != 0)
return AVERROR_INVALIDDATA;
ctx->handler_ret = pkt->size;
if (ff_data_identifier_is_teletext(*pkt->data)) {
if ((lines = slice_to_vbi_lines(ctx, pkt->data + 1, pkt->size - 1)) < 0)
return lines;
ff_dlog(avctx, "ctx=%p buf_size=%d lines=%u pkt_pts=%7.3f\n",
ctx, pkt->size, lines, (double)pkt->pts/90000.0);
if (lines > 0) {
vbi_decode(ctx->vbi, ctx->sliced, lines, 0.0);
ctx->lines_processed += lines;
}
}
ctx->pts = AV_NOPTS_VALUE;
ret = ctx->handler_ret;
}
if (ret < 0)
return ret;
// is there a subtitle to pass?
if (ctx->nb_pages) {
int i;
sub->format = !!ctx->format_id;
sub->start_display_time = 0;
sub->end_display_time = ctx->sub_duration;
sub->num_rects = 0;
sub->pts = ctx->pages->pts;
if (ctx->pages->sub_rect->type != SUBTITLE_NONE) {
sub->rects = av_malloc(sizeof(*sub->rects));
if (sub->rects) {
sub->num_rects = 1;
sub->rects[0] = ctx->pages->sub_rect;
} else {
ret = AVERROR(ENOMEM);
}
} else {
av_log(avctx, AV_LOG_DEBUG, "sending empty sub\n");
sub->rects = NULL;
}
if (!sub->rects) // no rect was passed
subtitle_rect_free(&ctx->pages->sub_rect);
for (i = 0; i < ctx->nb_pages - 1; i++)
ctx->pages[i] = ctx->pages[i + 1];
ctx->nb_pages--;
if (ret >= 0)
*got_sub_ptr = 1;
} else
*got_sub_ptr = 0;
return ret;
}
static int teletext_init_decoder(AVCodecContext *avctx)
{
TeletextContext *ctx = avctx->priv_data;
unsigned int maj, min, rev;
vbi_version(&maj, &min, &rev);
if (!(maj > 0 || min > 2 || min == 2 && rev >= 26)) {
av_log(avctx, AV_LOG_ERROR, "decoder needs zvbi version >= 0.2.26.\n");
return AVERROR_EXTERNAL;
}
if (ctx->format_id == 0) {
avctx->width = 41 * BITMAP_CHAR_WIDTH;
avctx->height = 25 * BITMAP_CHAR_HEIGHT;
}
ctx->vbi = NULL;
ctx->pts = AV_NOPTS_VALUE;
ctx->last_pgno = -1;
ctx->last_ass_alignment = 2;
if (ctx->opacity == -1)
ctx->opacity = ctx->transparent_bg ? 0 : 255;
av_log(avctx, AV_LOG_VERBOSE, "page filter: %s\n", ctx->pgno);
switch (ctx->format_id) {
case 0:
return 0;
case 1:
return ff_ass_subtitle_header_default(avctx);
case 2:
return my_ass_subtitle_header(avctx);
}
return AVERROR_BUG;
}
static int teletext_close_decoder(AVCodecContext *avctx)
{
TeletextContext *ctx = avctx->priv_data;
ff_dlog(avctx, "lines_total=%u\n", ctx->lines_processed);
while (ctx->nb_pages)
subtitle_rect_free(&ctx->pages[--ctx->nb_pages].sub_rect);
av_freep(&ctx->pages);
vbi_decoder_delete(ctx->vbi);
ctx->vbi = NULL;
ctx->pts = AV_NOPTS_VALUE;
ctx->last_pgno = -1;
ctx->last_ass_alignment = 2;
memset(ctx->subtitle_map, 0, sizeof(ctx->subtitle_map));
if (!(avctx->flags2 & AV_CODEC_FLAG2_RO_FLUSH_NOOP))
ctx->readorder = 0;
return 0;
}
static void teletext_flush(AVCodecContext *avctx)
{
teletext_close_decoder(avctx);
}
#define OFFSET(x) offsetof(TeletextContext, x)
#define SD AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM
static const AVOption options[] = {
{"txt_page", "page numbers to decode, subtitle for subtitles, * for all", OFFSET(pgno), AV_OPT_TYPE_STRING, {.str = "*"}, 0, 0, SD},
{"txt_default_region", "default G0 character set used for decoding", OFFSET(default_region), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 87, SD},
{"txt_chop_top", "discards the top teletext line", OFFSET(chop_top), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, SD},
{"txt_format", "format of the subtitles (bitmap or text or ass)", OFFSET(format_id), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 2, SD, "txt_format"},
{"bitmap", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 0}, 0, 0, SD, "txt_format"},
{"text", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 1}, 0, 0, SD, "txt_format"},
{"ass", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 2}, 0, 0, SD, "txt_format"},
{"txt_left", "x offset of generated bitmaps", OFFSET(x_offset), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 65535, SD},
{"txt_top", "y offset of generated bitmaps", OFFSET(y_offset), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 65535, SD},
{"txt_chop_spaces", "chops leading and trailing spaces from text", OFFSET(chop_spaces), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, SD},
{"txt_duration", "display duration of teletext pages in msecs", OFFSET(sub_duration), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 86400000, SD},
{"txt_transparent", "force transparent background of the teletext", OFFSET(transparent_bg), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, SD},
{"txt_opacity", "set opacity of the transparent background", OFFSET(opacity), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 255, SD},
{ NULL },
};
static const AVClass teletext_class = {
.class_name = "libzvbi_teletextdec",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
const FFCodec ff_libzvbi_teletext_decoder = {
.p.name = "libzvbi_teletextdec",
.p.long_name = NULL_IF_CONFIG_SMALL("Libzvbi DVB teletext decoder"),
.p.type = AVMEDIA_TYPE_SUBTITLE,
.p.id = AV_CODEC_ID_DVB_TELETEXT,
.p.capabilities = AV_CODEC_CAP_DELAY,
.p.priv_class = &teletext_class,
.p.wrapper_name = "libzvbi",
.priv_data_size = sizeof(TeletextContext),
.init = teletext_init_decoder,
.close = teletext_close_decoder,
FF_CODEC_DECODE_SUB_CB(teletext_decode_frame),
.flush = teletext_flush,
};
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