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avcodec/libzvbi-teletextdec: add formatted ass output

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Inspired by the VideoLAN text decoder and its port to FFmpeg made by Aman
Gupta.

Signed-off-by: Marton Balint <cus@passwd.hu>
pull/299/head
Marton Balint 7 years ago
parent 179ed2d2e0
commit b577153231
3 changed files with 269 additions and 14 deletions
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  1. 18
      doc/decoders.texi
  2. 263
      libavcodec/libzvbi-teletextdec.c
  3. 2
      libavcodec/version.h

18
doc/decoders.texi
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@ -261,12 +261,18 @@ Default value is *.
@item txt_chop_top
Discards the top teletext line. Default value is 1.
@item txt_format
Specifies the format of the decoded subtitles. The teletext decoder is capable
of decoding the teletext pages to bitmaps or to simple text, you should use
"bitmap" for teletext pages, because certain graphics and colors cannot be
expressed in simple text. You might use "text" for teletext based subtitles if
your application can handle simple text based subtitles. Default value is
bitmap.
Specifies the format of the decoded subtitles.
@table @option
@item bitmap
The default format, you should use this for teletext pages, because certain
graphics and colors cannot be expressed in simple text or even ASS.
@item text
Simple text based output without formatting.
@item ass
Formatted ASS output, subtitle pages and teletext pages are returned in
different styles, subtitle pages are stripped down to text, but an effort is
made to keep the text alignment and the formatting.
@end table
@item txt_left
X offset of generated bitmaps, default is 0.
@item txt_top

263
libavcodec/libzvbi-teletextdec.c
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@ -26,6 +26,7 @@
#include "libavutil/internal.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/log.h"
#include "libavutil/common.h"
#include <libzvbi.h>
@ -56,7 +57,7 @@ typedef struct TeletextContext
char *pgno;
int x_offset;
int y_offset;
int format_id; /* 0 = bitmap, 1 = text/ass */
int format_id; /* 0 = bitmap, 1 = text/ass, 2 = ass */
int chop_top;
int sub_duration; /* in msec */
int transparent_bg;
@ -76,8 +77,55 @@ typedef struct TeletextContext
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;
@ -181,6 +229,184 @@ static int gen_sub_text(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page
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)
{
@ -318,9 +544,20 @@ static void handler(vbi_event *ev, void *user_data)
cur_page->pgno = ev->ev.ttx_page.pgno;
cur_page->subno = ev->ev.ttx_page.subno;
if (cur_page->sub_rect) {
res = (ctx->format_id == 0) ?
gen_sub_bitmap(ctx, cur_page->sub_rect, &page, chop_top) :
gen_sub_text (ctx, cur_page->sub_rect, &page, chop_top);
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;
@ -448,7 +685,7 @@ static int teletext_decode_frame(AVCodecContext *avctx, void *data, int *data_si
// is there a subtitle to pass?
if (ctx->nb_pages) {
int i;
sub->format = ctx->format_id;
sub->format = !!ctx->format_id;
sub->start_display_time = 0;
sub->end_display_time = ctx->sub_duration;
sub->num_rects = 0;
@ -508,12 +745,22 @@ static int teletext_init_decoder(AVCodecContext *avctx)
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);
return (ctx->format_id == 1) ? ff_ass_subtitle_header_default(avctx) : 0;
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)
@ -529,6 +776,7 @@ static int teletext_close_decoder(AVCodecContext *avctx)
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;
@ -545,9 +793,10 @@ static void teletext_flush(AVCodecContext *avctx)
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_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)", OFFSET(format_id), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, SD, "txt_format"},
{"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},

2
libavcodec/version.h
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@ -29,7 +29,7 @@
#define LIBAVCODEC_VERSION_MAJOR 58
#define LIBAVCODEC_VERSION_MINOR 31
#define LIBAVCODEC_VERSION_MICRO 101
#define LIBAVCODEC_VERSION_MICRO 102
#define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
LIBAVCODEC_VERSION_MINOR, \

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