[FFmpeg-devel] [PATCH 2/2] avcodec/libzvbi-teletextdec: formatted ass output
Marton Balint
cus at passwd.hu
Mon May 7 00:05:14 EEST 2018
Inspired by the VideoLAN text decoder and its port to FFmpeg made by Aman
Gupta.
Signed-off-by: Marton Balint <cus at passwd.hu>
---
doc/decoders.texi | 18 ++-
libavcodec/libzvbi-teletextdec.c | 265 +++++++++++++++++++++++++++++++++++++--
2 files changed, 270 insertions(+), 13 deletions(-)
diff --git a/doc/decoders.texi b/doc/decoders.texi
index 8f07bc1afb..cc9b2ef123 100644
--- a/doc/decoders.texi
+++ b/doc/decoders.texi
@@ -255,12 +255,18 @@ 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.
+ at table @option
+ at 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.
+ at item text
+Simple text based output without formatting.
+ at 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.
+ at end table
@item txt_left
X offset of generated bitmaps, default is 0.
@item txt_top
diff --git a/libavcodec/libzvbi-teletextdec.c b/libavcodec/libzvbi-teletextdec.c
index 56a7182882..7541de0d53 100644
--- a/libavcodec/libzvbi-teletextdec.c
+++ b/libavcodec/libzvbi-teletextdec.c
@@ -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;
@@ -74,8 +75,55 @@ typedef struct TeletextContext
int readorder;
uint8_t subtitle_map[2048];
+ 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;
@@ -179,6 +227,186 @@ 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) {
+ alignment = ctx->last_ass_alignment;
+ } else 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)
+ leading = min_leading;
+ if (alignment == 3)
+ 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)
{
@@ -316,9 +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;
@@ -435,7 +674,7 @@ 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;
@@ -494,12 +733,22 @@ static int teletext_init_decoder(AVCodecContext *avctx)
ctx->vbi = NULL;
ctx->pts = AV_NOPTS_VALUE;
+ 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)
@@ -514,6 +763,7 @@ static int teletext_close_decoder(AVCodecContext *avctx)
vbi_decoder_delete(ctx->vbi);
ctx->vbi = NULL;
ctx->pts = AV_NOPTS_VALUE;
+ 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;
@@ -530,9 +780,10 @@ static void teletext_flush(AVCodecContext *avctx)
static const AVOption options[] = {
{"txt_page", "list of teletext page numbers to decode, * is 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},
--
2.13.6
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