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avcodec/libzvbi-teletextdec: add support for selecting subtitle pages only

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Signed-off-by: Marton Balint <cus@passwd.hu>
This commit is contained in:
Marton Balint 2018-04-28 21:42:34 +02:00
parent 3a56ade1f3
commit d9f72e53bf
3 changed files with 27 additions and 13 deletions
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5
doc/decoders.texi
View File

@ -248,8 +248,9 @@ configuration. You need to explicitly configure the build with
@table @option
@item txt_page
List of teletext page numbers to decode. You may use the special * string to
match all pages. Pages that do not match the specified list are dropped.
List of teletext page numbers to decode. Pages that do not match the specified
list are dropped. You may use the special @code{*} string to match all pages,
or @code{subtitle} to match all subtitle pages.
Default value is *.
@item txt_chop_top
Discards the top teletext line. Default value is 1.

33
libavcodec/libzvbi-teletextdec.c
View File

@ -73,6 +73,7 @@ typedef struct TeletextContext
vbi_sliced sliced[MAX_SLICES];
int readorder;
uint8_t subtitle_map[2048];
} TeletextContext;
static int chop_spaces_utf8(const unsigned char* t, int len)
@ -281,16 +282,14 @@ static void handler(vbi_event *ev, void *user_data)
vbi_page page;
int res;
char pgno_str[12];
vbi_subno subno;
vbi_page_type vpt;
int chop_top;
char *lang;
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, "*") && !strstr(ctx->pgno, pgno_str))
if (strcmp(ctx->pgno, "*") && (strcmp(ctx->pgno, "subtitle") || !is_subtitle_page) && !strstr(ctx->pgno, pgno_str))
return;
if (ctx->handler_ret < 0)
return;
@ -303,9 +302,7 @@ static void handler(vbi_event *ev, void *user_data)
if (!res)
return;
vpt = vbi_classify_page(ctx->vbi, ev->ev.ttx_page.pgno, &subno, &lang);
chop_top = ctx->chop_top ||
((page.rows > 1) && (vpt == VBI_SUBTITLE_PAGE));
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);
@ -357,11 +354,26 @@ static int slice_to_vbi_lines(TeletextContext *ctx, uint8_t* buf, int size)
else {
int line_offset = buf[2] & 0x1f;
int field_parity = buf[2] & 0x20;
int i;
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++)
ctx->sliced[lines].data[i] = vbi_rev8(buf[4 + 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);
}
}
lines++;
}
}
@ -502,6 +514,7 @@ static int teletext_close_decoder(AVCodecContext *avctx)
vbi_decoder_delete(ctx->vbi);
ctx->vbi = NULL;
ctx->pts = AV_NOPTS_VALUE;
memset(ctx->subtitle_map, 0, sizeof(ctx->subtitle_map));
if (!(avctx->flags2 & AV_CODEC_FLAG2_RO_FLUSH_NOOP))
ctx->readorder = 0;
return 0;
@ -515,7 +528,7 @@ static void teletext_flush(AVCodecContext *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", "list of teletext page numbers to decode, * is all", OFFSET(pgno), AV_OPT_TYPE_STRING, {.str = "*"}, 0, 0, SD},
{"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"},
{"bitmap", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 0}, 0, 0, SD, "txt_format"},

2
libavcodec/version.h
View File

@ -29,7 +29,7 @@
#define LIBAVCODEC_VERSION_MAJOR 58
#define LIBAVCODEC_VERSION_MINOR 20
#define LIBAVCODEC_VERSION_MICRO 100
#define LIBAVCODEC_VERSION_MICRO 101
#define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
LIBAVCODEC_VERSION_MINOR, \