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FFmpeg/libavcodec/libzvbi-teletextdec.c
Marton Balint b339dccbba lavc: add teletext decoder using libzvbi 
Based on a patch by Wolfram Gloger <wmglo@dent.med.uni-muenchen.de>.
http://lists.ffmpeg.org/pipermail/ffmpeg-devel/2012-December/136677.html

The original patch was rebased by Tudor SUCIU <tudor.suciu@gmail.com>.

Lots of additional features and fixes are made by me.

Fixes ticket #2086.

Changes since last version:
- change default page to all pages

Signed-off-by: Marton Balint <cus@passwd.hu>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
2013-09-02 01:19:52 +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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "avcodec.h"
#include "libavutil/opt.h"
#include "libavutil/intreadwrite.h"
#include <libzvbi.h>
#define TEXT_MAXSZ (25 * (56 + 1) * 4 + 2)
#define VBI_NB_COLORS 40
#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)
/* main data structure */
typedef struct TeletextContext
{
AVClass *class;
char *pgno;
int x_offset;
int y_offset;
char *format;
int format_id; /* 0 = bitmap, 1 = text */
int chop_top;
int sub_duration; /* in msec */
int transparent_bg;
int chop_spaces;
int lines_processed;
AVSubtitleRect *sub_rect;
vbi_decoder * vbi;
vbi_dvb_demux * dx;
#ifdef DEBUG
vbi_export * ex;
#endif
/* Don't even _think_ about making sliced stack-local! */
vbi_sliced sliced[64];
} TeletextContext;
/************************************************************************/
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;
}
// draw a page as text
static int
gen_sub_text(TeletextContext *ctx, vbi_page *page, int chop_top)
{
AVSubtitleRect *sub_rect = ctx->sub_rect;
char *text;
const char *in;
char *out;
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;
out = text = av_malloc(TEXT_MAXSZ);
if (!text) {
av_free(vbi_text);
return AVERROR(ENOMEM);
}
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);
memcpy(out, in, sz);
out += sz;
*out++ = '\n';
in += nl;
}
} else {
strcpy(text, vbi_text);
out += sz;
*out++ = '\n';
}
av_free(vbi_text);
*out = '\0';
if (out > text) {
sub_rect->type = SUBTITLE_TEXT;
sub_rect->text = text;
av_log(ctx, AV_LOG_DEBUG, "subtext:%s:txetbus\n", text);
} else {
sub_rect->type = SUBTITLE_NONE;
av_free(text);
}
return 0;
}
static void
fix_transparency(TeletextContext *ctx, vbi_page *page, int chop_top, uint8_t transparent_color, int resx, int resy)
{
AVSubtitleRect *sub_rect = ctx->sub_rect;
int iy;
// Hack for transparency, inspired by VLC code...
for (iy = 0; iy < resy; iy++) {
uint8_t *pixel = sub_rect->pict.data[0] + iy * sub_rect->pict.linesize[0];
vbi_char *vc = page->text + (iy / 10 + chop_top) * page->columns;
vbi_char *vcnext = vc + page->columns;
for (; vc < vcnext; vc++) {
uint8_t *pixelnext = pixel + 12;
switch (vc->opacity) {
case VBI_TRANSPARENT_SPACE:
memset(pixel, transparent_color, 12);
break;
case VBI_OPAQUE:
case VBI_SEMI_TRANSPARENT:
if (!ctx->transparent_bg)
break;
case VBI_TRANSPARENT_FULL:
for(; pixel < pixelnext; pixel++)
if (*pixel == vc->background)
*pixel = transparent_color;
break;
}
pixel = pixelnext;
}
}
}
// draw a page as bitmap
static int
gen_sub_bitmap(TeletextContext *ctx, vbi_page *page, int chop_top)
{
AVSubtitleRect *sub_rect = ctx->sub_rect;
int resx = page->columns * 12;
int resy = (page->rows - chop_top) * 10;
uint8_t ci, cmax = 0;
int ret;
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) {
cmax = VBI_NB_COLORS;
break;
}
}
if (cmax == 0) {
av_log(ctx, AV_LOG_DEBUG, "dropping empty page %3x\n", page->pgno);
sub_rect->type = SUBTITLE_NONE;
return 0;
}
if ((ret = avpicture_alloc(&sub_rect->pict, AV_PIX_FMT_PAL8, resx, resy)) < 0)
return ret;
// Yes, we want to allocate the palette on our own because AVSubtitle works this way
sub_rect->pict.data[1] = NULL;
vbi_draw_vt_page_region(page, VBI_PIXFMT_PAL8,
sub_rect->pict.data[0], sub_rect->pict.linesize[0],
0, chop_top, page->columns, page->rows - chop_top,
/*reveal*/ 1, /*flash*/ 1);
fix_transparency(ctx, page, chop_top, cmax, resx, resy);
sub_rect->x = ctx->x_offset;
sub_rect->y = ctx->y_offset;
sub_rect->w = resx;
sub_rect->h = resy;
sub_rect->nb_colors = (int)cmax + 1;
sub_rect->pict.data[1] = av_mallocz(AVPALETTE_SIZE);
if (!sub_rect->pict.data[1]) {
av_freep(&sub_rect->pict.data[0]);
return AVERROR(ENOMEM);
}
for (ci = 0; ci < cmax; 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->pict.data[1])[ci] = RGBA(r, g, b, a);
#ifdef DEBUG
av_log(ctx, AV_LOG_DEBUG, "palette %0x\n",
((uint32_t *)sub_rect->pict.data[1])[ci]);
#endif
}
((uint32_t *)sub_rect->pict.data[1])[cmax] = 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;
vbi_page page;
int res;
char pgno_str[12];
vbi_subno subno;
vbi_page_type vpt;
int chop_top;
char *lang;
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))
return;
/* Fetch the page. */
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;
#ifdef DEBUG
fprintf(stderr, "\nSaving res=%d dy0=%d dy1=%d...\n",
res, page.dirty.y0, page.dirty.y1);
fflush(stderr);
if (!vbi_export_stdio(ctx->ex, stderr, &page))
fprintf(stderr, "failed: %s\n", vbi_export_errstr(ctx->ex));
#endif
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));
av_log(ctx, AV_LOG_DEBUG, "%d x %d page chop:%d\n",
page.columns, page.rows, chop_top);
if (!ctx->sub_rect) {
ctx->sub_rect = av_mallocz(sizeof(*ctx->sub_rect));
if (ctx->sub_rect) {
res = (ctx->format_id == 0) ?
gen_sub_bitmap(ctx, &page, chop_top) :
gen_sub_text (ctx, &page, chop_top);
if (res)
av_freep(&ctx->sub_rect);
}
} else {
// FIXME: Multiple teletext pages in a single packet, some kind of buffering should be done instead of dropping the page...
av_log(ctx, AV_LOG_WARNING, "Missed page %s.%02x.\n", pgno_str, ev->ev.ttx_page.subno & 0xFF);
}
vbi_unref_page(&page);
}
static int
teletext_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
AVPacket *pkt)
{
TeletextContext *ctx = avctx->priv_data;
AVSubtitle *sub = data;
const uint8_t *buf = pkt->data;
unsigned int left = pkt->size;
uint8_t pesheader[45] = {0x00, 0x00, 0x01, 0xbd, 0x00, 0x00, 0x85, 0x80, 0x24, 0x21, 0x00, 0x01, 0x00, 0x01};
int pesheader_size = sizeof(pesheader);
const uint8_t *pesheader_buf = pesheader;
if (!ctx->vbi) {
if (!(ctx->vbi = vbi_decoder_new()))
return AVERROR(ENOMEM);
if (!vbi_event_handler_add(ctx->vbi, VBI_EVENT_TTX_PAGE, handler, ctx)) {
vbi_decoder_delete(ctx->vbi);
ctx->vbi = NULL;
return AVERROR(ENOMEM);
}
}
if (!ctx->dx && (!(ctx->dx = vbi_dvb_pes_demux_new (/* callback */ NULL, NULL))))
return AVERROR(ENOMEM);
// We allow unreasonably big packets, even if the standard only allows a max size of 1472
if ((pesheader_size + left) < 184 || (pesheader_size + left) > 65504 || (pesheader_size + left) % 184 != 0)
return AVERROR_INVALIDDATA;
memset(pesheader + 14, 0xff, pesheader_size - 14);
AV_WB16(pesheader + 4, left + pesheader_size - 6);
/* PTS is deliberately left as 0 in the PES header, otherwise libzvbi uses
* it to detect dropped frames. Unforunatey the guessed packet PTS values
* (see mpegts demuxer) are not accurate enough to pass that test. */
vbi_dvb_demux_cor(ctx->dx, ctx->sliced, 64, NULL, &pesheader_buf, &pesheader_size);
while (left > 0) {
int64_t pts = 0;
unsigned int lines = vbi_dvb_demux_cor(ctx->dx, ctx->sliced, 64, &pts, &buf, &left);
#ifdef DEBUG
av_log(avctx, AV_LOG_DEBUG,
"ctx=%p buf_size=%d left=%u lines=%u pts=%f pkt_pts=%f\n",
ctx, pkt->size, left, lines, (double)pts/90000.0, (double)pkt->pts/90000.0);
#endif
if (lines > 0) {
#ifdef DEBUGx
int i;
for(i=0; i<lines; ++i)
av_log(avctx, AV_LOG_DEBUG,
"lines=%d id=%x\n", i, ctx->sliced[i].id);
#endif
vbi_decode(ctx->vbi, ctx->sliced, lines, (double)pts/90000.0);
ctx->lines_processed += lines;
}
}
// is there a subtitle to pass?
if (ctx->sub_rect) {
sub->format = (ctx->sub_rect->type == SUBTITLE_TEXT ? 1: 0);
sub->start_display_time = 0;
sub->end_display_time = ctx->sub_duration;
sub->num_rects = 0;
if (ctx->sub_rect->type != SUBTITLE_NONE) {
sub->rects = av_malloc(sizeof(*sub->rects) * 1);
if (sub->rects) {
sub->num_rects = 1;
sub->rects[0] = ctx->sub_rect;
}
} else {
av_log(avctx, AV_LOG_DEBUG, "sending empty sub\n");
sub->rects = NULL;
}
if (!sub->rects) // no rect was passed
av_free(ctx->sub_rect);
ctx->sub_rect = NULL;
*data_size = 1;
} else
*data_size = 0;
return pkt->size;
}
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;
}
ctx->dx = NULL;
ctx->vbi = NULL;
ctx->sub_rect = NULL;
if (!strcmp(ctx->format, "bitmap")) {
ctx->format_id = 0;
} else if (!strcmp(ctx->format, "text")) {
ctx->format_id = 1;
} else {
av_log(avctx, AV_LOG_ERROR, "unkown format %s\n", ctx->format);
return AVERROR_OPTION_NOT_FOUND;
}
#ifdef DEBUG
{
char *t;
ctx->ex = vbi_export_new("text", &t);
}
#endif
av_log(avctx, AV_LOG_VERBOSE, "page filter: %s\n", ctx->pgno);
return 0;
}
static int teletext_close_decoder(AVCodecContext *avctx)
{
TeletextContext *ctx = avctx->priv_data;
#ifdef DEBUG
av_log(avctx, AV_LOG_DEBUG, "lines_total=%u\n", ctx->lines_processed);
#endif
vbi_dvb_demux_delete(ctx->dx);
vbi_decoder_delete(ctx->vbi);
ctx->dx = NULL;
ctx->vbi = NULL;
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", "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), AV_OPT_TYPE_STRING, {.str = "bitmap"}, 0, 0, SD},
{"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 = 30000}, 0, 86400000, SD},
{"txt_transparent", "force transparent background of the teletext", OFFSET(transparent_bg), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, SD},
{ NULL },
};
static const AVClass teletext_class = {
.class_name = "libzvbi_teletextdec",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
AVCodec ff_libzvbi_teletext_decoder = {
.name = "libzvbi_teletextdec",
.type = AVMEDIA_TYPE_SUBTITLE,
.id = CODEC_ID_DVB_TELETEXT,
.priv_data_size = sizeof(TeletextContext),
.init = teletext_init_decoder,
.close = teletext_close_decoder,
.decode = teletext_decode_frame,
.flush = teletext_flush,
.long_name = NULL_IF_CONFIG_SMALL("Libzvbi DVB teletext decoder"),
.priv_class= &teletext_class,
};
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