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FFmpeg/libavcodec/libzvbi-teletextdec.c
Marton Balint 085ca7dcdb libzvbi-teletextdec: split dvb packet to slices 
Instead of using the demux function of libzvbi to split the packet to slices
(vbi lines), lets do it ourselves.

- eliminates the 1 frame delay between page input and output
- handles non-ascending line numbers more gracefully
- enables us to return error codes on some invalid packets instead of silently
  ignoring them

Signed-off-by: Marton Balint <cus@passwd.hu>
2014-03-08 21:58:12 +01:00

571 lines
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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 "libavutil/opt.h"
#include "libavutil/bprint.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/log.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)
#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 x_offset;
int y_offset;
int format_id; /* 0 = bitmap, 1 = text/ass */
int chop_top;
int sub_duration; /* in msec */
int transparent_bg;
int chop_spaces;
int lines_processed;
TeletextPage *pages;
int nb_pages;
int64_t pts;
int handler_ret;
vbi_decoder * vbi;
#ifdef DEBUG
vbi_export * ex;
#endif
vbi_sliced sliced[MAX_SLICES];
} 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;
}
static void subtitle_rect_free(AVSubtitleRect **sub_rect)
{
av_freep(&(*sub_rect)->pict.data[0]);
av_freep(&(*sub_rect)->pict.data[1]);
av_freep(&(*sub_rect)->ass);
av_freep(sub_rect);
}
static int create_ass_text(TeletextContext *ctx, const char *text, char **ass)
{
int ret;
AVBPrint buf, buf2;
const int ts_start = av_rescale_q(ctx->pts, AV_TIME_BASE_Q, (AVRational){1, 100});
const int ts_duration = av_rescale_q(ctx->sub_duration, (AVRational){1, 1000}, (AVRational){1, 100});
/* First we escape the plain text into 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 AVERROR(ENOMEM);
}
/* Then we create the ass dialog line in buf2 from the escaped text in buf. */
av_bprint_init(&buf2, 0, AV_BPRINT_SIZE_UNLIMITED);
ff_ass_bprint_dialog(&buf2, buf.str, ts_start, ts_duration, 0);
av_bprint_finalize(&buf, NULL);
if (!av_bprint_is_complete(&buf2)) {
av_bprint_finalize(&buf2, NULL);
return AVERROR(ENOMEM);
}
if ((ret = av_bprint_finalize(&buf2, ass)) < 0)
return ret;
return 0;
}
/* 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) {
int ret;
sub_rect->type = SUBTITLE_ASS;
if ((ret = create_ass_text(ctx, buf.str, &sub_rect->ass)) < 0) {
av_bprint_finalize(&buf, NULL);
return ret;
}
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, uint8_t transparent_color, int resx, int resy)
{
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 / 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, transparent_color, BITMAP_CHAR_WIDTH);
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, 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, 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, sub_rect, page, chop_top, cmax, 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 = (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);
av_dlog(ctx, "palette %0x\n", ((uint32_t *)sub_rect->pict.data[1])[ci]);
}
((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;
TeletextPage *new_pages;
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;
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;
#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->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) {
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);
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 inline int data_identifier_is_teletext(int data_identifier) {
/* See EN 301 775 section 4.4.2. */
return (data_identifier >= 0x10 && data_identifier <= 0x1F ||
data_identifier >= 0x99 && data_identifier <= 0x9B);
}
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 (data_unit_id == 0x02 || data_unit_id == 0x03) {
if (data_unit_length != 0x2c)
return AVERROR_INVALIDDATA;
else {
int line_offset = buf[2] & 0x1f;
int field_parity = buf[2] & 0x20;
int i;
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]);
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, void *data, int *data_size, AVPacket *pkt)
{
TeletextContext *ctx = avctx->priv_data;
AVSubtitle *sub = data;
int ret = 0;
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 (avctx->pkt_timebase.den && 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 (data_identifier_is_teletext(*pkt->data)) {
if ((lines = slice_to_vbi_lines(ctx, pkt->data + 1, pkt->size - 1)) < 0)
return lines;
av_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) {
#ifdef DEBUG
int i;
av_log(avctx, AV_LOG_DEBUG, "line numbers:");
for(i = 0; i < lines; i++)
av_log(avctx, AV_LOG_DEBUG, " %d", ctx->sliced[i].line);
av_log(avctx, AV_LOG_DEBUG, "\n");
#endif
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) * 1);
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)
*data_size = 1;
} else
*data_size = 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;
#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 (ctx->format_id == 1) ? ff_ass_subtitle_header_default(avctx) : 0;
}
static int teletext_close_decoder(AVCodecContext *avctx)
{
TeletextContext *ctx = avctx->priv_data;
av_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;
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_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"},
{"text", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 1}, 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 = 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",
.long_name = NULL_IF_CONFIG_SMALL("Libzvbi DVB teletext decoder"),
.type = AVMEDIA_TYPE_SUBTITLE,
.id = AV_CODEC_ID_DVB_TELETEXT,
.priv_data_size = sizeof(TeletextContext),
.init = teletext_init_decoder,
.close = teletext_close_decoder,
.decode = teletext_decode_frame,
.capabilities = CODEC_CAP_DELAY,
.flush = teletext_flush,
.priv_class= &teletext_class,
};
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