237 lines
6.5 KiB
C
237 lines
6.5 KiB
C
/*
|
|
* WebVTT subtitle encoder
|
|
* Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
|
|
* Copyright (c) 2014 Aman Gupta <ffmpeg@tmm1.net>
|
|
*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg 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 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* FFmpeg 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 FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#include <stdarg.h>
|
|
#include "avcodec.h"
|
|
#include "libavutil/avstring.h"
|
|
#include "libavutil/bprint.h"
|
|
#include "ass_split.h"
|
|
#include "ass.h"
|
|
|
|
#define WEBVTT_STACK_SIZE 64
|
|
typedef struct {
|
|
AVCodecContext *avctx;
|
|
ASSSplitContext *ass_ctx;
|
|
AVBPrint buffer;
|
|
unsigned timestamp_end;
|
|
int count;
|
|
char stack[WEBVTT_STACK_SIZE];
|
|
int stack_ptr;
|
|
} WebVTTContext;
|
|
|
|
#ifdef __GNUC__
|
|
__attribute__ ((__format__ (__printf__, 2, 3)))
|
|
#endif
|
|
static void webvtt_print(WebVTTContext *s, const char *str, ...)
|
|
{
|
|
va_list vargs;
|
|
va_start(vargs, str);
|
|
av_vbprintf(&s->buffer, str, vargs);
|
|
va_end(vargs);
|
|
}
|
|
|
|
static int webvtt_stack_push(WebVTTContext *s, const char c)
|
|
{
|
|
if (s->stack_ptr >= WEBVTT_STACK_SIZE)
|
|
return -1;
|
|
s->stack[s->stack_ptr++] = c;
|
|
return 0;
|
|
}
|
|
|
|
static char webvtt_stack_pop(WebVTTContext *s)
|
|
{
|
|
if (s->stack_ptr <= 0)
|
|
return 0;
|
|
return s->stack[--s->stack_ptr];
|
|
}
|
|
|
|
static int webvtt_stack_find(WebVTTContext *s, const char c)
|
|
{
|
|
int i;
|
|
for (i = s->stack_ptr-1; i >= 0; i--)
|
|
if (s->stack[i] == c)
|
|
break;
|
|
return i;
|
|
}
|
|
|
|
static void webvtt_close_tag(WebVTTContext *s, char tag)
|
|
{
|
|
webvtt_print(s, "</%c>", tag);
|
|
}
|
|
|
|
static void webvtt_stack_push_pop(WebVTTContext *s, const char c, int close)
|
|
{
|
|
if (close) {
|
|
int i = c ? webvtt_stack_find(s, c) : 0;
|
|
if (i < 0)
|
|
return;
|
|
while (s->stack_ptr != i)
|
|
webvtt_close_tag(s, webvtt_stack_pop(s));
|
|
} else if (webvtt_stack_push(s, c) < 0)
|
|
av_log(s->avctx, AV_LOG_ERROR, "tag stack overflow\n");
|
|
}
|
|
|
|
static void webvtt_style_apply(WebVTTContext *s, const char *style)
|
|
{
|
|
ASSStyle *st = ff_ass_style_get(s->ass_ctx, style);
|
|
if (st) {
|
|
if (st->bold != ASS_DEFAULT_BOLD) {
|
|
webvtt_print(s, "<b>");
|
|
webvtt_stack_push(s, 'b');
|
|
}
|
|
if (st->italic != ASS_DEFAULT_ITALIC) {
|
|
webvtt_print(s, "<i>");
|
|
webvtt_stack_push(s, 'i');
|
|
}
|
|
if (st->underline != ASS_DEFAULT_UNDERLINE) {
|
|
webvtt_print(s, "<u>");
|
|
webvtt_stack_push(s, 'u');
|
|
}
|
|
}
|
|
}
|
|
|
|
static void webvtt_text_cb(void *priv, const char *text, int len)
|
|
{
|
|
WebVTTContext *s = priv;
|
|
av_bprint_append_data(&s->buffer, text, len);
|
|
}
|
|
|
|
static void webvtt_new_line_cb(void *priv, int forced)
|
|
{
|
|
webvtt_print(priv, "\n");
|
|
}
|
|
|
|
static void webvtt_style_cb(void *priv, char style, int close)
|
|
{
|
|
if (style == 's') // strikethrough unsupported
|
|
return;
|
|
|
|
webvtt_stack_push_pop(priv, style, close);
|
|
if (!close)
|
|
webvtt_print(priv, "<%c>", style);
|
|
}
|
|
|
|
static void webvtt_cancel_overrides_cb(void *priv, const char *style)
|
|
{
|
|
webvtt_stack_push_pop(priv, 0, 1);
|
|
webvtt_style_apply(priv, style);
|
|
}
|
|
|
|
static void webvtt_end_cb(void *priv)
|
|
{
|
|
webvtt_stack_push_pop(priv, 0, 1);
|
|
}
|
|
|
|
static const ASSCodesCallbacks webvtt_callbacks = {
|
|
.text = webvtt_text_cb,
|
|
.new_line = webvtt_new_line_cb,
|
|
.style = webvtt_style_cb,
|
|
.color = NULL,
|
|
.font_name = NULL,
|
|
.font_size = NULL,
|
|
.alignment = NULL,
|
|
.cancel_overrides = webvtt_cancel_overrides_cb,
|
|
.move = NULL,
|
|
.end = webvtt_end_cb,
|
|
};
|
|
|
|
static int webvtt_encode_frame(AVCodecContext *avctx,
|
|
unsigned char *buf, int bufsize, const AVSubtitle *sub)
|
|
{
|
|
WebVTTContext *s = avctx->priv_data;
|
|
ASSDialog *dialog;
|
|
int i;
|
|
|
|
av_bprint_clear(&s->buffer);
|
|
|
|
for (i=0; i<sub->num_rects; i++) {
|
|
const char *ass = sub->rects[i]->ass;
|
|
|
|
if (sub->rects[i]->type != SUBTITLE_ASS) {
|
|
av_log(avctx, AV_LOG_ERROR, "Only SUBTITLE_ASS type supported.\n");
|
|
return AVERROR(EINVAL);
|
|
}
|
|
|
|
#if FF_API_ASS_TIMING
|
|
if (!strncmp(ass, "Dialogue: ", 10)) {
|
|
int num;
|
|
dialog = ff_ass_split_dialog(s->ass_ctx, ass, 0, &num);
|
|
// TODO reindent
|
|
for (; dialog && num--; dialog++) {
|
|
webvtt_style_apply(s, dialog->style);
|
|
ff_ass_split_override_codes(&webvtt_callbacks, s, dialog->text);
|
|
}
|
|
} else {
|
|
#endif
|
|
dialog = ff_ass_split_dialog2(s->ass_ctx, ass);
|
|
if (!dialog)
|
|
return AVERROR(ENOMEM);
|
|
webvtt_style_apply(s, dialog->style);
|
|
ff_ass_split_override_codes(&webvtt_callbacks, s, dialog->text);
|
|
ff_ass_free_dialog(&dialog);
|
|
#if FF_API_ASS_TIMING
|
|
}
|
|
#endif
|
|
}
|
|
|
|
if (!av_bprint_is_complete(&s->buffer))
|
|
return AVERROR(ENOMEM);
|
|
if (!s->buffer.len)
|
|
return 0;
|
|
|
|
if (s->buffer.len > bufsize) {
|
|
av_log(avctx, AV_LOG_ERROR, "Buffer too small for ASS event.\n");
|
|
return AVERROR_BUFFER_TOO_SMALL;
|
|
}
|
|
memcpy(buf, s->buffer.str, s->buffer.len);
|
|
|
|
return s->buffer.len;
|
|
}
|
|
|
|
static int webvtt_encode_close(AVCodecContext *avctx)
|
|
{
|
|
WebVTTContext *s = avctx->priv_data;
|
|
ff_ass_split_free(s->ass_ctx);
|
|
av_bprint_finalize(&s->buffer, NULL);
|
|
return 0;
|
|
}
|
|
|
|
static av_cold int webvtt_encode_init(AVCodecContext *avctx)
|
|
{
|
|
WebVTTContext *s = avctx->priv_data;
|
|
s->avctx = avctx;
|
|
s->ass_ctx = ff_ass_split(avctx->subtitle_header);
|
|
av_bprint_init(&s->buffer, 0, AV_BPRINT_SIZE_UNLIMITED);
|
|
return s->ass_ctx ? 0 : AVERROR_INVALIDDATA;
|
|
}
|
|
|
|
AVCodec ff_webvtt_encoder = {
|
|
.name = "webvtt",
|
|
.long_name = NULL_IF_CONFIG_SMALL("WebVTT subtitle"),
|
|
.type = AVMEDIA_TYPE_SUBTITLE,
|
|
.id = AV_CODEC_ID_WEBVTT,
|
|
.priv_data_size = sizeof(WebVTTContext),
|
|
.init = webvtt_encode_init,
|
|
.encode_sub = webvtt_encode_frame,
|
|
.close = webvtt_encode_close,
|
|
};
|