GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/webvttenc.c Lines: 79 102 77.5 %
Date: 2020-10-23 17:01:47 Branches: 31 50 62.0 %

Line Branch Exec Source
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/*
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 * WebVTT subtitle encoder
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 * Copyright (c) 2010  Aurelien Jacobs <aurel@gnuage.org>
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 * Copyright (c) 2014  Aman Gupta <ffmpeg@tmm1.net>
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include <stdarg.h>
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#include "avcodec.h"
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#include "libavutil/avstring.h"
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#include "libavutil/bprint.h"
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#include "ass_split.h"
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#include "ass.h"
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#define WEBVTT_STACK_SIZE 64
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typedef struct {
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    AVCodecContext *avctx;
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    ASSSplitContext *ass_ctx;
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    AVBPrint buffer;
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    unsigned timestamp_end;
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    int count;
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    char stack[WEBVTT_STACK_SIZE];
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    int stack_ptr;
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} WebVTTContext;
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#ifdef __GNUC__
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__attribute__ ((__format__ (__printf__, 2, 3)))
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#endif
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static void webvtt_print(WebVTTContext *s, const char *str, ...)
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{
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    va_list vargs;
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    va_start(vargs, str);
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    av_vbprintf(&s->buffer, str, vargs);
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    va_end(vargs);
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}
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static int webvtt_stack_push(WebVTTContext *s, const char c)
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{
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    if (s->stack_ptr >= WEBVTT_STACK_SIZE)
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        return -1;
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    s->stack[s->stack_ptr++] = c;
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    return 0;
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}
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static char webvtt_stack_pop(WebVTTContext *s)
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{
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    if (s->stack_ptr <= 0)
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        return 0;
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    return s->stack[--s->stack_ptr];
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}
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static int webvtt_stack_find(WebVTTContext *s, const char c)
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{
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    int i;
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    for (i = s->stack_ptr-1; i >= 0; i--)
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        if (s->stack[i] == c)
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            break;
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    return i;
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}
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static void webvtt_close_tag(WebVTTContext *s, char tag)
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{
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    webvtt_print(s, "</%c>", tag);
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}
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static void webvtt_stack_push_pop(WebVTTContext *s, const char c, int close)
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{
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    if (close) {
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        int i = c ? webvtt_stack_find(s, c) : 0;
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        if (i < 0)
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1
            return;
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        while (s->stack_ptr != i)
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            webvtt_close_tag(s, webvtt_stack_pop(s));
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    } else if (webvtt_stack_push(s, c) < 0)
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        av_log(s->avctx, AV_LOG_ERROR, "tag stack overflow\n");
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}
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static void webvtt_style_apply(WebVTTContext *s, const char *style)
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{
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    ASSStyle *st = ff_ass_style_get(s->ass_ctx, style);
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    if (st) {
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        if (st->bold != ASS_DEFAULT_BOLD) {
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            webvtt_print(s, "<b>");
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            webvtt_stack_push(s, 'b');
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        }
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        if (st->italic != ASS_DEFAULT_ITALIC) {
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            webvtt_print(s, "<i>");
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            webvtt_stack_push(s, 'i');
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        }
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        if (st->underline != ASS_DEFAULT_UNDERLINE) {
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            webvtt_print(s, "<u>");
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            webvtt_stack_push(s, 'u');
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        }
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    }
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}
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static void webvtt_text_cb(void *priv, const char *text, int len)
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{
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    WebVTTContext *s = priv;
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    av_bprint_append_data(&s->buffer, text, len);
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}
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static void webvtt_new_line_cb(void *priv, int forced)
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{
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    webvtt_print(priv, "\n");
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}
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static void webvtt_style_cb(void *priv, char style, int close)
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{
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    if (style == 's') // strikethrough unsupported
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        return;
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    webvtt_stack_push_pop(priv, style, close);
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    if (!close)
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        webvtt_print(priv, "<%c>", style);
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}
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static void webvtt_cancel_overrides_cb(void *priv, const char *style)
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{
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    webvtt_stack_push_pop(priv, 0, 1);
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    webvtt_style_apply(priv, style);
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}
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static void webvtt_end_cb(void *priv)
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{
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    webvtt_stack_push_pop(priv, 0, 1);
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}
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static const ASSCodesCallbacks webvtt_callbacks = {
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    .text             = webvtt_text_cb,
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    .new_line         = webvtt_new_line_cb,
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    .style            = webvtt_style_cb,
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    .color            = NULL,
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    .font_name        = NULL,
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    .font_size        = NULL,
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    .alignment        = NULL,
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    .cancel_overrides = webvtt_cancel_overrides_cb,
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    .move             = NULL,
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    .end              = webvtt_end_cb,
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};
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static int webvtt_encode_frame(AVCodecContext *avctx,
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                               unsigned char *buf, int bufsize, const AVSubtitle *sub)
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{
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    WebVTTContext *s = avctx->priv_data;
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    ASSDialog *dialog;
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    int i;
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    av_bprint_clear(&s->buffer);
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    for (i=0; i<sub->num_rects; i++) {
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        const char *ass = sub->rects[i]->ass;
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        if (sub->rects[i]->type != SUBTITLE_ASS) {
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            av_log(avctx, AV_LOG_ERROR, "Only SUBTITLE_ASS type supported.\n");
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            return AVERROR(EINVAL);
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        }
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#if FF_API_ASS_TIMING
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        if (!strncmp(ass, "Dialogue: ", 10)) {
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            int num;
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            dialog = ff_ass_split_dialog(s->ass_ctx, ass, 0, &num);
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            // TODO reindent
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        for (; dialog && num--; dialog++) {
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            webvtt_style_apply(s, dialog->style);
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            ff_ass_split_override_codes(&webvtt_callbacks, s, dialog->text);
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        }
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        } else {
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#endif
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            dialog = ff_ass_split_dialog2(s->ass_ctx, ass);
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            if (!dialog)
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                return AVERROR(ENOMEM);
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            webvtt_style_apply(s, dialog->style);
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            ff_ass_split_override_codes(&webvtt_callbacks, s, dialog->text);
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            ff_ass_free_dialog(&dialog);
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#if FF_API_ASS_TIMING
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        }
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#endif
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    }
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    if (!av_bprint_is_complete(&s->buffer))
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        return AVERROR(ENOMEM);
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    if (!s->buffer.len)
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        return 0;
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    if (s->buffer.len > bufsize) {
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        av_log(avctx, AV_LOG_ERROR, "Buffer too small for ASS event.\n");
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        return AVERROR_BUFFER_TOO_SMALL;
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    }
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    memcpy(buf, s->buffer.str, s->buffer.len);
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    return s->buffer.len;
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}
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static int webvtt_encode_close(AVCodecContext *avctx)
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{
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    WebVTTContext *s = avctx->priv_data;
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    ff_ass_split_free(s->ass_ctx);
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    av_bprint_finalize(&s->buffer, NULL);
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    return 0;
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}
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static av_cold int webvtt_encode_init(AVCodecContext *avctx)
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{
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    WebVTTContext *s = avctx->priv_data;
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    s->avctx = avctx;
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    s->ass_ctx = ff_ass_split(avctx->subtitle_header);
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    av_bprint_init(&s->buffer, 0, AV_BPRINT_SIZE_UNLIMITED);
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    return s->ass_ctx ? 0 : AVERROR_INVALIDDATA;
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}
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AVCodec ff_webvtt_encoder = {
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    .name           = "webvtt",
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    .long_name      = NULL_IF_CONFIG_SMALL("WebVTT subtitle"),
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    .type           = AVMEDIA_TYPE_SUBTITLE,
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    .id             = AV_CODEC_ID_WEBVTT,
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    .priv_data_size = sizeof(WebVTTContext),
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    .init           = webvtt_encode_init,
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    .encode_sub     = webvtt_encode_frame,
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    .close          = webvtt_encode_close,
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};