| /* |
| * 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(ENOSYS); |
| } |
| |
| #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 -1; |
| } |
| 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, |
| }; |
