FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavformat/ttmlenc.c
Date: 2026-04-30 13:16:32
Exec Total Coverage
Lines: 64 84 76.2%
Functions: 5 5 100.0%
Branches: 11 27 40.7%
Line Branch Exec Source
1 /*
2 * TTML subtitle muxer
3 * Copyright (c) 2020 24i
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 /**
23 * @file
24 * TTML subtitle muxer
25 * @see https://www.w3.org/TR/ttml1/
26 * @see https://www.w3.org/TR/ttml2/
27 * @see https://www.w3.org/TR/ttml-imsc/rec
28 */
29
30 #include "libavutil/avstring.h"
31 #include "avformat.h"
32 #include "internal.h"
33 #include "mux.h"
34 #include "ttmlenc.h"
35 #include "libavcodec/ttmlenc.h"
36 #include "libavutil/internal.h"
37
38 enum TTMLPacketType {
39 PACKET_TYPE_PARAGRAPH,
40 PACKET_TYPE_DOCUMENT,
41 };
42
43 struct TTMLHeaderParameters {
44 const char *tt_element_params;
45 const char *pre_body_elements;
46 };
47
48 typedef struct TTMLMuxContext {
49 enum TTMLPacketType input_type;
50 unsigned int document_written;
51 } TTMLMuxContext;
52
53 static const char ttml_header_text[] =
54 "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n"
55 "<tt\n"
56 "%s"
57 " xml:lang=\"%s\">\n"
58 "%s"
59 " <body>\n"
60 " <div>\n";
61
62 static const char ttml_footer_text[] =
63 " </div>\n"
64 " </body>\n"
65 "</tt>\n";
66
67 342 static void ttml_write_time(AVIOContext *pb, const char tag[],
68 int64_t millisec)
69 {
70 int64_t sec, min, hour;
71 342 sec = millisec / 1000;
72 342 millisec -= 1000 * sec;
73 342 min = sec / 60;
74 342 sec -= 60 * min;
75 342 hour = min / 60;
76 342 min -= 60 * hour;
77
78 342 avio_printf(pb, "%s=\"%02"PRId64":%02"PRId64":%02"PRId64".%03"PRId64"\"",
79 tag, hour, min, sec, millisec);
80 342 }
81
82 29 static int ttml_set_header_values_from_extradata(
83 AVCodecParameters *par, struct TTMLHeaderParameters *header_params)
84 {
85 29 size_t additional_data_size =
86 29 par->extradata_size - TTMLENC_EXTRADATA_SIGNATURE_SIZE;
87 29 char *value =
88 29 (char *)par->extradata + TTMLENC_EXTRADATA_SIGNATURE_SIZE;
89 29 size_t value_size = av_strnlen(value, additional_data_size);
90 29 struct TTMLHeaderParameters local_params = { 0 };
91
92
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 29 if (!additional_data_size) {
93 // simple case, we don't have to go through local_params and just
94 // set default fall-back values (for old extradata format).
95 ✗ header_params->tt_element_params = TTML_DEFAULT_NAMESPACING;
96 ✗ header_params->pre_body_elements = "";
97
98 ✗ return 0;
99 }
100
101
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 29 if (value_size == additional_data_size ||
102
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 29 value[value_size] != '\0')
103 ✗ return AVERROR_INVALIDDATA;
104
105 29 local_params.tt_element_params = value;
106
107 29 additional_data_size -= value_size + 1;
108 29 value += value_size + 1;
109
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 29 if (!additional_data_size)
110 ✗ return AVERROR_INVALIDDATA;
111
112 29 value_size = av_strnlen(value, additional_data_size);
113
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 29 if (value_size == additional_data_size ||
114
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 29 value[value_size] != '\0')
115 ✗ return AVERROR_INVALIDDATA;
116
117 29 local_params.pre_body_elements = value;
118
119 29 *header_params = local_params;
120
121 29 return 0;
122 }
123
124 29 static int ttml_write_header(AVFormatContext *ctx)
125 {
126 29 TTMLMuxContext *ttml_ctx = ctx->priv_data;
127 29 AVStream *st = ctx->streams[0];
128 29 AVIOContext *pb = ctx->pb;
129
130 29 const AVDictionaryEntry *lang = av_dict_get(st->metadata, "language", NULL,
131 0);
132
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 29 const char *printed_lang = (lang && lang->value) ? lang->value : "";
133
134 29 ttml_ctx->document_written = 0;
135 29 ttml_ctx->input_type = ff_is_ttml_stream_paragraph_based(st->codecpar) ?
136 29 PACKET_TYPE_PARAGRAPH :
137 PACKET_TYPE_DOCUMENT;
138
139 29 avpriv_set_pts_info(st, 64, 1, 1000);
140
141
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 29 if (ttml_ctx->input_type == PACKET_TYPE_PARAGRAPH) {
142 struct TTMLHeaderParameters header_params;
143 29 int ret = ttml_set_header_values_from_extradata(
144 st->codecpar, &header_params);
145
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 29 if (ret < 0) {
146 ✗ av_log(ctx, AV_LOG_ERROR,
147 "Failed to parse TTML header values from extradata: "
148 ✗ "%s!\n", av_err2str(ret));
149 ✗ return ret;
150 }
151
152 29 avio_printf(pb, ttml_header_text,
153 header_params.tt_element_params,
154 printed_lang,
155 header_params.pre_body_elements);
156 }
157
158 29 return 0;
159 }
160
161 171 static int ttml_write_packet(AVFormatContext *ctx, AVPacket *pkt)
162 {
163 171 TTMLMuxContext *ttml_ctx = ctx->priv_data;
164 171 AVIOContext *pb = ctx->pb;
165
166
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 171 switch (ttml_ctx->input_type) {
167 171 case PACKET_TYPE_PARAGRAPH:
168 // write out a paragraph element with the given contents.
169 171 avio_printf(pb, " <p\n");
170 171 ttml_write_time(pb, " begin", pkt->pts);
171 171 avio_w8(pb, '\n');
172 171 ttml_write_time(pb, " end", pkt->pts + pkt->duration);
173 171 avio_printf(pb, ">");
174 171 avio_write(pb, pkt->data, pkt->size);
175 171 avio_printf(pb, "</p>\n");
176 171 break;
177 ✗ case PACKET_TYPE_DOCUMENT:
178 // dump the given document out as-is.
179 ✗ if (ttml_ctx->document_written) {
180 ✗ av_log(ctx, AV_LOG_ERROR,
181 "Attempting to write multiple TTML documents into a "
182 "single document! The XML specification forbids this "
183 "as there has to be a single root tag.\n");
184 ✗ return AVERROR(EINVAL);
185 }
186 ✗ avio_write(pb, pkt->data, pkt->size);
187 ✗ ttml_ctx->document_written = 1;
188 ✗ break;
189 ✗ default:
190 ✗ av_log(ctx, AV_LOG_ERROR,
191 "Internal error: invalid TTML input packet type: %d!\n",
192 ✗ ttml_ctx->input_type);
193 ✗ return AVERROR_BUG;
194 }
195
196 171 return 0;
197 }
198
199 29 static int ttml_write_trailer(AVFormatContext *ctx)
200 {
201 29 TTMLMuxContext *ttml_ctx = ctx->priv_data;
202 29 AVIOContext *pb = ctx->pb;
203
204
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 29 if (ttml_ctx->input_type == PACKET_TYPE_PARAGRAPH)
205 29 avio_printf(pb, ttml_footer_text);
206
207 29 return 0;
208 }
209
210 const FFOutputFormat ff_ttml_muxer = {
211 .p.name = "ttml",
212 .p.long_name = NULL_IF_CONFIG_SMALL("TTML subtitle"),
213 .p.extensions = "ttml",
214 .p.mime_type = "text/ttml",
215 .priv_data_size = sizeof(TTMLMuxContext),
216 .p.flags = AVFMT_GLOBALHEADER | AVFMT_VARIABLE_FPS |
217 AVFMT_TS_NONSTRICT,
218 .p.video_codec = AV_CODEC_ID_NONE,
219 .p.audio_codec = AV_CODEC_ID_NONE,
220 .p.subtitle_codec = AV_CODEC_ID_TTML,
221 .flags_internal = FF_OFMT_FLAG_MAX_ONE_OF_EACH |
222 FF_OFMT_FLAG_ONLY_DEFAULT_CODECS,
223 .write_header = ttml_write_header,
224 .write_packet = ttml_write_packet,
225 .write_trailer = ttml_write_trailer,
226 };
227