mirror of
https://git.videolan.org/git/ffmpeg.git
synced 2024-09-04 07:21:31 +02:00
![Andreas Rheinhardt](/assets/img/avatar_default.png)
Reviewed-by: James Almer <jamrial@gmail.com> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
397 lines
12 KiB
C
397 lines
12 KiB
C
/*
|
|
* TTML subtitle encoder
|
|
* Copyright (c) 2020 24i
|
|
*
|
|
* 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
|
|
*/
|
|
|
|
/**
|
|
* @file
|
|
* TTML subtitle encoder
|
|
* @see https://www.w3.org/TR/ttml1/
|
|
* @see https://www.w3.org/TR/ttml2/
|
|
* @see https://www.w3.org/TR/ttml-imsc/rec
|
|
*/
|
|
|
|
#include "avcodec.h"
|
|
#include "internal.h"
|
|
#include "libavutil/avstring.h"
|
|
#include "libavutil/bprint.h"
|
|
#include "libavutil/internal.h"
|
|
#include "ass_split.h"
|
|
#include "ass.h"
|
|
#include "ttmlenc.h"
|
|
|
|
typedef struct {
|
|
AVCodecContext *avctx;
|
|
ASSSplitContext *ass_ctx;
|
|
AVBPrint buffer;
|
|
} TTMLContext;
|
|
|
|
static void ttml_text_cb(void *priv, const char *text, int len)
|
|
{
|
|
TTMLContext *s = priv;
|
|
AVBPrint cur_line = { 0 };
|
|
AVBPrint *buffer = &s->buffer;
|
|
|
|
av_bprint_init(&cur_line, len, AV_BPRINT_SIZE_UNLIMITED);
|
|
|
|
av_bprint_append_data(&cur_line, text, len);
|
|
if (!av_bprint_is_complete(&cur_line)) {
|
|
av_log(s->avctx, AV_LOG_ERROR,
|
|
"Failed to move the current subtitle dialog to AVBPrint!\n");
|
|
av_bprint_finalize(&cur_line, NULL);
|
|
return;
|
|
}
|
|
|
|
|
|
av_bprint_escape(buffer, cur_line.str, NULL, AV_ESCAPE_MODE_XML,
|
|
0);
|
|
|
|
av_bprint_finalize(&cur_line, NULL);
|
|
}
|
|
|
|
static void ttml_new_line_cb(void *priv, int forced)
|
|
{
|
|
TTMLContext *s = priv;
|
|
|
|
av_bprintf(&s->buffer, "<br/>");
|
|
}
|
|
|
|
static const ASSCodesCallbacks ttml_callbacks = {
|
|
.text = ttml_text_cb,
|
|
.new_line = ttml_new_line_cb,
|
|
};
|
|
|
|
static int ttml_encode_frame(AVCodecContext *avctx, uint8_t *buf,
|
|
int bufsize, const AVSubtitle *sub)
|
|
{
|
|
TTMLContext *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;
|
|
int ret;
|
|
|
|
if (sub->rects[i]->type != SUBTITLE_ASS) {
|
|
av_log(avctx, AV_LOG_ERROR, "Only SUBTITLE_ASS type supported.\n");
|
|
return AVERROR(EINVAL);
|
|
}
|
|
|
|
dialog = ff_ass_split_dialog(s->ass_ctx, ass);
|
|
if (!dialog)
|
|
return AVERROR(ENOMEM);
|
|
|
|
if (dialog->style) {
|
|
av_bprintf(&s->buffer, "<span region=\"");
|
|
av_bprint_escape(&s->buffer, dialog->style, NULL,
|
|
AV_ESCAPE_MODE_XML,
|
|
AV_ESCAPE_FLAG_XML_DOUBLE_QUOTES);
|
|
av_bprintf(&s->buffer, "\">");
|
|
}
|
|
|
|
ret = ff_ass_split_override_codes(&ttml_callbacks, s, dialog->text);
|
|
if (ret < 0) {
|
|
int log_level = (ret != AVERROR_INVALIDDATA ||
|
|
avctx->err_recognition & AV_EF_EXPLODE) ?
|
|
AV_LOG_ERROR : AV_LOG_WARNING;
|
|
av_log(avctx, log_level,
|
|
"Splitting received ASS dialog text %s failed: %s\n",
|
|
dialog->text,
|
|
av_err2str(ret));
|
|
|
|
if (log_level == AV_LOG_ERROR) {
|
|
ff_ass_free_dialog(&dialog);
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
if (dialog->style)
|
|
av_bprintf(&s->buffer, "</span>");
|
|
|
|
ff_ass_free_dialog(&dialog);
|
|
}
|
|
|
|
if (!av_bprint_is_complete(&s->buffer))
|
|
return AVERROR(ENOMEM);
|
|
if (!s->buffer.len)
|
|
return 0;
|
|
|
|
// force null-termination, so in case our destination buffer is
|
|
// too small, the return value is larger than bufsize minus null.
|
|
if (av_strlcpy(buf, s->buffer.str, bufsize) > bufsize - 1) {
|
|
av_log(avctx, AV_LOG_ERROR, "Buffer too small for TTML event.\n");
|
|
return AVERROR_BUFFER_TOO_SMALL;
|
|
}
|
|
|
|
return s->buffer.len;
|
|
}
|
|
|
|
static av_cold int ttml_encode_close(AVCodecContext *avctx)
|
|
{
|
|
TTMLContext *s = avctx->priv_data;
|
|
|
|
ff_ass_split_free(s->ass_ctx);
|
|
|
|
av_bprint_finalize(&s->buffer, NULL);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const char *ttml_get_display_alignment(int alignment)
|
|
{
|
|
switch (alignment) {
|
|
case 1:
|
|
case 2:
|
|
case 3:
|
|
return "after";
|
|
case 4:
|
|
case 5:
|
|
case 6:
|
|
return "center";
|
|
case 7:
|
|
case 8:
|
|
case 9:
|
|
return "before";
|
|
default:
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
static const char *ttml_get_text_alignment(int alignment)
|
|
{
|
|
switch (alignment) {
|
|
case 1:
|
|
case 4:
|
|
case 7:
|
|
return "left";
|
|
case 2:
|
|
case 5:
|
|
case 8:
|
|
return "center";
|
|
case 3:
|
|
case 6:
|
|
case 9:
|
|
return "right";
|
|
default:
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
static void ttml_get_origin(ASSScriptInfo script_info, ASSStyle style,
|
|
int *origin_left, int *origin_top)
|
|
{
|
|
*origin_left = av_rescale(style.margin_l, 100, script_info.play_res_x);
|
|
*origin_top =
|
|
av_rescale((style.alignment >= 7) ? style.margin_v : 0,
|
|
100, script_info.play_res_y);
|
|
}
|
|
|
|
static void ttml_get_extent(ASSScriptInfo script_info, ASSStyle style,
|
|
int *width, int *height)
|
|
{
|
|
*width = av_rescale(script_info.play_res_x - style.margin_r,
|
|
100, script_info.play_res_x);
|
|
*height = av_rescale((style.alignment <= 3) ?
|
|
script_info.play_res_y - style.margin_v :
|
|
script_info.play_res_y,
|
|
100, script_info.play_res_y);
|
|
}
|
|
|
|
static int ttml_write_region(AVCodecContext *avctx, AVBPrint *buf,
|
|
ASSScriptInfo script_info, ASSStyle style)
|
|
{
|
|
const char *display_alignment = NULL;
|
|
const char *text_alignment = NULL;
|
|
int origin_left = 0;
|
|
int origin_top = 0;
|
|
int width = 0;
|
|
int height = 0;
|
|
|
|
if (!style.name) {
|
|
av_log(avctx, AV_LOG_ERROR, "Subtitle style name not set!\n");
|
|
return AVERROR_INVALIDDATA;
|
|
}
|
|
|
|
if (style.font_size < 0) {
|
|
av_log(avctx, AV_LOG_ERROR, "Invalid font size for TTML: %d!\n",
|
|
style.font_size);
|
|
return AVERROR_INVALIDDATA;
|
|
}
|
|
|
|
if (style.margin_l < 0 || style.margin_r < 0 || style.margin_v < 0) {
|
|
av_log(avctx, AV_LOG_ERROR,
|
|
"One or more negative margin values in subtitle style: "
|
|
"left: %d, right: %d, vertical: %d!\n",
|
|
style.margin_l, style.margin_r, style.margin_v);
|
|
return AVERROR_INVALIDDATA;
|
|
}
|
|
|
|
display_alignment = ttml_get_display_alignment(style.alignment);
|
|
text_alignment = ttml_get_text_alignment(style.alignment);
|
|
if (!display_alignment || !text_alignment) {
|
|
av_log(avctx, AV_LOG_ERROR,
|
|
"Failed to convert ASS style alignment %d of style %s to "
|
|
"TTML display and text alignment!\n",
|
|
style.alignment,
|
|
style.name);
|
|
return AVERROR_INVALIDDATA;
|
|
}
|
|
|
|
ttml_get_origin(script_info, style, &origin_left, &origin_top);
|
|
ttml_get_extent(script_info, style, &width, &height);
|
|
|
|
av_bprintf(buf, " <region xml:id=\"");
|
|
av_bprint_escape(buf, style.name, NULL, AV_ESCAPE_MODE_XML,
|
|
AV_ESCAPE_FLAG_XML_DOUBLE_QUOTES);
|
|
av_bprintf(buf, "\"\n");
|
|
|
|
av_bprintf(buf, " tts:origin=\"%d%% %d%%\"\n",
|
|
origin_left, origin_top);
|
|
av_bprintf(buf, " tts:extent=\"%d%% %d%%\"\n",
|
|
width, height);
|
|
|
|
av_bprintf(buf, " tts:displayAlign=\"");
|
|
av_bprint_escape(buf, display_alignment, NULL, AV_ESCAPE_MODE_XML,
|
|
AV_ESCAPE_FLAG_XML_DOUBLE_QUOTES);
|
|
av_bprintf(buf, "\"\n");
|
|
|
|
av_bprintf(buf, " tts:textAlign=\"");
|
|
av_bprint_escape(buf, text_alignment, NULL, AV_ESCAPE_MODE_XML,
|
|
AV_ESCAPE_FLAG_XML_DOUBLE_QUOTES);
|
|
av_bprintf(buf, "\"\n");
|
|
|
|
// if we set cell resolution to our script reference resolution,
|
|
// then a single line is a single "point" on our canvas. Thus, by setting
|
|
// our font size to font size in cells, we should gain a similar enough
|
|
// scale without resorting to explicit pixel based font sizing, which is
|
|
// frowned upon in the TTML community.
|
|
av_bprintf(buf, " tts:fontSize=\"%dc\"\n",
|
|
style.font_size);
|
|
|
|
if (style.font_name) {
|
|
av_bprintf(buf, " tts:fontFamily=\"");
|
|
av_bprint_escape(buf, style.font_name, NULL, AV_ESCAPE_MODE_XML,
|
|
AV_ESCAPE_FLAG_XML_DOUBLE_QUOTES);
|
|
av_bprintf(buf, "\"\n");
|
|
}
|
|
|
|
av_bprintf(buf, " tts:overflow=\"visible\" />\n");
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int ttml_write_header_content(AVCodecContext *avctx)
|
|
{
|
|
TTMLContext *s = avctx->priv_data;
|
|
ASS *ass = (ASS *)s->ass_ctx;
|
|
ASSScriptInfo script_info = ass->script_info;
|
|
const size_t base_extradata_size = TTMLENC_EXTRADATA_SIGNATURE_SIZE + 1 +
|
|
AV_INPUT_BUFFER_PADDING_SIZE;
|
|
size_t additional_extradata_size = 0;
|
|
|
|
if (script_info.play_res_x <= 0 || script_info.play_res_y <= 0) {
|
|
av_log(avctx, AV_LOG_ERROR,
|
|
"Invalid subtitle reference resolution %dx%d!\n",
|
|
script_info.play_res_x, script_info.play_res_y);
|
|
return AVERROR_INVALIDDATA;
|
|
}
|
|
|
|
// write the first string in extradata, attributes in the base "tt" element.
|
|
av_bprintf(&s->buffer, ttml_default_namespacing);
|
|
// the cell resolution is in character cells, so not exactly 1:1 against
|
|
// a pixel based resolution, but as the tts:extent in the root
|
|
// "tt" element is frowned upon (and disallowed in the EBU-TT profile),
|
|
// we mimic the reference resolution by setting it as the cell resolution.
|
|
av_bprintf(&s->buffer, " ttp:cellResolution=\"%d %d\"\n",
|
|
script_info.play_res_x, script_info.play_res_y);
|
|
av_bprint_chars(&s->buffer, '\0', 1);
|
|
|
|
// write the second string in extradata, head element containing the styles
|
|
av_bprintf(&s->buffer, " <head>\n");
|
|
av_bprintf(&s->buffer, " <layout>\n");
|
|
|
|
for (int i = 0; i < ass->styles_count; i++) {
|
|
int ret = ttml_write_region(avctx, &s->buffer, script_info,
|
|
ass->styles[i]);
|
|
if (ret < 0)
|
|
return ret;
|
|
}
|
|
|
|
av_bprintf(&s->buffer, " </layout>\n");
|
|
av_bprintf(&s->buffer, " </head>\n");
|
|
av_bprint_chars(&s->buffer, '\0', 1);
|
|
|
|
if (!av_bprint_is_complete(&s->buffer)) {
|
|
return AVERROR(ENOMEM);
|
|
}
|
|
|
|
additional_extradata_size = s->buffer.len;
|
|
|
|
if (!(avctx->extradata =
|
|
av_mallocz(base_extradata_size + additional_extradata_size))) {
|
|
return AVERROR(ENOMEM);
|
|
}
|
|
|
|
avctx->extradata_size =
|
|
TTMLENC_EXTRADATA_SIGNATURE_SIZE + additional_extradata_size;
|
|
memcpy(avctx->extradata, TTMLENC_EXTRADATA_SIGNATURE,
|
|
TTMLENC_EXTRADATA_SIGNATURE_SIZE);
|
|
|
|
if (additional_extradata_size)
|
|
memcpy(avctx->extradata + TTMLENC_EXTRADATA_SIGNATURE_SIZE,
|
|
s->buffer.str, additional_extradata_size);
|
|
|
|
av_bprint_clear(&s->buffer);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static av_cold int ttml_encode_init(AVCodecContext *avctx)
|
|
{
|
|
TTMLContext *s = avctx->priv_data;
|
|
int ret = AVERROR_BUG;
|
|
s->avctx = avctx;
|
|
|
|
av_bprint_init(&s->buffer, 0, AV_BPRINT_SIZE_UNLIMITED);
|
|
|
|
if (!(s->ass_ctx = ff_ass_split(avctx->subtitle_header))) {
|
|
return AVERROR_INVALIDDATA;
|
|
}
|
|
|
|
if ((ret = ttml_write_header_content(avctx)) < 0) {
|
|
return ret;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
const AVCodec ff_ttml_encoder = {
|
|
.name = "ttml",
|
|
.long_name = NULL_IF_CONFIG_SMALL("TTML subtitle"),
|
|
.type = AVMEDIA_TYPE_SUBTITLE,
|
|
.id = AV_CODEC_ID_TTML,
|
|
.priv_data_size = sizeof(TTMLContext),
|
|
.init = ttml_encode_init,
|
|
.encode_sub = ttml_encode_frame,
|
|
.close = ttml_encode_close,
|
|
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
|
|
};
|