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/*
* 3GPP TS 26.245 Timed Text encoder
* Copyright (c) 2012 Philip Langdale <philipl@overt.org>
*
* 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/avassert.h"
#include "libavutil/avstring.h"
#include "libavutil/intreadwrite.h"
#include "ass_split.h"
#include "ass.h"
typedef struct {
ASSSplitContext *ass_ctx;
char buffer[2048];
char *ptr;
char *end;
} MovTextContext;
static av_cold int mov_text_encode_init(AVCodecContext *avctx)
{
/*
* For now, we'll use a fixed default style. When we add styling
* support, this will be generated from the ASS style.
*/
static uint8_t text_sample_entry[] = {
0x00, 0x00, 0x00, 0x00, // uint32_t displayFlags
0x01, // int8_t horizontal-justification
0xFF, // int8_t vertical-justification
0x00, 0x00, 0x00, 0x00, // uint8_t background-color-rgba[4]
// BoxRecord {
0x00, 0x00, // int16_t top
0x00, 0x00, // int16_t left
0x00, 0x00, // int16_t bottom
0x00, 0x00, // int16_t right
// };
// StyleRecord {
0x00, 0x00, // uint16_t startChar
0x00, 0x00, // uint16_t endChar
0x00, 0x01, // uint16_t font-ID
0x00, // uint8_t face-style-flags
0x12, // uint8_t font-size
0xFF, 0xFF, 0xFF, 0xFF, // uint8_t text-color-rgba[4]
// };
// FontTableBox {
0x00, 0x00, 0x00, 0x12, // uint32_t size
'f', 't', 'a', 'b', // uint8_t name[4]
0x00, 0x01, // uint16_t entry-count
// FontRecord {
0x00, 0x01, // uint16_t font-ID
0x05, // uint8_t font-name-length
'S', 'e', 'r', 'i', 'f',// uint8_t font[font-name-length]
// };
// };
};
MovTextContext *s = avctx->priv_data;
avctx->extradata_size = sizeof text_sample_entry;
avctx->extradata = av_mallocz(avctx->extradata_size);
if (!avctx->extradata)
return AVERROR(ENOMEM);
memcpy(avctx->extradata, text_sample_entry, avctx->extradata_size);
s->ass_ctx = ff_ass_split(avctx->subtitle_header);
return s->ass_ctx ? 0 : AVERROR_INVALIDDATA;
}
static void mov_text_text_cb(void *priv, const char *text, int len)
{
MovTextContext *s = priv;
av_assert0(s->end >= s->ptr);
av_strlcpy(s->ptr, text, FFMIN(s->end - s->ptr, len + 1));
s->ptr += FFMIN(s->end - s->ptr, len);
}
static void mov_text_new_line_cb(void *priv, int forced)
{
MovTextContext *s = priv;
av_assert0(s->end >= s->ptr);
av_strlcpy(s->ptr, "\n", FFMIN(s->end - s->ptr, 2));
if (s->end > s->ptr)
s->ptr++;
}
static const ASSCodesCallbacks mov_text_callbacks = {
.text = mov_text_text_cb,
.new_line = mov_text_new_line_cb,
};
static int mov_text_encode_frame(AVCodecContext *avctx, unsigned char *buf,
int bufsize, const AVSubtitle *sub)
{
MovTextContext *s = avctx->priv_data;
ASSDialog *dialog;
int i, len, num;
s->ptr = s->buffer;
s->end = s->ptr + sizeof(s->buffer);
for (i = 0; i < sub->num_rects; i++) {
if (sub->rects[i]->type != SUBTITLE_ASS) {
av_log(avctx, AV_LOG_ERROR, "Only SUBTITLE_ASS type supported.\n");
return AVERROR(ENOSYS);
}
dialog = ff_ass_split_dialog(s->ass_ctx, sub->rects[i]->ass, 0, &num);
for (; dialog && num--; dialog++) {
ff_ass_split_override_codes(&mov_text_callbacks, s, dialog->text);
}
}
if (s->ptr == s->buffer)
return 0;
AV_WB16(buf, strlen(s->buffer));
buf += 2;
len = av_strlcpy(buf, s->buffer, bufsize - 2);
if (len > bufsize-3) {
av_log(avctx, AV_LOG_ERROR, "Buffer too small for ASS event.\n");
return AVERROR(EINVAL);
}
return len + 2;
}
static int mov_text_encode_close(AVCodecContext *avctx)
{
MovTextContext *s = avctx->priv_data;
ff_ass_split_free(s->ass_ctx);
return 0;
}
AVCodec ff_movtext_encoder = {
.name = "mov_text",
.long_name = NULL_IF_CONFIG_SMALL("3GPP Timed Text subtitle"),
.type = AVMEDIA_TYPE_SUBTITLE,
.id = AV_CODEC_ID_MOV_TEXT,
.priv_data_size = sizeof(MovTextContext),
.init = mov_text_encode_init,
.encode_sub = mov_text_encode_frame,
.close = mov_text_encode_close,
};
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