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ffmpeg/libavcodec/movtextenc.c

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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 "libavutil/mem.h"
#include "libavutil/common.h"
#include "ass_split.h"
#include "ass.h"
#define STYLE_FLAG_BOLD (1<<0)
#define STYLE_FLAG_ITALIC (1<<1)
#define STYLE_FLAG_UNDERLINE (1<<2)
#define STYLE_RECORD_SIZE 12
#define SIZE_ADD 10
#define STYL_BOX (1<<0)
#define HLIT_BOX (1<<1)
#define HCLR_BOX (1<<2)
#define av_bprint_append_any(buf, data, size) av_bprint_append_data(buf, ((const char*)data), size)
typedef struct {
uint16_t style_start;
uint16_t style_end;
uint8_t style_flag;
} StyleBox;
typedef struct {
uint16_t start;
uint16_t end;
} HighlightBox;
typedef struct {
uint32_t color;
} HilightcolorBox;
typedef struct {
AVCodecContext *avctx;
ASSSplitContext *ass_ctx;
AVBPrint buffer;
StyleBox **style_attributes;
StyleBox *style_attributes_temp;
HighlightBox hlit;
HilightcolorBox hclr;
int count;
uint8_t box_flags;
uint16_t style_entries;
uint16_t style_fontID;
uint8_t style_fontsize;
uint32_t style_color;
uint16_t text_pos;
uint16_t byte_count;
} MovTextContext;
typedef struct {
uint32_t type;
void (*encode)(MovTextContext *s, uint32_t tsmb_type);
} Box;
static void mov_text_cleanup(MovTextContext *s)
{
int j;
if (s->box_flags & STYL_BOX) {
for (j = 0; j < s->count; j++) {
av_freep(&s->style_attributes[j]);
}
av_freep(&s->style_attributes);
}
}
static void encode_styl(MovTextContext *s, uint32_t tsmb_type)
{
int j;
uint32_t tsmb_size;
if (s->box_flags & STYL_BOX) {
tsmb_size = s->count * STYLE_RECORD_SIZE + SIZE_ADD;
tsmb_size = AV_RB32(&tsmb_size);
s->style_entries = AV_RB16(&s->count);
s->style_fontID = 0x00 | 0x01<<8;
s->style_fontsize = 0x12;
s->style_color = MKTAG(0xFF, 0xFF, 0xFF, 0xFF);
/*The above three attributes are hard coded for now
but will come from ASS style in the future*/
av_bprint_append_any(&s->buffer, &tsmb_size, 4);
av_bprint_append_any(&s->buffer, &tsmb_type, 4);
av_bprint_append_any(&s->buffer, &s->style_entries, 2);
for (j = 0; j < s->count; j++) {
av_bprint_append_any(&s->buffer, &s->style_attributes[j]->style_start, 2);
av_bprint_append_any(&s->buffer, &s->style_attributes[j]->style_end, 2);
av_bprint_append_any(&s->buffer, &s->style_fontID, 2);
av_bprint_append_any(&s->buffer, &s->style_attributes[j]->style_flag, 1);
av_bprint_append_any(&s->buffer, &s->style_fontsize, 1);
av_bprint_append_any(&s->buffer, &s->style_color, 4);
}
mov_text_cleanup(s);
}
}
static void encode_hlit(MovTextContext *s, uint32_t tsmb_type)
{
uint32_t tsmb_size;
if (s->box_flags & HLIT_BOX) {
tsmb_size = 12;
tsmb_size = AV_RB32(&tsmb_size);
av_bprint_append_any(&s->buffer, &tsmb_size, 4);
av_bprint_append_any(&s->buffer, &tsmb_type, 4);
av_bprint_append_any(&s->buffer, &s->hlit.start, 2);
av_bprint_append_any(&s->buffer, &s->hlit.end, 2);
}
}
static void encode_hclr(MovTextContext *s, uint32_t tsmb_type)
{
uint32_t tsmb_size;
if (s->box_flags & HCLR_BOX) {
tsmb_size = 12;
tsmb_size = AV_RB32(&tsmb_size);
av_bprint_append_any(&s->buffer, &tsmb_size, 4);
av_bprint_append_any(&s->buffer, &tsmb_type, 4);
av_bprint_append_any(&s->buffer, &s->hclr.color, 4);
}
}
static const Box box_types[] = {
{ MKTAG('s','t','y','l'), encode_styl },
{ MKTAG('h','l','i','t'), encode_hlit },
{ MKTAG('h','c','l','r'), encode_hclr },
};
const static size_t box_count = FF_ARRAY_ELEMS(box_types);
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 const 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;
s->avctx = avctx;
avctx->extradata_size = sizeof text_sample_entry;
avctx->extradata = av_mallocz(avctx->extradata_size + AV_INPUT_BUFFER_PADDING_SIZE);
if (!avctx->extradata)
return AVERROR(ENOMEM);
av_bprint_init(&s->buffer, 0, AV_BPRINT_SIZE_UNLIMITED);
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_style_cb(void *priv, const char style, int close)
{
MovTextContext *s = priv;
if (!close) {
if (!(s->box_flags & STYL_BOX)) { //first style entry
s->style_attributes_temp = av_malloc(sizeof(*s->style_attributes_temp));
if (!s->style_attributes_temp) {
av_bprint_clear(&s->buffer);
s->box_flags &= ~STYL_BOX;
return;
}
s->style_attributes_temp->style_flag = 0;
s->style_attributes_temp->style_start = AV_RB16(&s->text_pos);
} else {
if (s->style_attributes_temp->style_flag) { //break the style record here and start a new one
s->style_attributes_temp->style_end = AV_RB16(&s->text_pos);
av_dynarray_add(&s->style_attributes, &s->count, s->style_attributes_temp);
s->style_attributes_temp = av_malloc(sizeof(*s->style_attributes_temp));
if (!s->style_attributes_temp) {
mov_text_cleanup(s);
av_bprint_clear(&s->buffer);
s->box_flags &= ~STYL_BOX;
return;
}
s->style_attributes_temp->style_flag = s->style_attributes[s->count - 1]->style_flag;
s->style_attributes_temp->style_start = AV_RB16(&s->text_pos);
} else {
s->style_attributes_temp->style_flag = 0;
s->style_attributes_temp->style_start = AV_RB16(&s->text_pos);
}
}
switch (style){
case 'b':
s->style_attributes_temp->style_flag |= STYLE_FLAG_BOLD;
break;
case 'i':
s->style_attributes_temp->style_flag |= STYLE_FLAG_ITALIC;
break;
case 'u':
s->style_attributes_temp->style_flag |= STYLE_FLAG_UNDERLINE;
break;
}
} else if (!s->style_attributes_temp) {
av_log(s->avctx, AV_LOG_WARNING, "Ignoring unmatched close tag\n");
return;
} else {
s->style_attributes_temp->style_end = AV_RB16(&s->text_pos);
av_dynarray_add(&s->style_attributes, &s->count, s->style_attributes_temp);
s->style_attributes_temp = av_malloc(sizeof(*s->style_attributes_temp));
if (!s->style_attributes_temp) {
mov_text_cleanup(s);
av_bprint_clear(&s->buffer);
s->box_flags &= ~STYL_BOX;
return;
}
s->style_attributes_temp->style_flag = s->style_attributes[s->count - 1]->style_flag;
switch (style){
case 'b':
s->style_attributes_temp->style_flag &= ~STYLE_FLAG_BOLD;
break;
case 'i':
s->style_attributes_temp->style_flag &= ~STYLE_FLAG_ITALIC;
break;
case 'u':
s->style_attributes_temp->style_flag &= ~STYLE_FLAG_UNDERLINE;
break;
}
if (s->style_attributes_temp->style_flag) { //start of new style record
s->style_attributes_temp->style_start = AV_RB16(&s->text_pos);
}
}
s->box_flags |= STYL_BOX;
}
static void mov_text_color_cb(void *priv, unsigned int color, unsigned int color_id)
{
MovTextContext *s = priv;
if (color_id == 2) { //secondary color changes
if (s->box_flags & HLIT_BOX) { //close tag
s->hlit.end = AV_RB16(&s->text_pos);
} else {
s->box_flags |= HCLR_BOX;
s->box_flags |= HLIT_BOX;
s->hlit.start = AV_RB16(&s->text_pos);
s->hclr.color = color | (0xFF << 24); //set alpha value to FF
}
}
/* If there are more than one secondary color changes in ASS, take start of
first section and end of last section. Movtext allows only one
highlight box per sample.
*/
}
static uint16_t utf8_strlen(const char *text, int len)
{
uint16_t i = 0, ret = 0;
while (i < len) {
char c = text[i];
if ((c & 0x80) == 0)
i += 1;
else if ((c & 0xE0) == 0xC0)
i += 2;
else if ((c & 0xF0) == 0xE0)
i += 3;
else if ((c & 0xF8) == 0xF0)
i += 4;
else
return 0;
ret++;
}
return ret;
}
static void mov_text_text_cb(void *priv, const char *text, int len)
{
uint16_t utf8_len = utf8_strlen(text, len);
MovTextContext *s = priv;
av_bprint_append_data(&s->buffer, text, len);
// If it's not utf-8, just use the byte length
s->text_pos += utf8_len ? utf8_len : len;
s->byte_count += len;
}
static void mov_text_new_line_cb(void *priv, int forced)
{
MovTextContext *s = priv;
av_bprint_append_data(&s->buffer, "\n", 1);
s->text_pos += 1;
s->byte_count += 1;
}
static const ASSCodesCallbacks mov_text_callbacks = {
.text = mov_text_text_cb,
.new_line = mov_text_new_line_cb,
.style = mov_text_style_cb,
.color = mov_text_color_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, length;
size_t j;
s->byte_count = 0;
s->text_pos = 0;
s->count = 0;
s->box_flags = 0;
s->style_entries = 0;
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);
for (; dialog && num--; dialog++) {
ff_ass_split_override_codes(&mov_text_callbacks, s, dialog->text);
}
} else {
#endif
dialog = ff_ass_split_dialog2(s->ass_ctx, ass);
if (!dialog)
return AVERROR(ENOMEM);
ff_ass_split_override_codes(&mov_text_callbacks, s, dialog->text);
ff_ass_free_dialog(&dialog);
#if FF_API_ASS_TIMING
}
#endif
for (j = 0; j < box_count; j++) {
box_types[j].encode(s, box_types[j].type);
}
}
AV_WB16(buf, s->byte_count);
buf += 2;
if (!av_bprint_is_complete(&s->buffer)) {
length = AVERROR(ENOMEM);
goto exit;
}
if (!s->buffer.len) {
length = 0;
goto exit;
}
if (s->buffer.len > bufsize - 3) {
av_log(avctx, AV_LOG_ERROR, "Buffer too small for ASS event.\n");
length = AVERROR(EINVAL);
goto exit;
}
memcpy(buf, s->buffer.str, s->buffer.len);
length = s->buffer.len + 2;
exit:
av_bprint_clear(&s->buffer);
return length;
}
static int mov_text_encode_close(AVCodecContext *avctx)
{
MovTextContext *s = avctx->priv_data;
ff_ass_split_free(s->ass_ctx);
av_bprint_finalize(&s->buffer, NULL);
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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