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FFmpeg/libavcodec/movtextenc.c
Andreas Rheinhardt a247ac640d avcodec: Constify AVCodecs 
Given that the AVCodec.next pointer has now been removed, most of the
AVCodecs are not modified at all any more and can therefore be made
const (as this patch does); the only exceptions are the very few codecs
for external libraries that have a init_static_data callback.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>
2021-04-27 10:43:15 -03:00

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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/opt.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"
#include "bytestream.h"
#include "internal.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 DEFAULT_STYLE_FONT_ID 0x01
#define DEFAULT_STYLE_FONTSIZE 0x12
#define DEFAULT_STYLE_COLOR 0xffffffff
#define DEFAULT_STYLE_FLAG 0x00
#define BGR_TO_RGB(c) (((c) & 0xff) << 16 | ((c) & 0xff00) | (((uint32_t)(c) >> 16) & 0xff))
#define FONTSIZE_SCALE(s,fs) ((fs) * (s)->font_scale_factor + 0.5)
#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;
uint16_t style_fontID;
uint8_t style_fontsize;
uint32_t style_color;
} StyleBox;
typedef struct {
uint16_t start;
uint16_t end;
} HighlightBox;
typedef struct {
uint32_t color;
} HilightcolorBox;
typedef struct {
AVClass *class;
AVCodecContext *avctx;
ASSSplitContext *ass_ctx;
ASSStyle *ass_dialog_style;
StyleBox *style_attributes;
unsigned count;
unsigned style_attributes_bytes_allocated;
StyleBox style_attributes_temp;
AVBPrint buffer;
HighlightBox hlit;
HilightcolorBox hclr;
uint8_t box_flags;
StyleBox d;
uint16_t text_pos;
uint16_t byte_count;
char **fonts;
int font_count;
double font_scale_factor;
int frame_height;
} MovTextContext;
typedef struct {
void (*encode)(MovTextContext *s);
} Box;
static void mov_text_cleanup(MovTextContext *s)
{
s->count = 0;
s->style_attributes_temp = s->d;
}
static void encode_styl(MovTextContext *s)
{
if ((s->box_flags & STYL_BOX) && s->count) {
uint8_t buf[12], *p = buf;
bytestream_put_be32(&p, s->count * STYLE_RECORD_SIZE + SIZE_ADD);
bytestream_put_be32(&p, MKBETAG('s','t','y','l'));
bytestream_put_be16(&p, s->count);
/*The above three attributes are hard coded for now
but will come from ASS style in the future*/
av_bprint_append_any(&s->buffer, buf, 10);
for (unsigned j = 0; j < s->count; j++) {
const StyleBox *style = &s->style_attributes[j];
p = buf;
bytestream_put_be16(&p, style->style_start);
bytestream_put_be16(&p, style->style_end);
bytestream_put_be16(&p, style->style_fontID);
bytestream_put_byte(&p, style->style_flag);
bytestream_put_byte(&p, style->style_fontsize);
bytestream_put_be32(&p, style->style_color);
av_bprint_append_any(&s->buffer, buf, 12);
}
}
mov_text_cleanup(s);
}
static void encode_hlit(MovTextContext *s)
{
if (s->box_flags & HLIT_BOX) {
uint8_t buf[12], *p = buf;
bytestream_put_be32(&p, 12);
bytestream_put_be32(&p, MKBETAG('h','l','i','t'));
bytestream_put_be16(&p, s->hlit.start);
bytestream_put_be16(&p, s->hlit.end);
av_bprint_append_any(&s->buffer, buf, 12);
}
}
static void encode_hclr(MovTextContext *s)
{
if (s->box_flags & HCLR_BOX) {
uint8_t buf[12], *p = buf;
bytestream_put_be32(&p, 12);
bytestream_put_be32(&p, MKBETAG('h','c','l','r'));
bytestream_put_be32(&p, s->hclr.color);
av_bprint_append_any(&s->buffer, buf, 12);
}
}
static const Box box_types[] = {
{ encode_styl },
{ encode_hlit },
{ encode_hclr },
};
const static size_t box_count = FF_ARRAY_ELEMS(box_types);
static int mov_text_encode_close(AVCodecContext *avctx)
{
MovTextContext *s = avctx->priv_data;
ff_ass_split_free(s->ass_ctx);
av_freep(&s->style_attributes);
av_freep(&s->fonts);
av_bprint_finalize(&s->buffer, NULL);
return 0;
}
static int encode_sample_description(AVCodecContext *avctx)
{
ASS *ass;
ASSStyle *style;
int i, j;
uint32_t back_color = 0;
int font_names_total_len = 0;
MovTextContext *s = avctx->priv_data;
uint8_t buf[30], *p = buf;
// 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]
// };
// };
// Populate sample description from ASS header
ass = (ASS*)s->ass_ctx;
// Compute font scaling factor based on (optionally) provided
// output video height and ASS script play_res_y
if (s->frame_height && ass->script_info.play_res_y)
s->font_scale_factor = (double)s->frame_height / ass->script_info.play_res_y;
else
s->font_scale_factor = 1;
style = ff_ass_style_get(s->ass_ctx, "Default");
if (!style && ass->styles_count) {
style = &ass->styles[0];
}
s->d.style_fontID = DEFAULT_STYLE_FONT_ID;
s->d.style_fontsize = DEFAULT_STYLE_FONTSIZE;
s->d.style_color = DEFAULT_STYLE_COLOR;
s->d.style_flag = DEFAULT_STYLE_FLAG;
if (style) {
s->d.style_fontsize = FONTSIZE_SCALE(s, style->font_size);
s->d.style_color = BGR_TO_RGB(style->primary_color & 0xffffff) << 8 |
255 - ((uint32_t)style->primary_color >> 24);
s->d.style_flag = (!!style->bold * STYLE_FLAG_BOLD) |
(!!style->italic * STYLE_FLAG_ITALIC) |
(!!style->underline * STYLE_FLAG_UNDERLINE);
back_color = (BGR_TO_RGB(style->back_color & 0xffffff) << 8) |
(255 - ((uint32_t)style->back_color >> 24));
}
bytestream_put_be32(&p, 0); // displayFlags
bytestream_put_be16(&p, 0x01FF); // horizontal/vertical justification (2x int8_t)
bytestream_put_be32(&p, back_color);
bytestream_put_be64(&p, 0); // BoxRecord - 4xint16_t: top, left, bottom, right
// StyleRecord {
bytestream_put_be16(&p, s->d.style_start);
bytestream_put_be16(&p, s->d.style_end);
bytestream_put_be16(&p, s->d.style_fontID);
bytestream_put_byte(&p, s->d.style_flag);
bytestream_put_byte(&p, s->d.style_fontsize);
bytestream_put_be32(&p, s->d.style_color);
// };
av_bprint_append_any(&s->buffer, buf, 30);
// Build font table
// We can't build a complete font table since that would require
// scanning all dialogs first. But we can at least fill in what
// is avaiable in the ASS header
if (style && ass->styles_count) {
// Find unique font names
if (style->font_name) {
av_dynarray_add(&s->fonts, &s->font_count, style->font_name);
font_names_total_len += strlen(style->font_name);
}
for (i = 0; i < ass->styles_count; i++) {
int found = 0;
if (!ass->styles[i].font_name)
continue;
for (j = 0; j < s->font_count; j++) {
if (!strcmp(s->fonts[j], ass->styles[i].font_name)) {
found = 1;
break;
}
}
if (!found) {
av_dynarray_add(&s->fonts, &s->font_count,
ass->styles[i].font_name);
font_names_total_len += strlen(ass->styles[i].font_name);
}
}
} else
av_dynarray_add(&s->fonts, &s->font_count, (char*)"Serif");
// FontTableBox {
p = buf;
bytestream_put_be32(&p, SIZE_ADD + 3 * s->font_count + font_names_total_len); // Size
bytestream_put_be32(&p, MKBETAG('f','t','a','b'));
bytestream_put_be16(&p, s->font_count);
av_bprint_append_any(&s->buffer, buf, 10);
// FontRecord {
for (i = 0; i < s->font_count; i++) {
size_t len = strlen(s->fonts[i]);
p = buf;
bytestream_put_be16(&p, i + 1); //fontID
bytestream_put_byte(&p, len);
av_bprint_append_any(&s->buffer, buf, 3);
av_bprint_append_any(&s->buffer, s->fonts[i], len);
}
// };
// };
if (!av_bprint_is_complete(&s->buffer)) {
return AVERROR(ENOMEM);
}
avctx->extradata_size = s->buffer.len;
avctx->extradata = av_mallocz(avctx->extradata_size + AV_INPUT_BUFFER_PADDING_SIZE);
if (!avctx->extradata) {
return AVERROR(ENOMEM);
}
memcpy(avctx->extradata, s->buffer.str, avctx->extradata_size);
av_bprint_clear(&s->buffer);
return 0;
}
static av_cold int mov_text_encode_init(AVCodecContext *avctx)
{
int ret;
MovTextContext *s = avctx->priv_data;
s->avctx = avctx;
av_bprint_init(&s->buffer, 0, AV_BPRINT_SIZE_UNLIMITED);
s->ass_ctx = ff_ass_split(avctx->subtitle_header);
if (!s->ass_ctx)
return AVERROR_INVALIDDATA;
ret = encode_sample_description(avctx);
if (ret < 0)
return ret;
return 0;
}
// Start a new style box if needed
static int mov_text_style_start(MovTextContext *s)
{
// there's an existing style entry
if (s->style_attributes_temp.style_start == s->text_pos)
// Still at same text pos, use same entry
return 1;
if (s->style_attributes_temp.style_flag != s->d.style_flag ||
s->style_attributes_temp.style_color != s->d.style_color ||
s->style_attributes_temp.style_fontID != s->d.style_fontID ||
s->style_attributes_temp.style_fontsize != s->d.style_fontsize) {
StyleBox *tmp;
// last style != defaults, end the style entry and start a new one
if (s->count + 1 > FFMIN(SIZE_MAX / sizeof(*s->style_attributes), UINT16_MAX) ||
!(tmp = av_fast_realloc(s->style_attributes,
&s->style_attributes_bytes_allocated,
(s->count + 1) * sizeof(*s->style_attributes)))) {
mov_text_cleanup(s);
av_bprint_clear(&s->buffer);
s->box_flags &= ~STYL_BOX;
return 0;
}
s->style_attributes = tmp;
s->style_attributes_temp.style_end = s->text_pos;
s->style_attributes[s->count++] = s->style_attributes_temp;
s->box_flags |= STYL_BOX;
s->style_attributes_temp = s->d;
s->style_attributes_temp.style_start = s->text_pos;
} else { // style entry matches defaults, drop entry
s->style_attributes_temp = s->d;
s->style_attributes_temp.style_start = s->text_pos;
}
return 1;
}
static uint8_t mov_text_style_to_flag(const char style)
{
uint8_t style_flag = 0;
switch (style){
case 'b':
style_flag = STYLE_FLAG_BOLD;
break;
case 'i':
style_flag = STYLE_FLAG_ITALIC;
break;
case 'u':
style_flag = STYLE_FLAG_UNDERLINE;
break;
}
return style_flag;
}
static void mov_text_style_set(MovTextContext *s, uint8_t style_flags)
{
if (!((s->style_attributes_temp.style_flag & style_flags) ^ style_flags)) {
// setting flags that that are already set
return;
}
if (mov_text_style_start(s))
s->style_attributes_temp.style_flag |= style_flags;
}
static void mov_text_style_cb(void *priv, const char style, int close)
{
MovTextContext *s = priv;
uint8_t style_flag = mov_text_style_to_flag(style);
if (!!(s->style_attributes_temp.style_flag & style_flag) != close) {
// setting flag that is already set
return;
}
if (mov_text_style_start(s)) {
if (!close)
s->style_attributes_temp.style_flag |= style_flag;
else
s->style_attributes_temp.style_flag &= ~style_flag;
}
}
static void mov_text_color_set(MovTextContext *s, uint32_t color)
{
if ((s->style_attributes_temp.style_color & 0xffffff00) == color) {
// color hasn't changed
return;
}
if (mov_text_style_start(s))
s->style_attributes_temp.style_color = (color & 0xffffff00) |
(s->style_attributes_temp.style_color & 0xff);
}
static void mov_text_color_cb(void *priv, unsigned int color, unsigned int color_id)
{
MovTextContext *s = priv;
color = BGR_TO_RGB(color) << 8;
if (color_id == 1) { //primary color changes
mov_text_color_set(s, color);
} else if (color_id == 2) { //secondary color changes
if (!(s->box_flags & HCLR_BOX))
// Highlight alpha not set yet, use current primary alpha
s->hclr.color = s->style_attributes_temp.style_color;
if (!(s->box_flags & HLIT_BOX) || s->hlit.start == s->text_pos) {
s->box_flags |= HCLR_BOX;
s->box_flags |= HLIT_BOX;
s->hlit.start = s->text_pos;
s->hclr.color = color | (s->hclr.color & 0xFF);
}
else //close tag
s->hlit.end = s->text_pos;
/* 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.
*/
}
// Movtext does not support changes to other color_id (outline, background)
}
static void mov_text_alpha_set(MovTextContext *s, uint8_t alpha)
{
if ((s->style_attributes_temp.style_color & 0xff) == alpha) {
// color hasn't changed
return;
}
if (mov_text_style_start(s))
s->style_attributes_temp.style_color =
(s->style_attributes_temp.style_color & 0xffffff00) | alpha;
}
static void mov_text_alpha_cb(void *priv, int alpha, int alpha_id)
{
MovTextContext *s = priv;
alpha = 255 - alpha;
if (alpha_id == 1) // primary alpha changes
mov_text_alpha_set(s, alpha);
else if (alpha_id == 2) { //secondary alpha changes
if (!(s->box_flags & HCLR_BOX))
// Highlight color not set yet, use current primary color
s->hclr.color = s->style_attributes_temp.style_color;
if (!(s->box_flags & HLIT_BOX) || s->hlit.start == s->text_pos) {
s->box_flags |= HCLR_BOX;
s->box_flags |= HLIT_BOX;
s->hlit.start = s->text_pos;
s->hclr.color = (s->hclr.color & 0xffffff00) | alpha;
}
else //close tag
s->hlit.end = s->text_pos;
}
// Movtext does not support changes to other alpha_id (outline, background)
}
static uint16_t find_font_id(MovTextContext *s, const char *name)
{
int i;
for (i = 0; i < s->font_count; i++) {
if (!strcmp(name, s->fonts[i]))
return i + 1;
}
return 1;
}
static void mov_text_font_name_set(MovTextContext *s, const char *name)
{
int fontID = find_font_id(s, name);
if (s->style_attributes_temp.style_fontID == fontID) {
// color hasn't changed
return;
}
if (mov_text_style_start(s))
s->style_attributes_temp.style_fontID = fontID;
}
static void mov_text_font_name_cb(void *priv, const char *name)
{
mov_text_font_name_set((MovTextContext*)priv, name);
}
static void mov_text_font_size_set(MovTextContext *s, int size)
{
size = FONTSIZE_SCALE(s, size);
if (s->style_attributes_temp.style_fontsize == size) {
// color hasn't changed
return;
}
if (mov_text_style_start(s))
s->style_attributes_temp.style_fontsize = size;
}
static void mov_text_font_size_cb(void *priv, int size)
{
mov_text_font_size_set((MovTextContext*)priv, size);
}
static void mov_text_end_cb(void *priv)
{
// End of text, close any open style record
mov_text_style_start((MovTextContext*)priv);
}
static void mov_text_ass_style_set(MovTextContext *s, ASSStyle *style)
{
uint8_t style_flags, alpha;
uint32_t color;
if (style) {
style_flags = (!!style->bold * STYLE_FLAG_BOLD) |
(!!style->italic * STYLE_FLAG_ITALIC) |
(!!style->underline * STYLE_FLAG_UNDERLINE);
mov_text_style_set(s, style_flags);
color = BGR_TO_RGB(style->primary_color & 0xffffff) << 8;
mov_text_color_set(s, color);
alpha = 255 - ((uint32_t)style->primary_color >> 24);
mov_text_alpha_set(s, alpha);
mov_text_font_size_set(s, style->font_size);
mov_text_font_name_set(s, style->font_name);
} else {
// End current style record, go back to defaults
mov_text_style_start(s);
}
}
static void mov_text_dialog(MovTextContext *s, ASSDialog *dialog)
{
ASSStyle *style = ff_ass_style_get(s->ass_ctx, dialog->style);
s->ass_dialog_style = style;
mov_text_ass_style_set(s, style);
}
static void mov_text_cancel_overrides_cb(void *priv, const char *style_name)
{
MovTextContext *s = priv;
ASSStyle *style;
if (!style_name || !*style_name)
style = s->ass_dialog_style;
else
style= ff_ass_style_get(s->ass_ctx, style_name);
mov_text_ass_style_set(s, style);
}
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,
.alpha = mov_text_alpha_cb,
.font_name = mov_text_font_name_cb,
.font_size = mov_text_font_size_cb,
.cancel_overrides = mov_text_cancel_overrides_cb,
.end = mov_text_end_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;
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(EINVAL);
}
dialog = ff_ass_split_dialog2(s->ass_ctx, ass);
if (!dialog)
return AVERROR(ENOMEM);
mov_text_dialog(s, dialog);
ff_ass_split_override_codes(&mov_text_callbacks, s, dialog->text);
ff_ass_free_dialog(&dialog);
for (j = 0; j < box_count; j++) {
box_types[j].encode(s);
}
}
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_BUFFER_TOO_SMALL;
goto exit;
}
memcpy(buf, s->buffer.str, s->buffer.len);
length = s->buffer.len + 2;
exit:
av_bprint_clear(&s->buffer);
return length;
}
#define OFFSET(x) offsetof(MovTextContext, x)
#define FLAGS AV_OPT_FLAG_ENCODING_PARAM | AV_OPT_FLAG_SUBTITLE_PARAM
static const AVOption options[] = {
{ "height", "Frame height, usually video height", OFFSET(frame_height), AV_OPT_TYPE_INT, {.i64=0}, 0, INT_MAX, FLAGS },
{ NULL },
};
static const AVClass mov_text_encoder_class = {
.class_name = "MOV text enoder",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
const 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),
.priv_class = &mov_text_encoder_class,
.init = mov_text_encode_init,
.encode_sub = mov_text_encode_frame,
.close = mov_text_encode_close,
.caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
};
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