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FFmpeg/libavcodec/ccaption_dec.c

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/*
* Closed Caption Decoding
* Copyright (c) 2015 Anshul Maheshwari
*
* 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 "avcodec.h"
#include "ass.h"
#include "codec_internal.h"
#include "libavutil/opt.h"
#define SCREEN_ROWS 15
#define SCREEN_COLUMNS 32
#define SET_FLAG(var, val) ( (var) |= ( 1 << (val)) )
#define UNSET_FLAG(var, val) ( (var) &= ~( 1 << (val)) )
#define CHECK_FLAG(var, val) ( (var) & ( 1 << (val)) )
static const AVRational ms_tb = {1, 1000};
enum cc_mode {
CCMODE_POPON,
CCMODE_PAINTON,
CCMODE_ROLLUP,
CCMODE_TEXT,
};
enum cc_color_code {
CCCOL_WHITE,
CCCOL_GREEN,
CCCOL_BLUE,
CCCOL_CYAN,
CCCOL_RED,
CCCOL_YELLOW,
CCCOL_MAGENTA,
CCCOL_USERDEFINED,
CCCOL_BLACK,
CCCOL_TRANSPARENT,
};
enum cc_font {
CCFONT_REGULAR,
CCFONT_ITALICS,
CCFONT_UNDERLINED,
CCFONT_UNDERLINED_ITALICS,
};
enum cc_charset {
CCSET_BASIC_AMERICAN,
CCSET_SPECIAL_AMERICAN,
CCSET_EXTENDED_SPANISH_FRENCH_MISC,
CCSET_EXTENDED_PORTUGUESE_GERMAN_DANISH,
};
static const char *charset_overrides[4][128] =
{
[CCSET_BASIC_AMERICAN] = {
[0x27] = "\u2019",
[0x2a] = "\u00e1",
[0x5c] = "\u00e9",
[0x5e] = "\u00ed",
[0x5f] = "\u00f3",
[0x60] = "\u00fa",
[0x7b] = "\u00e7",
[0x7c] = "\u00f7",
[0x7d] = "\u00d1",
[0x7e] = "\u00f1",
[0x7f] = "\u2588"
},
[CCSET_SPECIAL_AMERICAN] = {
[0x30] = "\u00ae",
[0x31] = "\u00b0",
[0x32] = "\u00bd",
[0x33] = "\u00bf",
[0x34] = "\u2122",
[0x35] = "\u00a2",
[0x36] = "\u00a3",
[0x37] = "\u266a",
[0x38] = "\u00e0",
[0x39] = "\u00A0",
[0x3a] = "\u00e8",
[0x3b] = "\u00e2",
[0x3c] = "\u00ea",
[0x3d] = "\u00ee",
[0x3e] = "\u00f4",
[0x3f] = "\u00fb",
},
[CCSET_EXTENDED_SPANISH_FRENCH_MISC] = {
[0x20] = "\u00c1",
[0x21] = "\u00c9",
[0x22] = "\u00d3",
[0x23] = "\u00da",
[0x24] = "\u00dc",
[0x25] = "\u00fc",
[0x26] = "\u00b4",
[0x27] = "\u00a1",
[0x28] = "*",
[0x29] = "\u2018",
[0x2a] = "-",
[0x2b] = "\u00a9",
[0x2c] = "\u2120",
[0x2d] = "\u00b7",
[0x2e] = "\u201c",
[0x2f] = "\u201d",
[0x30] = "\u00c0",
[0x31] = "\u00c2",
[0x32] = "\u00c7",
[0x33] = "\u00c8",
[0x34] = "\u00ca",
[0x35] = "\u00cb",
[0x36] = "\u00eb",
[0x37] = "\u00ce",
[0x38] = "\u00cf",
[0x39] = "\u00ef",
[0x3a] = "\u00d4",
[0x3b] = "\u00d9",
[0x3c] = "\u00f9",
[0x3d] = "\u00db",
[0x3e] = "\u00ab",
[0x3f] = "\u00bb",
},
[CCSET_EXTENDED_PORTUGUESE_GERMAN_DANISH] = {
[0x20] = "\u00c3",
[0x21] = "\u00e3",
[0x22] = "\u00cd",
[0x23] = "\u00cc",
[0x24] = "\u00ec",
[0x25] = "\u00d2",
[0x26] = "\u00f2",
[0x27] = "\u00d5",
[0x28] = "\u00f5",
[0x29] = "{",
[0x2a] = "}",
[0x2b] = "\\",
[0x2c] = "^",
[0x2d] = "_",
[0x2e] = "|",
[0x2f] = "~",
[0x30] = "\u00c4",
[0x31] = "\u00e4",
[0x32] = "\u00d6",
[0x33] = "\u00f6",
[0x34] = "\u00df",
[0x35] = "\u00a5",
[0x36] = "\u00a4",
[0x37] = "\u00a6",
[0x38] = "\u00c5",
[0x39] = "\u00e5",
[0x3a] = "\u00d8",
[0x3b] = "\u00f8",
[0x3c] = "\u250c",
[0x3d] = "\u2510",
[0x3e] = "\u2514",
[0x3f] = "\u2518",
},
};
static const unsigned char bg_attribs[8] = // Color
{
CCCOL_WHITE,
CCCOL_GREEN,
CCCOL_BLUE,
CCCOL_CYAN,
CCCOL_RED,
CCCOL_YELLOW,
CCCOL_MAGENTA,
CCCOL_BLACK,
};
static const unsigned char pac2_attribs[32][3] = // Color, font, ident
{
{ CCCOL_WHITE, CCFONT_REGULAR, 0 }, // 0x40 || 0x60
{ CCCOL_WHITE, CCFONT_UNDERLINED, 0 }, // 0x41 || 0x61
{ CCCOL_GREEN, CCFONT_REGULAR, 0 }, // 0x42 || 0x62
{ CCCOL_GREEN, CCFONT_UNDERLINED, 0 }, // 0x43 || 0x63
{ CCCOL_BLUE, CCFONT_REGULAR, 0 }, // 0x44 || 0x64
{ CCCOL_BLUE, CCFONT_UNDERLINED, 0 }, // 0x45 || 0x65
{ CCCOL_CYAN, CCFONT_REGULAR, 0 }, // 0x46 || 0x66
{ CCCOL_CYAN, CCFONT_UNDERLINED, 0 }, // 0x47 || 0x67
{ CCCOL_RED, CCFONT_REGULAR, 0 }, // 0x48 || 0x68
{ CCCOL_RED, CCFONT_UNDERLINED, 0 }, // 0x49 || 0x69
{ CCCOL_YELLOW, CCFONT_REGULAR, 0 }, // 0x4a || 0x6a
{ CCCOL_YELLOW, CCFONT_UNDERLINED, 0 }, // 0x4b || 0x6b
{ CCCOL_MAGENTA, CCFONT_REGULAR, 0 }, // 0x4c || 0x6c
{ CCCOL_MAGENTA, CCFONT_UNDERLINED, 0 }, // 0x4d || 0x6d
{ CCCOL_WHITE, CCFONT_ITALICS, 0 }, // 0x4e || 0x6e
{ CCCOL_WHITE, CCFONT_UNDERLINED_ITALICS, 0 }, // 0x4f || 0x6f
{ CCCOL_WHITE, CCFONT_REGULAR, 0 }, // 0x50 || 0x70
{ CCCOL_WHITE, CCFONT_UNDERLINED, 0 }, // 0x51 || 0x71
{ CCCOL_WHITE, CCFONT_REGULAR, 4 }, // 0x52 || 0x72
{ CCCOL_WHITE, CCFONT_UNDERLINED, 4 }, // 0x53 || 0x73
{ CCCOL_WHITE, CCFONT_REGULAR, 8 }, // 0x54 || 0x74
{ CCCOL_WHITE, CCFONT_UNDERLINED, 8 }, // 0x55 || 0x75
{ CCCOL_WHITE, CCFONT_REGULAR, 12 }, // 0x56 || 0x76
{ CCCOL_WHITE, CCFONT_UNDERLINED, 12 }, // 0x57 || 0x77
{ CCCOL_WHITE, CCFONT_REGULAR, 16 }, // 0x58 || 0x78
{ CCCOL_WHITE, CCFONT_UNDERLINED, 16 }, // 0x59 || 0x79
{ CCCOL_WHITE, CCFONT_REGULAR, 20 }, // 0x5a || 0x7a
{ CCCOL_WHITE, CCFONT_UNDERLINED, 20 }, // 0x5b || 0x7b
{ CCCOL_WHITE, CCFONT_REGULAR, 24 }, // 0x5c || 0x7c
{ CCCOL_WHITE, CCFONT_UNDERLINED, 24 }, // 0x5d || 0x7d
{ CCCOL_WHITE, CCFONT_REGULAR, 28 }, // 0x5e || 0x7e
{ CCCOL_WHITE, CCFONT_UNDERLINED, 28 } // 0x5f || 0x7f
/* total 32 entries */
};
struct Screen {
/* +1 is used to compensate null character of string */
uint8_t characters[SCREEN_ROWS+1][SCREEN_COLUMNS+1];
uint8_t charsets[SCREEN_ROWS+1][SCREEN_COLUMNS+1];
uint8_t colors[SCREEN_ROWS+1][SCREEN_COLUMNS+1];
uint8_t bgs[SCREEN_ROWS+1][SCREEN_COLUMNS+1];
uint8_t fonts[SCREEN_ROWS+1][SCREEN_COLUMNS+1];
/*
* Bitmask of used rows; if a bit is not set, the
* corresponding row is not used.
* for setting row 1 use row | (1 << 0)
* for setting row 15 use row | (1 << 14)
*/
int16_t row_used;
};
typedef struct CCaptionSubContext {
AVClass *class;
int real_time;
int real_time_latency_msec;
int data_field;
struct Screen screen[2];
int active_screen;
uint8_t cursor_row;
uint8_t cursor_column;
uint8_t cursor_color;
uint8_t bg_color;
uint8_t cursor_font;
uint8_t cursor_charset;
AVBPrint buffer[2];
int buffer_index;
int buffer_changed;
int rollup;
enum cc_mode mode;
int64_t buffer_time[2];
int screen_touched;
int64_t last_real_time;
uint8_t prev_cmd[2];
int readorder;
} CCaptionSubContext;
static av_cold int init_decoder(AVCodecContext *avctx)
{
CCaptionSubContext *ctx = avctx->priv_data;
av_bprint_init(&ctx->buffer[0], 0, AV_BPRINT_SIZE_UNLIMITED);
av_bprint_init(&ctx->buffer[1], 0, AV_BPRINT_SIZE_UNLIMITED);
/* taking by default roll up to 2 */
ctx->mode = CCMODE_ROLLUP;
ctx->bg_color = CCCOL_BLACK;
ctx->rollup = 2;
ctx->cursor_row = 10;
return ff_ass_subtitle_header(avctx, "Monospace",
ASS_DEFAULT_FONT_SIZE,
ASS_DEFAULT_COLOR,
ASS_DEFAULT_BACK_COLOR,
ASS_DEFAULT_BOLD,
ASS_DEFAULT_ITALIC,
ASS_DEFAULT_UNDERLINE,
3,
ASS_DEFAULT_ALIGNMENT);
}
static av_cold int close_decoder(AVCodecContext *avctx)
{
CCaptionSubContext *ctx = avctx->priv_data;
av_bprint_finalize(&ctx->buffer[0], NULL);
av_bprint_finalize(&ctx->buffer[1], NULL);
return 0;
}
static void flush_decoder(AVCodecContext *avctx)
{
CCaptionSubContext *ctx = avctx->priv_data;
ctx->screen[0].row_used = 0;
ctx->screen[1].row_used = 0;
ctx->prev_cmd[0] = 0;
ctx->prev_cmd[1] = 0;
ctx->mode = CCMODE_ROLLUP;
ctx->rollup = 2;
ctx->cursor_row = 10;
ctx->cursor_column = 0;
ctx->cursor_font = 0;
ctx->cursor_color = 0;
ctx->bg_color = CCCOL_BLACK;
ctx->cursor_charset = 0;
ctx->active_screen = 0;
ctx->last_real_time = 0;
ctx->screen_touched = 0;
ctx->buffer_changed = 0;
if (!(avctx->flags2 & AV_CODEC_FLAG2_RO_FLUSH_NOOP))
ctx->readorder = 0;
av_bprint_clear(&ctx->buffer[0]);
av_bprint_clear(&ctx->buffer[1]);
}
/**
* @param ctx closed caption context just to print log
*/
static void write_char(CCaptionSubContext *ctx, struct Screen *screen, char ch)
{
uint8_t col = ctx->cursor_column;
char *row = screen->characters[ctx->cursor_row];
char *font = screen->fonts[ctx->cursor_row];
char *color = screen->colors[ctx->cursor_row];
char *bg = screen->bgs[ctx->cursor_row];
char *charset = screen->charsets[ctx->cursor_row];
if (col < SCREEN_COLUMNS) {
row[col] = ch;
font[col] = ctx->cursor_font;
color[col] = ctx->cursor_color;
bg[col] = ctx->bg_color;
charset[col] = ctx->cursor_charset;
ctx->cursor_charset = CCSET_BASIC_AMERICAN;
if (ch) ctx->cursor_column++;
return;
}
/* We have extra space at end only for null character */
else if (col == SCREEN_COLUMNS && ch == 0) {
row[col] = ch;
return;
}
else {
av_log(ctx, AV_LOG_WARNING, "Data Ignored since exceeding screen width\n");
return;
}
}
/**
* This function after validating parity bit, also remove it from data pair.
* The first byte doesn't pass parity, we replace it with a solid blank
* and process the pair.
* If the second byte doesn't pass parity, it returns INVALIDDATA
* user can ignore the whole pair and pass the other pair.
*/
static int validate_cc_data_pair(const uint8_t *cc_data_pair, uint8_t *hi)
{
uint8_t cc_valid = (*cc_data_pair & 4) >>2;
uint8_t cc_type = *cc_data_pair & 3;
*hi = cc_data_pair[1];
if (!cc_valid)
return AVERROR_INVALIDDATA;
// if EIA-608 data then verify parity.
if (cc_type==0 || cc_type==1) {
if (!av_parity(cc_data_pair[2])) {
return AVERROR_INVALIDDATA;
}
if (!av_parity(cc_data_pair[1])) {
*hi = 0x7F;
}
}
//Skip non-data
if ((cc_data_pair[0] == 0xFA || cc_data_pair[0] == 0xFC || cc_data_pair[0] == 0xFD)
&& (cc_data_pair[1] & 0x7F) == 0 && (cc_data_pair[2] & 0x7F) == 0)
return AVERROR_PATCHWELCOME;
//skip 708 data
if (cc_type == 3 || cc_type == 2)
return AVERROR_PATCHWELCOME;
return 0;
}
static struct Screen *get_writing_screen(CCaptionSubContext *ctx)
{
switch (ctx->mode) {
case CCMODE_POPON:
// use Inactive screen
return ctx->screen + !ctx->active_screen;
case CCMODE_PAINTON:
case CCMODE_ROLLUP:
case CCMODE_TEXT:
// use active screen
return ctx->screen + ctx->active_screen;
}
/* It was never an option */
return NULL;
}
static void roll_up(CCaptionSubContext *ctx)
{
struct Screen *screen;
int i, keep_lines;
if (ctx->mode == CCMODE_TEXT)
return;
screen = get_writing_screen(ctx);
/* +1 signify cursor_row starts from 0
* Can't keep lines less then row cursor pos
*/
keep_lines = FFMIN(ctx->cursor_row + 1, ctx->rollup);
for (i = 0; i < SCREEN_ROWS; i++) {
if (i > ctx->cursor_row - keep_lines && i <= ctx->cursor_row)
continue;
UNSET_FLAG(screen->row_used, i);
}
for (i = 0; i < keep_lines && screen->row_used; i++) {
const int i_row = ctx->cursor_row - keep_lines + i + 1;
memcpy(screen->characters[i_row], screen->characters[i_row+1], SCREEN_COLUMNS);
memcpy(screen->colors[i_row], screen->colors[i_row+1], SCREEN_COLUMNS);
memcpy(screen->bgs[i_row], screen->bgs[i_row+1], SCREEN_COLUMNS);
memcpy(screen->fonts[i_row], screen->fonts[i_row+1], SCREEN_COLUMNS);
memcpy(screen->charsets[i_row], screen->charsets[i_row+1], SCREEN_COLUMNS);
if (CHECK_FLAG(screen->row_used, i_row + 1))
SET_FLAG(screen->row_used, i_row);
}
UNSET_FLAG(screen->row_used, ctx->cursor_row);
}
static int capture_screen(CCaptionSubContext *ctx)
{
int i, j, tab = 0;
struct Screen *screen = ctx->screen + ctx->active_screen;
enum cc_font prev_font = CCFONT_REGULAR;
enum cc_color_code prev_color = CCCOL_WHITE;
enum cc_color_code prev_bg_color = CCCOL_BLACK;
const int bidx = ctx->buffer_index;
av_bprint_clear(&ctx->buffer[bidx]);
for (i = 0; screen->row_used && i < SCREEN_ROWS; i++)
{
if (CHECK_FLAG(screen->row_used, i)) {
const char *row = screen->characters[i];
const char *charset = screen->charsets[i];
j = 0;
while (row[j] == ' ' && charset[j] == CCSET_BASIC_AMERICAN)
j++;
if (!tab || j < tab)
tab = j;
}
}
for (i = 0; screen->row_used && i < SCREEN_ROWS; i++)
{
if (CHECK_FLAG(screen->row_used, i)) {
const char *row = screen->characters[i];
const char *font = screen->fonts[i];
const char *bg = screen->bgs[i];
const char *color = screen->colors[i];
const char *charset = screen->charsets[i];
const char *override;
int x, y, seen_char = 0;
j = 0;
/* skip leading space */
while (row[j] == ' ' && charset[j] == CCSET_BASIC_AMERICAN && j < tab)
j++;
x = ASS_DEFAULT_PLAYRESX * (0.1 + 0.0250 * j);
y = ASS_DEFAULT_PLAYRESY * (0.1 + 0.0533 * i);
av_bprintf(&ctx->buffer[bidx], "{\\an7}{\\pos(%d,%d)}", x, y);
for (; j < SCREEN_COLUMNS; j++) {
const char *e_tag = "", *s_tag = "", *c_tag = "", *b_tag = "";
if (row[j] == 0)
break;
if (prev_font != font[j]) {
switch (prev_font) {
case CCFONT_ITALICS:
e_tag = "{\\i0}";
break;
case CCFONT_UNDERLINED:
e_tag = "{\\u0}";
break;
case CCFONT_UNDERLINED_ITALICS:
e_tag = "{\\u0}{\\i0}";
break;
}
switch (font[j]) {
case CCFONT_ITALICS:
s_tag = "{\\i1}";
break;
case CCFONT_UNDERLINED:
s_tag = "{\\u1}";
break;
case CCFONT_UNDERLINED_ITALICS:
s_tag = "{\\u1}{\\i1}";
break;
}
}
if (prev_color != color[j]) {
switch (color[j]) {
case CCCOL_WHITE:
c_tag = "{\\c&HFFFFFF&}";
break;
case CCCOL_GREEN:
c_tag = "{\\c&H00FF00&}";
break;
case CCCOL_BLUE:
c_tag = "{\\c&HFF0000&}";
break;
case CCCOL_CYAN:
c_tag = "{\\c&HFFFF00&}";
break;
case CCCOL_RED:
c_tag = "{\\c&H0000FF&}";
break;
case CCCOL_YELLOW:
c_tag = "{\\c&H00FFFF&}";
break;
case CCCOL_MAGENTA:
c_tag = "{\\c&HFF00FF&}";
break;
}
}
if (prev_bg_color != bg[j]) {
switch (bg[j]) {
case CCCOL_WHITE:
b_tag = "{\\3c&HFFFFFF&}";
break;
case CCCOL_GREEN:
b_tag = "{\\3c&H00FF00&}";
break;
case CCCOL_BLUE:
b_tag = "{\\3c&HFF0000&}";
break;
case CCCOL_CYAN:
b_tag = "{\\3c&HFFFF00&}";
break;
case CCCOL_RED:
b_tag = "{\\3c&H0000FF&}";
break;
case CCCOL_YELLOW:
b_tag = "{\\3c&H00FFFF&}";
break;
case CCCOL_MAGENTA:
b_tag = "{\\3c&HFF00FF&}";
break;
case CCCOL_BLACK:
b_tag = "{\\3c&H000000&}";
break;
}
}
prev_font = font[j];
prev_color = color[j];
prev_bg_color = bg[j];
override = charset_overrides[(int)charset[j]][(int)row[j]];
if (override) {
av_bprintf(&ctx->buffer[bidx], "%s%s%s%s%s", e_tag, s_tag, c_tag, b_tag, override);
seen_char = 1;
} else if (row[j] == ' ' && !seen_char) {
av_bprintf(&ctx->buffer[bidx], "%s%s%s%s\\h", e_tag, s_tag, c_tag, b_tag);
} else {
av_bprintf(&ctx->buffer[bidx], "%s%s%s%s%c", e_tag, s_tag, c_tag, b_tag, row[j]);
seen_char = 1;
}
}
av_bprintf(&ctx->buffer[bidx], "\\N");
}
}
if (!av_bprint_is_complete(&ctx->buffer[bidx]))
return AVERROR(ENOMEM);
if (screen->row_used && ctx->buffer[bidx].len >= 2) {
ctx->buffer[bidx].len -= 2;
ctx->buffer[bidx].str[ctx->buffer[bidx].len] = 0;
}
ctx->buffer_changed = 1;
return 0;
}
static void update_time(CCaptionSubContext *ctx, int64_t pts)
{
ctx->buffer_time[0] = ctx->buffer_time[1];
ctx->buffer_time[1] = pts;
}
static void handle_bgattr(CCaptionSubContext *ctx, uint8_t hi, uint8_t lo)
{
const int i = (lo & 0xf) >> 1;
ctx->bg_color = bg_attribs[i];
}
static void handle_textattr(CCaptionSubContext *ctx, uint8_t hi, uint8_t lo)
{
int i = lo - 0x20;
struct Screen *screen = get_writing_screen(ctx);
if (i >= 32)
return;
ctx->cursor_color = pac2_attribs[i][0];
ctx->cursor_font = pac2_attribs[i][1];
SET_FLAG(screen->row_used, ctx->cursor_row);
write_char(ctx, screen, ' ');
}
static void handle_pac(CCaptionSubContext *ctx, uint8_t hi, uint8_t lo)
{
static const int8_t row_map[] = {
11, -1, 1, 2, 3, 4, 12, 13, 14, 15, 5, 6, 7, 8, 9, 10
};
const int index = ( (hi<<1) & 0x0e) | ( (lo>>5) & 0x01 );
struct Screen *screen = get_writing_screen(ctx);
int indent, i;
if (row_map[index] <= 0) {
av_log(ctx, AV_LOG_DEBUG, "Invalid pac index encountered\n");
return;
}
lo &= 0x1f;
ctx->cursor_row = row_map[index] - 1;
ctx->cursor_color = pac2_attribs[lo][0];
ctx->cursor_font = pac2_attribs[lo][1];
ctx->cursor_charset = CCSET_BASIC_AMERICAN;
ctx->cursor_column = 0;
indent = pac2_attribs[lo][2];
for (i = 0; i < indent; i++) {
write_char(ctx, screen, ' ');
}
}
static int handle_edm(CCaptionSubContext *ctx)
{
struct Screen *screen = ctx->screen + ctx->active_screen;
int ret;
// In buffered mode, keep writing to screen until it is wiped.
// Before wiping the display, capture contents to emit subtitle.
if (!ctx->real_time)
ret = capture_screen(ctx);
screen->row_used = 0;
ctx->bg_color = CCCOL_BLACK;
// In realtime mode, emit an empty caption so the last one doesn't
// stay on the screen.
if (ctx->real_time)
ret = capture_screen(ctx);
return ret;
}
static int handle_eoc(CCaptionSubContext *ctx)
{
int ret;
ctx->active_screen = !ctx->active_screen;
// In buffered mode, we wait til the *next* EOC and
// capture what was already on the screen since the last EOC.
if (!ctx->real_time)
ret = handle_edm(ctx);
ctx->cursor_column = 0;
// In realtime mode, we display the buffered contents (after
// flipping the buffer to active above) as soon as EOC arrives.
if (ctx->real_time)
ret = capture_screen(ctx);
return ret;
}
static void handle_delete_end_of_row(CCaptionSubContext *ctx)
{
struct Screen *screen = get_writing_screen(ctx);
write_char(ctx, screen, 0);
}
static void handle_char(CCaptionSubContext *ctx, char hi, char lo)
{
struct Screen *screen = get_writing_screen(ctx);
SET_FLAG(screen->row_used, ctx->cursor_row);
switch (hi) {
case 0x11:
ctx->cursor_charset = CCSET_SPECIAL_AMERICAN;
break;
case 0x12:
if (ctx->cursor_column > 0)
ctx->cursor_column -= 1;
ctx->cursor_charset = CCSET_EXTENDED_SPANISH_FRENCH_MISC;
break;
case 0x13:
if (ctx->cursor_column > 0)
ctx->cursor_column -= 1;
ctx->cursor_charset = CCSET_EXTENDED_PORTUGUESE_GERMAN_DANISH;
break;
default:
ctx->cursor_charset = CCSET_BASIC_AMERICAN;
write_char(ctx, screen, hi);
break;
}
if (lo) {
write_char(ctx, screen, lo);
}
write_char(ctx, screen, 0);
if (ctx->mode != CCMODE_POPON)
ctx->screen_touched = 1;
if (lo)
ff_dlog(ctx, "(%c,%c)\n", hi, lo);
else
ff_dlog(ctx, "(%c)\n", hi);
}
static int process_cc608(CCaptionSubContext *ctx, uint8_t hi, uint8_t lo)
{
int ret = 0;
if (hi == ctx->prev_cmd[0] && lo == ctx->prev_cmd[1]) {
return 0;
}
/* set prev command */
ctx->prev_cmd[0] = hi;
ctx->prev_cmd[1] = lo;
if ( (hi == 0x10 && (lo >= 0x40 && lo <= 0x5f)) ||
( (hi >= 0x11 && hi <= 0x17) && (lo >= 0x40 && lo <= 0x7f) ) ) {
handle_pac(ctx, hi, lo);
} else if ( ( hi == 0x11 && lo >= 0x20 && lo <= 0x2f ) ||
( hi == 0x17 && lo >= 0x2e && lo <= 0x2f) ) {
handle_textattr(ctx, hi, lo);
} else if ((hi == 0x10 && lo >= 0x20 && lo <= 0x2f)) {
handle_bgattr(ctx, hi, lo);
} else if (hi == 0x14 || hi == 0x15 || hi == 0x1c) {
switch (lo) {
case 0x20:
/* resume caption loading */
ctx->mode = CCMODE_POPON;
break;
case 0x24:
handle_delete_end_of_row(ctx);
break;
case 0x25:
case 0x26:
case 0x27:
ctx->rollup = lo - 0x23;
ctx->mode = CCMODE_ROLLUP;
break;
case 0x29:
/* resume direct captioning */
ctx->mode = CCMODE_PAINTON;
break;
case 0x2b:
/* resume text display */
ctx->mode = CCMODE_TEXT;
break;
case 0x2c:
/* erase display memory */
handle_edm(ctx);
break;
case 0x2d:
/* carriage return */
ff_dlog(ctx, "carriage return\n");
if (!ctx->real_time)
ret = capture_screen(ctx);
roll_up(ctx);
ctx->cursor_column = 0;
break;
case 0x2e:
/* erase buffered (non displayed) memory */
// Only in realtime mode. In buffered mode, we re-use the inactive screen
// for our own buffering.
if (ctx->real_time) {
struct Screen *screen = ctx->screen + !ctx->active_screen;
screen->row_used = 0;
}
break;
case 0x2f:
/* end of caption */
ff_dlog(ctx, "handle_eoc\n");
ret = handle_eoc(ctx);
break;
default:
ff_dlog(ctx, "Unknown command 0x%hhx 0x%hhx\n", hi, lo);
break;
}
} else if (hi >= 0x11 && hi <= 0x13) {
/* Special characters */
handle_char(ctx, hi, lo);
} else if (hi >= 0x20) {
/* Standard characters (always in pairs) */
handle_char(ctx, hi, lo);
ctx->prev_cmd[0] = ctx->prev_cmd[1] = 0;
} else if (hi == 0x17 && lo >= 0x21 && lo <= 0x23) {
int i;
/* Tab offsets (spacing) */
for (i = 0; i < lo - 0x20; i++) {
handle_char(ctx, ' ', 0);
}
} else {
/* Ignoring all other non data code */
ff_dlog(ctx, "Unknown command 0x%hhx 0x%hhx\n", hi, lo);
}
return ret;
}
static int decode(AVCodecContext *avctx, AVSubtitle *sub,
int *got_sub, const AVPacket *avpkt)
{
CCaptionSubContext *ctx = avctx->priv_data;
int64_t in_time = sub->pts;
int64_t start_time;
int64_t end_time;
int bidx = ctx->buffer_index;
const uint8_t *bptr = avpkt->data;
int len = avpkt->size;
int ret = 0;
int i;
unsigned nb_rect_allocated = 0;
for (i = 0; i < len; i += 3) {
uint8_t hi, cc_type = bptr[i] & 1;
if (ctx->data_field < 0)
ctx->data_field = cc_type;
if (validate_cc_data_pair(bptr + i, &hi))
continue;
if (cc_type != ctx->data_field)
continue;
ret = process_cc608(ctx, hi & 0x7f, bptr[i + 2] & 0x7f);
if (ret < 0)
return ret;
if (!ctx->buffer_changed)
continue;
ctx->buffer_changed = 0;
if (!ctx->real_time && ctx->mode == CCMODE_POPON)
ctx->buffer_index = bidx = !ctx->buffer_index;
update_time(ctx, in_time);
if (ctx->buffer[bidx].str[0] || ctx->real_time) {
ff_dlog(ctx, "cdp writing data (%s)\n", ctx->buffer[bidx].str);
start_time = ctx->buffer_time[0];
sub->pts = start_time;
end_time = ctx->buffer_time[1];
if (!ctx->real_time)
sub->end_display_time = av_rescale_q(end_time - start_time,
AV_TIME_BASE_Q, ms_tb);
else
sub->end_display_time = -1;
ret = ff_ass_add_rect2(sub, ctx->buffer[bidx].str, ctx->readorder++, 0, NULL, NULL, &nb_rect_allocated);
if (ret < 0)
return ret;
ctx->last_real_time = sub->pts;
ctx->screen_touched = 0;
}
}
if (!bptr && !ctx->real_time && ctx->buffer[!ctx->buffer_index].str[0]) {
bidx = !ctx->buffer_index;
ret = ff_ass_add_rect2(sub, ctx->buffer[bidx].str, ctx->readorder++, 0, NULL, NULL, &nb_rect_allocated);
if (ret < 0)
return ret;
av_bprint_clear(&ctx->buffer[bidx]);
sub->pts = ctx->buffer_time[1];
sub->end_display_time = av_rescale_q(ctx->buffer_time[1] - ctx->buffer_time[0],
AV_TIME_BASE_Q, ms_tb);
if (sub->end_display_time == 0)
sub->end_display_time = ctx->buffer[bidx].len * 20;
}
if (ctx->real_time && ctx->screen_touched &&
sub->pts >= ctx->last_real_time + av_rescale_q(ctx->real_time_latency_msec, ms_tb, AV_TIME_BASE_Q)) {
ctx->last_real_time = sub->pts;
ctx->screen_touched = 0;
capture_screen(ctx);
ctx->buffer_changed = 0;
ret = ff_ass_add_rect2(sub, ctx->buffer[bidx].str, ctx->readorder++, 0, NULL, NULL, &nb_rect_allocated);
if (ret < 0)
return ret;
sub->end_display_time = -1;
}
*got_sub = sub->num_rects > 0;
return avpkt->size;
}
#define OFFSET(x) offsetof(CCaptionSubContext, x)
#define SD AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM
static const AVOption options[] = {
{ "real_time", "emit subtitle events as they are decoded for real-time display", OFFSET(real_time), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, SD },
{ "real_time_latency_msec", "minimum elapsed time between emitting real-time subtitle events", OFFSET(real_time_latency_msec), AV_OPT_TYPE_INT, { .i64 = 200 }, 0, 500, SD },
{ "data_field", "select data field", OFFSET(data_field), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, 1, SD, "data_field" },
{ "auto", "pick first one that appears", 0, AV_OPT_TYPE_CONST, { .i64 =-1 }, 0, 0, SD, "data_field" },
{ "first", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = 0 }, 0, 0, SD, "data_field" },
{ "second", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = 1 }, 0, 0, SD, "data_field" },
{NULL}
};
static const AVClass ccaption_dec_class = {
.class_name = "Closed caption Decoder",
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
const FFCodec ff_ccaption_decoder = {
.p.name = "cc_dec",
CODEC_LONG_NAME("Closed Caption (EIA-608 / CEA-708)"),
.p.type = AVMEDIA_TYPE_SUBTITLE,
.p.id = AV_CODEC_ID_EIA_608,
.p.priv_class = &ccaption_dec_class,
.p.capabilities = AV_CODEC_CAP_DELAY,
.priv_data_size = sizeof(CCaptionSubContext),
.init = init_decoder,
.close = close_decoder,
.flush = flush_decoder,
FF_CODEC_DECODE_SUB_CB(decode),
};