diff options
Diffstat (limited to 'libavcodec/ccaption_dec.c')
| -rw-r--r-- | libavcodec/ccaption_dec.c | 591 |
1 files changed, 591 insertions, 0 deletions
diff --git a/libavcodec/ccaption_dec.c b/libavcodec/ccaption_dec.c new file mode 100644 index 0000000..264d21c --- /dev/null +++ b/libavcodec/ccaption_dec.c @@ -0,0 +1,591 @@ +/* + * 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 "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)) ) + +/* + * TODO list + * 1) handle font and color completely + */ +enum cc_mode { + CCMODE_POPON, + CCMODE_PAINTON, + CCMODE_ROLLUP_2, + CCMODE_ROLLUP_3, + CCMODE_ROLLUP_4, + 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, +}; + +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 */ +}; + +/* 0-255 needs 256 spaces */ +static const uint8_t parity_table[256] = { 0, 1, 1, 0, 1, 0, 0, 1, + 1, 0, 0, 1, 0, 1, 1, 0, + 1, 0, 0, 1, 0, 1, 1, 0, + 0, 1, 1, 0, 1, 0, 0, 1, + 1, 0, 0, 1, 0, 1, 1, 0, + 0, 1, 1, 0, 1, 0, 0, 1, + 0, 1, 1, 0, 1, 0, 0, 1, + 1, 0, 0, 1, 0, 1, 1, 0, + 1, 0, 0, 1, 0, 1, 1, 0, + 0, 1, 1, 0, 1, 0, 0, 1, + 0, 1, 1, 0, 1, 0, 0, 1, + 1, 0, 0, 1, 0, 1, 1, 0, + 0, 1, 1, 0, 1, 0, 0, 1, + 1, 0, 0, 1, 0, 1, 1, 0, + 1, 0, 0, 1, 0, 1, 1, 0, + 0, 1, 1, 0, 1, 0, 0, 1, + 1, 0, 0, 1, 0, 1, 1, 0, + 0, 1, 1, 0, 1, 0, 0, 1, + 0, 1, 1, 0, 1, 0, 0, 1, + 1, 0, 0, 1, 0, 1, 1, 0, + 0, 1, 1, 0, 1, 0, 0, 1, + 1, 0, 0, 1, 0, 1, 1, 0, + 1, 0, 0, 1, 0, 1, 1, 0, + 0, 1, 1, 0, 1, 0, 0, 1, + 0, 1, 1, 0, 1, 0, 0, 1, + 1, 0, 0, 1, 0, 1, 1, 0, + 1, 0, 0, 1, 0, 1, 1, 0, + 0, 1, 1, 0, 1, 0, 0, 1, + 1, 0, 0, 1, 0, 1, 1, 0, + 0, 1, 1, 0, 1, 0, 0, 1, + 0, 1, 1, 0, 1, 0, 0, 1, + 1, 0, 0, 1, 0, 1, 1, 0 }; + +struct Screen { + /* +1 is used to compensate null character of string */ + uint8_t characters[SCREEN_ROWS][SCREEN_COLUMNS+1]; + uint8_t colors[SCREEN_ROWS][SCREEN_COLUMNS+1]; + uint8_t fonts[SCREEN_ROWS][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; + struct Screen screen[2]; + int active_screen; + uint8_t cursor_row; + uint8_t cursor_column; + uint8_t cursor_color; + uint8_t cursor_font; + AVBPrint buffer; + int screen_changed; + int rollup; + enum cc_mode mode; + int64_t start_time; + /* visible screen time */ + int64_t startv_time; + int64_t end_time; + char prev_cmd[2]; + /* buffer to store pkt data */ + AVBufferRef *pktbuf; +}CCaptionSubContext; + + +static av_cold int init_decoder(AVCodecContext *avctx) +{ + int ret; + CCaptionSubContext *ctx = avctx->priv_data; + + av_bprint_init(&ctx->buffer, 0, AV_BPRINT_SIZE_UNLIMITED); + /* taking by default roll up to 2 */ + ctx->mode = CCMODE_ROLLUP_2; + ctx->rollup = 2; + ret = ff_ass_subtitle_header_default(avctx); + if(ret < 0) { + return ret; + } + /* allocate pkt buffer */ + ctx->pktbuf = av_buffer_alloc(128); + if( !ctx->pktbuf) { + ret = AVERROR(ENOMEM); + } + return ret; +} + +static av_cold int close_decoder(AVCodecContext *avctx) +{ + CCaptionSubContext *ctx = avctx->priv_data; + av_bprint_finalize( &ctx->buffer, NULL); + av_buffer_unref(&ctx->pktbuf); + return 0; +} + +/** + * @param ctx closed caption context just to print log + */ +static int write_char (CCaptionSubContext *ctx, char *row,uint8_t col, char ch) +{ + if(col < SCREEN_COLUMNS) { + row[col] = ch; + return 0; + } + /* We have extra space at end only for null character */ + else if ( col == SCREEN_COLUMNS && ch == 0) { + row[col] = ch; + return 0; + } + else { + av_log(ctx, AV_LOG_WARNING,"Data Ignored since exceeding screen width\n"); + return AVERROR_INVALIDDATA; + } +} + +/** + * 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 (uint8_t *cc_data_pair) +{ + uint8_t cc_valid = (*cc_data_pair & 4) >>2; + uint8_t cc_type = *cc_data_pair & 3; + + if (!cc_valid) + return AVERROR_INVALIDDATA; + + // if EIA-608 data then verify parity. + if (cc_type==0 || cc_type==1) { + if (!parity_table[cc_data_pair[2]]) { + return AVERROR_INVALIDDATA; + } + if (!parity_table[cc_data_pair[1]]) { + cc_data_pair[1]=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; + + /* remove parity bit */ + cc_data_pair[1] &= 0x7F; + cc_data_pair[2] &= 0x7F; + + + 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_2: + case CCMODE_ROLLUP_3: + case CCMODE_ROLLUP_4: + 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 < ctx->cursor_row - keep_lines; i++ ) + 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->fonts[i_row], screen->fonts[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 reap_screen(CCaptionSubContext *ctx, int64_t pts) +{ + int i; + int ret = 0; + struct Screen *screen = ctx->screen + ctx->active_screen; + ctx->start_time = ctx->startv_time; + + for( i = 0; screen->row_used && i < SCREEN_ROWS; i++) + { + if(CHECK_FLAG(screen->row_used,i)) { + char *str = screen->characters[i]; + /* skip space */ + while (*str == ' ') + str++; + + av_bprintf(&ctx->buffer, "%s\\N", str); + ret = av_bprint_is_complete(&ctx->buffer); + if( ret == 0) { + ret = AVERROR(ENOMEM); + break; + } + } + + } + if(screen->row_used && ctx->buffer.len >= 2 ) { + ctx->buffer.len -= 2; + ctx->buffer.str[ctx->buffer.len] = 0; + } + ctx->startv_time = pts; + ctx->end_time = pts; + return ret; +} + +static void handle_textattr( CCaptionSubContext *ctx, uint8_t hi, uint8_t lo ) +{ + int i = lo - 0x20; + int ret; + struct Screen *screen = get_writing_screen(ctx); + char *row = screen->characters[ctx->cursor_row]; + + 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); + ret = write_char(ctx, row, ctx->cursor_column, ' '); + if(ret == 0) + ctx->cursor_column++; +} + +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); + char *row; + int indent,i,ret; + + 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_column = 0; + indent = pac2_attribs[lo][2]; + row = screen->characters[ctx->cursor_row]; + for(i = 0;i < indent; i++) { + ret = write_char(ctx, row, ctx->cursor_column, ' '); + if( ret == 0 ) + ctx->cursor_column++; + } + +} + +/** + * @param pts it is required to set end time + */ +static int handle_edm(CCaptionSubContext *ctx,int64_t pts) +{ + int ret = 0; + struct Screen *screen = ctx->screen + ctx->active_screen; + + reap_screen(ctx, pts); + screen->row_used = 0; + ctx->screen_changed = 1; + return ret; +} + +static int handle_eoc(CCaptionSubContext *ctx, int64_t pts) +{ + int ret; + ret = handle_edm(ctx,pts); + ctx->active_screen = !ctx->active_screen; + ctx->cursor_column = 0; + return ret; +} + +static void handle_delete_end_of_row( CCaptionSubContext *ctx, char hi, char lo) +{ + struct Screen *screen = get_writing_screen(ctx); + char *row = screen->characters[ctx->cursor_row]; + write_char(ctx, row, ctx->cursor_column, 0); + +} + +static void handle_char(CCaptionSubContext *ctx, char hi, char lo, int64_t pts) +{ + struct Screen *screen = get_writing_screen(ctx); + char *row = screen->characters[ctx->cursor_row]; + int ret; + + SET_FLAG(screen->row_used,ctx->cursor_row); + + ret = write_char(ctx, row, ctx->cursor_column, hi); + if( ret == 0 ) + ctx->cursor_column++; + + if(lo) { + ret = write_char(ctx, row, ctx->cursor_column, lo); + if ( ret == 0 ) + ctx->cursor_column++; + } + write_char(ctx, row, ctx->cursor_column, 0); + + /* reset prev command since character can repeat */ + ctx->prev_cmd[0] = 0; + ctx->prev_cmd[1] = 0; + if (lo) + av_dlog(ctx, "(%c,%c)\n",hi,lo); + else + av_dlog(ctx, "(%c)\n",hi); +} + +static int process_cc608(CCaptionSubContext *ctx, int64_t pts, uint8_t hi, uint8_t lo) +{ + int ret = 0; +#define COR3(var, with1, with2, with3) ( (var) == (with1) || (var) == (with2) || (var) == (with3) ) + if ( hi == ctx->prev_cmd[0] && lo == ctx->prev_cmd[1]) { + /* ignore redundant command */ + } else 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 ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x20 ) { + /* resume caption loading */ + ctx->mode = CCMODE_POPON; + } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x24 ) { + handle_delete_end_of_row(ctx, hi, lo); + } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x25 ) { + ctx->rollup = 2; + ctx->mode = CCMODE_ROLLUP_2; + } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x26 ) { + ctx->rollup = 3; + ctx->mode = CCMODE_ROLLUP_3; + } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x27 ) { + ctx->rollup = 4; + ctx->mode = CCMODE_ROLLUP_4; + } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x29 ) { + /* resume direct captioning */ + ctx->mode = CCMODE_PAINTON; + } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x2B ) { + /* resume text display */ + ctx->mode = CCMODE_TEXT; + } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x2C ) { + /* erase display memory */ + ret = handle_edm(ctx, pts); + } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x2D ) { + /* carriage return */ + av_dlog(ctx, "carriage return\n"); + reap_screen(ctx, pts); + roll_up(ctx); + ctx->screen_changed = 1; + ctx->cursor_column = 0; + } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x2F ) { + /* end of caption */ + av_dlog(ctx, "handle_eoc\n"); + ret = handle_eoc(ctx, pts); + } else if (hi>=0x20) { + /* Standard characters (always in pairs) */ + handle_char(ctx, hi, lo, pts); + } else { + /* Ignoring all other non data code */ + av_dlog(ctx, "Unknown command 0x%hhx 0x%hhx\n", hi, lo); + } + + /* set prev command */ + ctx->prev_cmd[0] = hi; + ctx->prev_cmd[1] = lo; + +#undef COR3 + return ret; + +} + +static int decode(AVCodecContext *avctx, void *data, int *got_sub, AVPacket *avpkt) +{ + CCaptionSubContext *ctx = avctx->priv_data; + AVSubtitle *sub = data; + uint8_t *bptr = NULL; + int len = avpkt->size; + int ret = 0; + int i; + + if ( ctx->pktbuf->size < len) { + ret = av_buffer_realloc(&ctx->pktbuf, len); + if(ret < 0) { + av_log(ctx, AV_LOG_WARNING, "Insufficient Memory of %d truncated to %d\n",len, ctx->pktbuf->size); + len = ctx->pktbuf->size; + ret = 0; + } + } + memcpy(ctx->pktbuf->data, avpkt->data, len); + bptr = ctx->pktbuf->data; + + + for (i = 0; i < len; i += 3) { + uint8_t cc_type = *(bptr + i) & 3; + if (validate_cc_data_pair( bptr + i) ) + continue; + /* ignoring data field 1 */ + if(cc_type == 1) + continue; + else + process_cc608(ctx, avpkt->pts, *(bptr + i + 1) & 0x7f, *(bptr + i + 2) & 0x7f); + if(ctx->screen_changed && *ctx->buffer.str) + { + int start_time = av_rescale_q(ctx->start_time, avctx->time_base, (AVRational){ 1, 100 }); + int end_time = av_rescale_q(ctx->end_time, avctx->time_base, (AVRational){ 1, 100 }); + av_dlog(ctx, "cdp writing data (%s)\n",ctx->buffer.str); + ret = ff_ass_add_rect_bprint(sub, &ctx->buffer, start_time, end_time - start_time); + if (ret < 0) + return ret; + sub->pts = av_rescale_q(ctx->start_time, avctx->time_base, AV_TIME_BASE_Q); + ctx->screen_changed = 0; + av_bprint_clear(&ctx->buffer); + } + } + + *got_sub = sub->num_rects > 0; + return ret; +} + +static const AVOption options[] = { + {NULL} +}; + +static const AVClass ccaption_dec_class = { + .class_name = "Closed caption Decoder", + .item_name = av_default_item_name, + .option = options, + .version = LIBAVUTIL_VERSION_INT, +}; + +AVCodec ff_ccaption_decoder = { + .name = "cc_dec", + .long_name = NULL_IF_CONFIG_SMALL("Closed Caption (EIA-608 / CEA-708) Decoder"), + .type = AVMEDIA_TYPE_SUBTITLE, + .id = AV_CODEC_ID_EIA_608, + .priv_data_size = sizeof(CCaptionSubContext), + .init = init_decoder, + .close = close_decoder, + .decode = decode, + .priv_class = &ccaption_dec_class, +}; 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