diff options
Diffstat (limited to 'libavcodec/htmlsubtitles.c')
| -rw-r--r-- | libavcodec/htmlsubtitles.c | 319 |
1 files changed, 319 insertions, 0 deletions
diff --git a/libavcodec/htmlsubtitles.c b/libavcodec/htmlsubtitles.c new file mode 100644 index 0000000000..d9221ba16b --- /dev/null +++ b/libavcodec/htmlsubtitles.c @@ -0,0 +1,319 @@ +/* + * Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org> + * Copyright (c) 2017 Clément Bœsch <u@pkh.me> + * + * 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 "libavutil/avassert.h" +#include "libavutil/avstring.h" +#include "libavutil/common.h" +#include "libavutil/parseutils.h" +#include "htmlsubtitles.h" +#include <ctype.h> + +static int html_color_parse(void *log_ctx, const char *str) +{ + uint8_t rgba[4]; + int nb_sharps = 0; + while (str[nb_sharps] == '#') + nb_sharps++; + str += FFMAX(0, nb_sharps - 1); + if (av_parse_color(rgba, str, strcspn(str, "\" >"), log_ctx) < 0) + return -1; + return rgba[0] | rgba[1] << 8 | rgba[2] << 16; +} + +static void rstrip_spaces_buf(AVBPrint *buf) +{ + if (av_bprint_is_complete(buf)) + while (buf->len > 0 && buf->str[buf->len - 1] == ' ') + buf->str[--buf->len] = 0; +} + +/* + * Fast code for scanning text enclosed in braces. Functionally + * equivalent to this sscanf call: + * + * sscanf(in, "{\\an%*1u}%n", &len) >= 0 && len > 0 + */ +static int scanbraces(const char* in) { + if (strncmp(in, "{\\an", 4) != 0) { + return 0; + } + if (!isdigit(in[4])) { + return 0; + } + if (in[5] != '}') { + return 0; + } + return 1; +} + +/* skip all {\xxx} substrings except for {\an%d} + and all microdvd like styles such as {Y:xxx} */ +static void handle_open_brace(AVBPrint *dst, const char **inp, int *an, int *closing_brace_missing) +{ + const char *in = *inp; + + *an += scanbraces(in); + + if (!*closing_brace_missing) { + if ( (*an != 1 && in[1] == '\\') + || (in[1] && strchr("CcFfoPSsYy", in[1]) && in[2] == ':')) { + char *bracep = strchr(in+2, '}'); + if (bracep) { + *inp = bracep; + return; + } else + *closing_brace_missing = 1; + } + } + + av_bprint_chars(dst, *in, 1); +} + +struct font_tag { + char face[128]; + int size; + uint32_t color; +}; + +/* + * Fast code for scanning the rest of a tag. Functionally equivalent to + * this sscanf call: + * + * sscanf(in, "%127[^<>]>%n", buffer, lenp) == 2 + */ +static int scantag(const char* in, char* buffer, int* lenp) { + int len; + + for (len = 0; len < 128; len++) { + const char c = *in++; + switch (c) { + case '\0': + return 0; + case '<': + return 0; + case '>': + buffer[len] = '\0'; + *lenp = len+1; + return 1; + default: + break; + } + buffer[len] = c; + } + return 0; +} + +/* + * The general politic of the convert is to mask unsupported tags or formatting + * errors (but still alert the user/subtitles writer with an error/warning) + * without dropping any actual text content for the final user. + */ +int ff_htmlmarkup_to_ass(void *log_ctx, AVBPrint *dst, const char *in) +{ + char *param, buffer[128]; + int len, tag_close, sptr = 0, line_start = 1, an = 0, end = 0; + int closing_brace_missing = 0; + int i, likely_a_tag; + + /* + * state stack is only present for fonts since they are the only tags where + * the state is not binary. Here is a typical use case: + * + * <font color="red" size=10> + * red 10 + * <font size=50> RED AND BIG </font> + * red 10 again + * </font> + * + * On the other hand, using the state system for all the tags should be + * avoided because it breaks wrongly nested tags such as: + * + * <b> foo <i> bar </b> bla </i> + * + * We don't want to break here; instead, we will treat all these tags as + * binary state markers. Basically, "<b>" will activate bold, and "</b>" + * will deactivate it, whatever the current state. + * + * This will also prevents cases where we have a random closing tag + * remaining after the opening one was dropped. Yes, this happens and we + * still don't want to print a "</b>" at the end of the dialog event. + */ + struct font_tag stack[16]; + + memset(&stack[0], 0, sizeof(stack[0])); + + for (; !end && *in; in++) { + switch (*in) { + case '\r': + break; + case '\n': + if (line_start) { + end = 1; + break; + } + rstrip_spaces_buf(dst); + av_bprintf(dst, "\\N"); + line_start = 1; + break; + case ' ': + if (!line_start) + av_bprint_chars(dst, *in, 1); + break; + case '{': + handle_open_brace(dst, &in, &an, &closing_brace_missing); + break; + case '<': + /* + * "<<" are likely latin guillemets in ASCII or some kind of random + * style effect; see sub/badsyntax.srt in the FATE samples + * directory for real test cases. + */ + + likely_a_tag = 1; + for (i = 0; in[1] == '<'; i++) { + av_bprint_chars(dst, '<', 1); + likely_a_tag = 0; + in++; + } + + tag_close = in[1] == '/'; + if (tag_close) + likely_a_tag = 1; + + av_assert0(in[0] == '<'); + + len = 0; + + if (scantag(in+tag_close+1, buffer, &len) && len > 0) { + const int skip = len + tag_close; + const char *tagname = buffer; + while (*tagname == ' ') { + likely_a_tag = 0; + tagname++; + } + if ((param = strchr(tagname, ' '))) + *param++ = 0; + + /* Check if this is likely a tag */ +#define LIKELY_A_TAG_CHAR(x) (((x) >= '0' && (x) <= '9') || \ + ((x) >= 'a' && (x) <= 'z') || \ + ((x) >= 'A' && (x) <= 'Z') || \ + (x) == '_' || (x) == '/') + for (i = 0; tagname[i]; i++) { + if (!LIKELY_A_TAG_CHAR(tagname[i])) { + likely_a_tag = 0; + break; + } + } + + if (!av_strcasecmp(tagname, "font")) { + if (tag_close && sptr > 0) { + struct font_tag *cur_tag = &stack[sptr--]; + struct font_tag *last_tag = &stack[sptr]; + + if (cur_tag->size) { + if (!last_tag->size) + av_bprintf(dst, "{\\fs}"); + else if (last_tag->size != cur_tag->size) + av_bprintf(dst, "{\\fs%d}", last_tag->size); + } + + if (cur_tag->color & 0xff000000) { + if (!(last_tag->color & 0xff000000)) + av_bprintf(dst, "{\\c}"); + else if (last_tag->color != cur_tag->color) + av_bprintf(dst, "{\\c&H%"PRIX32"&}", last_tag->color & 0xffffff); + } + + if (cur_tag->face[0]) { + if (!last_tag->face[0]) + av_bprintf(dst, "{\\fn}"); + else if (strcmp(last_tag->face, cur_tag->face)) + av_bprintf(dst, "{\\fn%s}", last_tag->face); + } + } else if (!tag_close && sptr < FF_ARRAY_ELEMS(stack) - 1) { + struct font_tag *new_tag = &stack[sptr + 1]; + + *new_tag = stack[sptr++]; + + while (param) { + if (!av_strncasecmp(param, "size=", 5)) { + param += 5 + (param[5] == '"'); + if (sscanf(param, "%u", &new_tag->size) == 1) + av_bprintf(dst, "{\\fs%u}", new_tag->size); + } else if (!av_strncasecmp(param, "color=", 6)) { + int color; + param += 6 + (param[6] == '"'); + color = html_color_parse(log_ctx, param); + if (color >= 0) { + new_tag->color = 0xff000000 | color; + av_bprintf(dst, "{\\c&H%"PRIX32"&}", new_tag->color & 0xffffff); + } + } else if (!av_strncasecmp(param, "face=", 5)) { + param += 5 + (param[5] == '"'); + len = strcspn(param, + param[-1] == '"' ? "\"" :" "); + av_strlcpy(new_tag->face, param, + FFMIN(sizeof(new_tag->face), len+1)); + param += len; + av_bprintf(dst, "{\\fn%s}", new_tag->face); + } + if ((param = strchr(param, ' '))) + param++; + } + } + in += skip; + } else if (tagname[0] && !tagname[1] && strchr("bisu", av_tolower(tagname[0]))) { + av_bprintf(dst, "{\\%c%d}", (char)av_tolower(tagname[0]), !tag_close); + in += skip; + } else if (!av_strncasecmp(tagname, "br", 2) && + (!tagname[2] || (tagname[2] == '/' && !tagname[3]))) { + av_bprintf(dst, "\\N"); + in += skip; + } else if (likely_a_tag) { + if (!tag_close) // warn only once + av_log(log_ctx, AV_LOG_WARNING, "Unrecognized tag %s\n", tagname); + in += skip; + } else { + av_bprint_chars(dst, '<', 1); + } + } else { + av_bprint_chars(dst, *in, 1); + } + break; + default: + av_bprint_chars(dst, *in, 1); + break; + } + if (*in != ' ' && *in != '\r' && *in != '\n') + line_start = 0; + } + + if (!av_bprint_is_complete(dst)) + return AVERROR(ENOMEM); + + while (dst->len >= 2 && !strncmp(&dst->str[dst->len - 2], "\\N", 2)) + dst->len -= 2; + dst->str[dst->len] = 0; + rstrip_spaces_buf(dst); + + return 0; +} |