mpv/demux/demux_libass.c

121 lines
3.8 KiB
C

/*
* This file is part of mpv.
*
* mpv is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* mpv 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with mpv. If not, see <http://www.gnu.org/licenses/>.
*/
// Note: just wraps libass, and makes the subtitle track available though
// sh_sub->track. It doesn't produce packets and doesn't support seeking.
#include <ass/ass.h>
#include <ass/ass_types.h>
#include "mpvcore/options.h"
#include "mpvcore/mp_msg.h"
#include "mpvcore/charset_conv.h"
#include "stream/stream.h"
#include "demux.h"
#define PROBE_SIZE (8 * 1024)
struct priv {
ASS_Track *track;
};
static int d_check_file(struct demuxer *demuxer, enum demux_check check)
{
const char *user_cp = demuxer->opts->sub_cp;
struct stream *s = demuxer->stream;
// Older versions of libass will behave strange if renderer and track
// library handles mismatch, so make sure everything uses a global handle.
ASS_Library *lib = demuxer->params ? demuxer->params->ass_library : NULL;
if (!lib)
return -1;
if (check >= DEMUX_CHECK_UNSAFE) {
// Probe by loading a part of the beginning of the file with libass.
// Incomplete scripts are usually ok, and we hope libass is not verbose
// when dealing with (from its perspective) completely broken binary
// garbage.
bstr buf = stream_peek(s, PROBE_SIZE);
// Older versions of libass will overwrite the input buffer, and despite
// passing length, expect a 0 termination.
void *tmp = talloc_size(NULL, buf.len + 1);
memcpy(tmp, buf.start, buf.len);
buf.start = tmp;
buf.start[buf.len] = '\0';
bstr cbuf = mp_charset_guess_and_conv_to_utf8(buf, user_cp,
MP_ICONV_ALLOW_CUTOFF);
if (cbuf.start == NULL)
cbuf = buf;
ASS_Track *track = ass_read_memory(lib, cbuf.start, cbuf.len, NULL);
if (cbuf.start != buf.start)
talloc_free(cbuf.start);
talloc_free(buf.start);
if (!track)
return -1;
ass_free_track(track);
}
// Actually load the full thing.
bstr buf = stream_read_complete(s, NULL, 100000000);
if (!buf.start) {
mp_tmsg(MSGT_ASS, MSGL_ERR, "Refusing to load subtitle file "
"larger than 100 MB: %s\n", demuxer->filename);
return -1;
}
bstr cbuf = mp_charset_guess_and_conv_to_utf8(buf, user_cp,
MP_ICONV_VERBOSE);
if (cbuf.start == NULL)
cbuf = buf;
ASS_Track *track = ass_read_memory(lib, cbuf.start, cbuf.len, NULL);
if (cbuf.start != buf.start)
talloc_free(cbuf.start);
talloc_free(buf.start);
if (!track)
return -1;
track->name = strdup(demuxer->filename);
struct priv *p = talloc_ptrtype(demuxer, p);
*p = (struct priv) {
.track = track,
};
demuxer->priv = p;
struct sh_stream *sh = new_sh_stream(demuxer, STREAM_SUB);
sh->sub->track = track;
sh->codec = "ass";
return 0;
}
static void d_close(struct demuxer *demuxer)
{
struct priv *p = demuxer->priv;
if (p) {
if (p->track)
ass_free_track(p->track);
}
}
const struct demuxer_desc demuxer_desc_libass = {
.name = "libass",
.desc = "ASS/SSA subtitles (libass)",
.open = d_check_file,
.close = d_close,
};