ffmpeg/libavformat/samidec.c

133 lines
3.8 KiB
C

/*
* Copyright (c) 2012 Clément Bœsch
*
* 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
*/
/**
* @file
* SAMI subtitle demuxer
* @see http://msdn.microsoft.com/en-us/library/ms971327.aspx
*/
#include "avformat.h"
#include "internal.h"
#include "subtitles.h"
#include "libavutil/avstring.h"
#include "libavutil/bprint.h"
#include "libavutil/intreadwrite.h"
typedef struct {
FFDemuxSubtitlesQueue q;
} SAMIContext;
static int sami_probe(AVProbeData *p)
{
const unsigned char *ptr = p->buf;
if (AV_RB24(ptr) == 0xEFBBBF)
ptr += 3; /* skip UTF-8 BOM */
return !strncmp(ptr, "<SAMI>", 6) ? AVPROBE_SCORE_MAX : 0;
}
static int sami_read_header(AVFormatContext *s)
{
SAMIContext *sami = s->priv_data;
AVStream *st = avformat_new_stream(s, NULL);
AVBPrint buf, hdr_buf;
char c = 0;
int res = 0, got_first_sync_point = 0;
if (!st)
return AVERROR(ENOMEM);
avpriv_set_pts_info(st, 64, 1, 1000);
st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
st->codec->codec_id = CODEC_ID_SAMI;
av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
av_bprint_init(&hdr_buf, 0, AV_BPRINT_SIZE_UNLIMITED);
while (!url_feof(s->pb)) {
AVPacket *sub;
const int64_t pos = avio_tell(s->pb) - (c != 0);
int is_sync, n = ff_smil_extract_next_chunk(s->pb, &buf, &c);
if (n == 0)
break;
is_sync = !av_strncasecmp(buf.str, "<SYNC", 5);
if (is_sync)
got_first_sync_point = 1;
if (!got_first_sync_point) {
av_bprintf(&hdr_buf, "%s", buf.str);
} else {
sub = ff_subtitles_queue_insert(&sami->q, buf.str, buf.len, !is_sync);
if (!sub) {
res = AVERROR(ENOMEM);
goto end;
}
if (is_sync) {
const char *p = ff_smil_get_attr_ptr(buf.str, "Start");
sub->pos = pos;
sub->pts = p ? strtol(p, NULL, 10) : 0;
sub->duration = -1;
}
}
av_bprint_clear(&buf);
}
st->codec->extradata_size = hdr_buf.len + 1;
av_bprint_finalize(&hdr_buf, (char **)&st->codec->extradata);
if (!st->codec->extradata) {
st->codec->extradata_size = 0;
res = AVERROR(ENOMEM);
goto end;
}
ff_subtitles_queue_finalize(&sami->q);
end:
av_bprint_finalize(&buf, NULL);
return res;
}
static int sami_read_packet(AVFormatContext *s, AVPacket *pkt)
{
SAMIContext *sami = s->priv_data;
return ff_subtitles_queue_read_packet(&sami->q, pkt);
}
static int sami_read_close(AVFormatContext *s)
{
SAMIContext *sami = s->priv_data;
ff_subtitles_queue_clean(&sami->q);
return 0;
}
AVInputFormat ff_sami_demuxer = {
.name = "sami",
.long_name = NULL_IF_CONFIG_SMALL("SAMI subtitle format"),
.priv_data_size = sizeof(SAMIContext),
.read_probe = sami_probe,
.read_header = sami_read_header,
.read_packet = sami_read_packet,
.read_close = sami_read_close,
.flags = AVFMT_GENERIC_INDEX,
.extensions = "smi,sami",
};